1This is gfortran.info, produced by makeinfo version 6.5 from 2gfortran.texi. 3 4Copyright (C) 1999-2018 Free Software Foundation, Inc. 5 6 Permission is granted to copy, distribute and/or modify this document 7under the terms of the GNU Free Documentation License, Version 1.3 or 8any later version published by the Free Software Foundation; with the 9Invariant Sections being "Funding Free Software", the Front-Cover Texts 10being (a) (see below), and with the Back-Cover Texts being (b) (see 11below). A copy of the license is included in the section entitled "GNU 12Free Documentation License". 13 14 (a) The FSF's Front-Cover Text is: 15 16 A GNU Manual 17 18 (b) The FSF's Back-Cover Text is: 19 20 You have freedom to copy and modify this GNU Manual, like GNU 21software. Copies published by the Free Software Foundation raise funds 22for GNU development. 23INFO-DIR-SECTION Software development 24START-INFO-DIR-ENTRY 25* gfortran: (gfortran). The GNU Fortran Compiler. 26END-INFO-DIR-ENTRY 27 28 This file documents the use and the internals of the GNU Fortran 29compiler, ('gfortran'). 30 31 Published by the Free Software Foundation 51 Franklin Street, Fifth 32Floor Boston, MA 02110-1301 USA 33 34 Copyright (C) 1999-2018 Free Software Foundation, Inc. 35 36 Permission is granted to copy, distribute and/or modify this document 37under the terms of the GNU Free Documentation License, Version 1.3 or 38any later version published by the Free Software Foundation; with the 39Invariant Sections being "Funding Free Software", the Front-Cover Texts 40being (a) (see below), and with the Back-Cover Texts being (b) (see 41below). A copy of the license is included in the section entitled "GNU 42Free Documentation License". 43 44 (a) The FSF's Front-Cover Text is: 45 46 A GNU Manual 47 48 (b) The FSF's Back-Cover Text is: 49 50 You have freedom to copy and modify this GNU Manual, like GNU 51software. Copies published by the Free Software Foundation raise funds 52for GNU development. 53 54 55File: gfortran.info, Node: Top, Next: Introduction, Up: (dir) 56 57Introduction 58************ 59 60This manual documents the use of 'gfortran', the GNU Fortran compiler. 61You can find in this manual how to invoke 'gfortran', as well as its 62features and incompatibilities. 63 64* Menu: 65 66* Introduction:: 67 68Part I: Invoking GNU Fortran 69* Invoking GNU Fortran:: Command options supported by 'gfortran'. 70* Runtime:: Influencing runtime behavior with environment variables. 71 72Part II: Language Reference 73* Fortran standards status:: Fortran 2003, 2008 and 2018 features supported by GNU Fortran. 74* Compiler Characteristics:: User-visible implementation details. 75* Extensions:: Language extensions implemented by GNU Fortran. 76* Mixed-Language Programming:: Interoperability with C 77* Coarray Programming:: 78* Intrinsic Procedures:: Intrinsic procedures supported by GNU Fortran. 79* Intrinsic Modules:: Intrinsic modules supported by GNU Fortran. 80 81* Contributing:: How you can help. 82* Copying:: GNU General Public License says 83 how you can copy and share GNU Fortran. 84* GNU Free Documentation License:: 85 How you can copy and share this manual. 86* Funding:: How to help assure continued work for free software. 87* Option Index:: Index of command line options 88* Keyword Index:: Index of concepts 89 90 91File: gfortran.info, Node: Introduction, Next: Invoking GNU Fortran, Prev: Top, Up: Top 92 931 Introduction 94************** 95 96The GNU Fortran compiler front end was designed initially as a free 97replacement for, or alternative to, the Unix 'f95' command; 'gfortran' 98is the command you will use to invoke the compiler. 99 100* Menu: 101 102* About GNU Fortran:: What you should know about the GNU Fortran compiler. 103* GNU Fortran and GCC:: You can compile Fortran, C, or other programs. 104* Preprocessing and conditional compilation:: The Fortran preprocessor 105* GNU Fortran and G77:: Why we chose to start from scratch. 106* Project Status:: Status of GNU Fortran, roadmap, proposed extensions. 107* Standards:: Standards supported by GNU Fortran. 108 109 110File: gfortran.info, Node: About GNU Fortran, Next: GNU Fortran and GCC, Up: Introduction 111 1121.1 About GNU Fortran 113===================== 114 115The GNU Fortran compiler supports the Fortran 77, 90 and 95 standards 116completely, parts of the Fortran 2003, 2008 and 2018 standards, and 117several vendor extensions. The development goal is to provide the 118following features: 119 120 * Read a user's program, stored in a file and containing instructions 121 written in Fortran 77, Fortran 90, Fortran 95, Fortran 2003, 122 Fortran 2008 or Fortran 2018. This file contains "source code". 123 124 * Translate the user's program into instructions a computer can carry 125 out more quickly than it takes to translate the instructions in the 126 first place. The result after compilation of a program is "machine 127 code", code designed to be efficiently translated and processed by 128 a machine such as your computer. Humans usually are not as good 129 writing machine code as they are at writing Fortran (or C++, Ada, 130 or Java), because it is easy to make tiny mistakes writing machine 131 code. 132 133 * Provide the user with information about the reasons why the 134 compiler is unable to create a binary from the source code. 135 Usually this will be the case if the source code is flawed. The 136 Fortran 90 standard requires that the compiler can point out 137 mistakes to the user. An incorrect usage of the language causes an 138 "error message". 139 140 The compiler will also attempt to diagnose cases where the user's 141 program contains a correct usage of the language, but instructs the 142 computer to do something questionable. This kind of diagnostics 143 message is called a "warning message". 144 145 * Provide optional information about the translation passes from the 146 source code to machine code. This can help a user of the compiler 147 to find the cause of certain bugs which may not be obvious in the 148 source code, but may be more easily found at a lower level compiler 149 output. It also helps developers to find bugs in the compiler 150 itself. 151 152 * Provide information in the generated machine code that can make it 153 easier to find bugs in the program (using a debugging tool, called 154 a "debugger", such as the GNU Debugger 'gdb'). 155 156 * Locate and gather machine code already generated to perform actions 157 requested by statements in the user's program. This machine code 158 is organized into "modules" and is located and "linked" to the user 159 program. 160 161 The GNU Fortran compiler consists of several components: 162 163 * A version of the 'gcc' command (which also might be installed as 164 the system's 'cc' command) that also understands and accepts 165 Fortran source code. The 'gcc' command is the "driver" program for 166 all the languages in the GNU Compiler Collection (GCC); With 'gcc', 167 you can compile the source code of any language for which a front 168 end is available in GCC. 169 170 * The 'gfortran' command itself, which also might be installed as the 171 system's 'f95' command. 'gfortran' is just another driver program, 172 but specifically for the Fortran compiler only. The difference 173 with 'gcc' is that 'gfortran' will automatically link the correct 174 libraries to your program. 175 176 * A collection of run-time libraries. These libraries contain the 177 machine code needed to support capabilities of the Fortran language 178 that are not directly provided by the machine code generated by the 179 'gfortran' compilation phase, such as intrinsic functions and 180 subroutines, and routines for interaction with files and the 181 operating system. 182 183 * The Fortran compiler itself, ('f951'). This is the GNU Fortran 184 parser and code generator, linked to and interfaced with the GCC 185 backend library. 'f951' "translates" the source code to assembler 186 code. You would typically not use this program directly; instead, 187 the 'gcc' or 'gfortran' driver programs will call it for you. 188 189 190File: gfortran.info, Node: GNU Fortran and GCC, Next: Preprocessing and conditional compilation, Prev: About GNU Fortran, Up: Introduction 191 1921.2 GNU Fortran and GCC 193======================= 194 195GNU Fortran is a part of GCC, the "GNU Compiler Collection". GCC 196consists of a collection of front ends for various languages, which 197translate the source code into a language-independent form called 198"GENERIC". This is then processed by a common middle end which provides 199optimization, and then passed to one of a collection of back ends which 200generate code for different computer architectures and operating 201systems. 202 203 Functionally, this is implemented with a driver program ('gcc') which 204provides the command-line interface for the compiler. It calls the 205relevant compiler front-end program (e.g., 'f951' for Fortran) for each 206file in the source code, and then calls the assembler and linker as 207appropriate to produce the compiled output. In a copy of GCC which has 208been compiled with Fortran language support enabled, 'gcc' will 209recognize files with '.f', '.for', '.ftn', '.f90', '.f95', '.f03' and 210'.f08' extensions as Fortran source code, and compile it accordingly. A 211'gfortran' driver program is also provided, which is identical to 'gcc' 212except that it automatically links the Fortran runtime libraries into 213the compiled program. 214 215 Source files with '.f', '.for', '.fpp', '.ftn', '.F', '.FOR', '.FPP', 216and '.FTN' extensions are treated as fixed form. Source files with 217'.f90', '.f95', '.f03', '.f08', '.F90', '.F95', '.F03' and '.F08' 218extensions are treated as free form. The capitalized versions of either 219form are run through preprocessing. Source files with the lower case 220'.fpp' extension are also run through preprocessing. 221 222 This manual specifically documents the Fortran front end, which 223handles the programming language's syntax and semantics. The aspects of 224GCC which relate to the optimization passes and the back-end code 225generation are documented in the GCC manual; see *note Introduction: 226(gcc)Top. The two manuals together provide a complete reference for the 227GNU Fortran compiler. 228 229 230File: gfortran.info, Node: Preprocessing and conditional compilation, Next: GNU Fortran and G77, Prev: GNU Fortran and GCC, Up: Introduction 231 2321.3 Preprocessing and conditional compilation 233============================================= 234 235Many Fortran compilers including GNU Fortran allow passing the source 236code through a C preprocessor (CPP; sometimes also called the Fortran 237preprocessor, FPP) to allow for conditional compilation. In the case of 238GNU Fortran, this is the GNU C Preprocessor in the traditional mode. On 239systems with case-preserving file names, the preprocessor is 240automatically invoked if the filename extension is '.F', '.FOR', '.FTN', 241'.fpp', '.FPP', '.F90', '.F95', '.F03' or '.F08'. To manually invoke 242the preprocessor on any file, use '-cpp', to disable preprocessing on 243files where the preprocessor is run automatically, use '-nocpp'. 244 245 If a preprocessed file includes another file with the Fortran 246'INCLUDE' statement, the included file is not preprocessed. To 247preprocess included files, use the equivalent preprocessor statement 248'#include'. 249 250 If GNU Fortran invokes the preprocessor, '__GFORTRAN__' is defined 251and '__GNUC__', '__GNUC_MINOR__' and '__GNUC_PATCHLEVEL__' can be used 252to determine the version of the compiler. See *note Overview: (cpp)Top. 253for details. 254 255 While CPP is the de-facto standard for preprocessing Fortran code, 256Part 3 of the Fortran 95 standard (ISO/IEC 1539-3:1998) defines 257Conditional Compilation, which is not widely used and not directly 258supported by the GNU Fortran compiler. You can use the program coco to 259preprocess such files (<http://www.daniellnagle.com/coco.html>). 260 261 262File: gfortran.info, Node: GNU Fortran and G77, Next: Project Status, Prev: Preprocessing and conditional compilation, Up: Introduction 263 2641.4 GNU Fortran and G77 265======================= 266 267The GNU Fortran compiler is the successor to 'g77', the Fortran 77 front 268end included in GCC prior to version 4. It is an entirely new program 269that has been designed to provide Fortran 95 support and extensibility 270for future Fortran language standards, as well as providing backwards 271compatibility for Fortran 77 and nearly all of the GNU language 272extensions supported by 'g77'. 273 274 275File: gfortran.info, Node: Project Status, Next: Standards, Prev: GNU Fortran and G77, Up: Introduction 276 2771.5 Project Status 278================== 279 280 As soon as 'gfortran' can parse all of the statements correctly, it 281 will be in the "larva" state. When we generate code, the "puppa" 282 state. When 'gfortran' is done, we'll see if it will be a 283 beautiful butterfly, or just a big bug.... 284 285 -Andy Vaught, April 2000 286 287 The start of the GNU Fortran 95 project was announced on the GCC 288homepage in March 18, 2000 (even though Andy had already been working on 289it for a while, of course). 290 291 The GNU Fortran compiler is able to compile nearly all 292standard-compliant Fortran 95, Fortran 90, and Fortran 77 programs, 293including a number of standard and non-standard extensions, and can be 294used on real-world programs. In particular, the supported extensions 295include OpenMP, Cray-style pointers, some old vendor extensions, and 296several Fortran 2003 and Fortran 2008 features, including TR 15581. 297However, it is still under development and has a few remaining rough 298edges. There also is initial support for OpenACC. Note that this is an 299experimental feature, incomplete, and subject to change in future 300versions of GCC. See <https://gcc.gnu.org/wiki/OpenACC> for more 301information. 302 303 At present, the GNU Fortran compiler passes the NIST Fortran 77 Test 304Suite (http://www.fortran-2000.com/ArnaudRecipes/fcvs21_f95.html), and 305produces acceptable results on the LAPACK Test Suite 306(http://www.netlib.org/lapack/faq.html#1.21). It also provides 307respectable performance on the Polyhedron Fortran compiler benchmarks 308(http://www.polyhedron.com/fortran-compiler-comparisons/polyhedron-benchmark-suite) 309and the Livermore Fortran Kernels test 310(http://www.netlib.org/benchmark/livermore). It has been used to 311compile a number of large real-world programs, including the HARMONIE 312and HIRLAM weather forecasting code (http://hirlam.org/) and the Tonto 313quantum chemistry package 314(http://physical-chemistry.scb.uwa.edu.au/tonto/wiki/index.php/Main_Page); 315see <https://gcc.gnu.org/wiki/GfortranApps> for an extended list. 316 317 Among other things, the GNU Fortran compiler is intended as a 318replacement for G77. At this point, nearly all programs that could be 319compiled with G77 can be compiled with GNU Fortran, although there are a 320few minor known regressions. 321 322 The primary work remaining to be done on GNU Fortran falls into three 323categories: bug fixing (primarily regarding the treatment of invalid 324code and providing useful error messages), improving the compiler 325optimizations and the performance of compiled code, and extending the 326compiler to support future standards--in particular, Fortran 2003, 327Fortran 2008 and Fortran 2018. 328 329 330File: gfortran.info, Node: Standards, Prev: Project Status, Up: Introduction 331 3321.6 Standards 333============= 334 335* Menu: 336 337* Varying Length Character Strings:: 338 339The GNU Fortran compiler implements ISO/IEC 1539:1997 (Fortran 95). As 340such, it can also compile essentially all standard-compliant Fortran 90 341and Fortran 77 programs. It also supports the ISO/IEC TR-15581 342enhancements to allocatable arrays. 343 344 GNU Fortran also have a partial support for ISO/IEC 1539-1:2004 345(Fortran 2003), ISO/IEC 1539-1:2010 (Fortran 2008), the Technical 346Specification 'Further Interoperability of Fortran with C' (ISO/IEC TS 34729113:2012). Full support of those standards and future Fortran 348standards is planned. The current status of the support is can be found 349in the *note Fortran 2003 status::, *note Fortran 2008 status::, *note 350TS 29113 status::, *note TS 18508 status:: and *note Fortran 2018 351status:: sections of the documentation. 352 353 Additionally, the GNU Fortran compilers supports the OpenMP 354specification (version 4.0 and most of the features of the 4.5 version, 355<http://openmp.org/wp/openmp-specifications/>). There also is initial 356support for the OpenACC specification (targeting version 2.0, 357<http://www.openacc.org/>). Note that this is an experimental feature, 358incomplete, and subject to change in future versions of GCC. See 359<https://gcc.gnu.org/wiki/OpenACC> for more information. 360 361 362File: gfortran.info, Node: Varying Length Character Strings, Up: Standards 363 3641.6.1 Varying Length Character Strings 365-------------------------------------- 366 367The Fortran 95 standard specifies in Part 2 (ISO/IEC 1539-2:2000) 368varying length character strings. While GNU Fortran currently does not 369support such strings directly, there exist two Fortran implementations 370for them, which work with GNU Fortran. They can be found at 371<http://www.fortran.com/iso_varying_string.f95> and at 372<ftp://ftp.nag.co.uk/sc22wg5/ISO_VARYING_STRING/>. 373 374 Deferred-length character strings of Fortran 2003 supports part of 375the features of 'ISO_VARYING_STRING' and should be considered as 376replacement. (Namely, allocatable or pointers of the type 377'character(len=:)'.) 378 379 380File: gfortran.info, Node: Invoking GNU Fortran, Next: Runtime, Prev: Introduction, Up: Top 381 3822 GNU Fortran Command Options 383***************************** 384 385The 'gfortran' command supports all the options supported by the 'gcc' 386command. Only options specific to GNU Fortran are documented here. 387 388 *Note GCC Command Options: (gcc)Invoking GCC, for information on the 389non-Fortran-specific aspects of the 'gcc' command (and, therefore, the 390'gfortran' command). 391 392 All GCC and GNU Fortran options are accepted both by 'gfortran' and 393by 'gcc' (as well as any other drivers built at the same time, such as 394'g++'), since adding GNU Fortran to the GCC distribution enables 395acceptance of GNU Fortran options by all of the relevant drivers. 396 397 In some cases, options have positive and negative forms; the negative 398form of '-ffoo' would be '-fno-foo'. This manual documents only one of 399these two forms, whichever one is not the default. 400 401* Menu: 402 403* Option Summary:: Brief list of all 'gfortran' options, 404 without explanations. 405* Fortran Dialect Options:: Controlling the variant of Fortran language 406 compiled. 407* Preprocessing Options:: Enable and customize preprocessing. 408* Error and Warning Options:: How picky should the compiler be? 409* Debugging Options:: Symbol tables, measurements, and debugging dumps. 410* Directory Options:: Where to find module files 411* Link Options :: Influencing the linking step 412* Runtime Options:: Influencing runtime behavior 413* Code Gen Options:: Specifying conventions for function calls, data layout 414 and register usage. 415* Interoperability Options:: Options for interoperability with other 416 languages. 417* Environment Variables:: Environment variables that affect 'gfortran'. 418 419 420File: gfortran.info, Node: Option Summary, Next: Fortran Dialect Options, Up: Invoking GNU Fortran 421 4222.1 Option summary 423================== 424 425Here is a summary of all the options specific to GNU Fortran, grouped by 426type. Explanations are in the following sections. 427 428_Fortran Language Options_ 429 *Note Options controlling Fortran dialect: Fortran Dialect Options. 430 -fall-intrinsics -fbackslash -fcray-pointer -fd-lines-as-code 431 -fd-lines-as-comments 432 -fdec -fdec-structure -fdec-intrinsic-ints -fdec-static -fdec-math 433 -fdefault-double-8 -fdefault-integer-8 -fdefault-real-8 434 -fdefault-real-10 -fdefault-real-16 -fdollar-ok -ffixed-line-length-N 435 -ffixed-line-length-none -ffree-form -ffree-line-length-N 436 -ffree-line-length-none -fimplicit-none -finteger-4-integer-8 437 -fmax-identifier-length -fmodule-private -ffixed-form -fno-range-check 438 -fopenacc -fopenmp -freal-4-real-10 -freal-4-real-16 -freal-4-real-8 439 -freal-8-real-10 -freal-8-real-16 -freal-8-real-4 -std=STD 440 -ftest-forall-temp 441 442 443_Preprocessing Options_ 444 *Note Enable and customize preprocessing: Preprocessing Options. 445 -A-QUESTION[=ANSWER] 446 -AQUESTION=ANSWER -C -CC -DMACRO[=DEFN] 447 -H -P 448 -UMACRO -cpp -dD -dI -dM -dN -dU -fworking-directory 449 -imultilib DIR 450 -iprefix FILE -iquote -isysroot DIR -isystem DIR -nocpp 451 -nostdinc 452 -undef 453 454 455_Error and Warning Options_ 456 *Note Options to request or suppress errors and warnings: Error and 457 Warning Options. 458 -Waliasing -Wall -Wampersand -Wargument-mismatch -Warray-bounds 459 -Wc-binding-type -Wcharacter-truncation -Wconversion 460 -Wdo-subscript -Wfunction-elimination -Wimplicit-interface 461 -Wimplicit-procedure -Wintrinsic-shadow -Wuse-without-only -Wintrinsics-std 462 -Wline-truncation -Wno-align-commons -Wno-tabs -Wreal-q-constant 463 -Wsurprising -Wunderflow -Wunused-parameter -Wrealloc-lhs 464 -Wrealloc-lhs-all -Wfrontend-loop-interchange -Wtarget-lifetime 465 -fmax-errors=N -fsyntax-only -pedantic -pedantic-errors 466 467 468_Debugging Options_ 469 *Note Options for debugging your program or GNU Fortran: Debugging 470 Options. 471 -fbacktrace -fdump-fortran-optimized -fdump-fortran-original 472 -fdump-parse-tree -ffpe-trap=LIST -ffpe-summary=LIST 473 474 475_Directory Options_ 476 *Note Options for directory search: Directory Options. 477 -IDIR -JDIR -fintrinsic-modules-path DIR 478 479_Link Options_ 480 *Note Options for influencing the linking step: Link Options. 481 -static-libgfortran 482 483_Runtime Options_ 484 *Note Options for influencing runtime behavior: Runtime Options. 485 -fconvert=CONVERSION -fmax-subrecord-length=LENGTH 486 -frecord-marker=LENGTH -fsign-zero 487 488 489_Interoperability Options_ 490 *Note Options for interoperability: Interoperability Options. 491 -fc-prototypes 492 493_Code Generation Options_ 494 *Note Options for code generation conventions: Code Gen Options. 495 -faggressive-function-elimination -fblas-matmul-limit=N 496 -fbounds-check -ftail-call-workaround -ftail-call-workaround=N 497 -fcheck-array-temporaries 498 -fcheck=<ALL|ARRAY-TEMPS|BOUNDS|DO|MEM|POINTER|RECURSION> 499 -fcoarray=<NONE|SINGLE|LIB> -fexternal-blas -ff2c 500 -ffrontend-loop-interchange 501 -ffrontend-optimize 502 -finit-character=N -finit-integer=N -finit-local-zero 503 -finit-derived 504 -finit-logical=<TRUE|FALSE> 505 -finit-real=<ZERO|INF|-INF|NAN|SNAN> 506 -finline-matmul-limit=N 507 -fmax-array-constructor=N -fmax-stack-var-size=N 508 -fno-align-commons 509 -fno-automatic -fno-protect-parens -fno-underscoring 510 -fsecond-underscore -fpack-derived -frealloc-lhs -frecursive 511 -frepack-arrays -fshort-enums -fstack-arrays 512 513 514 515File: gfortran.info, Node: Fortran Dialect Options, Next: Preprocessing Options, Prev: Option Summary, Up: Invoking GNU Fortran 516 5172.2 Options controlling Fortran dialect 518======================================= 519 520The following options control the details of the Fortran dialect 521accepted by the compiler: 522 523'-ffree-form' 524'-ffixed-form' 525 Specify the layout used by the source file. The free form layout 526 was introduced in Fortran 90. Fixed form was traditionally used in 527 older Fortran programs. When neither option is specified, the 528 source form is determined by the file extension. 529 530'-fall-intrinsics' 531 This option causes all intrinsic procedures (including the 532 GNU-specific extensions) to be accepted. This can be useful with 533 '-std=f95' to force standard-compliance but get access to the full 534 range of intrinsics available with 'gfortran'. As a consequence, 535 '-Wintrinsics-std' will be ignored and no user-defined procedure 536 with the same name as any intrinsic will be called except when it 537 is explicitly declared 'EXTERNAL'. 538 539'-fd-lines-as-code' 540'-fd-lines-as-comments' 541 Enable special treatment for lines beginning with 'd' or 'D' in 542 fixed form sources. If the '-fd-lines-as-code' option is given 543 they are treated as if the first column contained a blank. If the 544 '-fd-lines-as-comments' option is given, they are treated as 545 comment lines. 546 547'-fdec' 548 DEC compatibility mode. Enables extensions and other features that 549 mimic the default behavior of older compilers (such as DEC). These 550 features are non-standard and should be avoided at all costs. For 551 details on GNU Fortran's implementation of these extensions see the 552 full documentation. 553 554 Other flags enabled by this switch are: '-fdollar-ok' 555 '-fcray-pointer' '-fdec-structure' '-fdec-intrinsic-ints' 556 '-fdec-static' '-fdec-math' 557 558 If '-fd-lines-as-code'/'-fd-lines-as-comments' are unset, then 559 '-fdec' also sets '-fd-lines-as-comments'. 560 561'-fdec-structure' 562 Enable DEC 'STRUCTURE' and 'RECORD' as well as 'UNION', 'MAP', and 563 dot ('.') as a member separator (in addition to '%'). This is 564 provided for compatibility only; Fortran 90 derived types should be 565 used instead where possible. 566 567'-fdec-intrinsic-ints' 568 Enable B/I/J/K kind variants of existing integer functions (e.g. 569 BIAND, IIAND, JIAND, etc...). For a complete list of intrinsics 570 see the full documentation. 571 572'-fdec-math' 573 Enable legacy math intrinsics such as COTAN and degree-valued 574 trigonometric functions (e.g. TAND, ATAND, etc...) for 575 compatability with older code. 576 577'-fdec-static' 578 Enable DEC-style STATIC and AUTOMATIC attributes to explicitly 579 specify the storage of variables and other objects. 580 581'-fdollar-ok' 582 Allow '$' as a valid non-first character in a symbol name. Symbols 583 that start with '$' are rejected since it is unclear which rules to 584 apply to implicit typing as different vendors implement different 585 rules. Using '$' in 'IMPLICIT' statements is also rejected. 586 587'-fbackslash' 588 Change the interpretation of backslashes in string literals from a 589 single backslash character to "C-style" escape characters. The 590 following combinations are expanded '\a', '\b', '\f', '\n', '\r', 591 '\t', '\v', '\\', and '\0' to the ASCII characters alert, 592 backspace, form feed, newline, carriage return, horizontal tab, 593 vertical tab, backslash, and NUL, respectively. Additionally, 594 '\x'NN, '\u'NNNN and '\U'NNNNNNNN (where each N is a hexadecimal 595 digit) are translated into the Unicode characters corresponding to 596 the specified code points. All other combinations of a character 597 preceded by \ are unexpanded. 598 599'-fmodule-private' 600 Set the default accessibility of module entities to 'PRIVATE'. 601 Use-associated entities will not be accessible unless they are 602 explicitly declared as 'PUBLIC'. 603 604'-ffixed-line-length-N' 605 Set column after which characters are ignored in typical fixed-form 606 lines in the source file, and through which spaces are assumed (as 607 if padded to that length) after the ends of short fixed-form lines. 608 609 Popular values for N include 72 (the standard and the default), 80 610 (card image), and 132 (corresponding to "extended-source" options 611 in some popular compilers). N may also be 'none', meaning that the 612 entire line is meaningful and that continued character constants 613 never have implicit spaces appended to them to fill out the line. 614 '-ffixed-line-length-0' means the same thing as 615 '-ffixed-line-length-none'. 616 617'-ffree-line-length-N' 618 Set column after which characters are ignored in typical free-form 619 lines in the source file. The default value is 132. N may be 620 'none', meaning that the entire line is meaningful. 621 '-ffree-line-length-0' means the same thing as 622 '-ffree-line-length-none'. 623 624'-fmax-identifier-length=N' 625 Specify the maximum allowed identifier length. Typical values are 626 31 (Fortran 95) and 63 (Fortran 2003 and Fortran 2008). 627 628'-fimplicit-none' 629 Specify that no implicit typing is allowed, unless overridden by 630 explicit 'IMPLICIT' statements. This is the equivalent of adding 631 'implicit none' to the start of every procedure. 632 633'-fcray-pointer' 634 Enable the Cray pointer extension, which provides C-like pointer 635 functionality. 636 637'-fopenacc' 638 Enable the OpenACC extensions. This includes OpenACC '!$acc' 639 directives in free form and 'c$acc', '*$acc' and '!$acc' directives 640 in fixed form, '!$' conditional compilation sentinels in free form 641 and 'c$', '*$' and '!$' sentinels in fixed form, and when linking 642 arranges for the OpenACC runtime library to be linked in. 643 644 Note that this is an experimental feature, incomplete, and subject 645 to change in future versions of GCC. See 646 <https://gcc.gnu.org/wiki/OpenACC> for more information. 647 648'-fopenmp' 649 Enable the OpenMP extensions. This includes OpenMP '!$omp' 650 directives in free form and 'c$omp', '*$omp' and '!$omp' directives 651 in fixed form, '!$' conditional compilation sentinels in free form 652 and 'c$', '*$' and '!$' sentinels in fixed form, and when linking 653 arranges for the OpenMP runtime library to be linked in. The 654 option '-fopenmp' implies '-frecursive'. 655 656'-fno-range-check' 657 Disable range checking on results of simplification of constant 658 expressions during compilation. For example, GNU Fortran will give 659 an error at compile time when simplifying 'a = 1. / 0'. With this 660 option, no error will be given and 'a' will be assigned the value 661 '+Infinity'. If an expression evaluates to a value outside of the 662 relevant range of ['-HUGE()':'HUGE()'], then the expression will be 663 replaced by '-Inf' or '+Inf' as appropriate. Similarly, 'DATA 664 i/Z'FFFFFFFF'/' will result in an integer overflow on most systems, 665 but with '-fno-range-check' the value will "wrap around" and 'i' 666 will be initialized to -1 instead. 667 668'-fdefault-integer-8' 669 Set the default integer and logical types to an 8 byte wide type. 670 This option also affects the kind of integer constants like '42'. 671 Unlike '-finteger-4-integer-8', it does not promote variables with 672 explicit kind declaration. 673 674'-fdefault-real-8' 675 Set the default real type to an 8 byte wide type. This option also 676 affects the kind of non-double real constants like '1.0', and does 677 promote the default width of 'DOUBLE PRECISION' to 16 bytes if 678 possible, unless '-fdefault-double-8' is given, too. Unlike 679 '-freal-4-real-8', it does not promote variables with explicit kind 680 declaration. 681 682'-fdefault-real-10' 683 Set the default real type to a 10 byte wide type. This option also 684 affects the kind of non-double real constants like '1.0', and does 685 promote the default width of 'DOUBLE PRECISION' to 16 bytes if 686 possible, unless '-fdefault-double-8' is given. Unlike 687 '-freal-4-real-10', it does not promote variables with explicit 688 kind declaration. 689 690'-fdefault-real-16' 691 Set the default real type to a 16 byte wide type. This option also 692 affects the kind of non-double real constants like '1.0', and does 693 promote the default width of 'DOUBLE PRECISION' to 16 bytes if 694 possible, unless '-fdefault-double-8' is given. Unlike 695 '-freal-4-real-16', it does not promote variables with explicit 696 kind declaration. 697 698'-fdefault-double-8' 699 Set the 'DOUBLE PRECISION' type to an 8 byte wide type. Do nothing 700 if this is already the default. If '-fdefault-real-8' is given, 701 'DOUBLE PRECISION' would instead be promoted to 16 bytes if 702 possible, and '-fdefault-double-8' can be used to prevent this. 703 The kind of real constants like '1.d0' will not be changed by 704 '-fdefault-real-8' though, so also '-fdefault-double-8' does not 705 affect it. 706 707'-finteger-4-integer-8' 708 Promote all 'INTEGER(KIND=4)' entities to an 'INTEGER(KIND=8)' 709 entities. If 'KIND=8' is unavailable, then an error will be 710 issued. This option should be used with care and may not be 711 suitable for your codes. Areas of possible concern include calls 712 to external procedures, alignment in 'EQUIVALENCE' and/or 'COMMON', 713 generic interfaces, BOZ literal constant conversion, and I/O. 714 Inspection of the intermediate representation of the translated 715 Fortran code, produced by '-fdump-tree-original', is suggested. 716 717'-freal-4-real-8' 718'-freal-4-real-10' 719'-freal-4-real-16' 720'-freal-8-real-4' 721'-freal-8-real-10' 722'-freal-8-real-16' 723 Promote all 'REAL(KIND=M)' entities to 'REAL(KIND=N)' entities. If 724 'REAL(KIND=N)' is unavailable, then an error will be issued. All 725 other real kind types are unaffected by this option. These options 726 should be used with care and may not be suitable for your codes. 727 Areas of possible concern include calls to external procedures, 728 alignment in 'EQUIVALENCE' and/or 'COMMON', generic interfaces, BOZ 729 literal constant conversion, and I/O. Inspection of the 730 intermediate representation of the translated Fortran code, 731 produced by '-fdump-tree-original', is suggested. 732 733'-std=STD' 734 Specify the standard to which the program is expected to conform, 735 which may be one of 'f95', 'f2003', 'f2008', 'f2018', 'gnu', or 736 'legacy'. The default value for STD is 'gnu', which specifies a 737 superset of the latest Fortran standard that includes all of the 738 extensions supported by GNU Fortran, although warnings will be 739 given for obsolete extensions not recommended for use in new code. 740 The 'legacy' value is equivalent but without the warnings for 741 obsolete extensions, and may be useful for old non-standard 742 programs. The 'f95', 'f2003', 'f2008', and 'f2018' values specify 743 strict conformance to the Fortran 95, Fortran 2003, Fortran 2008 744 and Fortran 2018 standards, respectively; errors are given for all 745 extensions beyond the relevant language standard, and warnings are 746 given for the Fortran 77 features that are permitted but 747 obsolescent in later standards. '-std=f2008ts' allows the Fortran 748 2008 standard including the additions of the Technical 749 Specification (TS) 29113 on Further Interoperability of Fortran 750 with C and TS 18508 on Additional Parallel Features in Fortran. 751 752'-ftest-forall-temp' 753 Enhance test coverage by forcing most forall assignments to use 754 temporary. 755 756 757File: gfortran.info, Node: Preprocessing Options, Next: Error and Warning Options, Prev: Fortran Dialect Options, Up: Invoking GNU Fortran 758 7592.3 Enable and customize preprocessing 760====================================== 761 762Preprocessor related options. See section *note Preprocessing and 763conditional compilation:: for more detailed information on preprocessing 764in 'gfortran'. 765 766'-cpp' 767'-nocpp' 768 Enable preprocessing. The preprocessor is automatically invoked if 769 the file extension is '.fpp', '.FPP', '.F', '.FOR', '.FTN', '.F90', 770 '.F95', '.F03' or '.F08'. Use this option to manually enable 771 preprocessing of any kind of Fortran file. 772 773 To disable preprocessing of files with any of the above listed 774 extensions, use the negative form: '-nocpp'. 775 776 The preprocessor is run in traditional mode. Any restrictions of 777 the file-format, especially the limits on line length, apply for 778 preprocessed output as well, so it might be advisable to use the 779 '-ffree-line-length-none' or '-ffixed-line-length-none' options. 780 781'-dM' 782 Instead of the normal output, generate a list of ''#define'' 783 directives for all the macros defined during the execution of the 784 preprocessor, including predefined macros. This gives you a way of 785 finding out what is predefined in your version of the preprocessor. 786 Assuming you have no file 'foo.f90', the command 787 touch foo.f90; gfortran -cpp -E -dM foo.f90 788 will show all the predefined macros. 789 790'-dD' 791 Like '-dM' except in two respects: it does not include the 792 predefined macros, and it outputs both the '#define' directives and 793 the result of preprocessing. Both kinds of output go to the 794 standard output file. 795 796'-dN' 797 Like '-dD', but emit only the macro names, not their expansions. 798 799'-dU' 800 Like 'dD' except that only macros that are expanded, or whose 801 definedness is tested in preprocessor directives, are output; the 802 output is delayed until the use or test of the macro; and 803 ''#undef'' directives are also output for macros tested but 804 undefined at the time. 805 806'-dI' 807 Output ''#include'' directives in addition to the result of 808 preprocessing. 809 810'-fworking-directory' 811 Enable generation of linemarkers in the preprocessor output that 812 will let the compiler know the current working directory at the 813 time of preprocessing. When this option is enabled, the 814 preprocessor will emit, after the initial linemarker, a second 815 linemarker with the current working directory followed by two 816 slashes. GCC will use this directory, when it is present in the 817 preprocessed input, as the directory emitted as the current working 818 directory in some debugging information formats. This option is 819 implicitly enabled if debugging information is enabled, but this 820 can be inhibited with the negated form '-fno-working-directory'. 821 If the '-P' flag is present in the command line, this option has no 822 effect, since no '#line' directives are emitted whatsoever. 823 824'-idirafter DIR' 825 Search DIR for include files, but do it after all directories 826 specified with '-I' and the standard system directories have been 827 exhausted. DIR is treated as a system include directory. If dir 828 begins with '=', then the '=' will be replaced by the sysroot 829 prefix; see '--sysroot' and '-isysroot'. 830 831'-imultilib DIR' 832 Use DIR as a subdirectory of the directory containing 833 target-specific C++ headers. 834 835'-iprefix PREFIX' 836 Specify PREFIX as the prefix for subsequent '-iwithprefix' options. 837 If the PREFIX represents a directory, you should include the final 838 ''/''. 839 840'-isysroot DIR' 841 This option is like the '--sysroot' option, but applies only to 842 header files. See the '--sysroot' option for more information. 843 844'-iquote DIR' 845 Search DIR only for header files requested with '#include "file"'; 846 they are not searched for '#include <file>', before all directories 847 specified by '-I' and before the standard system directories. If 848 DIR begins with '=', then the '=' will be replaced by the sysroot 849 prefix; see '--sysroot' and '-isysroot'. 850 851'-isystem DIR' 852 Search DIR for header files, after all directories specified by 853 '-I' but before the standard system directories. Mark it as a 854 system directory, so that it gets the same special treatment as is 855 applied to the standard system directories. If DIR begins with 856 '=', then the '=' will be replaced by the sysroot prefix; see 857 '--sysroot' and '-isysroot'. 858 859'-nostdinc' 860 Do not search the standard system directories for header files. 861 Only the directories you have specified with '-I' options (and the 862 directory of the current file, if appropriate) are searched. 863 864'-undef' 865 Do not predefine any system-specific or GCC-specific macros. The 866 standard predefined macros remain defined. 867 868'-APREDICATE=ANSWER' 869 Make an assertion with the predicate PREDICATE and answer ANSWER. 870 This form is preferred to the older form -A predicate(answer), 871 which is still supported, because it does not use shell special 872 characters. 873 874'-A-PREDICATE=ANSWER' 875 Cancel an assertion with the predicate PREDICATE and answer ANSWER. 876 877'-C' 878 Do not discard comments. All comments are passed through to the 879 output file, except for comments in processed directives, which are 880 deleted along with the directive. 881 882 You should be prepared for side effects when using '-C'; it causes 883 the preprocessor to treat comments as tokens in their own right. 884 For example, comments appearing at the start of what would be a 885 directive line have the effect of turning that line into an 886 ordinary source line, since the first token on the line is no 887 longer a ''#''. 888 889 Warning: this currently handles C-Style comments only. The 890 preprocessor does not yet recognize Fortran-style comments. 891 892'-CC' 893 Do not discard comments, including during macro expansion. This is 894 like '-C', except that comments contained within macros are also 895 passed through to the output file where the macro is expanded. 896 897 In addition to the side-effects of the '-C' option, the '-CC' 898 option causes all C++-style comments inside a macro to be converted 899 to C-style comments. This is to prevent later use of that macro 900 from inadvertently commenting out the remainder of the source line. 901 The '-CC' option is generally used to support lint comments. 902 903 Warning: this currently handles C- and C++-Style comments only. 904 The preprocessor does not yet recognize Fortran-style comments. 905 906'-DNAME' 907 Predefine name as a macro, with definition '1'. 908 909'-DNAME=DEFINITION' 910 The contents of DEFINITION are tokenized and processed as if they 911 appeared during translation phase three in a ''#define'' directive. 912 In particular, the definition will be truncated by embedded newline 913 characters. 914 915 If you are invoking the preprocessor from a shell or shell-like 916 program you may need to use the shell's quoting syntax to protect 917 characters such as spaces that have a meaning in the shell syntax. 918 919 If you wish to define a function-like macro on the command line, 920 write its argument list with surrounding parentheses before the 921 equals sign (if any). Parentheses are meaningful to most shells, 922 so you will need to quote the option. With sh and csh, 923 '-D'name(args...)=definition'' works. 924 925 '-D' and '-U' options are processed in the order they are given on 926 the command line. All -imacros file and -include file options are 927 processed after all -D and -U options. 928 929'-H' 930 Print the name of each header file used, in addition to other 931 normal activities. Each name is indented to show how deep in the 932 ''#include'' stack it is. 933 934'-P' 935 Inhibit generation of linemarkers in the output from the 936 preprocessor. This might be useful when running the preprocessor 937 on something that is not C code, and will be sent to a program 938 which might be confused by the linemarkers. 939 940'-UNAME' 941 Cancel any previous definition of NAME, either built in or provided 942 with a '-D' option. 943 944 945File: gfortran.info, Node: Error and Warning Options, Next: Debugging Options, Prev: Preprocessing Options, Up: Invoking GNU Fortran 946 9472.4 Options to request or suppress errors and warnings 948====================================================== 949 950Errors are diagnostic messages that report that the GNU Fortran compiler 951cannot compile the relevant piece of source code. The compiler will 952continue to process the program in an attempt to report further errors 953to aid in debugging, but will not produce any compiled output. 954 955 Warnings are diagnostic messages that report constructions which are 956not inherently erroneous but which are risky or suggest there is likely 957to be a bug in the program. Unless '-Werror' is specified, they do not 958prevent compilation of the program. 959 960 You can request many specific warnings with options beginning '-W', 961for example '-Wimplicit' to request warnings on implicit declarations. 962Each of these specific warning options also has a negative form 963beginning '-Wno-' to turn off warnings; for example, '-Wno-implicit'. 964This manual lists only one of the two forms, whichever is not the 965default. 966 967 These options control the amount and kinds of errors and warnings 968produced by GNU Fortran: 969 970'-fmax-errors=N' 971 Limits the maximum number of error messages to N, at which point 972 GNU Fortran bails out rather than attempting to continue processing 973 the source code. If N is 0, there is no limit on the number of 974 error messages produced. 975 976'-fsyntax-only' 977 Check the code for syntax errors, but do not actually compile it. 978 This will generate module files for each module present in the 979 code, but no other output file. 980 981'-Wpedantic' 982'-pedantic' 983 Issue warnings for uses of extensions to Fortran. '-pedantic' also 984 applies to C-language constructs where they occur in GNU Fortran 985 source files, such as use of '\e' in a character constant within a 986 directive like '#include'. 987 988 Valid Fortran programs should compile properly with or without this 989 option. However, without this option, certain GNU extensions and 990 traditional Fortran features are supported as well. With this 991 option, many of them are rejected. 992 993 Some users try to use '-pedantic' to check programs for 994 conformance. They soon find that it does not do quite what they 995 want--it finds some nonstandard practices, but not all. However, 996 improvements to GNU Fortran in this area are welcome. 997 998 This should be used in conjunction with '-std=f95', '-std=f2003', 999 '-std=f2008' or '-std=f2018'. 1000 1001'-pedantic-errors' 1002 Like '-pedantic', except that errors are produced rather than 1003 warnings. 1004 1005'-Wall' 1006 Enables commonly used warning options pertaining to usage that we 1007 recommend avoiding and that we believe are easy to avoid. This 1008 currently includes '-Waliasing', '-Wampersand', '-Wconversion', 1009 '-Wsurprising', '-Wc-binding-type', '-Wintrinsics-std', '-Wtabs', 1010 '-Wintrinsic-shadow', '-Wline-truncation', '-Wtarget-lifetime', 1011 '-Winteger-division', '-Wreal-q-constant', '-Wunused' and 1012 '-Wundefined-do-loop'. 1013 1014'-Waliasing' 1015 Warn about possible aliasing of dummy arguments. Specifically, it 1016 warns if the same actual argument is associated with a dummy 1017 argument with 'INTENT(IN)' and a dummy argument with 'INTENT(OUT)' 1018 in a call with an explicit interface. 1019 1020 The following example will trigger the warning. 1021 interface 1022 subroutine bar(a,b) 1023 integer, intent(in) :: a 1024 integer, intent(out) :: b 1025 end subroutine 1026 end interface 1027 integer :: a 1028 1029 call bar(a,a) 1030 1031'-Wampersand' 1032 Warn about missing ampersand in continued character constants. The 1033 warning is given with '-Wampersand', '-pedantic', '-std=f95', 1034 '-std=f2003', '-std=f2008' and '-std=f2018'. Note: With no 1035 ampersand given in a continued character constant, GNU Fortran 1036 assumes continuation at the first non-comment, non-whitespace 1037 character after the ampersand that initiated the continuation. 1038 1039'-Wargument-mismatch' 1040 Warn about type, rank, and other mismatches between formal 1041 parameters and actual arguments to functions and subroutines. 1042 These warnings are recommended and thus enabled by default. 1043 1044'-Warray-temporaries' 1045 Warn about array temporaries generated by the compiler. The 1046 information generated by this warning is sometimes useful in 1047 optimization, in order to avoid such temporaries. 1048 1049'-Wc-binding-type' 1050 Warn if the a variable might not be C interoperable. In 1051 particular, warn if the variable has been declared using an 1052 intrinsic type with default kind instead of using a kind parameter 1053 defined for C interoperability in the intrinsic 'ISO_C_Binding' 1054 module. This option is implied by '-Wall'. 1055 1056'-Wcharacter-truncation' 1057 Warn when a character assignment will truncate the assigned string. 1058 1059'-Wline-truncation' 1060 Warn when a source code line will be truncated. This option is 1061 implied by '-Wall'. For free-form source code, the default is 1062 '-Werror=line-truncation' such that truncations are reported as 1063 error. 1064 1065'-Wconversion' 1066 Warn about implicit conversions that are likely to change the value 1067 of the expression after conversion. Implied by '-Wall'. 1068 1069'-Wconversion-extra' 1070 Warn about implicit conversions between different types and kinds. 1071 This option does _not_ imply '-Wconversion'. 1072 1073'-Wextra' 1074 Enables some warning options for usages of language features which 1075 may be problematic. This currently includes '-Wcompare-reals', 1076 '-Wunused-parameter' and '-Wdo-subscript'. 1077 1078'-Wfrontend-loop-interchange' 1079 Enable warning for loop interchanges performed by the 1080 '-ffrontend-loop-interchange' option. 1081 1082'-Wimplicit-interface' 1083 Warn if a procedure is called without an explicit interface. Note 1084 this only checks that an explicit interface is present. It does 1085 not check that the declared interfaces are consistent across 1086 program units. 1087 1088'-Wimplicit-procedure' 1089 Warn if a procedure is called that has neither an explicit 1090 interface nor has been declared as 'EXTERNAL'. 1091 1092'-Winteger-division' 1093 Warn if a constant integer division truncates it result. As an 1094 example, 3/5 evaluates to 0. 1095 1096'-Wintrinsics-std' 1097 Warn if 'gfortran' finds a procedure named like an intrinsic not 1098 available in the currently selected standard (with '-std') and 1099 treats it as 'EXTERNAL' procedure because of this. 1100 '-fall-intrinsics' can be used to never trigger this behavior and 1101 always link to the intrinsic regardless of the selected standard. 1102 1103'-Wreal-q-constant' 1104 Produce a warning if a real-literal-constant contains a 'q' 1105 exponent-letter. 1106 1107'-Wsurprising' 1108 Produce a warning when "suspicious" code constructs are 1109 encountered. While technically legal these usually indicate that 1110 an error has been made. 1111 1112 This currently produces a warning under the following 1113 circumstances: 1114 1115 * An INTEGER SELECT construct has a CASE that can never be 1116 matched as its lower value is greater than its upper value. 1117 1118 * A LOGICAL SELECT construct has three CASE statements. 1119 1120 * A TRANSFER specifies a source that is shorter than the 1121 destination. 1122 1123 * The type of a function result is declared more than once with 1124 the same type. If '-pedantic' or standard-conforming mode is 1125 enabled, this is an error. 1126 1127 * A 'CHARACTER' variable is declared with negative length. 1128 1129'-Wtabs' 1130 By default, tabs are accepted as whitespace, but tabs are not 1131 members of the Fortran Character Set. For continuation lines, a 1132 tab followed by a digit between 1 and 9 is supported. '-Wtabs' 1133 will cause a warning to be issued if a tab is encountered. Note, 1134 '-Wtabs' is active for '-pedantic', '-std=f95', '-std=f2003', 1135 '-std=f2008', '-std=f2008ts', '-std=f2018' and '-Wall'. 1136 1137'-Wundefined-do-loop' 1138 Warn if a DO loop with step either 1 or -1 yields an underflow or 1139 an overflow during iteration of an induction variable of the loop. 1140 This option is implied by '-Wall'. 1141 1142'-Wunderflow' 1143 Produce a warning when numerical constant expressions are 1144 encountered, which yield an UNDERFLOW during compilation. Enabled 1145 by default. 1146 1147'-Wintrinsic-shadow' 1148 Warn if a user-defined procedure or module procedure has the same 1149 name as an intrinsic; in this case, an explicit interface or 1150 'EXTERNAL' or 'INTRINSIC' declaration might be needed to get calls 1151 later resolved to the desired intrinsic/procedure. This option is 1152 implied by '-Wall'. 1153 1154'-Wuse-without-only' 1155 Warn if a 'USE' statement has no 'ONLY' qualifier and thus 1156 implicitly imports all public entities of the used module. 1157 1158'-Wunused-dummy-argument' 1159 Warn about unused dummy arguments. This option is implied by 1160 '-Wall'. 1161 1162'-Wunused-parameter' 1163 Contrary to 'gcc''s meaning of '-Wunused-parameter', 'gfortran''s 1164 implementation of this option does not warn about unused dummy 1165 arguments (see '-Wunused-dummy-argument'), but about unused 1166 'PARAMETER' values. '-Wunused-parameter' is implied by '-Wextra' 1167 if also '-Wunused' or '-Wall' is used. 1168 1169'-Walign-commons' 1170 By default, 'gfortran' warns about any occasion of variables being 1171 padded for proper alignment inside a 'COMMON' block. This warning 1172 can be turned off via '-Wno-align-commons'. See also 1173 '-falign-commons'. 1174 1175'-Wfunction-elimination' 1176 Warn if any calls to functions are eliminated by the optimizations 1177 enabled by the '-ffrontend-optimize' option. 1178 1179'-Wrealloc-lhs' 1180 Warn when the compiler might insert code to for allocation or 1181 reallocation of an allocatable array variable of intrinsic type in 1182 intrinsic assignments. In hot loops, the Fortran 2003 reallocation 1183 feature may reduce the performance. If the array is already 1184 allocated with the correct shape, consider using a whole-array 1185 array-spec (e.g. '(:,:,:)') for the variable on the left-hand side 1186 to prevent the reallocation check. Note that in some cases the 1187 warning is shown, even if the compiler will optimize reallocation 1188 checks away. For instance, when the right-hand side contains the 1189 same variable multiplied by a scalar. See also '-frealloc-lhs'. 1190 1191'-Wrealloc-lhs-all' 1192 Warn when the compiler inserts code to for allocation or 1193 reallocation of an allocatable variable; this includes scalars and 1194 derived types. 1195 1196'-Wcompare-reals' 1197 Warn when comparing real or complex types for equality or 1198 inequality. This option is implied by '-Wextra'. 1199 1200'-Wtarget-lifetime' 1201 Warn if the pointer in a pointer assignment might be longer than 1202 the its target. This option is implied by '-Wall'. 1203 1204'-Wzerotrip' 1205 Warn if a 'DO' loop is known to execute zero times at compile time. 1206 This option is implied by '-Wall'. 1207 1208'-Wdo-subscript' 1209 Warn if an array subscript inside a DO loop could lead to an 1210 out-of-bounds access even if the compiler can not prove that the 1211 statement is actually executed, in cases like 1212 real a(3) 1213 do i=1,4 1214 if (condition(i)) then 1215 a(i) = 1.2 1216 end if 1217 end do 1218 This option is implied by '-Wextra'. 1219 1220'-Werror' 1221 Turns all warnings into errors. 1222 1223 *Note Options to Request or Suppress Errors and Warnings: 1224(gcc)Warning Options, for information on more options offered by the GBE 1225shared by 'gfortran', 'gcc' and other GNU compilers. 1226 1227 Some of these have no effect when compiling programs written in 1228Fortran. 1229 1230 1231File: gfortran.info, Node: Debugging Options, Next: Directory Options, Prev: Error and Warning Options, Up: Invoking GNU Fortran 1232 12332.5 Options for debugging your program or GNU Fortran 1234===================================================== 1235 1236GNU Fortran has various special options that are used for debugging 1237either your program or the GNU Fortran compiler. 1238 1239'-fdump-fortran-original' 1240 Output the internal parse tree after translating the source program 1241 into internal representation. This option is mostly useful for 1242 debugging the GNU Fortran compiler itself. The output generated by 1243 this option might change between releases. This option may also 1244 generate internal compiler errors for features which have only 1245 recently been added. 1246 1247'-fdump-fortran-optimized' 1248 Output the parse tree after front-end optimization. Mostly useful 1249 for debugging the GNU Fortran compiler itself. The output 1250 generated by this option might change between releases. This 1251 option may also generate internal compiler errors for features 1252 which have only recently been added. 1253 1254'-fdump-parse-tree' 1255 Output the internal parse tree after translating the source program 1256 into internal representation. Mostly useful for debugging the GNU 1257 Fortran compiler itself. The output generated by this option might 1258 change between releases. This option may also generate internal 1259 compiler errors for features which have only recently been added. 1260 This option is deprecated; use '-fdump-fortran-original' instead. 1261 1262'-ffpe-trap=LIST' 1263 Specify a list of floating point exception traps to enable. On 1264 most systems, if a floating point exception occurs and the trap for 1265 that exception is enabled, a SIGFPE signal will be sent and the 1266 program being aborted, producing a core file useful for debugging. 1267 LIST is a (possibly empty) comma-separated list of the following 1268 exceptions: 'invalid' (invalid floating point operation, such as 1269 'SQRT(-1.0)'), 'zero' (division by zero), 'overflow' (overflow in a 1270 floating point operation), 'underflow' (underflow in a floating 1271 point operation), 'inexact' (loss of precision during operation), 1272 and 'denormal' (operation performed on a denormal value). The 1273 first five exceptions correspond to the five IEEE 754 exceptions, 1274 whereas the last one ('denormal') is not part of the IEEE 754 1275 standard but is available on some common architectures such as x86. 1276 1277 The first three exceptions ('invalid', 'zero', and 'overflow') 1278 often indicate serious errors, and unless the program has 1279 provisions for dealing with these exceptions, enabling traps for 1280 these three exceptions is probably a good idea. 1281 1282 Many, if not most, floating point operations incur loss of 1283 precision due to rounding, and hence the 'ffpe-trap=inexact' is 1284 likely to be uninteresting in practice. 1285 1286 By default no exception traps are enabled. 1287 1288'-ffpe-summary=LIST' 1289 Specify a list of floating-point exceptions, whose flag status is 1290 printed to 'ERROR_UNIT' when invoking 'STOP' and 'ERROR STOP'. 1291 LIST can be either 'none', 'all' or a comma-separated list of the 1292 following exceptions: 'invalid', 'zero', 'overflow', 'underflow', 1293 'inexact' and 'denormal'. (See '-ffpe-trap' for a description of 1294 the exceptions.) 1295 1296 By default, a summary for all exceptions but 'inexact' is shown. 1297 1298'-fno-backtrace' 1299 When a serious runtime error is encountered or a deadly signal is 1300 emitted (segmentation fault, illegal instruction, bus error, 1301 floating-point exception, and the other POSIX signals that have the 1302 action 'core'), the Fortran runtime library tries to output a 1303 backtrace of the error. '-fno-backtrace' disables the backtrace 1304 generation. This option only has influence for compilation of the 1305 Fortran main program. 1306 1307 *Note Options for Debugging Your Program or GCC: (gcc)Debugging 1308Options, for more information on debugging options. 1309 1310 1311File: gfortran.info, Node: Directory Options, Next: Link Options, Prev: Debugging Options, Up: Invoking GNU Fortran 1312 13132.6 Options for directory search 1314================================ 1315 1316These options affect how GNU Fortran searches for files specified by the 1317'INCLUDE' directive and where it searches for previously compiled 1318modules. 1319 1320 It also affects the search paths used by 'cpp' when used to 1321preprocess Fortran source. 1322 1323'-IDIR' 1324 These affect interpretation of the 'INCLUDE' directive (as well as 1325 of the '#include' directive of the 'cpp' preprocessor). 1326 1327 Also note that the general behavior of '-I' and 'INCLUDE' is pretty 1328 much the same as of '-I' with '#include' in the 'cpp' preprocessor, 1329 with regard to looking for 'header.gcc' files and other such 1330 things. 1331 1332 This path is also used to search for '.mod' files when previously 1333 compiled modules are required by a 'USE' statement. 1334 1335 *Note Options for Directory Search: (gcc)Directory Options, for 1336 information on the '-I' option. 1337 1338'-JDIR' 1339 This option specifies where to put '.mod' files for compiled 1340 modules. It is also added to the list of directories to searched 1341 by an 'USE' statement. 1342 1343 The default is the current directory. 1344 1345'-fintrinsic-modules-path DIR' 1346 This option specifies the location of pre-compiled intrinsic 1347 modules, if they are not in the default location expected by the 1348 compiler. 1349 1350 1351File: gfortran.info, Node: Link Options, Next: Runtime Options, Prev: Directory Options, Up: Invoking GNU Fortran 1352 13532.7 Influencing the linking step 1354================================ 1355 1356These options come into play when the compiler links object files into 1357an executable output file. They are meaningless if the compiler is not 1358doing a link step. 1359 1360'-static-libgfortran' 1361 On systems that provide 'libgfortran' as a shared and a static 1362 library, this option forces the use of the static version. If no 1363 shared version of 'libgfortran' was built when the compiler was 1364 configured, this option has no effect. 1365 1366 1367File: gfortran.info, Node: Runtime Options, Next: Code Gen Options, Prev: Link Options, Up: Invoking GNU Fortran 1368 13692.8 Influencing runtime behavior 1370================================ 1371 1372These options affect the runtime behavior of programs compiled with GNU 1373Fortran. 1374 1375'-fconvert=CONVERSION' 1376 Specify the representation of data for unformatted files. Valid 1377 values for conversion are: 'native', the default; 'swap', swap 1378 between big- and little-endian; 'big-endian', use big-endian 1379 representation for unformatted files; 'little-endian', use 1380 little-endian representation for unformatted files. 1381 1382 _This option has an effect only when used in the main program. The 1383 'CONVERT' specifier and the GFORTRAN_CONVERT_UNIT environment 1384 variable override the default specified by '-fconvert'._ 1385 1386'-frecord-marker=LENGTH' 1387 Specify the length of record markers for unformatted files. Valid 1388 values for LENGTH are 4 and 8. Default is 4. _This is different 1389 from previous versions of 'gfortran'_, which specified a default 1390 record marker length of 8 on most systems. If you want to read or 1391 write files compatible with earlier versions of 'gfortran', use 1392 '-frecord-marker=8'. 1393 1394'-fmax-subrecord-length=LENGTH' 1395 Specify the maximum length for a subrecord. The maximum permitted 1396 value for length is 2147483639, which is also the default. Only 1397 really useful for use by the gfortran testsuite. 1398 1399'-fsign-zero' 1400 When enabled, floating point numbers of value zero with the sign 1401 bit set are written as negative number in formatted output and 1402 treated as negative in the 'SIGN' intrinsic. '-fno-sign-zero' does 1403 not print the negative sign of zero values (or values rounded to 1404 zero for I/O) and regards zero as positive number in the 'SIGN' 1405 intrinsic for compatibility with Fortran 77. The default is 1406 '-fsign-zero'. 1407 1408 1409File: gfortran.info, Node: Code Gen Options, Next: Interoperability Options, Prev: Runtime Options, Up: Invoking GNU Fortran 1410 14112.9 Options for code generation conventions 1412=========================================== 1413 1414These machine-independent options control the interface conventions used 1415in code generation. 1416 1417 Most of them have both positive and negative forms; the negative form 1418of '-ffoo' would be '-fno-foo'. In the table below, only one of the 1419forms is listed--the one which is not the default. You can figure out 1420the other form by either removing 'no-' or adding it. 1421 1422'-fno-automatic' 1423 Treat each program unit (except those marked as RECURSIVE) as if 1424 the 'SAVE' statement were specified for every local variable and 1425 array referenced in it. Does not affect common blocks. (Some 1426 Fortran compilers provide this option under the name '-static' or 1427 '-save'.) The default, which is '-fautomatic', uses the stack for 1428 local variables smaller than the value given by 1429 '-fmax-stack-var-size'. Use the option '-frecursive' to use no 1430 static memory. 1431 1432'-ff2c' 1433 Generate code designed to be compatible with code generated by 1434 'g77' and 'f2c'. 1435 1436 The calling conventions used by 'g77' (originally implemented in 1437 'f2c') require functions that return type default 'REAL' to 1438 actually return the C type 'double', and functions that return type 1439 'COMPLEX' to return the values via an extra argument in the calling 1440 sequence that points to where to store the return value. Under the 1441 default GNU calling conventions, such functions simply return their 1442 results as they would in GNU C--default 'REAL' functions return the 1443 C type 'float', and 'COMPLEX' functions return the GNU C type 1444 'complex'. Additionally, this option implies the 1445 '-fsecond-underscore' option, unless '-fno-second-underscore' is 1446 explicitly requested. 1447 1448 This does not affect the generation of code that interfaces with 1449 the 'libgfortran' library. 1450 1451 _Caution:_ It is not a good idea to mix Fortran code compiled with 1452 '-ff2c' with code compiled with the default '-fno-f2c' calling 1453 conventions as, calling 'COMPLEX' or default 'REAL' functions 1454 between program parts which were compiled with different calling 1455 conventions will break at execution time. 1456 1457 _Caution:_ This will break code which passes intrinsic functions of 1458 type default 'REAL' or 'COMPLEX' as actual arguments, as the 1459 library implementations use the '-fno-f2c' calling conventions. 1460 1461'-fno-underscoring' 1462 Do not transform names of entities specified in the Fortran source 1463 file by appending underscores to them. 1464 1465 With '-funderscoring' in effect, GNU Fortran appends one underscore 1466 to external names with no underscores. This is done to ensure 1467 compatibility with code produced by many UNIX Fortran compilers. 1468 1469 _Caution_: The default behavior of GNU Fortran is incompatible with 1470 'f2c' and 'g77', please use the '-ff2c' option if you want object 1471 files compiled with GNU Fortran to be compatible with object code 1472 created with these tools. 1473 1474 Use of '-fno-underscoring' is not recommended unless you are 1475 experimenting with issues such as integration of GNU Fortran into 1476 existing system environments (vis-a`-vis existing libraries, tools, 1477 and so on). 1478 1479 For example, with '-funderscoring', and assuming that 'j()' and 1480 'max_count()' are external functions while 'my_var' and 'lvar' are 1481 local variables, a statement like 1482 I = J() + MAX_COUNT (MY_VAR, LVAR) 1483 is implemented as something akin to: 1484 i = j_() + max_count__(&my_var__, &lvar); 1485 1486 With '-fno-underscoring', the same statement is implemented as: 1487 1488 i = j() + max_count(&my_var, &lvar); 1489 1490 Use of '-fno-underscoring' allows direct specification of 1491 user-defined names while debugging and when interfacing GNU Fortran 1492 code with other languages. 1493 1494 Note that just because the names match does _not_ mean that the 1495 interface implemented by GNU Fortran for an external name matches 1496 the interface implemented by some other language for that same 1497 name. That is, getting code produced by GNU Fortran to link to 1498 code produced by some other compiler using this or any other method 1499 can be only a small part of the overall solution--getting the code 1500 generated by both compilers to agree on issues other than naming 1501 can require significant effort, and, unlike naming disagreements, 1502 linkers normally cannot detect disagreements in these other areas. 1503 1504 Also, note that with '-fno-underscoring', the lack of appended 1505 underscores introduces the very real possibility that a 1506 user-defined external name will conflict with a name in a system 1507 library, which could make finding unresolved-reference bugs quite 1508 difficult in some cases--they might occur at program run time, and 1509 show up only as buggy behavior at run time. 1510 1511 In future versions of GNU Fortran we hope to improve naming and 1512 linking issues so that debugging always involves using the names as 1513 they appear in the source, even if the names as seen by the linker 1514 are mangled to prevent accidental linking between procedures with 1515 incompatible interfaces. 1516 1517'-fsecond-underscore' 1518 By default, GNU Fortran appends an underscore to external names. 1519 If this option is used GNU Fortran appends two underscores to names 1520 with underscores and one underscore to external names with no 1521 underscores. GNU Fortran also appends two underscores to internal 1522 names with underscores to avoid naming collisions with external 1523 names. 1524 1525 This option has no effect if '-fno-underscoring' is in effect. It 1526 is implied by the '-ff2c' option. 1527 1528 Otherwise, with this option, an external name such as 'MAX_COUNT' 1529 is implemented as a reference to the link-time external symbol 1530 'max_count__', instead of 'max_count_'. This is required for 1531 compatibility with 'g77' and 'f2c', and is implied by use of the 1532 '-ff2c' option. 1533 1534'-fcoarray=<KEYWORD>' 1535 1536 'none' 1537 Disable coarray support; using coarray declarations and 1538 image-control statements will produce a compile-time error. 1539 (Default) 1540 1541 'single' 1542 Single-image mode, i.e. 'num_images()' is always one. 1543 1544 'lib' 1545 Library-based coarray parallelization; a suitable GNU Fortran 1546 coarray library needs to be linked. 1547 1548'-fcheck=<KEYWORD>' 1549 1550 Enable the generation of run-time checks; the argument shall be a 1551 comma-delimited list of the following keywords. Prefixing a check 1552 with 'no-' disables it if it was activated by a previous 1553 specification. 1554 1555 'all' 1556 Enable all run-time test of '-fcheck'. 1557 1558 'array-temps' 1559 Warns at run time when for passing an actual argument a 1560 temporary array had to be generated. The information 1561 generated by this warning is sometimes useful in optimization, 1562 in order to avoid such temporaries. 1563 1564 Note: The warning is only printed once per location. 1565 1566 'bounds' 1567 Enable generation of run-time checks for array subscripts and 1568 against the declared minimum and maximum values. It also 1569 checks array indices for assumed and deferred shape arrays 1570 against the actual allocated bounds and ensures that all 1571 string lengths are equal for character array constructors 1572 without an explicit typespec. 1573 1574 Some checks require that '-fcheck=bounds' is set for the 1575 compilation of the main program. 1576 1577 Note: In the future this may also include other forms of 1578 checking, e.g., checking substring references. 1579 1580 'do' 1581 Enable generation of run-time checks for invalid modification 1582 of loop iteration variables. 1583 1584 'mem' 1585 Enable generation of run-time checks for memory allocation. 1586 Note: This option does not affect explicit allocations using 1587 the 'ALLOCATE' statement, which will be always checked. 1588 1589 'pointer' 1590 Enable generation of run-time checks for pointers and 1591 allocatables. 1592 1593 'recursion' 1594 Enable generation of run-time checks for recursively called 1595 subroutines and functions which are not marked as recursive. 1596 See also '-frecursive'. Note: This check does not work for 1597 OpenMP programs and is disabled if used together with 1598 '-frecursive' and '-fopenmp'. 1599 1600 Example: Assuming you have a file 'foo.f90', the command 1601 gfortran -fcheck=all,no-array-temps foo.f90 1602 will compile the file with all checks enabled as specified above 1603 except warnings for generated array temporaries. 1604 1605'-fbounds-check' 1606 Deprecated alias for '-fcheck=bounds'. 1607 1608'-ftail-call-workaround' 1609'-ftail-call-workaround=N' 1610 Some C interfaces to Fortran codes violate the gfortran ABI by 1611 omitting the hidden character length arguments as described in 1612 *Note Argument passing conventions::. This can lead to crashes 1613 because pushing arguments for tail calls can overflow the stack. 1614 1615 To provide a workaround for existing binary packages, this option 1616 disables tail call optimization for gfortran procedures with 1617 character arguments. With '-ftail-call-workaround=2' tail call 1618 optimization is disabled in all gfortran procedures with character 1619 arguments, with '-ftail-call-workaround=1' or equivalent 1620 '-ftail-call-workaround' only in gfortran procedures with character 1621 arguments that call implicitly prototyped procedures. 1622 1623 Using this option can lead to problems including crashes due to 1624 insufficient stack space. 1625 1626 It is _very strongly_ recommended to fix the code in question. The 1627 '-fc-prototypes-external' option can be used to generate prototypes 1628 which conform to gfortran's ABI, for inclusion in the source code. 1629 1630 Support for this option will likely be withdrawn in a future 1631 release of gfortran. 1632 1633 The negative form, '-fno-tail-call-workaround' or equivalent 1634 '-ftail-call-workaround=0', can be used to disable this option. 1635 1636 Default is currently '-ftail-call-workaround', this will change in 1637 future releases. 1638 1639'-fcheck-array-temporaries' 1640 Deprecated alias for '-fcheck=array-temps'. 1641 1642'-fmax-array-constructor=N' 1643 This option can be used to increase the upper limit permitted in 1644 array constructors. The code below requires this option to expand 1645 the array at compile time. 1646 1647 program test 1648 implicit none 1649 integer j 1650 integer, parameter :: n = 100000 1651 integer, parameter :: i(n) = (/ (2*j, j = 1, n) /) 1652 print '(10(I0,1X))', i 1653 end program test 1654 1655 _Caution: This option can lead to long compile times and 1656 excessively large object files._ 1657 1658 The default value for N is 65535. 1659 1660'-fmax-stack-var-size=N' 1661 This option specifies the size in bytes of the largest array that 1662 will be put on the stack; if the size is exceeded static memory is 1663 used (except in procedures marked as RECURSIVE). Use the option 1664 '-frecursive' to allow for recursive procedures which do not have a 1665 RECURSIVE attribute or for parallel programs. Use '-fno-automatic' 1666 to never use the stack. 1667 1668 This option currently only affects local arrays declared with 1669 constant bounds, and may not apply to all character variables. 1670 Future versions of GNU Fortran may improve this behavior. 1671 1672 The default value for N is 32768. 1673 1674'-fstack-arrays' 1675 Adding this option will make the Fortran compiler put all arrays of 1676 unknown size and array temporaries onto stack memory. If your 1677 program uses very large local arrays it is possible that you will 1678 have to extend your runtime limits for stack memory on some 1679 operating systems. This flag is enabled by default at optimization 1680 level '-Ofast' unless '-fmax-stack-var-size' is specified. 1681 1682'-fpack-derived' 1683 This option tells GNU Fortran to pack derived type members as 1684 closely as possible. Code compiled with this option is likely to 1685 be incompatible with code compiled without this option, and may 1686 execute slower. 1687 1688'-frepack-arrays' 1689 In some circumstances GNU Fortran may pass assumed shape array 1690 sections via a descriptor describing a noncontiguous area of 1691 memory. This option adds code to the function prologue to repack 1692 the data into a contiguous block at runtime. 1693 1694 This should result in faster accesses to the array. However it can 1695 introduce significant overhead to the function call, especially 1696 when the passed data is noncontiguous. 1697 1698'-fshort-enums' 1699 This option is provided for interoperability with C code that was 1700 compiled with the '-fshort-enums' option. It will make GNU Fortran 1701 choose the smallest 'INTEGER' kind a given enumerator set will fit 1702 in, and give all its enumerators this kind. 1703 1704'-fexternal-blas' 1705 This option will make 'gfortran' generate calls to BLAS functions 1706 for some matrix operations like 'MATMUL', instead of using our own 1707 algorithms, if the size of the matrices involved is larger than a 1708 given limit (see '-fblas-matmul-limit'). This may be profitable if 1709 an optimized vendor BLAS library is available. The BLAS library 1710 will have to be specified at link time. 1711 1712'-fblas-matmul-limit=N' 1713 Only significant when '-fexternal-blas' is in effect. Matrix 1714 multiplication of matrices with size larger than (or equal to) N 1715 will be performed by calls to BLAS functions, while others will be 1716 handled by 'gfortran' internal algorithms. If the matrices 1717 involved are not square, the size comparison is performed using the 1718 geometric mean of the dimensions of the argument and result 1719 matrices. 1720 1721 The default value for N is 30. 1722 1723'-finline-matmul-limit=N' 1724 When front-end optimiztion is active, some calls to the 'MATMUL' 1725 intrinsic function will be inlined. This may result in code size 1726 increase if the size of the matrix cannot be determined at compile 1727 time, as code for both cases is generated. Setting 1728 '-finline-matmul-limit=0' will disable inlining in all cases. 1729 Setting this option with a value of N will produce inline code for 1730 matrices with size up to N. If the matrices involved are not 1731 square, the size comparison is performed using the geometric mean 1732 of the dimensions of the argument and result matrices. 1733 1734 The default value for N is 30. The '-fblas-matmul-limit' can be 1735 used to change this value. 1736 1737'-frecursive' 1738 Allow indirect recursion by forcing all local arrays to be 1739 allocated on the stack. This flag cannot be used together with 1740 '-fmax-stack-var-size=' or '-fno-automatic'. 1741 1742'-finit-local-zero' 1743'-finit-derived' 1744'-finit-integer=N' 1745'-finit-real=<ZERO|INF|-INF|NAN|SNAN>' 1746'-finit-logical=<TRUE|FALSE>' 1747'-finit-character=N' 1748 The '-finit-local-zero' option instructs the compiler to initialize 1749 local 'INTEGER', 'REAL', and 'COMPLEX' variables to zero, 'LOGICAL' 1750 variables to false, and 'CHARACTER' variables to a string of null 1751 bytes. Finer-grained initialization options are provided by the 1752 '-finit-integer=N', '-finit-real=<ZERO|INF|-INF|NAN|SNAN>' (which 1753 also initializes the real and imaginary parts of local 'COMPLEX' 1754 variables), '-finit-logical=<TRUE|FALSE>', and '-finit-character=N' 1755 (where N is an ASCII character value) options. 1756 1757 With '-finit-derived', components of derived type variables will be 1758 initialized according to these flags. Components whose type is not 1759 covered by an explicit '-finit-*' flag will be treated as described 1760 above with '-finit-local-zero'. 1761 1762 These options do not initialize 1763 * objects with the POINTER attribute 1764 * allocatable arrays 1765 * variables that appear in an 'EQUIVALENCE' statement. 1766 (These limitations may be removed in future releases). 1767 1768 Note that the '-finit-real=nan' option initializes 'REAL' and 1769 'COMPLEX' variables with a quiet NaN. For a signalling NaN use 1770 '-finit-real=snan'; note, however, that compile-time optimizations 1771 may convert them into quiet NaN and that trapping needs to be 1772 enabled (e.g. via '-ffpe-trap'). 1773 1774 Finally, note that enabling any of the '-finit-*' options will 1775 silence warnings that would have been emitted by '-Wuninitialized' 1776 for the affected local variables. 1777 1778'-falign-commons' 1779 By default, 'gfortran' enforces proper alignment of all variables 1780 in a 'COMMON' block by padding them as needed. On certain 1781 platforms this is mandatory, on others it increases performance. 1782 If a 'COMMON' block is not declared with consistent data types 1783 everywhere, this padding can cause trouble, and 1784 '-fno-align-commons' can be used to disable automatic alignment. 1785 The same form of this option should be used for all files that 1786 share a 'COMMON' block. To avoid potential alignment issues in 1787 'COMMON' blocks, it is recommended to order objects from largest to 1788 smallest. 1789 1790'-fno-protect-parens' 1791 By default the parentheses in expression are honored for all 1792 optimization levels such that the compiler does not do any 1793 re-association. Using '-fno-protect-parens' allows the compiler to 1794 reorder 'REAL' and 'COMPLEX' expressions to produce faster code. 1795 Note that for the re-association optimization '-fno-signed-zeros' 1796 and '-fno-trapping-math' need to be in effect. The parentheses 1797 protection is enabled by default, unless '-Ofast' is given. 1798 1799'-frealloc-lhs' 1800 An allocatable left-hand side of an intrinsic assignment is 1801 automatically (re)allocated if it is either unallocated or has a 1802 different shape. The option is enabled by default except when 1803 '-std=f95' is given. See also '-Wrealloc-lhs'. 1804 1805'-faggressive-function-elimination' 1806 Functions with identical argument lists are eliminated within 1807 statements, regardless of whether these functions are marked 'PURE' 1808 or not. For example, in 1809 a = f(b,c) + f(b,c) 1810 there will only be a single call to 'f'. This option only works if 1811 '-ffrontend-optimize' is in effect. 1812 1813'-ffrontend-optimize' 1814 This option performs front-end optimization, based on manipulating 1815 parts the Fortran parse tree. Enabled by default by any '-O' 1816 option. Optimizations enabled by this option include inlining 1817 calls to 'MATMUL', elimination of identical function calls within 1818 expressions, removing unnecessary calls to 'TRIM' in comparisons 1819 and assignments and replacing 'TRIM(a)' with 'a(1:LEN_TRIM(a))'. 1820 It can be deselected by specifying '-fno-frontend-optimize'. 1821 1822'-ffrontend-loop-interchange' 1823 Attempt to interchange loops in the Fortran front end where 1824 profitable. Enabled by default by any '-O' option. At the moment, 1825 this option only affects 'FORALL' and 'DO CONCURRENT' statements 1826 with several forall triplets. 1827 1828 *Note Options for Code Generation Conventions: (gcc)Code Gen Options, 1829for information on more options offered by the GBE shared by 'gfortran', 1830'gcc', and other GNU compilers. 1831 1832 1833File: gfortran.info, Node: Interoperability Options, Next: Environment Variables, Prev: Code Gen Options, Up: Invoking GNU Fortran 1834 18352.10 Options for interoperability with other languages 1836====================================================== 1837 1838-fc-prototypes 1839 This option will generate C prototypes from 'BIND(C)' variable 1840 declarations, types and procedure interfaces and writes them to 1841 standard output. 'ENUM' is not yet supported. 1842 1843 The generated prototypes may need inclusion of an appropriate 1844 header, such as '<stdint.h>' or '<stdlib.h>'. For types which are 1845 not specified using the appropriate kind from the 'iso_c_binding' 1846 module, a warning is added as a comment to the code. 1847 1848 For function pointers, a pointer to a function returning 'int' 1849 without an explicit argument list is generated. 1850 1851 Example of use: 1852 $ gfortran -fc-prototypes -fsyntax-only foo.f90 > foo.h 1853 where the C code intended for interoperating with the Fortran code 1854 then uses '#include "foo.h"'. 1855 1856 1857File: gfortran.info, Node: Environment Variables, Prev: Interoperability Options, Up: Invoking GNU Fortran 1858 18592.11 Environment variables affecting 'gfortran' 1860=============================================== 1861 1862The 'gfortran' compiler currently does not make use of any environment 1863variables to control its operation above and beyond those that affect 1864the operation of 'gcc'. 1865 1866 *Note Environment Variables Affecting GCC: (gcc)Environment 1867Variables, for information on environment variables. 1868 1869 *Note Runtime::, for environment variables that affect the run-time 1870behavior of programs compiled with GNU Fortran. 1871 1872 1873File: gfortran.info, Node: Runtime, Next: Fortran standards status, Prev: Invoking GNU Fortran, Up: Top 1874 18753 Runtime: Influencing runtime behavior with environment variables 1876****************************************************************** 1877 1878The behavior of the 'gfortran' can be influenced by environment 1879variables. 1880 1881 Malformed environment variables are silently ignored. 1882 1883* Menu: 1884 1885* TMPDIR:: Directory for scratch files 1886* GFORTRAN_STDIN_UNIT:: Unit number for standard input 1887* GFORTRAN_STDOUT_UNIT:: Unit number for standard output 1888* GFORTRAN_STDERR_UNIT:: Unit number for standard error 1889* GFORTRAN_UNBUFFERED_ALL:: Do not buffer I/O for all units. 1890* GFORTRAN_UNBUFFERED_PRECONNECTED:: Do not buffer I/O for preconnected units. 1891* GFORTRAN_SHOW_LOCUS:: Show location for runtime errors 1892* GFORTRAN_OPTIONAL_PLUS:: Print leading + where permitted 1893* GFORTRAN_LIST_SEPARATOR:: Separator for list output 1894* GFORTRAN_CONVERT_UNIT:: Set endianness for unformatted I/O 1895* GFORTRAN_ERROR_BACKTRACE:: Show backtrace on run-time errors 1896 1897 1898File: gfortran.info, Node: TMPDIR, Next: GFORTRAN_STDIN_UNIT, Up: Runtime 1899 19003.1 'TMPDIR'--Directory for scratch files 1901========================================= 1902 1903When opening a file with 'STATUS='SCRATCH'', GNU Fortran tries to create 1904the file in one of the potential directories by testing each directory 1905in the order below. 1906 1907 1. The environment variable 'TMPDIR', if it exists. 1908 1909 2. On the MinGW target, the directory returned by the 'GetTempPath' 1910 function. Alternatively, on the Cygwin target, the 'TMP' and 1911 'TEMP' environment variables, if they exist, in that order. 1912 1913 3. The 'P_tmpdir' macro if it is defined, otherwise the directory 1914 '/tmp'. 1915 1916 1917File: gfortran.info, Node: GFORTRAN_STDIN_UNIT, Next: GFORTRAN_STDOUT_UNIT, Prev: TMPDIR, Up: Runtime 1918 19193.2 'GFORTRAN_STDIN_UNIT'--Unit number for standard input 1920========================================================= 1921 1922This environment variable can be used to select the unit number 1923preconnected to standard input. This must be a positive integer. The 1924default value is 5. 1925 1926 1927File: gfortran.info, Node: GFORTRAN_STDOUT_UNIT, Next: GFORTRAN_STDERR_UNIT, Prev: GFORTRAN_STDIN_UNIT, Up: Runtime 1928 19293.3 'GFORTRAN_STDOUT_UNIT'--Unit number for standard output 1930=========================================================== 1931 1932This environment variable can be used to select the unit number 1933preconnected to standard output. This must be a positive integer. The 1934default value is 6. 1935 1936 1937File: gfortran.info, Node: GFORTRAN_STDERR_UNIT, Next: GFORTRAN_UNBUFFERED_ALL, Prev: GFORTRAN_STDOUT_UNIT, Up: Runtime 1938 19393.4 'GFORTRAN_STDERR_UNIT'--Unit number for standard error 1940========================================================== 1941 1942This environment variable can be used to select the unit number 1943preconnected to standard error. This must be a positive integer. The 1944default value is 0. 1945 1946 1947File: gfortran.info, Node: GFORTRAN_UNBUFFERED_ALL, Next: GFORTRAN_UNBUFFERED_PRECONNECTED, Prev: GFORTRAN_STDERR_UNIT, Up: Runtime 1948 19493.5 'GFORTRAN_UNBUFFERED_ALL'--Do not buffer I/O on all units 1950============================================================= 1951 1952This environment variable controls whether all I/O is unbuffered. If 1953the first letter is 'y', 'Y' or '1', all I/O is unbuffered. This will 1954slow down small sequential reads and writes. If the first letter is 1955'n', 'N' or '0', I/O is buffered. This is the default. 1956 1957 1958File: gfortran.info, Node: GFORTRAN_UNBUFFERED_PRECONNECTED, Next: GFORTRAN_SHOW_LOCUS, Prev: GFORTRAN_UNBUFFERED_ALL, Up: Runtime 1959 19603.6 'GFORTRAN_UNBUFFERED_PRECONNECTED'--Do not buffer I/O on preconnected units 1961=============================================================================== 1962 1963The environment variable named 'GFORTRAN_UNBUFFERED_PRECONNECTED' 1964controls whether I/O on a preconnected unit (i.e. STDOUT or STDERR) is 1965unbuffered. If the first letter is 'y', 'Y' or '1', I/O is unbuffered. 1966This will slow down small sequential reads and writes. If the first 1967letter is 'n', 'N' or '0', I/O is buffered. This is the default. 1968 1969 1970File: gfortran.info, Node: GFORTRAN_SHOW_LOCUS, Next: GFORTRAN_OPTIONAL_PLUS, Prev: GFORTRAN_UNBUFFERED_PRECONNECTED, Up: Runtime 1971 19723.7 'GFORTRAN_SHOW_LOCUS'--Show location for runtime errors 1973=========================================================== 1974 1975If the first letter is 'y', 'Y' or '1', filename and line numbers for 1976runtime errors are printed. If the first letter is 'n', 'N' or '0', do 1977not print filename and line numbers for runtime errors. The default is 1978to print the location. 1979 1980 1981File: gfortran.info, Node: GFORTRAN_OPTIONAL_PLUS, Next: GFORTRAN_LIST_SEPARATOR, Prev: GFORTRAN_SHOW_LOCUS, Up: Runtime 1982 19833.8 'GFORTRAN_OPTIONAL_PLUS'--Print leading + where permitted 1984============================================================= 1985 1986If the first letter is 'y', 'Y' or '1', a plus sign is printed where 1987permitted by the Fortran standard. If the first letter is 'n', 'N' or 1988'0', a plus sign is not printed in most cases. Default is not to print 1989plus signs. 1990 1991 1992File: gfortran.info, Node: GFORTRAN_LIST_SEPARATOR, Next: GFORTRAN_CONVERT_UNIT, Prev: GFORTRAN_OPTIONAL_PLUS, Up: Runtime 1993 19943.9 'GFORTRAN_LIST_SEPARATOR'--Separator for list output 1995======================================================== 1996 1997This environment variable specifies the separator when writing 1998list-directed output. It may contain any number of spaces and at most 1999one comma. If you specify this on the command line, be sure to quote 2000spaces, as in 2001 $ GFORTRAN_LIST_SEPARATOR=' , ' ./a.out 2002 when 'a.out' is the compiled Fortran program that you want to run. 2003Default is a single space. 2004 2005 2006File: gfortran.info, Node: GFORTRAN_CONVERT_UNIT, Next: GFORTRAN_ERROR_BACKTRACE, Prev: GFORTRAN_LIST_SEPARATOR, Up: Runtime 2007 20083.10 'GFORTRAN_CONVERT_UNIT'--Set endianness for unformatted I/O 2009================================================================ 2010 2011By setting the 'GFORTRAN_CONVERT_UNIT' variable, it is possible to 2012change the representation of data for unformatted files. The syntax for 2013the 'GFORTRAN_CONVERT_UNIT' variable is: 2014 GFORTRAN_CONVERT_UNIT: mode | mode ';' exception | exception ; 2015 mode: 'native' | 'swap' | 'big_endian' | 'little_endian' ; 2016 exception: mode ':' unit_list | unit_list ; 2017 unit_list: unit_spec | unit_list unit_spec ; 2018 unit_spec: INTEGER | INTEGER '-' INTEGER ; 2019 The variable consists of an optional default mode, followed by a list 2020of optional exceptions, which are separated by semicolons from the 2021preceding default and each other. Each exception consists of a format 2022and a comma-separated list of units. Valid values for the modes are the 2023same as for the 'CONVERT' specifier: 2024 2025 'NATIVE' Use the native format. This is the default. 2026 'SWAP' Swap between little- and big-endian. 2027 'LITTLE_ENDIAN' Use the little-endian format for unformatted files. 2028 'BIG_ENDIAN' Use the big-endian format for unformatted files. 2029 A missing mode for an exception is taken to mean 'BIG_ENDIAN'. 2030Examples of values for 'GFORTRAN_CONVERT_UNIT' are: 2031 ''big_endian'' Do all unformatted I/O in big_endian mode. 2032 ''little_endian;native:10-20,25'' Do all unformatted I/O in 2033 little_endian mode, except for units 10 to 20 and 25, which are in 2034 native format. 2035 ''10-20'' Units 10 to 20 are big-endian, the rest is native. 2036 2037 Setting the environment variables should be done on the command line 2038or via the 'export' command for 'sh'-compatible shells and via 'setenv' 2039for 'csh'-compatible shells. 2040 2041 Example for 'sh': 2042 $ gfortran foo.f90 2043 $ GFORTRAN_CONVERT_UNIT='big_endian;native:10-20' ./a.out 2044 2045 Example code for 'csh': 2046 % gfortran foo.f90 2047 % setenv GFORTRAN_CONVERT_UNIT 'big_endian;native:10-20' 2048 % ./a.out 2049 2050 Using anything but the native representation for unformatted data 2051carries a significant speed overhead. If speed in this area matters to 2052you, it is best if you use this only for data that needs to be portable. 2053 2054 *Note CONVERT specifier::, for an alternative way to specify the data 2055representation for unformatted files. *Note Runtime Options::, for 2056setting a default data representation for the whole program. The 2057'CONVERT' specifier overrides the '-fconvert' compile options. 2058 2059 _Note that the values specified via the GFORTRAN_CONVERT_UNIT 2060environment variable will override the CONVERT specifier in the open 2061statement_. This is to give control over data formats to users who do 2062not have the source code of their program available. 2063 2064 2065File: gfortran.info, Node: GFORTRAN_ERROR_BACKTRACE, Prev: GFORTRAN_CONVERT_UNIT, Up: Runtime 2066 20673.11 'GFORTRAN_ERROR_BACKTRACE'--Show backtrace on run-time errors 2068================================================================== 2069 2070If the 'GFORTRAN_ERROR_BACKTRACE' variable is set to 'y', 'Y' or '1' 2071(only the first letter is relevant) then a backtrace is printed when a 2072serious run-time error occurs. To disable the backtracing, set the 2073variable to 'n', 'N', '0'. Default is to print a backtrace unless the 2074'-fno-backtrace' compile option was used. 2075 2076 2077File: gfortran.info, Node: Fortran standards status, Next: Compiler Characteristics, Prev: Runtime, Up: Top 2078 20794 Fortran standards status 2080************************** 2081 2082* Menu: 2083 2084* Fortran 2003 status:: 2085* Fortran 2008 status:: 2086* TS 29113 status:: 2087* TS 18508 status:: 2088* Fortran 2018 status:: 2089 2090 2091File: gfortran.info, Node: Fortran 2003 status, Next: Fortran 2008 status, Up: Fortran standards status 2092 20934.1 Fortran 2003 status 2094======================= 2095 2096GNU Fortran supports several Fortran 2003 features; an incomplete list 2097can be found below. See also the wiki page 2098(https://gcc.gnu.org/wiki/Fortran2003) about Fortran 2003. 2099 2100 * Procedure pointers including procedure-pointer components with 2101 'PASS' attribute. 2102 2103 * Procedures which are bound to a derived type (type-bound 2104 procedures) including 'PASS', 'PROCEDURE' and 'GENERIC', and 2105 operators bound to a type. 2106 2107 * Abstract interfaces and type extension with the possibility to 2108 override type-bound procedures or to have deferred binding. 2109 2110 * Polymorphic entities ("'CLASS'") for derived types and unlimited 2111 polymorphism ("'CLASS(*)'") - including 'SAME_TYPE_AS', 2112 'EXTENDS_TYPE_OF' and 'SELECT TYPE' for scalars and arrays and 2113 finalization. 2114 2115 * Generic interface names, which have the same name as derived types, 2116 are now supported. This allows one to write constructor functions. 2117 Note that Fortran does not support static constructor functions. 2118 For static variables, only default initialization or 2119 structure-constructor initialization are available. 2120 2121 * The 'ASSOCIATE' construct. 2122 2123 * Interoperability with C including enumerations, 2124 2125 * In structure constructors the components with default values may be 2126 omitted. 2127 2128 * Extensions to the 'ALLOCATE' statement, allowing for a 2129 type-specification with type parameter and for allocation and 2130 initialization from a 'SOURCE=' expression; 'ALLOCATE' and 2131 'DEALLOCATE' optionally return an error message string via 2132 'ERRMSG='. 2133 2134 * Reallocation on assignment: If an intrinsic assignment is used, an 2135 allocatable variable on the left-hand side is automatically 2136 allocated (if unallocated) or reallocated (if the shape is 2137 different). Currently, scalar deferred character length left-hand 2138 sides are correctly handled but arrays are not yet fully 2139 implemented. 2140 2141 * Deferred-length character variables and scalar deferred-length 2142 character components of derived types are supported. (Note that 2143 array-valued compoents are not yet implemented.) 2144 2145 * Transferring of allocations via 'MOVE_ALLOC'. 2146 2147 * The 'PRIVATE' and 'PUBLIC' attributes may be given individually to 2148 derived-type components. 2149 2150 * In pointer assignments, the lower bound may be specified and the 2151 remapping of elements is supported. 2152 2153 * For pointers an 'INTENT' may be specified which affect the 2154 association status not the value of the pointer target. 2155 2156 * Intrinsics 'command_argument_count', 'get_command', 2157 'get_command_argument', and 'get_environment_variable'. 2158 2159 * Support for Unicode characters (ISO 10646) and UTF-8, including the 2160 'SELECTED_CHAR_KIND' and 'NEW_LINE' intrinsic functions. 2161 2162 * Support for binary, octal and hexadecimal (BOZ) constants in the 2163 intrinsic functions 'INT', 'REAL', 'CMPLX' and 'DBLE'. 2164 2165 * Support for namelist variables with allocatable and pointer 2166 attribute and nonconstant length type parameter. 2167 2168 * Array constructors using square brackets. That is, '[...]' rather 2169 than '(/.../)'. Type-specification for array constructors like '(/ 2170 some-type :: ... /)'. 2171 2172 * Extensions to the specification and initialization expressions, 2173 including the support for intrinsics with real and complex 2174 arguments. 2175 2176 * Support for the asynchronous input/output syntax; however, the data 2177 transfer is currently always synchronously performed. 2178 2179 * 'FLUSH' statement. 2180 2181 * 'IOMSG=' specifier for I/O statements. 2182 2183 * Support for the declaration of enumeration constants via the 'ENUM' 2184 and 'ENUMERATOR' statements. Interoperability with 'gcc' is 2185 guaranteed also for the case where the '-fshort-enums' command line 2186 option is given. 2187 2188 * TR 15581: 2189 * 'ALLOCATABLE' dummy arguments. 2190 * 'ALLOCATABLE' function results 2191 * 'ALLOCATABLE' components of derived types 2192 2193 * The 'OPEN' statement supports the 'ACCESS='STREAM'' specifier, 2194 allowing I/O without any record structure. 2195 2196 * Namelist input/output for internal files. 2197 2198 * Minor I/O features: Rounding during formatted output, using of a 2199 decimal comma instead of a decimal point, setting whether a plus 2200 sign should appear for positive numbers. On systems where 'strtod' 2201 honours the rounding mode, the rounding mode is also supported for 2202 input. 2203 2204 * The 'PROTECTED' statement and attribute. 2205 2206 * The 'VALUE' statement and attribute. 2207 2208 * The 'VOLATILE' statement and attribute. 2209 2210 * The 'IMPORT' statement, allowing to import host-associated derived 2211 types. 2212 2213 * The intrinsic modules 'ISO_FORTRAN_ENVIRONMENT' is supported, which 2214 contains parameters of the I/O units, storage sizes. Additionally, 2215 procedures for C interoperability are available in the 2216 'ISO_C_BINDING' module. 2217 2218 * 'USE' statement with 'INTRINSIC' and 'NON_INTRINSIC' attribute; 2219 supported intrinsic modules: 'ISO_FORTRAN_ENV', 'ISO_C_BINDING', 2220 'OMP_LIB' and 'OMP_LIB_KINDS', and 'OPENACC'. 2221 2222 * Renaming of operators in the 'USE' statement. 2223 2224 2225File: gfortran.info, Node: Fortran 2008 status, Next: TS 29113 status, Prev: Fortran 2003 status, Up: Fortran standards status 2226 22274.2 Fortran 2008 status 2228======================= 2229 2230The latest version of the Fortran standard is ISO/IEC 1539-1:2010, 2231informally known as Fortran 2008. The official version is available 2232from International Organization for Standardization (ISO) or its 2233national member organizations. The the final draft (FDIS) can be 2234downloaded free of charge from 2235<http://www.nag.co.uk/sc22wg5/links.html>. Fortran is developed by the 2236Working Group 5 of Sub-Committee 22 of the Joint Technical Committee 1 2237of the International Organization for Standardization and the 2238International Electrotechnical Commission (IEC). This group is known as 2239WG5 (http://www.nag.co.uk/sc22wg5/). 2240 2241 The GNU Fortran compiler supports several of the new features of 2242Fortran 2008; the wiki (https://gcc.gnu.org/wiki/Fortran2008Status) has 2243some information about the current Fortran 2008 implementation status. 2244In particular, the following is implemented. 2245 2246 * The '-std=f2008' option and support for the file extensions '.f08' 2247 and '.F08'. 2248 2249 * The 'OPEN' statement now supports the 'NEWUNIT=' option, which 2250 returns a unique file unit, thus preventing inadvertent use of the 2251 same unit in different parts of the program. 2252 2253 * The 'g0' format descriptor and unlimited format items. 2254 2255 * The mathematical intrinsics 'ASINH', 'ACOSH', 'ATANH', 'ERF', 2256 'ERFC', 'GAMMA', 'LOG_GAMMA', 'BESSEL_J0', 'BESSEL_J1', 2257 'BESSEL_JN', 'BESSEL_Y0', 'BESSEL_Y1', 'BESSEL_YN', 'HYPOT', 2258 'NORM2', and 'ERFC_SCALED'. 2259 2260 * Using complex arguments with 'TAN', 'SINH', 'COSH', 'TANH', 'ASIN', 2261 'ACOS', and 'ATAN' is now possible; 'ATAN'(Y,X) is now an alias for 2262 'ATAN2'(Y,X). 2263 2264 * Support of the 'PARITY' intrinsic functions. 2265 2266 * The following bit intrinsics: 'LEADZ' and 'TRAILZ' for counting the 2267 number of leading and trailing zero bits, 'POPCNT' and 'POPPAR' for 2268 counting the number of one bits and returning the parity; 'BGE', 2269 'BGT', 'BLE', and 'BLT' for bitwise comparisons; 'DSHIFTL' and 2270 'DSHIFTR' for combined left and right shifts, 'MASKL' and 'MASKR' 2271 for simple left and right justified masks, 'MERGE_BITS' for a 2272 bitwise merge using a mask, 'SHIFTA', 'SHIFTL' and 'SHIFTR' for 2273 shift operations, and the transformational bit intrinsics 'IALL', 2274 'IANY' and 'IPARITY'. 2275 2276 * Support of the 'EXECUTE_COMMAND_LINE' intrinsic subroutine. 2277 2278 * Support for the 'STORAGE_SIZE' intrinsic inquiry function. 2279 2280 * The 'INT{8,16,32}' and 'REAL{32,64,128}' kind type parameters and 2281 the array-valued named constants 'INTEGER_KINDS', 'LOGICAL_KINDS', 2282 'REAL_KINDS' and 'CHARACTER_KINDS' of the intrinsic module 2283 'ISO_FORTRAN_ENV'. 2284 2285 * The module procedures 'C_SIZEOF' of the intrinsic module 2286 'ISO_C_BINDINGS' and 'COMPILER_VERSION' and 'COMPILER_OPTIONS' of 2287 'ISO_FORTRAN_ENV'. 2288 2289 * Coarray support for serial programs with '-fcoarray=single' flag 2290 and experimental support for multiple images with the 2291 '-fcoarray=lib' flag. 2292 2293 * Submodules are supported. It should noted that 'MODULEs' do not 2294 produce the smod file needed by the descendent 'SUBMODULEs' unless 2295 they contain at least one 'MODULE PROCEDURE' interface. The reason 2296 for this is that 'SUBMODULEs' are useless without 'MODULE 2297 PROCEDUREs'. See http://j3-fortran.org/doc/meeting/207/15-209.txt 2298 for a discussion and a draft interpretation. Adopting this 2299 interpretation has the advantage that code that does not use 2300 submodules does not generate smod files. 2301 2302 * The 'DO CONCURRENT' construct is supported. 2303 2304 * The 'BLOCK' construct is supported. 2305 2306 * The 'STOP' and the new 'ERROR STOP' statements now support all 2307 constant expressions. Both show the signals which were signaling 2308 at termination. 2309 2310 * Support for the 'CONTIGUOUS' attribute. 2311 2312 * Support for 'ALLOCATE' with 'MOLD'. 2313 2314 * Support for the 'IMPURE' attribute for procedures, which allows for 2315 'ELEMENTAL' procedures without the restrictions of 'PURE'. 2316 2317 * Null pointers (including 'NULL()') and not-allocated variables can 2318 be used as actual argument to optional non-pointer, non-allocatable 2319 dummy arguments, denoting an absent argument. 2320 2321 * Non-pointer variables with 'TARGET' attribute can be used as actual 2322 argument to 'POINTER' dummies with 'INTENT(IN)'. 2323 2324 * Pointers including procedure pointers and those in a derived type 2325 (pointer components) can now be initialized by a target instead of 2326 only by 'NULL'. 2327 2328 * The 'EXIT' statement (with construct-name) can be now be used to 2329 leave not only the 'DO' but also the 'ASSOCIATE', 'BLOCK', 'IF', 2330 'SELECT CASE' and 'SELECT TYPE' constructs. 2331 2332 * Internal procedures can now be used as actual argument. 2333 2334 * Minor features: obsolesce diagnostics for 'ENTRY' with 2335 '-std=f2008'; a line may start with a semicolon; for internal and 2336 module procedures 'END' can be used instead of 'END SUBROUTINE' and 2337 'END FUNCTION'; 'SELECTED_REAL_KIND' now also takes a 'RADIX' 2338 argument; intrinsic types are supported for 2339 'TYPE'(INTRINSIC-TYPE-SPEC); multiple type-bound procedures can be 2340 declared in a single 'PROCEDURE' statement; implied-shape arrays 2341 are supported for named constants ('PARAMETER'). 2342 2343 2344File: gfortran.info, Node: TS 29113 status, Next: TS 18508 status, Prev: Fortran 2008 status, Up: Fortran standards status 2345 23464.3 Technical Specification 29113 Status 2347======================================== 2348 2349GNU Fortran supports some of the new features of the Technical 2350Specification (TS) 29113 on Further Interoperability of Fortran with C. 2351The wiki (https://gcc.gnu.org/wiki/TS29113Status) has some information 2352about the current TS 29113 implementation status. In particular, the 2353following is implemented. 2354 2355 See also *note Further Interoperability of Fortran with C::. 2356 2357 * The '-std=f2008ts' option. 2358 2359 * The 'OPTIONAL' attribute is allowed for dummy arguments of 'BIND(C) 2360 procedures.' 2361 2362 * The 'RANK' intrinsic is supported. 2363 2364 * GNU Fortran's implementation for variables with 'ASYNCHRONOUS' 2365 attribute is compatible with TS 29113. 2366 2367 * Assumed types ('TYPE(*)'). 2368 2369 * Assumed-rank ('DIMENSION(..)'). However, the array descriptor of 2370 the TS is not yet supported. 2371 2372 2373File: gfortran.info, Node: TS 18508 status, Next: Fortran 2018 status, Prev: TS 29113 status, Up: Fortran standards status 2374 23754.4 Technical Specification 18508 Status 2376======================================== 2377 2378GNU Fortran supports the following new features of the Technical 2379Specification 18508 on Additional Parallel Features in Fortran: 2380 2381 * The new atomic ADD, CAS, FETCH and ADD/OR/XOR, OR and XOR 2382 intrinsics. 2383 2384 * The 'CO_MIN' and 'CO_MAX' and 'SUM' reduction intrinsics. And the 2385 'CO_BROADCAST' and 'CO_REDUCE' intrinsic, except that those do not 2386 support polymorphic types or types with allocatable, pointer or 2387 polymorphic components. 2388 2389 * Events ('EVENT POST', 'EVENT WAIT', 'EVENT_QUERY') 2390 2391 * Failed images ('FAIL IMAGE', 'IMAGE_STATUS', 'FAILED_IMAGES', 2392 'STOPPED_IMAGES') 2393 2394 2395File: gfortran.info, Node: Fortran 2018 status, Prev: TS 18508 status, Up: Fortran standards status 2396 23974.5 Status of Fortran 2018 support 2398================================== 2399 2400So far very little work has been done to support Fortran 2018. 2401 2402 * ERROR STOP in a PURE procedure An 'ERROR STOP' statement is 2403 permitted in a 'PURE' procedure. 2404 2405 * IMPLICIT NONE with a spec-list Support the 'IMPLICIT NONE' 2406 statement with an 'implicit-none-spec-list'. 2407 2408 * Behavior of INQUIRE with the RECL= specifier 2409 2410 The behavior of the 'INQUIRE' statement with the 'RECL=' specifier 2411 now conforms to Fortran 2018. 2412 2413 2414File: gfortran.info, Node: Compiler Characteristics, Next: Extensions, Prev: Fortran standards status, Up: Top 2415 24165 Compiler Characteristics 2417************************** 2418 2419This chapter describes certain characteristics of the GNU Fortran 2420compiler, that are not specified by the Fortran standard, but which 2421might in some way or another become visible to the programmer. 2422 2423* Menu: 2424 2425* KIND Type Parameters:: 2426* Internal representation of LOGICAL variables:: 2427* Thread-safety of the runtime library:: 2428* Data consistency and durability:: 2429* Files opened without an explicit ACTION= specifier:: 2430* File operations on symbolic links:: 2431* File format of unformatted sequential files:: 2432 2433 2434File: gfortran.info, Node: KIND Type Parameters, Next: Internal representation of LOGICAL variables, Up: Compiler Characteristics 2435 24365.1 KIND Type Parameters 2437======================== 2438 2439The 'KIND' type parameters supported by GNU Fortran for the primitive 2440data types are: 2441 2442'INTEGER' 2443 1, 2, 4, 8*, 16*, default: 4** 2444 2445'LOGICAL' 2446 1, 2, 4, 8*, 16*, default: 4** 2447 2448'REAL' 2449 4, 8, 10*, 16*, default: 4*** 2450 2451'COMPLEX' 2452 4, 8, 10*, 16*, default: 4*** 2453 2454'DOUBLE PRECISION' 2455 4, 8, 10*, 16*, default: 8*** 2456 2457'CHARACTER' 2458 1, 4, default: 1 2459 2460* not available on all systems 2461** unless '-fdefault-integer-8' is used 2462*** unless '-fdefault-real-8' is used (see *note Fortran Dialect 2463Options::) 2464 2465The 'KIND' value matches the storage size in bytes, except for 'COMPLEX' 2466where the storage size is twice as much (or both real and imaginary part 2467are a real value of the given size). It is recommended to use the *note 2468SELECTED_CHAR_KIND::, *note SELECTED_INT_KIND:: and *note 2469SELECTED_REAL_KIND:: intrinsics or the 'INT8', 'INT16', 'INT32', 2470'INT64', 'REAL32', 'REAL64', and 'REAL128' parameters of the 2471'ISO_FORTRAN_ENV' module instead of the concrete values. The available 2472kind parameters can be found in the constant arrays 'CHARACTER_KINDS', 2473'INTEGER_KINDS', 'LOGICAL_KINDS' and 'REAL_KINDS' in the *note 2474ISO_FORTRAN_ENV:: module. For C interoperability, the kind parameters 2475of the *note ISO_C_BINDING:: module should be used. 2476 2477 2478File: gfortran.info, Node: Internal representation of LOGICAL variables, Next: Thread-safety of the runtime library, Prev: KIND Type Parameters, Up: Compiler Characteristics 2479 24805.2 Internal representation of LOGICAL variables 2481================================================ 2482 2483The Fortran standard does not specify how variables of 'LOGICAL' type 2484are represented, beyond requiring that 'LOGICAL' variables of default 2485kind have the same storage size as default 'INTEGER' and 'REAL' 2486variables. The GNU Fortran internal representation is as follows. 2487 2488 A 'LOGICAL(KIND=N)' variable is represented as an 'INTEGER(KIND=N)' 2489variable, however, with only two permissible values: '1' for '.TRUE.' 2490and '0' for '.FALSE.'. Any other integer value results in undefined 2491behavior. 2492 2493 See also *note Argument passing conventions:: and *note 2494Interoperability with C::. 2495 2496 2497File: gfortran.info, Node: Thread-safety of the runtime library, Next: Data consistency and durability, Prev: Internal representation of LOGICAL variables, Up: Compiler Characteristics 2498 24995.3 Thread-safety of the runtime library 2500======================================== 2501 2502GNU Fortran can be used in programs with multiple threads, e.g. by using 2503OpenMP, by calling OS thread handling functions via the 'ISO_C_BINDING' 2504facility, or by GNU Fortran compiled library code being called from a 2505multi-threaded program. 2506 2507 The GNU Fortran runtime library, ('libgfortran'), supports being 2508called concurrently from multiple threads with the following exceptions. 2509 2510 During library initialization, the C 'getenv' function is used, which 2511need not be thread-safe. Similarly, the 'getenv' function is used to 2512implement the 'GET_ENVIRONMENT_VARIABLE' and 'GETENV' intrinsics. It is 2513the responsibility of the user to ensure that the environment is not 2514being updated concurrently when any of these actions are taking place. 2515 2516 The 'EXECUTE_COMMAND_LINE' and 'SYSTEM' intrinsics are implemented 2517with the 'system' function, which need not be thread-safe. It is the 2518responsibility of the user to ensure that 'system' is not called 2519concurrently. 2520 2521 For platforms not supporting thread-safe POSIX functions, further 2522functionality might not be thread-safe. For details, please consult the 2523documentation for your operating system. 2524 2525 The GNU Fortran runtime library uses various C library functions that 2526depend on the locale, such as 'strtod' and 'snprintf'. In order to work 2527correctly in locale-aware programs that set the locale using 2528'setlocale', the locale is reset to the default "C" locale while 2529executing a formatted 'READ' or 'WRITE' statement. On targets 2530supporting the POSIX 2008 per-thread locale functions (e.g. 2531'newlocale', 'uselocale', 'freelocale'), these are used and thus the 2532global locale set using 'setlocale' or the per-thread locales in other 2533threads are not affected. However, on targets lacking this 2534functionality, the global LC_NUMERIC locale is set to "C" during the 2535formatted I/O. Thus, on such targets it's not safe to call 'setlocale' 2536concurrently from another thread while a Fortran formatted I/O operation 2537is in progress. Also, other threads doing something dependent on the 2538LC_NUMERIC locale might not work correctly if a formatted I/O operation 2539is in progress in another thread. 2540 2541 2542File: gfortran.info, Node: Data consistency and durability, Next: Files opened without an explicit ACTION= specifier, Prev: Thread-safety of the runtime library, Up: Compiler Characteristics 2543 25445.4 Data consistency and durability 2545=================================== 2546 2547This section contains a brief overview of data and metadata consistency 2548and durability issues when doing I/O. 2549 2550 With respect to durability, GNU Fortran makes no effort to ensure 2551that data is committed to stable storage. If this is required, the GNU 2552Fortran programmer can use the intrinsic 'FNUM' to retrieve the low 2553level file descriptor corresponding to an open Fortran unit. Then, 2554using e.g. the 'ISO_C_BINDING' feature, one can call the underlying 2555system call to flush dirty data to stable storage, such as 'fsync' on 2556POSIX, '_commit' on MingW, or 'fcntl(fd, F_FULLSYNC, 0)' on Mac OS X. 2557The following example shows how to call fsync: 2558 2559 ! Declare the interface for POSIX fsync function 2560 interface 2561 function fsync (fd) bind(c,name="fsync") 2562 use iso_c_binding, only: c_int 2563 integer(c_int), value :: fd 2564 integer(c_int) :: fsync 2565 end function fsync 2566 end interface 2567 2568 ! Variable declaration 2569 integer :: ret 2570 2571 ! Opening unit 10 2572 open (10,file="foo") 2573 2574 ! ... 2575 ! Perform I/O on unit 10 2576 ! ... 2577 2578 ! Flush and sync 2579 flush(10) 2580 ret = fsync(fnum(10)) 2581 2582 ! Handle possible error 2583 if (ret /= 0) stop "Error calling FSYNC" 2584 2585 With respect to consistency, for regular files GNU Fortran uses 2586buffered I/O in order to improve performance. This buffer is flushed 2587automatically when full and in some other situations, e.g. when closing 2588a unit. It can also be explicitly flushed with the 'FLUSH' statement. 2589Also, the buffering can be turned off with the 'GFORTRAN_UNBUFFERED_ALL' 2590and 'GFORTRAN_UNBUFFERED_PRECONNECTED' environment variables. Special 2591files, such as terminals and pipes, are always unbuffered. Sometimes, 2592however, further things may need to be done in order to allow other 2593processes to see data that GNU Fortran has written, as follows. 2594 2595 The Windows platform supports a relaxed metadata consistency model, 2596where file metadata is written to the directory lazily. This means 2597that, for instance, the 'dir' command can show a stale size for a file. 2598One can force a directory metadata update by closing the unit, or by 2599calling '_commit' on the file descriptor. Note, though, that '_commit' 2600will force all dirty data to stable storage, which is often a very slow 2601operation. 2602 2603 The Network File System (NFS) implements a relaxed consistency model 2604called open-to-close consistency. Closing a file forces dirty data and 2605metadata to be flushed to the server, and opening a file forces the 2606client to contact the server in order to revalidate cached data. 2607'fsync' will also force a flush of dirty data and metadata to the 2608server. Similar to 'open' and 'close', acquiring and releasing 'fcntl' 2609file locks, if the server supports them, will also force cache 2610validation and flushing dirty data and metadata. 2611 2612 2613File: gfortran.info, Node: Files opened without an explicit ACTION= specifier, Next: File operations on symbolic links, Prev: Data consistency and durability, Up: Compiler Characteristics 2614 26155.5 Files opened without an explicit ACTION= specifier 2616====================================================== 2617 2618The Fortran standard says that if an 'OPEN' statement is executed 2619without an explicit 'ACTION=' specifier, the default value is processor 2620dependent. GNU Fortran behaves as follows: 2621 2622 1. Attempt to open the file with 'ACTION='READWRITE'' 2623 2. If that fails, try to open with 'ACTION='READ'' 2624 3. If that fails, try to open with 'ACTION='WRITE'' 2625 4. If that fails, generate an error 2626 2627 2628File: gfortran.info, Node: File operations on symbolic links, Next: File format of unformatted sequential files, Prev: Files opened without an explicit ACTION= specifier, Up: Compiler Characteristics 2629 26305.6 File operations on symbolic links 2631===================================== 2632 2633This section documents the behavior of GNU Fortran for file operations 2634on symbolic links, on systems that support them. 2635 2636 * Results of INQUIRE statements of the "inquire by file" form will 2637 relate to the target of the symbolic link. For example, 2638 'INQUIRE(FILE="foo",EXIST=ex)' will set EX to .TRUE. if FOO is a 2639 symbolic link pointing to an existing file, and .FALSE. if FOO 2640 points to an non-existing file ("dangling" symbolic link). 2641 2642 * Using the 'OPEN' statement with a 'STATUS="NEW"' specifier on a 2643 symbolic link will result in an error condition, whether the 2644 symbolic link points to an existing target or is dangling. 2645 2646 * If a symbolic link was connected, using the 'CLOSE' statement with 2647 a 'STATUS="DELETE"' specifier will cause the symbolic link itself 2648 to be deleted, not its target. 2649 2650 2651File: gfortran.info, Node: File format of unformatted sequential files, Prev: File operations on symbolic links, Up: Compiler Characteristics 2652 26535.7 File format of unformatted sequential files 2654=============================================== 2655 2656Unformatted sequential files are stored as logical records using record 2657markers. Each logical record consists of one of more subrecords. 2658 2659 Each subrecord consists of a leading record marker, the data written 2660by the user program, and a trailing record marker. The record markers 2661are four-byte integers by default, and eight-byte integers if the 2662'-fmax-subrecord-length=8' option (which exists for backwards 2663compability only) is in effect. 2664 2665 The representation of the record markers is that of unformatted files 2666given with the '-fconvert' option, the *note CONVERT specifier:: in an 2667open statement or the *note GFORTRAN_CONVERT_UNIT:: environment 2668variable. 2669 2670 The maximum number of bytes of user data in a subrecord is 2147483639 2671(2 GiB - 9) for a four-byte record marker. This limit can be lowered 2672with the '-fmax-subrecord-length' option, altough this is rarely useful. 2673If the length of a logical record exceeds this limit, the data is 2674distributed among several subrecords. 2675 2676 The absolute of the number stored in the record markers is the number 2677of bytes of user data in the corresponding subrecord. If the leading 2678record marker of a subrecord contains a negative number, another 2679subrecord follows the current one. If the trailing record marker 2680contains a negative number, then there is a preceding subrecord. 2681 2682 In the most simple case, with only one subrecord per logical record, 2683both record markers contain the number of bytes of user data in the 2684record, 2685 2686 The format for unformatted sequential data can be duplicated using 2687unformatted stream, as shown in the example program for an unformatted 2688record containing a single subrecord: 2689 2690 program main 2691 use iso_fortran_env, only: int32 2692 implicit none 2693 integer(int32) :: i 2694 real, dimension(10) :: a, b 2695 call random_number(a) 2696 open (10,file='test.dat',form='unformatted',access='stream') 2697 inquire (iolength=i) a 2698 write (10) i, a, i 2699 close (10) 2700 open (10,file='test.dat',form='unformatted') 2701 read (10) b 2702 if (all (a == b)) print *,'success!' 2703 end program main 2704 2705 2706File: gfortran.info, Node: Extensions, Next: Mixed-Language Programming, Prev: Compiler Characteristics, Up: Top 2707 27086 Extensions 2709************ 2710 2711The two sections below detail the extensions to standard Fortran that 2712are implemented in GNU Fortran, as well as some of the popular or 2713historically important extensions that are not (or not yet) implemented. 2714For the latter case, we explain the alternatives available to GNU 2715Fortran users, including replacement by standard-conforming code or GNU 2716extensions. 2717 2718* Menu: 2719 2720* Extensions implemented in GNU Fortran:: 2721* Extensions not implemented in GNU Fortran:: 2722 2723 2724File: gfortran.info, Node: Extensions implemented in GNU Fortran, Next: Extensions not implemented in GNU Fortran, Up: Extensions 2725 27266.1 Extensions implemented in GNU Fortran 2727========================================= 2728 2729GNU Fortran implements a number of extensions over standard Fortran. 2730This chapter contains information on their syntax and meaning. There 2731are currently two categories of GNU Fortran extensions, those that 2732provide functionality beyond that provided by any standard, and those 2733that are supported by GNU Fortran purely for backward compatibility with 2734legacy compilers. By default, '-std=gnu' allows the compiler to accept 2735both types of extensions, but to warn about the use of the latter. 2736Specifying either '-std=f95', '-std=f2003', '-std=f2008', or 2737'-std=f2018' disables both types of extensions, and '-std=legacy' allows 2738both without warning. The special compile flag '-fdec' enables 2739additional compatibility extensions along with those enabled by 2740'-std=legacy'. 2741 2742* Menu: 2743 2744* Old-style kind specifications:: 2745* Old-style variable initialization:: 2746* Extensions to namelist:: 2747* X format descriptor without count field:: 2748* Commas in FORMAT specifications:: 2749* Missing period in FORMAT specifications:: 2750* I/O item lists:: 2751* Q exponent-letter:: 2752* BOZ literal constants:: 2753* Real array indices:: 2754* Unary operators:: 2755* Implicitly convert LOGICAL and INTEGER values:: 2756* Hollerith constants support:: 2757* Cray pointers:: 2758* CONVERT specifier:: 2759* OpenMP:: 2760* OpenACC:: 2761* Argument list functions:: 2762* Read/Write after EOF marker:: 2763* STRUCTURE and RECORD:: 2764* UNION and MAP:: 2765* Type variants for integer intrinsics:: 2766* AUTOMATIC and STATIC attributes:: 2767* Extended math intrinsics:: 2768* Form feed as whitespace:: 2769* TYPE as an alias for PRINT:: 2770* %LOC as an rvalue:: 2771* .XOR. operator:: 2772* Bitwise logical operators:: 2773* Extended I/O specifiers:: 2774* Legacy PARAMETER statements:: 2775* Default exponents:: 2776 2777 2778File: gfortran.info, Node: Old-style kind specifications, Next: Old-style variable initialization, Up: Extensions implemented in GNU Fortran 2779 27806.1.1 Old-style kind specifications 2781----------------------------------- 2782 2783GNU Fortran allows old-style kind specifications in declarations. These 2784look like: 2785 TYPESPEC*size x,y,z 2786where 'TYPESPEC' is a basic type ('INTEGER', 'REAL', etc.), and where 2787'size' is a byte count corresponding to the storage size of a valid kind 2788for that type. (For 'COMPLEX' variables, 'size' is the total size of 2789the real and imaginary parts.) The statement then declares 'x', 'y' and 2790'z' to be of type 'TYPESPEC' with the appropriate kind. This is 2791equivalent to the standard-conforming declaration 2792 TYPESPEC(k) x,y,z 2793where 'k' is the kind parameter suitable for the intended precision. As 2794kind parameters are implementation-dependent, use the 'KIND', 2795'SELECTED_INT_KIND' and 'SELECTED_REAL_KIND' intrinsics to retrieve the 2796correct value, for instance 'REAL*8 x' can be replaced by: 2797 INTEGER, PARAMETER :: dbl = KIND(1.0d0) 2798 REAL(KIND=dbl) :: x 2799 2800 2801File: gfortran.info, Node: Old-style variable initialization, Next: Extensions to namelist, Prev: Old-style kind specifications, Up: Extensions implemented in GNU Fortran 2802 28036.1.2 Old-style variable initialization 2804--------------------------------------- 2805 2806GNU Fortran allows old-style initialization of variables of the form: 2807 INTEGER i/1/,j/2/ 2808 REAL x(2,2) /3*0.,1./ 2809 The syntax for the initializers is as for the 'DATA' statement, but 2810unlike in a 'DATA' statement, an initializer only applies to the 2811variable immediately preceding the initialization. In other words, 2812something like 'INTEGER I,J/2,3/' is not valid. This style of 2813initialization is only allowed in declarations without double colons 2814('::'); the double colons were introduced in Fortran 90, which also 2815introduced a standard syntax for initializing variables in type 2816declarations. 2817 2818 Examples of standard-conforming code equivalent to the above example 2819are: 2820 ! Fortran 90 2821 INTEGER :: i = 1, j = 2 2822 REAL :: x(2,2) = RESHAPE((/0.,0.,0.,1./),SHAPE(x)) 2823 ! Fortran 77 2824 INTEGER i, j 2825 REAL x(2,2) 2826 DATA i/1/, j/2/, x/3*0.,1./ 2827 2828 Note that variables which are explicitly initialized in declarations 2829or in 'DATA' statements automatically acquire the 'SAVE' attribute. 2830 2831 2832File: gfortran.info, Node: Extensions to namelist, Next: X format descriptor without count field, Prev: Old-style variable initialization, Up: Extensions implemented in GNU Fortran 2833 28346.1.3 Extensions to namelist 2835---------------------------- 2836 2837GNU Fortran fully supports the Fortran 95 standard for namelist I/O 2838including array qualifiers, substrings and fully qualified derived 2839types. The output from a namelist write is compatible with namelist 2840read. The output has all names in upper case and indentation to column 28411 after the namelist name. Two extensions are permitted: 2842 2843 Old-style use of '$' instead of '&' 2844 $MYNML 2845 X(:)%Y(2) = 1.0 2.0 3.0 2846 CH(1:4) = "abcd" 2847 $END 2848 2849 It should be noted that the default terminator is '/' rather than 2850'&END'. 2851 2852 Querying of the namelist when inputting from stdin. After at least 2853one space, entering '?' sends to stdout the namelist name and the names 2854of the variables in the namelist: 2855 ? 2856 2857 &mynml 2858 x 2859 x%y 2860 ch 2861 &end 2862 2863 Entering '=?' outputs the namelist to stdout, as if 'WRITE(*,NML = 2864mynml)' had been called: 2865 =? 2866 2867 &MYNML 2868 X(1)%Y= 0.000000 , 1.000000 , 0.000000 , 2869 X(2)%Y= 0.000000 , 2.000000 , 0.000000 , 2870 X(3)%Y= 0.000000 , 3.000000 , 0.000000 , 2871 CH=abcd, / 2872 2873 To aid this dialog, when input is from stdin, errors send their 2874messages to stderr and execution continues, even if 'IOSTAT' is set. 2875 2876 'PRINT' namelist is permitted. This causes an error if '-std=f95' is 2877used. 2878 PROGRAM test_print 2879 REAL, dimension (4) :: x = (/1.0, 2.0, 3.0, 4.0/) 2880 NAMELIST /mynml/ x 2881 PRINT mynml 2882 END PROGRAM test_print 2883 2884 Expanded namelist reads are permitted. This causes an error if 2885'-std=f95' is used. In the following example, the first element of the 2886array will be given the value 0.00 and the two succeeding elements will 2887be given the values 1.00 and 2.00. 2888 &MYNML 2889 X(1,1) = 0.00 , 1.00 , 2.00 2890 / 2891 2892 When writing a namelist, if no 'DELIM=' is specified, by default a 2893double quote is used to delimit character strings. If -std=F95, F2003, 2894or F2008, etc, the delim status is set to 'none'. Defaulting to quotes 2895ensures that namelists with character strings can be subsequently read 2896back in accurately. 2897 2898 2899File: gfortran.info, Node: X format descriptor without count field, Next: Commas in FORMAT specifications, Prev: Extensions to namelist, Up: Extensions implemented in GNU Fortran 2900 29016.1.4 'X' format descriptor without count field 2902----------------------------------------------- 2903 2904To support legacy codes, GNU Fortran permits the count field of the 'X' 2905edit descriptor in 'FORMAT' statements to be omitted. When omitted, the 2906count is implicitly assumed to be one. 2907 2908 PRINT 10, 2, 3 2909 10 FORMAT (I1, X, I1) 2910 2911 2912File: gfortran.info, Node: Commas in FORMAT specifications, Next: Missing period in FORMAT specifications, Prev: X format descriptor without count field, Up: Extensions implemented in GNU Fortran 2913 29146.1.5 Commas in 'FORMAT' specifications 2915--------------------------------------- 2916 2917To support legacy codes, GNU Fortran allows the comma separator to be 2918omitted immediately before and after character string edit descriptors 2919in 'FORMAT' statements. 2920 2921 PRINT 10, 2, 3 2922 10 FORMAT ('FOO='I1' BAR='I2) 2923 2924 2925File: gfortran.info, Node: Missing period in FORMAT specifications, Next: I/O item lists, Prev: Commas in FORMAT specifications, Up: Extensions implemented in GNU Fortran 2926 29276.1.6 Missing period in 'FORMAT' specifications 2928----------------------------------------------- 2929 2930To support legacy codes, GNU Fortran allows missing periods in format 2931specifications if and only if '-std=legacy' is given on the command 2932line. This is considered non-conforming code and is discouraged. 2933 2934 REAL :: value 2935 READ(*,10) value 2936 10 FORMAT ('F4') 2937 2938 2939File: gfortran.info, Node: I/O item lists, Next: Q exponent-letter, Prev: Missing period in FORMAT specifications, Up: Extensions implemented in GNU Fortran 2940 29416.1.7 I/O item lists 2942-------------------- 2943 2944To support legacy codes, GNU Fortran allows the input item list of the 2945'READ' statement, and the output item lists of the 'WRITE' and 'PRINT' 2946statements, to start with a comma. 2947 2948 2949File: gfortran.info, Node: Q exponent-letter, Next: BOZ literal constants, Prev: I/O item lists, Up: Extensions implemented in GNU Fortran 2950 29516.1.8 'Q' exponent-letter 2952------------------------- 2953 2954GNU Fortran accepts real literal constants with an exponent-letter of 2955'Q', for example, '1.23Q45'. The constant is interpreted as a 2956'REAL(16)' entity on targets that support this type. If the target does 2957not support 'REAL(16)' but has a 'REAL(10)' type, then the 2958real-literal-constant will be interpreted as a 'REAL(10)' entity. In 2959the absence of 'REAL(16)' and 'REAL(10)', an error will occur. 2960 2961 2962File: gfortran.info, Node: BOZ literal constants, Next: Real array indices, Prev: Q exponent-letter, Up: Extensions implemented in GNU Fortran 2963 29646.1.9 BOZ literal constants 2965--------------------------- 2966 2967Besides decimal constants, Fortran also supports binary ('b'), octal 2968('o') and hexadecimal ('z') integer constants. The syntax is: 'prefix 2969quote digits quote', were the prefix is either 'b', 'o' or 'z', quote is 2970either ''' or '"' and the digits are for binary '0' or '1', for octal 2971between '0' and '7', and for hexadecimal between '0' and 'F'. (Example: 2972'b'01011101''.) 2973 2974 Up to Fortran 95, BOZ literals were only allowed to initialize 2975integer variables in DATA statements. Since Fortran 2003 BOZ literals 2976are also allowed as argument of 'REAL', 'DBLE', 'INT' and 'CMPLX'; the 2977result is the same as if the integer BOZ literal had been converted by 2978'TRANSFER' to, respectively, 'real', 'double precision', 'integer' or 2979'complex'. As GNU Fortran extension the intrinsic procedures 'FLOAT', 2980'DFLOAT', 'COMPLEX' and 'DCMPLX' are treated alike. 2981 2982 As an extension, GNU Fortran allows hexadecimal BOZ literal constants 2983to be specified using the 'X' prefix, in addition to the standard 'Z' 2984prefix. The BOZ literal can also be specified by adding a suffix to the 2985string, for example, 'Z'ABC'' and ''ABC'Z' are equivalent. 2986 2987 Furthermore, GNU Fortran allows using BOZ literal constants outside 2988DATA statements and the four intrinsic functions allowed by Fortran 29892003. In DATA statements, in direct assignments, where the right-hand 2990side only contains a BOZ literal constant, and for old-style 2991initializers of the form 'integer i /o'0173'/', the constant is 2992transferred as if 'TRANSFER' had been used; for 'COMPLEX' numbers, only 2993the real part is initialized unless 'CMPLX' is used. In all other 2994cases, the BOZ literal constant is converted to an 'INTEGER' value with 2995the largest decimal representation. This value is then converted 2996numerically to the type and kind of the variable in question. (For 2997instance, 'real :: r = b'0000001' + 1' initializes 'r' with '2.0'.) As 2998different compilers implement the extension differently, one should be 2999careful when doing bitwise initialization of non-integer variables. 3000 3001 Note that initializing an 'INTEGER' variable with a statement such as 3002'DATA i/Z'FFFFFFFF'/' will give an integer overflow error rather than 3003the desired result of -1 when 'i' is a 32-bit integer on a system that 3004supports 64-bit integers. The '-fno-range-check' option can be used as 3005a workaround for legacy code that initializes integers in this manner. 3006 3007 3008File: gfortran.info, Node: Real array indices, Next: Unary operators, Prev: BOZ literal constants, Up: Extensions implemented in GNU Fortran 3009 30106.1.10 Real array indices 3011------------------------- 3012 3013As an extension, GNU Fortran allows the use of 'REAL' expressions or 3014variables as array indices. 3015 3016 3017File: gfortran.info, Node: Unary operators, Next: Implicitly convert LOGICAL and INTEGER values, Prev: Real array indices, Up: Extensions implemented in GNU Fortran 3018 30196.1.11 Unary operators 3020---------------------- 3021 3022As an extension, GNU Fortran allows unary plus and unary minus operators 3023to appear as the second operand of binary arithmetic operators without 3024the need for parenthesis. 3025 3026 X = Y * -Z 3027 3028 3029File: gfortran.info, Node: Implicitly convert LOGICAL and INTEGER values, Next: Hollerith constants support, Prev: Unary operators, Up: Extensions implemented in GNU Fortran 3030 30316.1.12 Implicitly convert 'LOGICAL' and 'INTEGER' values 3032-------------------------------------------------------- 3033 3034As an extension for backwards compatibility with other compilers, GNU 3035Fortran allows the implicit conversion of 'LOGICAL' values to 'INTEGER' 3036values and vice versa. When converting from a 'LOGICAL' to an 3037'INTEGER', '.FALSE.' is interpreted as zero, and '.TRUE.' is interpreted 3038as one. When converting from 'INTEGER' to 'LOGICAL', the value zero is 3039interpreted as '.FALSE.' and any nonzero value is interpreted as 3040'.TRUE.'. 3041 3042 LOGICAL :: l 3043 l = 1 3044 INTEGER :: i 3045 i = .TRUE. 3046 3047 However, there is no implicit conversion of 'INTEGER' values in 3048'if'-statements, nor of 'LOGICAL' or 'INTEGER' values in I/O operations. 3049 3050 3051File: gfortran.info, Node: Hollerith constants support, Next: Cray pointers, Prev: Implicitly convert LOGICAL and INTEGER values, Up: Extensions implemented in GNU Fortran 3052 30536.1.13 Hollerith constants support 3054---------------------------------- 3055 3056GNU Fortran supports Hollerith constants in assignments, function 3057arguments, and 'DATA' and 'ASSIGN' statements. A Hollerith constant is 3058written as a string of characters preceded by an integer constant 3059indicating the character count, and the letter 'H' or 'h', and stored in 3060bytewise fashion in a numeric ('INTEGER', 'REAL', or 'complex') or 3061'LOGICAL' variable. The constant will be padded or truncated to fit the 3062size of the variable in which it is stored. 3063 3064 Examples of valid uses of Hollerith constants: 3065 complex*16 x(2) 3066 data x /16Habcdefghijklmnop, 16Hqrstuvwxyz012345/ 3067 x(1) = 16HABCDEFGHIJKLMNOP 3068 call foo (4h abc) 3069 3070 Invalid Hollerith constants examples: 3071 integer*4 a 3072 a = 8H12345678 ! Valid, but the Hollerith constant will be truncated. 3073 a = 0H ! At least one character is needed. 3074 3075 In general, Hollerith constants were used to provide a rudimentary 3076facility for handling character strings in early Fortran compilers, 3077prior to the introduction of 'CHARACTER' variables in Fortran 77; in 3078those cases, the standard-compliant equivalent is to convert the program 3079to use proper character strings. On occasion, there may be a case where 3080the intent is specifically to initialize a numeric variable with a given 3081byte sequence. In these cases, the same result can be obtained by using 3082the 'TRANSFER' statement, as in this example. 3083 INTEGER(KIND=4) :: a 3084 a = TRANSFER ("abcd", a) ! equivalent to: a = 4Habcd 3085 3086 3087File: gfortran.info, Node: Cray pointers, Next: CONVERT specifier, Prev: Hollerith constants support, Up: Extensions implemented in GNU Fortran 3088 30896.1.14 Cray pointers 3090-------------------- 3091 3092Cray pointers are part of a non-standard extension that provides a 3093C-like pointer in Fortran. This is accomplished through a pair of 3094variables: an integer "pointer" that holds a memory address, and a 3095"pointee" that is used to dereference the pointer. 3096 3097 Pointer/pointee pairs are declared in statements of the form: 3098 pointer ( <pointer> , <pointee> ) 3099 or, 3100 pointer ( <pointer1> , <pointee1> ), ( <pointer2> , <pointee2> ), ... 3101 The pointer is an integer that is intended to hold a memory address. 3102The pointee may be an array or scalar. A pointee can be an assumed size 3103array--that is, the last dimension may be left unspecified by using a 3104'*' in place of a value--but a pointee cannot be an assumed shape array. 3105No space is allocated for the pointee. 3106 3107 The pointee may have its type declared before or after the pointer 3108statement, and its array specification (if any) may be declared before, 3109during, or after the pointer statement. The pointer may be declared as 3110an integer prior to the pointer statement. However, some machines have 3111default integer sizes that are different than the size of a pointer, and 3112so the following code is not portable: 3113 integer ipt 3114 pointer (ipt, iarr) 3115 If a pointer is declared with a kind that is too small, the compiler 3116will issue a warning; the resulting binary will probably not work 3117correctly, because the memory addresses stored in the pointers may be 3118truncated. It is safer to omit the first line of the above example; if 3119explicit declaration of ipt's type is omitted, then the compiler will 3120ensure that ipt is an integer variable large enough to hold a pointer. 3121 3122 Pointer arithmetic is valid with Cray pointers, but it is not the 3123same as C pointer arithmetic. Cray pointers are just ordinary integers, 3124so the user is responsible for determining how many bytes to add to a 3125pointer in order to increment it. Consider the following example: 3126 real target(10) 3127 real pointee(10) 3128 pointer (ipt, pointee) 3129 ipt = loc (target) 3130 ipt = ipt + 1 3131 The last statement does not set 'ipt' to the address of 'target(1)', 3132as it would in C pointer arithmetic. Adding '1' to 'ipt' just adds one 3133byte to the address stored in 'ipt'. 3134 3135 Any expression involving the pointee will be translated to use the 3136value stored in the pointer as the base address. 3137 3138 To get the address of elements, this extension provides an intrinsic 3139function 'LOC()'. The 'LOC()' function is equivalent to the '&' 3140operator in C, except the address is cast to an integer type: 3141 real ar(10) 3142 pointer(ipt, arpte(10)) 3143 real arpte 3144 ipt = loc(ar) ! Makes arpte is an alias for ar 3145 arpte(1) = 1.0 ! Sets ar(1) to 1.0 3146 The pointer can also be set by a call to the 'MALLOC' intrinsic (see 3147*note MALLOC::). 3148 3149 Cray pointees often are used to alias an existing variable. For 3150example: 3151 integer target(10) 3152 integer iarr(10) 3153 pointer (ipt, iarr) 3154 ipt = loc(target) 3155 As long as 'ipt' remains unchanged, 'iarr' is now an alias for 3156'target'. The optimizer, however, will not detect this aliasing, so it 3157is unsafe to use 'iarr' and 'target' simultaneously. Using a pointee in 3158any way that violates the Fortran aliasing rules or assumptions is 3159illegal. It is the user's responsibility to avoid doing this; the 3160compiler works under the assumption that no such aliasing occurs. 3161 3162 Cray pointers will work correctly when there is no aliasing (i.e., 3163when they are used to access a dynamically allocated block of memory), 3164and also in any routine where a pointee is used, but any variable with 3165which it shares storage is not used. Code that violates these rules may 3166not run as the user intends. This is not a bug in the optimizer; any 3167code that violates the aliasing rules is illegal. (Note that this is 3168not unique to GNU Fortran; any Fortran compiler that supports Cray 3169pointers will "incorrectly" optimize code with illegal aliasing.) 3170 3171 There are a number of restrictions on the attributes that can be 3172applied to Cray pointers and pointees. Pointees may not have the 3173'ALLOCATABLE', 'INTENT', 'OPTIONAL', 'DUMMY', 'TARGET', 'INTRINSIC', or 3174'POINTER' attributes. Pointers may not have the 'DIMENSION', 'POINTER', 3175'TARGET', 'ALLOCATABLE', 'EXTERNAL', or 'INTRINSIC' attributes, nor may 3176they be function results. Pointees may not occur in more than one 3177pointer statement. A pointee cannot be a pointer. Pointees cannot 3178occur in equivalence, common, or data statements. 3179 3180 A Cray pointer may also point to a function or a subroutine. For 3181example, the following excerpt is valid: 3182 implicit none 3183 external sub 3184 pointer (subptr,subpte) 3185 external subpte 3186 subptr = loc(sub) 3187 call subpte() 3188 [...] 3189 subroutine sub 3190 [...] 3191 end subroutine sub 3192 3193 A pointer may be modified during the course of a program, and this 3194will change the location to which the pointee refers. However, when 3195pointees are passed as arguments, they are treated as ordinary variables 3196in the invoked function. Subsequent changes to the pointer will not 3197change the base address of the array that was passed. 3198 3199 3200File: gfortran.info, Node: CONVERT specifier, Next: OpenMP, Prev: Cray pointers, Up: Extensions implemented in GNU Fortran 3201 32026.1.15 'CONVERT' specifier 3203-------------------------- 3204 3205GNU Fortran allows the conversion of unformatted data between little- 3206and big-endian representation to facilitate moving of data between 3207different systems. The conversion can be indicated with the 'CONVERT' 3208specifier on the 'OPEN' statement. *Note GFORTRAN_CONVERT_UNIT::, for 3209an alternative way of specifying the data format via an environment 3210variable. 3211 3212 Valid values for 'CONVERT' are: 3213 'CONVERT='NATIVE'' Use the native format. This is the default. 3214 'CONVERT='SWAP'' Swap between little- and big-endian. 3215 'CONVERT='LITTLE_ENDIAN'' Use the little-endian representation for 3216 unformatted files. 3217 'CONVERT='BIG_ENDIAN'' Use the big-endian representation for 3218 unformatted files. 3219 3220 Using the option could look like this: 3221 open(file='big.dat',form='unformatted',access='sequential', & 3222 convert='big_endian') 3223 3224 The value of the conversion can be queried by using 3225'INQUIRE(CONVERT=ch)'. The values returned are ''BIG_ENDIAN'' and 3226''LITTLE_ENDIAN''. 3227 3228 'CONVERT' works between big- and little-endian for 'INTEGER' values 3229of all supported kinds and for 'REAL' on IEEE systems of kinds 4 and 8. 3230Conversion between different "extended double" types on different 3231architectures such as m68k and x86_64, which GNU Fortran supports as 3232'REAL(KIND=10)' and 'REAL(KIND=16)', will probably not work. 3233 3234 _Note that the values specified via the GFORTRAN_CONVERT_UNIT 3235environment variable will override the CONVERT specifier in the open 3236statement_. This is to give control over data formats to users who do 3237not have the source code of their program available. 3238 3239 Using anything but the native representation for unformatted data 3240carries a significant speed overhead. If speed in this area matters to 3241you, it is best if you use this only for data that needs to be portable. 3242 3243 3244File: gfortran.info, Node: OpenMP, Next: OpenACC, Prev: CONVERT specifier, Up: Extensions implemented in GNU Fortran 3245 32466.1.16 OpenMP 3247------------- 3248 3249OpenMP (Open Multi-Processing) is an application programming interface 3250(API) that supports multi-platform shared memory multiprocessing 3251programming in C/C++ and Fortran on many architectures, including Unix 3252and Microsoft Windows platforms. It consists of a set of compiler 3253directives, library routines, and environment variables that influence 3254run-time behavior. 3255 3256 GNU Fortran strives to be compatible to the OpenMP Application 3257Program Interface v4.5 (http://openmp.org/wp/openmp-specifications/). 3258 3259 To enable the processing of the OpenMP directive '!$omp' in free-form 3260source code; the 'c$omp', '*$omp' and '!$omp' directives in fixed form; 3261the '!$' conditional compilation sentinels in free form; and the 'c$', 3262'*$' and '!$' sentinels in fixed form, 'gfortran' needs to be invoked 3263with the '-fopenmp'. This also arranges for automatic linking of the 3264GNU Offloading and Multi Processing Runtime Library *note libgomp: 3265(libgomp)Top. 3266 3267 The OpenMP Fortran runtime library routines are provided both in a 3268form of a Fortran 90 module named 'omp_lib' and in a form of a Fortran 3269'include' file named 'omp_lib.h'. 3270 3271 An example of a parallelized loop taken from Appendix A.1 of the 3272OpenMP Application Program Interface v2.5: 3273 SUBROUTINE A1(N, A, B) 3274 INTEGER I, N 3275 REAL B(N), A(N) 3276 !$OMP PARALLEL DO !I is private by default 3277 DO I=2,N 3278 B(I) = (A(I) + A(I-1)) / 2.0 3279 ENDDO 3280 !$OMP END PARALLEL DO 3281 END SUBROUTINE A1 3282 3283 Please note: 3284 * '-fopenmp' implies '-frecursive', i.e., all local arrays will be 3285 allocated on the stack. When porting existing code to OpenMP, this 3286 may lead to surprising results, especially to segmentation faults 3287 if the stacksize is limited. 3288 3289 * On glibc-based systems, OpenMP enabled applications cannot be 3290 statically linked due to limitations of the underlying 3291 pthreads-implementation. It might be possible to get a working 3292 solution if '-Wl,--whole-archive -lpthread -Wl,--no-whole-archive' 3293 is added to the command line. However, this is not supported by 3294 'gcc' and thus not recommended. 3295 3296 3297File: gfortran.info, Node: OpenACC, Next: Argument list functions, Prev: OpenMP, Up: Extensions implemented in GNU Fortran 3298 32996.1.17 OpenACC 3300-------------- 3301 3302OpenACC is an application programming interface (API) that supports 3303offloading of code to accelerator devices. It consists of a set of 3304compiler directives, library routines, and environment variables that 3305influence run-time behavior. 3306 3307 GNU Fortran strives to be compatible to the OpenACC Application 3308Programming Interface v2.0 (http://www.openacc.org/). 3309 3310 To enable the processing of the OpenACC directive '!$acc' in 3311free-form source code; the 'c$acc', '*$acc' and '!$acc' directives in 3312fixed form; the '!$' conditional compilation sentinels in free form; and 3313the 'c$', '*$' and '!$' sentinels in fixed form, 'gfortran' needs to be 3314invoked with the '-fopenacc'. This also arranges for automatic linking 3315of the GNU Offloading and Multi Processing Runtime Library *note 3316libgomp: (libgomp)Top. 3317 3318 The OpenACC Fortran runtime library routines are provided both in a 3319form of a Fortran 90 module named 'openacc' and in a form of a Fortran 3320'include' file named 'openacc_lib.h'. 3321 3322 Note that this is an experimental feature, incomplete, and subject to 3323change in future versions of GCC. See <https://gcc.gnu.org/wiki/OpenACC> 3324for more information. 3325 3326 3327File: gfortran.info, Node: Argument list functions, Next: Read/Write after EOF marker, Prev: OpenACC, Up: Extensions implemented in GNU Fortran 3328 33296.1.18 Argument list functions '%VAL', '%REF' and '%LOC' 3330-------------------------------------------------------- 3331 3332GNU Fortran supports argument list functions '%VAL', '%REF' and '%LOC' 3333statements, for backward compatibility with g77. It is recommended that 3334these should be used only for code that is accessing facilities outside 3335of GNU Fortran, such as operating system or windowing facilities. It is 3336best to constrain such uses to isolated portions of a program-portions 3337that deal specifically and exclusively with low-level, system-dependent 3338facilities. Such portions might well provide a portable interface for 3339use by the program as a whole, but are themselves not portable, and 3340should be thoroughly tested each time they are rebuilt using a new 3341compiler or version of a compiler. 3342 3343 '%VAL' passes a scalar argument by value, '%REF' passes it by 3344reference and '%LOC' passes its memory location. Since gfortran already 3345passes scalar arguments by reference, '%REF' is in effect a do-nothing. 3346'%LOC' has the same effect as a Fortran pointer. 3347 3348 An example of passing an argument by value to a C subroutine foo.: 3349 C 3350 C prototype void foo_ (float x); 3351 C 3352 external foo 3353 real*4 x 3354 x = 3.14159 3355 call foo (%VAL (x)) 3356 end 3357 3358 For details refer to the g77 manual 3359<https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/index.html#Top>. 3360 3361 Also, 'c_by_val.f' and its partner 'c_by_val.c' of the GNU Fortran 3362testsuite are worth a look. 3363 3364 3365File: gfortran.info, Node: Read/Write after EOF marker, Next: STRUCTURE and RECORD, Prev: Argument list functions, Up: Extensions implemented in GNU Fortran 3366 33676.1.19 Read/Write after EOF marker 3368---------------------------------- 3369 3370Some legacy codes rely on allowing 'READ' or 'WRITE' after the EOF file 3371marker in order to find the end of a file. GNU Fortran normally rejects 3372these codes with a run-time error message and suggests the user consider 3373'BACKSPACE' or 'REWIND' to properly position the file before the EOF 3374marker. As an extension, the run-time error may be disabled using 3375-std=legacy. 3376 3377 3378File: gfortran.info, Node: STRUCTURE and RECORD, Next: UNION and MAP, Prev: Read/Write after EOF marker, Up: Extensions implemented in GNU Fortran 3379 33806.1.20 'STRUCTURE' and 'RECORD' 3381------------------------------- 3382 3383Record structures are a pre-Fortran-90 vendor extension to create 3384user-defined aggregate data types. Support for record structures in GNU 3385Fortran can be enabled with the '-fdec-structure' compile flag. If you 3386have a choice, you should instead use Fortran 90's "derived types", 3387which have a different syntax. 3388 3389 In many cases, record structures can easily be converted to derived 3390types. To convert, replace 'STRUCTURE /'STRUCTURE-NAME'/' by 'TYPE' 3391TYPE-NAME. Additionally, replace 'RECORD /'STRUCTURE-NAME'/' by 3392'TYPE('TYPE-NAME')'. Finally, in the component access, replace the 3393period ('.') by the percent sign ('%'). 3394 3395 Here is an example of code using the non portable record structure 3396syntax: 3397 3398 ! Declaring a structure named ``item'' and containing three fields: 3399 ! an integer ID, an description string and a floating-point price. 3400 STRUCTURE /item/ 3401 INTEGER id 3402 CHARACTER(LEN=200) description 3403 REAL price 3404 END STRUCTURE 3405 3406 ! Define two variables, an single record of type ``item'' 3407 ! named ``pear'', and an array of items named ``store_catalog'' 3408 RECORD /item/ pear, store_catalog(100) 3409 3410 ! We can directly access the fields of both variables 3411 pear.id = 92316 3412 pear.description = "juicy D'Anjou pear" 3413 pear.price = 0.15 3414 store_catalog(7).id = 7831 3415 store_catalog(7).description = "milk bottle" 3416 store_catalog(7).price = 1.2 3417 3418 ! We can also manipulate the whole structure 3419 store_catalog(12) = pear 3420 print *, store_catalog(12) 3421 3422This code can easily be rewritten in the Fortran 90 syntax as following: 3423 3424 ! ``STRUCTURE /name/ ... END STRUCTURE'' becomes 3425 ! ``TYPE name ... END TYPE'' 3426 TYPE item 3427 INTEGER id 3428 CHARACTER(LEN=200) description 3429 REAL price 3430 END TYPE 3431 3432 ! ``RECORD /name/ variable'' becomes ``TYPE(name) variable'' 3433 TYPE(item) pear, store_catalog(100) 3434 3435 ! Instead of using a dot (.) to access fields of a record, the 3436 ! standard syntax uses a percent sign (%) 3437 pear%id = 92316 3438 pear%description = "juicy D'Anjou pear" 3439 pear%price = 0.15 3440 store_catalog(7)%id = 7831 3441 store_catalog(7)%description = "milk bottle" 3442 store_catalog(7)%price = 1.2 3443 3444 ! Assignments of a whole variable do not change 3445 store_catalog(12) = pear 3446 print *, store_catalog(12) 3447 3448GNU Fortran implements STRUCTURES like derived types with the following 3449rules and exceptions: 3450 3451 * Structures act like derived types with the 'SEQUENCE' attribute. 3452 Otherwise they may contain no specifiers. 3453 3454 * Structures may contain a special field with the name '%FILL'. This 3455 will create an anonymous component which cannot be accessed but 3456 occupies space just as if a component of the same type was declared 3457 in its place, useful for alignment purposes. As an example, the 3458 following structure will consist of at least sixteen bytes: 3459 3460 structure /padded/ 3461 character(4) start 3462 character(8) %FILL 3463 character(4) end 3464 end structure 3465 3466 * Structures may share names with other symbols. For example, the 3467 following is invalid for derived types, but valid for structures: 3468 3469 structure /header/ 3470 ! ... 3471 end structure 3472 record /header/ header 3473 3474 * Structure types may be declared nested within another parent 3475 structure. The syntax is: 3476 structure /type-name/ 3477 ... 3478 structure [/<type-name>/] <field-list> 3479 ... 3480 3481 The type name may be ommitted, in which case the structure type 3482 itself is anonymous, and other structures of the same type cannot 3483 be instantiated. The following shows some examples: 3484 3485 structure /appointment/ 3486 ! nested structure definition: app_time is an array of two 'time' 3487 structure /time/ app_time (2) 3488 integer(1) hour, minute 3489 end structure 3490 character(10) memo 3491 end structure 3492 3493 ! The 'time' structure is still usable 3494 record /time/ now 3495 now = time(5, 30) 3496 3497 ... 3498 3499 structure /appointment/ 3500 ! anonymous nested structure definition 3501 structure start, end 3502 integer(1) hour, minute 3503 end structure 3504 character(10) memo 3505 end structure 3506 3507 * Structures may contain 'UNION' blocks. For more detail see the 3508 section on *note UNION and MAP::. 3509 3510 * Structures support old-style initialization of components, like 3511 those described in *note Old-style variable initialization::. For 3512 array initializers, an initializer may contain a repeat 3513 specification of the form '<literal-integer> * 3514 <constant-initializer>'. The value of the integer indicates the 3515 number of times to repeat the constant initializer when expanding 3516 the initializer list. 3517 3518 3519File: gfortran.info, Node: UNION and MAP, Next: Type variants for integer intrinsics, Prev: STRUCTURE and RECORD, Up: Extensions implemented in GNU Fortran 3520 35216.1.21 'UNION' and 'MAP' 3522------------------------ 3523 3524Unions are an old vendor extension which were commonly used with the 3525non-standard *note STRUCTURE and RECORD:: extensions. Use of 'UNION' 3526and 'MAP' is automatically enabled with '-fdec-structure'. 3527 3528 A 'UNION' declaration occurs within a structure; within the 3529definition of each union is a number of 'MAP' blocks. Each 'MAP' shares 3530storage with its sibling maps (in the same union), and the size of the 3531union is the size of the largest map within it, just as with unions in 3532C. The major difference is that component references do not indicate 3533which union or map the component is in (the compiler gets to figure that 3534out). 3535 3536 Here is a small example: 3537 structure /myunion/ 3538 union 3539 map 3540 character(2) w0, w1, w2 3541 end map 3542 map 3543 character(6) long 3544 end map 3545 end union 3546 end structure 3547 3548 record /myunion/ rec 3549 ! After this assignment... 3550 rec.long = 'hello!' 3551 3552 ! The following is true: 3553 ! rec.w0 === 'he' 3554 ! rec.w1 === 'll' 3555 ! rec.w2 === 'o!' 3556 3557 The two maps share memory, and the size of the union is ultimately 3558six bytes: 3559 3560 0 1 2 3 4 5 6 Byte offset 3561 ------------------------------- 3562 | | | | | | | 3563 ------------------------------- 3564 3565 ^ W0 ^ W1 ^ W2 ^ 3566 \-------/ \-------/ \-------/ 3567 3568 ^ LONG ^ 3569 \---------------------------/ 3570 3571 Following is an example mirroring the layout of an Intel x86_64 3572register: 3573 3574 structure /reg/ 3575 union ! U0 ! rax 3576 map 3577 character(16) rx 3578 end map 3579 map 3580 character(8) rh ! rah 3581 union ! U1 3582 map 3583 character(8) rl ! ral 3584 end map 3585 map 3586 character(8) ex ! eax 3587 end map 3588 map 3589 character(4) eh ! eah 3590 union ! U2 3591 map 3592 character(4) el ! eal 3593 end map 3594 map 3595 character(4) x ! ax 3596 end map 3597 map 3598 character(2) h ! ah 3599 character(2) l ! al 3600 end map 3601 end union 3602 end map 3603 end union 3604 end map 3605 end union 3606 end structure 3607 record /reg/ a 3608 3609 ! After this assignment... 3610 a.rx = 'AAAAAAAA.BBB.C.D' 3611 3612 ! The following is true: 3613 a.rx === 'AAAAAAAA.BBB.C.D' 3614 a.rh === 'AAAAAAAA' 3615 a.rl === '.BBB.C.D' 3616 a.ex === '.BBB.C.D' 3617 a.eh === '.BBB' 3618 a.el === '.C.D' 3619 a.x === '.C.D' 3620 a.h === '.C' 3621 a.l === '.D' 3622 3623 3624File: gfortran.info, Node: Type variants for integer intrinsics, Next: AUTOMATIC and STATIC attributes, Prev: UNION and MAP, Up: Extensions implemented in GNU Fortran 3625 36266.1.22 Type variants for integer intrinsics 3627------------------------------------------- 3628 3629Similar to the D/C prefixes to real functions to specify the 3630input/output types, GNU Fortran offers B/I/J/K prefixes to integer 3631functions for compatibility with DEC programs. The types implied by 3632each are: 3633 3634 B - INTEGER(kind=1) 3635 I - INTEGER(kind=2) 3636 J - INTEGER(kind=4) 3637 K - INTEGER(kind=8) 3638 3639 GNU Fortran supports these with the flag '-fdec-intrinsic-ints'. 3640Intrinsics for which prefixed versions are available and in what form 3641are noted in *note Intrinsic Procedures::. The complete list of 3642supported intrinsics is here: 3643 3644Intrinsic B I J K 3645 3646--------------------------------------------------------------------------- 3647'*note ABS::' 'BABS' 'IIABS' 'JIABS' 'KIABS' 3648'*note BTEST::''BBTEST' 'BITEST' 'BJTEST' 'BKTEST' 3649'*note IAND::' 'BIAND' 'IIAND' 'JIAND' 'KIAND' 3650'*note IBCLR::''BBCLR' 'IIBCLR' 'JIBCLR' 'KIBCLR' 3651'*note IBITS::''BBITS' 'IIBITS' 'JIBITS' 'KIBITS' 3652'*note IBSET::''BBSET' 'IIBSET' 'JIBSET' 'KIBSET' 3653'*note IEOR::' 'BIEOR' 'IIEOR' 'JIEOR' 'KIEOR' 3654'*note IOR::' 'BIOR' 'IIOR' 'JIOR' 'KIOR' 3655'*note ISHFT::''BSHFT' 'IISHFT' 'JISHFT' 'KISHFT' 3656'*note ISHFTC::''BSHFTC' 'IISHFTC' 'JISHFTC' 'KISHFTC' 3657'*note MOD::' 'BMOD' 'IMOD' 'JMOD' 'KMOD' 3658'*note NOT::' 'BNOT' 'INOT' 'JNOT' 'KNOT' 3659'*note REAL::' '--' 'FLOATI' 'FLOATJ' 'FLOATK' 3660 3661 3662File: gfortran.info, Node: AUTOMATIC and STATIC attributes, Next: Extended math intrinsics, Prev: Type variants for integer intrinsics, Up: Extensions implemented in GNU Fortran 3663 36646.1.23 'AUTOMATIC' and 'STATIC' attributes 3665------------------------------------------ 3666 3667With '-fdec-static' GNU Fortran supports the DEC extended attributes 3668'STATIC' and 'AUTOMATIC' to provide explicit specification of entity 3669storage. These follow the syntax of the Fortran standard 'SAVE' 3670attribute. 3671 3672 'STATIC' is exactly equivalent to 'SAVE', and specifies that an 3673entity should be allocated in static memory. As an example, 'STATIC' 3674local variables will retain their values across multiple calls to a 3675function. 3676 3677 Entities marked 'AUTOMATIC' will be stack automatic whenever 3678possible. 'AUTOMATIC' is the default for local variables smaller than 3679'-fmax-stack-var-size', unless '-fno-automatic' is given. This 3680attribute overrides '-fno-automatic', '-fmax-stack-var-size', and 3681blanket 'SAVE' statements. 3682 3683 Examples: 3684 3685 subroutine f 3686 integer, automatic :: i ! automatic variable 3687 integer x, y ! static variables 3688 save 3689 ... 3690 endsubroutine 3691 subroutine f 3692 integer a, b, c, x, y, z 3693 static :: x 3694 save y 3695 automatic z, c 3696 ! a, b, c, and z are automatic 3697 ! x and y are static 3698 endsubroutine 3699 ! Compiled with -fno-automatic 3700 subroutine f 3701 integer a, b, c, d 3702 automatic :: a 3703 ! a is automatic; b, c, and d are static 3704 endsubroutine 3705 3706 3707File: gfortran.info, Node: Extended math intrinsics, Next: Form feed as whitespace, Prev: AUTOMATIC and STATIC attributes, Up: Extensions implemented in GNU Fortran 3708 37096.1.24 Extended math intrinsics 3710------------------------------- 3711 3712GNU Fortran supports an extended list of mathematical intrinsics with 3713the compile flag '-fdec-math' for compatability with legacy code. These 3714intrinsics are described fully in *note Intrinsic Procedures:: where it 3715is noted that they are extensions and should be avoided whenever 3716possible. 3717 3718 Specifically, '-fdec-math' enables the *note COTAN:: intrinsic, and 3719trigonometric intrinsics which accept or produce values in degrees 3720instead of radians. Here is a summary of the new intrinsics: 3721 3722Radians Degrees 3723-------------------------------------------------------------------------- 3724'*note ACOS::' '*note ACOSD::'* 3725'*note ASIN::' '*note ASIND::'* 3726'*note ATAN::' '*note ATAND::'* 3727'*note ATAN2::' '*note ATAN2D::'* 3728'*note COS::' '*note COSD::'* 3729'*note COTAN::'* '*note COTAND::'* 3730'*note SIN::' '*note SIND::'* 3731'*note TAN::' '*note TAND::'* 3732 3733 * Enabled with '-fdec-math'. 3734 3735 For advanced users, it may be important to know the implementation of 3736these functions. They are simply wrappers around the standard radian 3737functions, which have more accurate builtin versions. These functions 3738convert their arguments (or results) to degrees (or radians) by taking 3739the value modulus 360 (or 2*pi) and then multiplying it by a constant 3740radian-to-degree (or degree-to-radian) factor, as appropriate. The 3741factor is computed at compile-time as 180/pi (or pi/180). 3742 3743 3744File: gfortran.info, Node: Form feed as whitespace, Next: TYPE as an alias for PRINT, Prev: Extended math intrinsics, Up: Extensions implemented in GNU Fortran 3745 37466.1.25 Form feed as whitespace 3747------------------------------ 3748 3749Historically, legacy compilers allowed insertion of form feed characters 3750('\f', ASCII 0xC) at the beginning of lines for formatted output to line 3751printers, though the Fortran standard does not mention this. GNU 3752Fortran supports the interpretation of form feed characters in source as 3753whitespace for compatibility. 3754 3755 3756File: gfortran.info, Node: TYPE as an alias for PRINT, Next: %LOC as an rvalue, Prev: Form feed as whitespace, Up: Extensions implemented in GNU Fortran 3757 37586.1.26 TYPE as an alias for PRINT 3759--------------------------------- 3760 3761For compatibility, GNU Fortran will interpret 'TYPE' statements as 3762'PRINT' statements with the flag '-fdec'. With this flag asserted, the 3763following two examples are equivalent: 3764 3765 TYPE *, 'hello world' 3766 3767 PRINT *, 'hello world' 3768 3769 3770File: gfortran.info, Node: %LOC as an rvalue, Next: .XOR. operator, Prev: TYPE as an alias for PRINT, Up: Extensions implemented in GNU Fortran 3771 37726.1.27 %LOC as an rvalue 3773------------------------ 3774 3775Normally '%LOC' is allowed only in parameter lists. However the 3776intrinsic function 'LOC' does the same thing, and is usable as the 3777right-hand-side of assignments. For compatibility, GNU Fortran supports 3778the use of '%LOC' as an alias for the builtin 'LOC' with '-std=legacy'. 3779With this feature enabled the following two examples are equivalent: 3780 3781 integer :: i, l 3782 l = %loc(i) 3783 call sub(l) 3784 3785 integer :: i 3786 call sub(%loc(i)) 3787 3788 3789File: gfortran.info, Node: .XOR. operator, Next: Bitwise logical operators, Prev: %LOC as an rvalue, Up: Extensions implemented in GNU Fortran 3790 37916.1.28 .XOR. operator 3792--------------------- 3793 3794GNU Fortran supports '.XOR.' as a logical operator with '-std=legacy' 3795for compatibility with legacy code. '.XOR.' is equivalent to '.NEQV.'. 3796That is, the output is true if and only if the inputs differ. 3797 3798 3799File: gfortran.info, Node: Bitwise logical operators, Next: Extended I/O specifiers, Prev: .XOR. operator, Up: Extensions implemented in GNU Fortran 3800 38016.1.29 Bitwise logical operators 3802-------------------------------- 3803 3804With '-fdec', GNU Fortran relaxes the type constraints on logical 3805operators to allow integer operands, and performs the corresponding 3806bitwise operation instead. This flag is for compatibility only, and 3807should be avoided in new code. Consider: 3808 3809 INTEGER :: i, j 3810 i = z'33' 3811 j = z'cc' 3812 print *, i .AND. j 3813 3814 In this example, compiled with '-fdec', GNU Fortran will replace the 3815'.AND.' operation with a call to the intrinsic '*note IAND::' function, 3816yielding the bitwise-and of 'i' and 'j'. 3817 3818 Note that this conversion will occur if at least one operand is of 3819integral type. As a result, a logical operand will be converted to an 3820integer when the other operand is an integer in a logical operation. In 3821this case, '.TRUE.' is converted to '1' and '.FALSE.' to '0'. 3822 3823 Here is the mapping of logical operator to bitwise intrinsic used 3824with '-fdec': 3825 3826Operator Intrinsic Bitwise operation 3827--------------------------------------------------------------------------- 3828'.NOT.' '*note NOT::' complement 3829'.AND.' '*note IAND::' intersection 3830'.OR.' '*note IOR::' union 3831'.NEQV.' '*note IEOR::' exclusive or 3832'.EQV.' '*note NOT::(*note IEOR::)'complement of exclusive or 3833 3834 3835File: gfortran.info, Node: Extended I/O specifiers, Next: Legacy PARAMETER statements, Prev: Bitwise logical operators, Up: Extensions implemented in GNU Fortran 3836 38376.1.30 Extended I/O specifiers 3838------------------------------ 3839 3840GNU Fortran supports the additional legacy I/O specifiers 3841'CARRIAGECONTROL', 'READONLY', and 'SHARE' with the compile flag 3842'-fdec', for compatibility. 3843 3844'CARRIAGECONTROL' 3845 The 'CARRIAGECONTROL' specifier allows a user to control line 3846 termination settings between output records for an I/O unit. The 3847 specifier has no meaning for readonly files. When 3848 'CARRAIGECONTROL' is specified upon opening a unit for formatted 3849 writing, the exact 'CARRIAGECONTROL' setting determines what 3850 characters to write between output records. The syntax is: 3851 3852 OPEN(..., CARRIAGECONTROL=cc) 3853 3854 Where _cc_ is a character expression that evaluates to one of the 3855 following values: 3856 3857 ''LIST'' One line feed between records (default) 3858 ''FORTRAN'' Legacy interpretation of the first character (see below) 3859 ''NONE'' No separator between records 3860 3861 With 'CARRIAGECONTROL='FORTRAN'', when a record is written, the 3862 first character of the input record is not written, and instead 3863 determines the output record separator as follows: 3864 3865 Leading character Meaning Output separating 3866 character(s) 3867 ---------------------------------------------------------------------------- 3868 ''+'' Overprinting Carriage return only 3869 ''-'' New line Line feed and carriage 3870 return 3871 ''0'' Skip line Two line feeds and carriage 3872 return 3873 ''1'' New page Form feed and carriage 3874 return 3875 ''$'' Prompting Line feed (no carriage 3876 return) 3877 'CHAR(0)' Overprinting (no None 3878 advance) 3879 3880'READONLY' 3881 The 'READONLY' specifier may be given upon opening a unit, and is 3882 equivalent to specifying 'ACTION='READ'', except that the file may 3883 not be deleted on close (i.e. 'CLOSE' with 'STATUS="DELETE"'). 3884 The syntax is: 3885 3886 OPEN(..., READONLY) 3887 3888'SHARE' 3889 The 'SHARE' specifier allows system-level locking on a unit upon 3890 opening it for controlled access from multiple processes/threads. 3891 The 'SHARE' specifier has several forms: 3892 3893 OPEN(..., SHARE=sh) 3894 OPEN(..., SHARED) 3895 OPEN(..., NOSHARED) 3896 3897 Where _sh_ in the first form is a character expression that 3898 evaluates to a value as seen in the table below. The latter two 3899 forms are aliases for particular values of _sh_: 3900 3901 Explicit form Short form Meaning 3902 ---------------------------------------------------------------------------- 3903 'SHARE='DENYRW'' 'NOSHARED' Exclusive (write) lock 3904 'SHARE='DENYNONE'' 'SHARED' Shared (read) lock 3905 3906 In general only one process may hold an exclusive (write) lock for 3907 a given file at a time, whereas many processes may hold shared 3908 (read) locks for the same file. 3909 3910 The behavior of locking may vary with your operating system. On 3911 POSIX systems, locking is implemented with 'fcntl'. Consult your 3912 corresponding operating system's manual pages for further details. 3913 Locking via 'SHARE=' is not supported on other systems. 3914 3915 3916File: gfortran.info, Node: Legacy PARAMETER statements, Next: Default exponents, Prev: Extended I/O specifiers, Up: Extensions implemented in GNU Fortran 3917 39186.1.31 Legacy PARAMETER statements 3919---------------------------------- 3920 3921For compatibility, GNU Fortran supports legacy PARAMETER statements 3922without parentheses with '-std=legacy'. A warning is emitted if used 3923with '-std=gnu', and an error is acknowledged with a real Fortran 3924standard flag ('-std=f95', etc...). These statements take the following 3925form: 3926 3927 implicit real (E) 3928 parameter e = 2.718282 3929 real c 3930 parameter c = 3.0e8 3931 3932 3933File: gfortran.info, Node: Default exponents, Prev: Legacy PARAMETER statements, Up: Extensions implemented in GNU Fortran 3934 39356.1.32 Default exponents 3936------------------------ 3937 3938For compatibility, GNU Fortran supports a default exponent of zero in 3939real constants with '-fdec'. For example, '9e' would be interpreted as 3940'9e0', rather than an error. 3941 3942 3943File: gfortran.info, Node: Extensions not implemented in GNU Fortran, Prev: Extensions implemented in GNU Fortran, Up: Extensions 3944 39456.2 Extensions not implemented in GNU Fortran 3946============================================= 3947 3948The long history of the Fortran language, its wide use and broad 3949userbase, the large number of different compiler vendors and the lack of 3950some features crucial to users in the first standards have lead to the 3951existence of a number of important extensions to the language. While 3952some of the most useful or popular extensions are supported by the GNU 3953Fortran compiler, not all existing extensions are supported. This 3954section aims at listing these extensions and offering advice on how best 3955make code that uses them running with the GNU Fortran compiler. 3956 3957* Menu: 3958 3959* ENCODE and DECODE statements:: 3960* Variable FORMAT expressions:: 3961* Alternate complex function syntax:: 3962* Volatile COMMON blocks:: 3963* OPEN( ... NAME=):: 3964 3965 3966File: gfortran.info, Node: ENCODE and DECODE statements, Next: Variable FORMAT expressions, Up: Extensions not implemented in GNU Fortran 3967 39686.2.1 'ENCODE' and 'DECODE' statements 3969-------------------------------------- 3970 3971GNU Fortran does not support the 'ENCODE' and 'DECODE' statements. 3972These statements are best replaced by 'READ' and 'WRITE' statements 3973involving internal files ('CHARACTER' variables and arrays), which have 3974been part of the Fortran standard since Fortran 77. For example, 3975replace a code fragment like 3976 3977 INTEGER*1 LINE(80) 3978 REAL A, B, C 3979 c ... Code that sets LINE 3980 DECODE (80, 9000, LINE) A, B, C 3981 9000 FORMAT (1X, 3(F10.5)) 3982 3983with the following: 3984 3985 CHARACTER(LEN=80) LINE 3986 REAL A, B, C 3987 c ... Code that sets LINE 3988 READ (UNIT=LINE, FMT=9000) A, B, C 3989 9000 FORMAT (1X, 3(F10.5)) 3990 3991 Similarly, replace a code fragment like 3992 3993 INTEGER*1 LINE(80) 3994 REAL A, B, C 3995 c ... Code that sets A, B and C 3996 ENCODE (80, 9000, LINE) A, B, C 3997 9000 FORMAT (1X, 'OUTPUT IS ', 3(F10.5)) 3998 3999with the following: 4000 4001 CHARACTER(LEN=80) LINE 4002 REAL A, B, C 4003 c ... Code that sets A, B and C 4004 WRITE (UNIT=LINE, FMT=9000) A, B, C 4005 9000 FORMAT (1X, 'OUTPUT IS ', 3(F10.5)) 4006 4007 4008File: gfortran.info, Node: Variable FORMAT expressions, Next: Alternate complex function syntax, Prev: ENCODE and DECODE statements, Up: Extensions not implemented in GNU Fortran 4009 40106.2.2 Variable 'FORMAT' expressions 4011----------------------------------- 4012 4013A variable 'FORMAT' expression is format statement which includes angle 4014brackets enclosing a Fortran expression: 'FORMAT(I<N>)'. GNU Fortran 4015does not support this legacy extension. The effect of variable format 4016expressions can be reproduced by using the more powerful (and standard) 4017combination of internal output and string formats. For example, replace 4018a code fragment like this: 4019 4020 WRITE(6,20) INT1 4021 20 FORMAT(I<N+1>) 4022 4023with the following: 4024 4025 c Variable declaration 4026 CHARACTER(LEN=20) FMT 4027 c 4028 c Other code here... 4029 c 4030 WRITE(FMT,'("(I", I0, ")")') N+1 4031 WRITE(6,FMT) INT1 4032 4033or with: 4034 4035 c Variable declaration 4036 CHARACTER(LEN=20) FMT 4037 c 4038 c Other code here... 4039 c 4040 WRITE(FMT,*) N+1 4041 WRITE(6,"(I" // ADJUSTL(FMT) // ")") INT1 4042 4043 4044File: gfortran.info, Node: Alternate complex function syntax, Next: Volatile COMMON blocks, Prev: Variable FORMAT expressions, Up: Extensions not implemented in GNU Fortran 4045 40466.2.3 Alternate complex function syntax 4047--------------------------------------- 4048 4049Some Fortran compilers, including 'g77', let the user declare complex 4050functions with the syntax 'COMPLEX FUNCTION name*16()', as well as 4051'COMPLEX*16 FUNCTION name()'. Both are non-standard, legacy extensions. 4052'gfortran' accepts the latter form, which is more common, but not the 4053former. 4054 4055 4056File: gfortran.info, Node: Volatile COMMON blocks, Next: OPEN( ... NAME=), Prev: Alternate complex function syntax, Up: Extensions not implemented in GNU Fortran 4057 40586.2.4 Volatile 'COMMON' blocks 4059------------------------------ 4060 4061Some Fortran compilers, including 'g77', let the user declare 'COMMON' 4062with the 'VOLATILE' attribute. This is invalid standard Fortran syntax 4063and is not supported by 'gfortran'. Note that 'gfortran' accepts 4064'VOLATILE' variables in 'COMMON' blocks since revision 4.3. 4065 4066 4067File: gfortran.info, Node: OPEN( ... NAME=), Prev: Volatile COMMON blocks, Up: Extensions not implemented in GNU Fortran 4068 40696.2.5 'OPEN( ... NAME=)' 4070------------------------ 4071 4072Some Fortran compilers, including 'g77', let the user declare 'OPEN( ... 4073NAME=)'. This is invalid standard Fortran syntax and is not supported 4074by 'gfortran'. 'OPEN( ... NAME=)' should be replaced with 'OPEN( ... 4075FILE=)'. 4076 4077 4078File: gfortran.info, Node: Mixed-Language Programming, Next: Coarray Programming, Prev: Extensions, Up: Top 4079 40807 Mixed-Language Programming 4081**************************** 4082 4083* Menu: 4084 4085* Interoperability with C:: 4086* GNU Fortran Compiler Directives:: 4087* Non-Fortran Main Program:: 4088* Naming and argument-passing conventions:: 4089 4090This chapter is about mixed-language interoperability, but also applies 4091if one links Fortran code compiled by different compilers. In most 4092cases, use of the C Binding features of the Fortran 2003 standard is 4093sufficient, and their use is highly recommended. 4094 4095 4096File: gfortran.info, Node: Interoperability with C, Next: GNU Fortran Compiler Directives, Up: Mixed-Language Programming 4097 40987.1 Interoperability with C 4099=========================== 4100 4101* Menu: 4102 4103* Intrinsic Types:: 4104* Derived Types and struct:: 4105* Interoperable Global Variables:: 4106* Interoperable Subroutines and Functions:: 4107* Working with Pointers:: 4108* Further Interoperability of Fortran with C:: 4109 4110Since Fortran 2003 (ISO/IEC 1539-1:2004(E)) there is a standardized way 4111to generate procedure and derived-type declarations and global variables 4112which are interoperable with C (ISO/IEC 9899:1999). The 'bind(C)' 4113attribute has been added to inform the compiler that a symbol shall be 4114interoperable with C; also, some constraints are added. Note, however, 4115that not all C features have a Fortran equivalent or vice versa. For 4116instance, neither C's unsigned integers nor C's functions with variable 4117number of arguments have an equivalent in Fortran. 4118 4119 Note that array dimensions are reversely ordered in C and that arrays 4120in C always start with index 0 while in Fortran they start by default 4121with 1. Thus, an array declaration 'A(n,m)' in Fortran matches 4122'A[m][n]' in C and accessing the element 'A(i,j)' matches 'A[j-1][i-1]'. 4123The element following 'A(i,j)' (C: 'A[j-1][i-1]'; assuming i < n) in 4124memory is 'A(i+1,j)' (C: 'A[j-1][i]'). 4125 4126 4127File: gfortran.info, Node: Intrinsic Types, Next: Derived Types and struct, Up: Interoperability with C 4128 41297.1.1 Intrinsic Types 4130--------------------- 4131 4132In order to ensure that exactly the same variable type and kind is used 4133in C and Fortran, the named constants shall be used which are defined in 4134the 'ISO_C_BINDING' intrinsic module. That module contains named 4135constants for kind parameters and character named constants for the 4136escape sequences in C. For a list of the constants, see *note 4137ISO_C_BINDING::. 4138 4139 For logical types, please note that the Fortran standard only 4140guarantees interoperability between C99's '_Bool' and Fortran's 4141'C_Bool'-kind logicals and C99 defines that 'true' has the value 1 and 4142'false' the value 0. Using any other integer value with GNU Fortran's 4143'LOGICAL' (with any kind parameter) gives an undefined result. (Passing 4144other integer values than 0 and 1 to GCC's '_Bool' is also undefined, 4145unless the integer is explicitly or implicitly casted to '_Bool'.) 4146 4147 4148File: gfortran.info, Node: Derived Types and struct, Next: Interoperable Global Variables, Prev: Intrinsic Types, Up: Interoperability with C 4149 41507.1.2 Derived Types and struct 4151------------------------------ 4152 4153For compatibility of derived types with 'struct', one needs to use the 4154'BIND(C)' attribute in the type declaration. For instance, the 4155following type declaration 4156 4157 USE ISO_C_BINDING 4158 TYPE, BIND(C) :: myType 4159 INTEGER(C_INT) :: i1, i2 4160 INTEGER(C_SIGNED_CHAR) :: i3 4161 REAL(C_DOUBLE) :: d1 4162 COMPLEX(C_FLOAT_COMPLEX) :: c1 4163 CHARACTER(KIND=C_CHAR) :: str(5) 4164 END TYPE 4165 4166 matches the following 'struct' declaration in C 4167 4168 struct { 4169 int i1, i2; 4170 /* Note: "char" might be signed or unsigned. */ 4171 signed char i3; 4172 double d1; 4173 float _Complex c1; 4174 char str[5]; 4175 } myType; 4176 4177 Derived types with the C binding attribute shall not have the 4178'sequence' attribute, type parameters, the 'extends' attribute, nor 4179type-bound procedures. Every component must be of interoperable type 4180and kind and may not have the 'pointer' or 'allocatable' attribute. The 4181names of the components are irrelevant for interoperability. 4182 4183 As there exist no direct Fortran equivalents, neither unions nor 4184structs with bit field or variable-length array members are 4185interoperable. 4186 4187 4188File: gfortran.info, Node: Interoperable Global Variables, Next: Interoperable Subroutines and Functions, Prev: Derived Types and struct, Up: Interoperability with C 4189 41907.1.3 Interoperable Global Variables 4191------------------------------------ 4192 4193Variables can be made accessible from C using the C binding attribute, 4194optionally together with specifying a binding name. Those variables 4195have to be declared in the declaration part of a 'MODULE', be of 4196interoperable type, and have neither the 'pointer' nor the 'allocatable' 4197attribute. 4198 4199 MODULE m 4200 USE myType_module 4201 USE ISO_C_BINDING 4202 integer(C_INT), bind(C, name="_MyProject_flags") :: global_flag 4203 type(myType), bind(C) :: tp 4204 END MODULE 4205 4206 Here, '_MyProject_flags' is the case-sensitive name of the variable 4207as seen from C programs while 'global_flag' is the case-insensitive name 4208as seen from Fortran. If no binding name is specified, as for TP, the C 4209binding name is the (lowercase) Fortran binding name. If a binding name 4210is specified, only a single variable may be after the double colon. 4211Note of warning: You cannot use a global variable to access ERRNO of the 4212C library as the C standard allows it to be a macro. Use the 'IERRNO' 4213intrinsic (GNU extension) instead. 4214 4215 4216File: gfortran.info, Node: Interoperable Subroutines and Functions, Next: Working with Pointers, Prev: Interoperable Global Variables, Up: Interoperability with C 4217 42187.1.4 Interoperable Subroutines and Functions 4219--------------------------------------------- 4220 4221Subroutines and functions have to have the 'BIND(C)' attribute to be 4222compatible with C. The dummy argument declaration is relatively 4223straightforward. However, one needs to be careful because C uses 4224call-by-value by default while Fortran behaves usually similar to 4225call-by-reference. Furthermore, strings and pointers are handled 4226differently. Note that in Fortran 2003 and 2008 only explicit size and 4227assumed-size arrays are supported but not assumed-shape or 4228deferred-shape (i.e. allocatable or pointer) arrays. However, those 4229are allowed since the Technical Specification 29113, see *note Further 4230Interoperability of Fortran with C:: 4231 4232 To pass a variable by value, use the 'VALUE' attribute. Thus, the 4233following C prototype 4234 4235 int func(int i, int *j) 4236 4237 matches the Fortran declaration 4238 4239 integer(c_int) function func(i,j) 4240 use iso_c_binding, only: c_int 4241 integer(c_int), VALUE :: i 4242 integer(c_int) :: j 4243 4244 Note that pointer arguments also frequently need the 'VALUE' 4245attribute, see *note Working with Pointers::. 4246 4247 Strings are handled quite differently in C and Fortran. In C a 4248string is a 'NUL'-terminated array of characters while in Fortran each 4249string has a length associated with it and is thus not terminated (by 4250e.g. 'NUL'). For example, if one wants to use the following C 4251function, 4252 4253 #include <stdio.h> 4254 void print_C(char *string) /* equivalent: char string[] */ 4255 { 4256 printf("%s\n", string); 4257 } 4258 4259 to print "Hello World" from Fortran, one can call it using 4260 4261 use iso_c_binding, only: C_CHAR, C_NULL_CHAR 4262 interface 4263 subroutine print_c(string) bind(C, name="print_C") 4264 use iso_c_binding, only: c_char 4265 character(kind=c_char) :: string(*) 4266 end subroutine print_c 4267 end interface 4268 call print_c(C_CHAR_"Hello World"//C_NULL_CHAR) 4269 4270 As the example shows, one needs to ensure that the string is 'NUL' 4271terminated. Additionally, the dummy argument STRING of 'print_C' is a 4272length-one assumed-size array; using 'character(len=*)' is not allowed. 4273The example above uses 'c_char_"Hello World"' to ensure the string 4274literal has the right type; typically the default character kind and 4275'c_char' are the same and thus '"Hello World"' is equivalent. However, 4276the standard does not guarantee this. 4277 4278 The use of strings is now further illustrated using the C library 4279function 'strncpy', whose prototype is 4280 4281 char *strncpy(char *restrict s1, const char *restrict s2, size_t n); 4282 4283 The function 'strncpy' copies at most N characters from string S2 to 4284S1 and returns S1. In the following example, we ignore the return 4285value: 4286 4287 use iso_c_binding 4288 implicit none 4289 character(len=30) :: str,str2 4290 interface 4291 ! Ignore the return value of strncpy -> subroutine 4292 ! "restrict" is always assumed if we do not pass a pointer 4293 subroutine strncpy(dest, src, n) bind(C) 4294 import 4295 character(kind=c_char), intent(out) :: dest(*) 4296 character(kind=c_char), intent(in) :: src(*) 4297 integer(c_size_t), value, intent(in) :: n 4298 end subroutine strncpy 4299 end interface 4300 str = repeat('X',30) ! Initialize whole string with 'X' 4301 call strncpy(str, c_char_"Hello World"//C_NULL_CHAR, & 4302 len(c_char_"Hello World",kind=c_size_t)) 4303 print '(a)', str ! prints: "Hello WorldXXXXXXXXXXXXXXXXXXX" 4304 end 4305 4306 The intrinsic procedures are described in *note Intrinsic 4307Procedures::. 4308 4309 4310File: gfortran.info, Node: Working with Pointers, Next: Further Interoperability of Fortran with C, Prev: Interoperable Subroutines and Functions, Up: Interoperability with C 4311 43127.1.5 Working with Pointers 4313--------------------------- 4314 4315C pointers are represented in Fortran via the special opaque derived 4316type 'type(c_ptr)' (with private components). Thus one needs to use 4317intrinsic conversion procedures to convert from or to C pointers. 4318 4319 For some applications, using an assumed type ('TYPE(*)') can be an 4320alternative to a C pointer; see *note Further Interoperability of 4321Fortran with C::. 4322 4323 For example, 4324 4325 use iso_c_binding 4326 type(c_ptr) :: cptr1, cptr2 4327 integer, target :: array(7), scalar 4328 integer, pointer :: pa(:), ps 4329 cptr1 = c_loc(array(1)) ! The programmer needs to ensure that the 4330 ! array is contiguous if required by the C 4331 ! procedure 4332 cptr2 = c_loc(scalar) 4333 call c_f_pointer(cptr2, ps) 4334 call c_f_pointer(cptr2, pa, shape=[7]) 4335 4336 When converting C to Fortran arrays, the one-dimensional 'SHAPE' 4337argument has to be passed. 4338 4339 If a pointer is a dummy-argument of an interoperable procedure, it 4340usually has to be declared using the 'VALUE' attribute. 'void*' matches 4341'TYPE(C_PTR), VALUE', while 'TYPE(C_PTR)' alone matches 'void**'. 4342 4343 Procedure pointers are handled analogously to pointers; the C type is 4344'TYPE(C_FUNPTR)' and the intrinsic conversion procedures are 4345'C_F_PROCPOINTER' and 'C_FUNLOC'. 4346 4347 Let us consider two examples of actually passing a procedure pointer 4348from C to Fortran and vice versa. Note that these examples are also 4349very similar to passing ordinary pointers between both languages. 4350First, consider this code in C: 4351 4352 /* Procedure implemented in Fortran. */ 4353 void get_values (void (*)(double)); 4354 4355 /* Call-back routine we want called from Fortran. */ 4356 void 4357 print_it (double x) 4358 { 4359 printf ("Number is %f.\n", x); 4360 } 4361 4362 /* Call Fortran routine and pass call-back to it. */ 4363 void 4364 foobar () 4365 { 4366 get_values (&print_it); 4367 } 4368 4369 A matching implementation for 'get_values' in Fortran, that correctly 4370receives the procedure pointer from C and is able to call it, is given 4371in the following 'MODULE': 4372 4373 MODULE m 4374 IMPLICIT NONE 4375 4376 ! Define interface of call-back routine. 4377 ABSTRACT INTERFACE 4378 SUBROUTINE callback (x) 4379 USE, INTRINSIC :: ISO_C_BINDING 4380 REAL(KIND=C_DOUBLE), INTENT(IN), VALUE :: x 4381 END SUBROUTINE callback 4382 END INTERFACE 4383 4384 CONTAINS 4385 4386 ! Define C-bound procedure. 4387 SUBROUTINE get_values (cproc) BIND(C) 4388 USE, INTRINSIC :: ISO_C_BINDING 4389 TYPE(C_FUNPTR), INTENT(IN), VALUE :: cproc 4390 4391 PROCEDURE(callback), POINTER :: proc 4392 4393 ! Convert C to Fortran procedure pointer. 4394 CALL C_F_PROCPOINTER (cproc, proc) 4395 4396 ! Call it. 4397 CALL proc (1.0_C_DOUBLE) 4398 CALL proc (-42.0_C_DOUBLE) 4399 CALL proc (18.12_C_DOUBLE) 4400 END SUBROUTINE get_values 4401 4402 END MODULE m 4403 4404 Next, we want to call a C routine that expects a procedure pointer 4405argument and pass it a Fortran procedure (which clearly must be 4406interoperable!). Again, the C function may be: 4407 4408 int 4409 call_it (int (*func)(int), int arg) 4410 { 4411 return func (arg); 4412 } 4413 4414 It can be used as in the following Fortran code: 4415 4416 MODULE m 4417 USE, INTRINSIC :: ISO_C_BINDING 4418 IMPLICIT NONE 4419 4420 ! Define interface of C function. 4421 INTERFACE 4422 INTEGER(KIND=C_INT) FUNCTION call_it (func, arg) BIND(C) 4423 USE, INTRINSIC :: ISO_C_BINDING 4424 TYPE(C_FUNPTR), INTENT(IN), VALUE :: func 4425 INTEGER(KIND=C_INT), INTENT(IN), VALUE :: arg 4426 END FUNCTION call_it 4427 END INTERFACE 4428 4429 CONTAINS 4430 4431 ! Define procedure passed to C function. 4432 ! It must be interoperable! 4433 INTEGER(KIND=C_INT) FUNCTION double_it (arg) BIND(C) 4434 INTEGER(KIND=C_INT), INTENT(IN), VALUE :: arg 4435 double_it = arg + arg 4436 END FUNCTION double_it 4437 4438 ! Call C function. 4439 SUBROUTINE foobar () 4440 TYPE(C_FUNPTR) :: cproc 4441 INTEGER(KIND=C_INT) :: i 4442 4443 ! Get C procedure pointer. 4444 cproc = C_FUNLOC (double_it) 4445 4446 ! Use it. 4447 DO i = 1_C_INT, 10_C_INT 4448 PRINT *, call_it (cproc, i) 4449 END DO 4450 END SUBROUTINE foobar 4451 4452 END MODULE m 4453 4454 4455File: gfortran.info, Node: Further Interoperability of Fortran with C, Prev: Working with Pointers, Up: Interoperability with C 4456 44577.1.6 Further Interoperability of Fortran with C 4458------------------------------------------------ 4459 4460The Technical Specification ISO/IEC TS 29113:2012 on further 4461interoperability of Fortran with C extends the interoperability support 4462of Fortran 2003 and Fortran 2008. Besides removing some restrictions 4463and constraints, it adds assumed-type ('TYPE(*)') and assumed-rank 4464('dimension') variables and allows for interoperability of 4465assumed-shape, assumed-rank and deferred-shape arrays, including 4466allocatables and pointers. 4467 4468 Note: Currently, GNU Fortran does not support the array descriptor 4469(dope vector) as specified in the Technical Specification, but uses an 4470array descriptor with different fields. The Chasm Language 4471Interoperability Tools, <http://chasm-interop.sourceforge.net/>, provide 4472an interface to GNU Fortran's array descriptor. 4473 4474 The Technical Specification adds the following new features, which 4475are supported by GNU Fortran: 4476 4477 * The 'ASYNCHRONOUS' attribute has been clarified and extended to 4478 allow its use with asynchronous communication in user-provided 4479 libraries such as in implementations of the Message Passing 4480 Interface specification. 4481 4482 * Many constraints have been relaxed, in particular for the 'C_LOC' 4483 and 'C_F_POINTER' intrinsics. 4484 4485 * The 'OPTIONAL' attribute is now allowed for dummy arguments; an 4486 absent argument matches a 'NULL' pointer. 4487 4488 * Assumed types ('TYPE(*)') have been added, which may only be used 4489 for dummy arguments. They are unlimited polymorphic but contrary 4490 to 'CLASS(*)' they do not contain any type information, similar to 4491 C's 'void *' pointers. Expressions of any type and kind can be 4492 passed; thus, it can be used as replacement for 'TYPE(C_PTR)', 4493 avoiding the use of 'C_LOC' in the caller. 4494 4495 Note, however, that 'TYPE(*)' only accepts scalar arguments, unless 4496 the 'DIMENSION' is explicitly specified. As 'DIMENSION(*)' only 4497 supports array (including array elements) but no scalars, it is not 4498 a full replacement for 'C_LOC'. On the other hand, assumed-type 4499 assumed-rank dummy arguments ('TYPE(*), DIMENSION(..)') allow for 4500 both scalars and arrays, but require special code on the callee 4501 side to handle the array descriptor. 4502 4503 * Assumed-rank arrays ('DIMENSION(..)') as dummy argument allow that 4504 scalars and arrays of any rank can be passed as actual argument. 4505 As the Technical Specification does not provide for direct means to 4506 operate with them, they have to be used either from the C side or 4507 be converted using 'C_LOC' and 'C_F_POINTER' to scalars or arrays 4508 of a specific rank. The rank can be determined using the 'RANK' 4509 intrinisic. 4510 4511 Currently unimplemented: 4512 4513 * GNU Fortran always uses an array descriptor, which does not match 4514 the one of the Technical Specification. The 4515 'ISO_Fortran_binding.h' header file and the C functions it 4516 specifies are not available. 4517 4518 * Using assumed-shape, assumed-rank and deferred-shape arrays in 4519 'BIND(C)' procedures is not fully supported. In particular, C 4520 interoperable strings of other length than one are not supported as 4521 this requires the new array descriptor. 4522 4523 4524File: gfortran.info, Node: GNU Fortran Compiler Directives, Next: Non-Fortran Main Program, Prev: Interoperability with C, Up: Mixed-Language Programming 4525 45267.2 GNU Fortran Compiler Directives 4527=================================== 4528 4529* Menu: 4530 4531* ATTRIBUTES directive:: 4532* UNROLL directive:: 4533 4534 4535File: gfortran.info, Node: ATTRIBUTES directive, Next: UNROLL directive, Up: GNU Fortran Compiler Directives 4536 45377.2.1 ATTRIBUTES directive 4538-------------------------- 4539 4540The Fortran standard describes how a conforming program shall behave; 4541however, the exact implementation is not standardized. In order to 4542allow the user to choose specific implementation details, compiler 4543directives can be used to set attributes of variables and procedures 4544which are not part of the standard. Whether a given attribute is 4545supported and its exact effects depend on both the operating system and 4546on the processor; see *note C Extensions: (gcc)Top. for details. 4547 4548 For procedures and procedure pointers, the following attributes can 4549be used to change the calling convention: 4550 4551 * 'CDECL' - standard C calling convention 4552 * 'STDCALL' - convention where the called procedure pops the stack 4553 * 'FASTCALL' - part of the arguments are passed via registers instead 4554 using the stack 4555 4556 Besides changing the calling convention, the attributes also 4557influence the decoration of the symbol name, e.g., by a leading 4558underscore or by a trailing at-sign followed by the number of bytes on 4559the stack. When assigning a procedure to a procedure pointer, both 4560should use the same calling convention. 4561 4562 On some systems, procedures and global variables (module variables 4563and 'COMMON' blocks) need special handling to be accessible when they 4564are in a shared library. The following attributes are available: 4565 4566 * 'DLLEXPORT' - provide a global pointer to a pointer in the DLL 4567 * 'DLLIMPORT' - reference the function or variable using a global 4568 pointer 4569 4570 For dummy arguments, the 'NO_ARG_CHECK' attribute can be used; in 4571other compilers, it is also known as 'IGNORE_TKR'. For dummy arguments 4572with this attribute actual arguments of any type and kind (similar to 4573'TYPE(*)'), scalars and arrays of any rank (no equivalent in Fortran 4574standard) are accepted. As with 'TYPE(*)', the argument is unlimited 4575polymorphic and no type information is available. Additionally, the 4576argument may only be passed to dummy arguments with the 'NO_ARG_CHECK' 4577attribute and as argument to the 'PRESENT' intrinsic function and to 4578'C_LOC' of the 'ISO_C_BINDING' module. 4579 4580 Variables with 'NO_ARG_CHECK' attribute shall be of assumed-type 4581('TYPE(*)'; recommended) or of type 'INTEGER', 'LOGICAL', 'REAL' or 4582'COMPLEX'. They shall not have the 'ALLOCATE', 'CODIMENSION', 4583'INTENT(OUT)', 'POINTER' or 'VALUE' attribute; furthermore, they shall 4584be either scalar or of assumed-size ('dimension(*)'). As 'TYPE(*)', the 4585'NO_ARG_CHECK' attribute requires an explicit interface. 4586 4587 * 'NO_ARG_CHECK' - disable the type, kind and rank checking 4588 4589 The attributes are specified using the syntax 4590 4591 '!GCC$ ATTRIBUTES' ATTRIBUTE-LIST '::' VARIABLE-LIST 4592 4593 where in free-form source code only whitespace is allowed before 4594'!GCC$' and in fixed-form source code '!GCC$', 'cGCC$' or '*GCC$' shall 4595start in the first column. 4596 4597 For procedures, the compiler directives shall be placed into the body 4598of the procedure; for variables and procedure pointers, they shall be in 4599the same declaration part as the variable or procedure pointer. 4600 4601 4602File: gfortran.info, Node: UNROLL directive, Prev: ATTRIBUTES directive, Up: GNU Fortran Compiler Directives 4603 46047.2.2 UNROLL directive 4605---------------------- 4606 4607The syntax of the directive is 4608 4609 '!GCC$ unroll N' 4610 4611 You can use this directive to control how many times a loop should be 4612unrolled. It must be placed immediately before a 'DO' loop and applies 4613only to the loop that follows. N is an integer constant specifying the 4614unrolling factor. The values of 0 and 1 block any unrolling of the 4615loop. 4616 4617 4618File: gfortran.info, Node: Non-Fortran Main Program, Next: Naming and argument-passing conventions, Prev: GNU Fortran Compiler Directives, Up: Mixed-Language Programming 4619 46207.3 Non-Fortran Main Program 4621============================ 4622 4623* Menu: 4624 4625* _gfortran_set_args:: Save command-line arguments 4626* _gfortran_set_options:: Set library option flags 4627* _gfortran_set_convert:: Set endian conversion 4628* _gfortran_set_record_marker:: Set length of record markers 4629* _gfortran_set_fpe:: Set when a Floating Point Exception should be raised 4630* _gfortran_set_max_subrecord_length:: Set subrecord length 4631 4632Even if you are doing mixed-language programming, it is very likely that 4633you do not need to know or use the information in this section. Since 4634it is about the internal structure of GNU Fortran, it may also change in 4635GCC minor releases. 4636 4637 When you compile a 'PROGRAM' with GNU Fortran, a function with the 4638name 'main' (in the symbol table of the object file) is generated, which 4639initializes the libgfortran library and then calls the actual program 4640which uses the name 'MAIN__', for historic reasons. If you link GNU 4641Fortran compiled procedures to, e.g., a C or C++ program or to a Fortran 4642program compiled by a different compiler, the libgfortran library is not 4643initialized and thus a few intrinsic procedures do not work properly, 4644e.g. those for obtaining the command-line arguments. 4645 4646 Therefore, if your 'PROGRAM' is not compiled with GNU Fortran and the 4647GNU Fortran compiled procedures require intrinsics relying on the 4648library initialization, you need to initialize the library yourself. 4649Using the default options, gfortran calls '_gfortran_set_args' and 4650'_gfortran_set_options'. The initialization of the former is needed if 4651the called procedures access the command line (and for backtracing); the 4652latter sets some flags based on the standard chosen or to enable 4653backtracing. In typical programs, it is not necessary to call any 4654initialization function. 4655 4656 If your 'PROGRAM' is compiled with GNU Fortran, you shall not call 4657any of the following functions. The libgfortran initialization 4658functions are shown in C syntax but using C bindings they are also 4659accessible from Fortran. 4660 4661 4662File: gfortran.info, Node: _gfortran_set_args, Next: _gfortran_set_options, Up: Non-Fortran Main Program 4663 46647.3.1 '_gfortran_set_args' -- Save command-line arguments 4665--------------------------------------------------------- 4666 4667_Description_: 4668 '_gfortran_set_args' saves the command-line arguments; this 4669 initialization is required if any of the command-line intrinsics is 4670 called. Additionally, it shall be called if backtracing is enabled 4671 (see '_gfortran_set_options'). 4672 4673_Syntax_: 4674 'void _gfortran_set_args (int argc, char *argv[])' 4675 4676_Arguments_: 4677 ARGC number of command line argument strings 4678 ARGV the command-line argument strings; argv[0] is 4679 the pathname of the executable itself. 4680 4681_Example_: 4682 int main (int argc, char *argv[]) 4683 { 4684 /* Initialize libgfortran. */ 4685 _gfortran_set_args (argc, argv); 4686 return 0; 4687 } 4688 4689 4690File: gfortran.info, Node: _gfortran_set_options, Next: _gfortran_set_convert, Prev: _gfortran_set_args, Up: Non-Fortran Main Program 4691 46927.3.2 '_gfortran_set_options' -- Set library option flags 4693--------------------------------------------------------- 4694 4695_Description_: 4696 '_gfortran_set_options' sets several flags related to the Fortran 4697 standard to be used, whether backtracing should be enabled and 4698 whether range checks should be performed. The syntax allows for 4699 upward compatibility since the number of passed flags is specified; 4700 for non-passed flags, the default value is used. See also *note 4701 Code Gen Options::. Please note that not all flags are actually 4702 used. 4703 4704_Syntax_: 4705 'void _gfortran_set_options (int num, int options[])' 4706 4707_Arguments_: 4708 NUM number of options passed 4709 ARGV The list of flag values 4710 4711_option flag list_: 4712 OPTION[0] Allowed standard; can give run-time errors if 4713 e.g. an input-output edit descriptor is invalid 4714 in a given standard. Possible values are 4715 (bitwise or-ed) 'GFC_STD_F77' (1), 4716 'GFC_STD_F95_OBS' (2), 'GFC_STD_F95_DEL' (4), 4717 'GFC_STD_F95' (8), 'GFC_STD_F2003' (16), 4718 'GFC_STD_GNU' (32), 'GFC_STD_LEGACY' (64), 4719 'GFC_STD_F2008' (128), 'GFC_STD_F2008_OBS' 4720 (256), 'GFC_STD_F2008_TS' (512), 'GFC_STD_F2018' 4721 (1024), 'GFC_STD_F2018_OBS' (2048), and 4722 'GFC_STD=F2018_DEL' (4096). Default: 4723 'GFC_STD_F95_OBS | GFC_STD_F95_DEL | GFC_STD_F95 4724 | GFC_STD_F2003 | GFC_STD_F2008 | 4725 GFC_STD_F2008_TS | GFC_STD_F2008_OBS | 4726 GFC_STD_F77 | GFC_STD_F2018 | GFC_STD_F2018_OBS 4727 | GFC_STD_F2018_DEL | GFC_STD_GNU | 4728 GFC_STD_LEGACY'. 4729 OPTION[1] Standard-warning flag; prints a warning to 4730 standard error. Default: 'GFC_STD_F95_DEL | 4731 GFC_STD_LEGACY'. 4732 OPTION[2] If non zero, enable pedantic checking. Default: 4733 off. 4734 OPTION[3] Unused. 4735 OPTION[4] If non zero, enable backtracing on run-time 4736 errors. Default: off. (Default in the 4737 compiler: on.) Note: Installs a signal handler 4738 and requires command-line initialization using 4739 '_gfortran_set_args'. 4740 OPTION[5] If non zero, supports signed zeros. Default: 4741 enabled. 4742 OPTION[6] Enables run-time checking. Possible values are 4743 (bitwise or-ed): GFC_RTCHECK_BOUNDS (1), 4744 GFC_RTCHECK_ARRAY_TEMPS (2), 4745 GFC_RTCHECK_RECURSION (4), GFC_RTCHECK_DO (16), 4746 GFC_RTCHECK_POINTER (32). Default: disabled. 4747 OPTION[7] Unused. 4748 OPTION[8] Show a warning when invoking 'STOP' and 'ERROR 4749 STOP' if a floating-point exception occurred. 4750 Possible values are (bitwise or-ed) 4751 'GFC_FPE_INVALID' (1), 'GFC_FPE_DENORMAL' (2), 4752 'GFC_FPE_ZERO' (4), 'GFC_FPE_OVERFLOW' (8), 4753 'GFC_FPE_UNDERFLOW' (16), 'GFC_FPE_INEXACT' 4754 (32). Default: None (0). (Default in the 4755 compiler: 'GFC_FPE_INVALID | GFC_FPE_DENORMAL | 4756 GFC_FPE_ZERO | GFC_FPE_OVERFLOW | 4757 GFC_FPE_UNDERFLOW'.) 4758 4759_Example_: 4760 /* Use gfortran 4.9 default options. */ 4761 static int options[] = {68, 511, 0, 0, 1, 1, 0, 0, 31}; 4762 _gfortran_set_options (9, &options); 4763 4764 4765File: gfortran.info, Node: _gfortran_set_convert, Next: _gfortran_set_record_marker, Prev: _gfortran_set_options, Up: Non-Fortran Main Program 4766 47677.3.3 '_gfortran_set_convert' -- Set endian conversion 4768------------------------------------------------------ 4769 4770_Description_: 4771 '_gfortran_set_convert' set the representation of data for 4772 unformatted files. 4773 4774_Syntax_: 4775 'void _gfortran_set_convert (int conv)' 4776 4777_Arguments_: 4778 CONV Endian conversion, possible values: 4779 GFC_CONVERT_NATIVE (0, default), 4780 GFC_CONVERT_SWAP (1), GFC_CONVERT_BIG (2), 4781 GFC_CONVERT_LITTLE (3). 4782 4783_Example_: 4784 int main (int argc, char *argv[]) 4785 { 4786 /* Initialize libgfortran. */ 4787 _gfortran_set_args (argc, argv); 4788 _gfortran_set_convert (1); 4789 return 0; 4790 } 4791 4792 4793File: gfortran.info, Node: _gfortran_set_record_marker, Next: _gfortran_set_fpe, Prev: _gfortran_set_convert, Up: Non-Fortran Main Program 4794 47957.3.4 '_gfortran_set_record_marker' -- Set length of record markers 4796------------------------------------------------------------------- 4797 4798_Description_: 4799 '_gfortran_set_record_marker' sets the length of record markers for 4800 unformatted files. 4801 4802_Syntax_: 4803 'void _gfortran_set_record_marker (int val)' 4804 4805_Arguments_: 4806 VAL Length of the record marker; valid values are 4 4807 and 8. Default is 4. 4808 4809_Example_: 4810 int main (int argc, char *argv[]) 4811 { 4812 /* Initialize libgfortran. */ 4813 _gfortran_set_args (argc, argv); 4814 _gfortran_set_record_marker (8); 4815 return 0; 4816 } 4817 4818 4819File: gfortran.info, Node: _gfortran_set_fpe, Next: _gfortran_set_max_subrecord_length, Prev: _gfortran_set_record_marker, Up: Non-Fortran Main Program 4820 48217.3.5 '_gfortran_set_fpe' -- Enable floating point exception traps 4822------------------------------------------------------------------ 4823 4824_Description_: 4825 '_gfortran_set_fpe' enables floating point exception traps for the 4826 specified exceptions. On most systems, this will result in a 4827 SIGFPE signal being sent and the program being aborted. 4828 4829_Syntax_: 4830 'void _gfortran_set_fpe (int val)' 4831 4832_Arguments_: 4833 OPTION[0] IEEE exceptions. Possible values are (bitwise 4834 or-ed) zero (0, default) no trapping, 4835 'GFC_FPE_INVALID' (1), 'GFC_FPE_DENORMAL' (2), 4836 'GFC_FPE_ZERO' (4), 'GFC_FPE_OVERFLOW' (8), 4837 'GFC_FPE_UNDERFLOW' (16), and 'GFC_FPE_INEXACT' 4838 (32). 4839 4840_Example_: 4841 int main (int argc, char *argv[]) 4842 { 4843 /* Initialize libgfortran. */ 4844 _gfortran_set_args (argc, argv); 4845 /* FPE for invalid operations such as SQRT(-1.0). */ 4846 _gfortran_set_fpe (1); 4847 return 0; 4848 } 4849 4850 4851File: gfortran.info, Node: _gfortran_set_max_subrecord_length, Prev: _gfortran_set_fpe, Up: Non-Fortran Main Program 4852 48537.3.6 '_gfortran_set_max_subrecord_length' -- Set subrecord length 4854------------------------------------------------------------------ 4855 4856_Description_: 4857 '_gfortran_set_max_subrecord_length' set the maximum length for a 4858 subrecord. This option only makes sense for testing and debugging 4859 of unformatted I/O. 4860 4861_Syntax_: 4862 'void _gfortran_set_max_subrecord_length (int val)' 4863 4864_Arguments_: 4865 VAL the maximum length for a subrecord; the maximum 4866 permitted value is 2147483639, which is also the 4867 default. 4868 4869_Example_: 4870 int main (int argc, char *argv[]) 4871 { 4872 /* Initialize libgfortran. */ 4873 _gfortran_set_args (argc, argv); 4874 _gfortran_set_max_subrecord_length (8); 4875 return 0; 4876 } 4877 4878 4879File: gfortran.info, Node: Naming and argument-passing conventions, Prev: Non-Fortran Main Program, Up: Mixed-Language Programming 4880 48817.4 Naming and argument-passing conventions 4882=========================================== 4883 4884This section gives an overview about the naming convention of procedures 4885and global variables and about the argument passing conventions used by 4886GNU Fortran. If a C binding has been specified, the naming convention 4887and some of the argument-passing conventions change. If possible, 4888mixed-language and mixed-compiler projects should use the better defined 4889C binding for interoperability. See *note Interoperability with C::. 4890 4891* Menu: 4892 4893* Naming conventions:: 4894* Argument passing conventions:: 4895 4896 4897File: gfortran.info, Node: Naming conventions, Next: Argument passing conventions, Up: Naming and argument-passing conventions 4898 48997.4.1 Naming conventions 4900------------------------ 4901 4902According the Fortran standard, valid Fortran names consist of a letter 4903between 'A' to 'Z', 'a' to 'z', digits '0', '1' to '9' and underscores 4904('_') with the restriction that names may only start with a letter. As 4905vendor extension, the dollar sign ('$') is additionally permitted with 4906the option '-fdollar-ok', but not as first character and only if the 4907target system supports it. 4908 4909 By default, the procedure name is the lower-cased Fortran name with 4910an appended underscore ('_'); using '-fno-underscoring' no underscore is 4911appended while '-fsecond-underscore' appends two underscores. Depending 4912on the target system and the calling convention, the procedure might be 4913additionally dressed; for instance, on 32bit Windows with 'stdcall', an 4914at-sign '@' followed by an integer number is appended. For the changing 4915the calling convention, see *note GNU Fortran Compiler Directives::. 4916 4917 For common blocks, the same convention is used, i.e. by default an 4918underscore is appended to the lower-cased Fortran name. Blank commons 4919have the name '__BLNK__'. 4920 4921 For procedures and variables declared in the specification space of a 4922module, the name is formed by '__', followed by the lower-cased module 4923name, '_MOD_', and the lower-cased Fortran name. Note that no 4924underscore is appended. 4925 4926 4927File: gfortran.info, Node: Argument passing conventions, Prev: Naming conventions, Up: Naming and argument-passing conventions 4928 49297.4.2 Argument passing conventions 4930---------------------------------- 4931 4932Subroutines do not return a value (matching C99's 'void') while 4933functions either return a value as specified in the platform ABI or the 4934result variable is passed as hidden argument to the function and no 4935result is returned. A hidden result variable is used when the result 4936variable is an array or of type 'CHARACTER'. 4937 4938 Arguments are passed according to the platform ABI. In particular, 4939complex arguments might not be compatible to a struct with two real 4940components for the real and imaginary part. The argument passing 4941matches the one of C99's '_Complex'. Functions with scalar complex 4942result variables return their value and do not use a by-reference 4943argument. Note that with the '-ff2c' option, the argument passing is 4944modified and no longer completely matches the platform ABI. Some other 4945Fortran compilers use 'f2c' semantic by default; this might cause 4946problems with interoperablility. 4947 4948 GNU Fortran passes most arguments by reference, i.e. by passing a 4949pointer to the data. Note that the compiler might use a temporary 4950variable into which the actual argument has been copied, if required 4951semantically (copy-in/copy-out). 4952 4953 For arguments with 'ALLOCATABLE' and 'POINTER' attribute (including 4954procedure pointers), a pointer to the pointer is passed such that the 4955pointer address can be modified in the procedure. 4956 4957 For dummy arguments with the 'VALUE' attribute: Scalar arguments of 4958the type 'INTEGER', 'LOGICAL', 'REAL' and 'COMPLEX' are passed by value 4959according to the platform ABI. (As vendor extension and not recommended, 4960using '%VAL()' in the call to a procedure has the same effect.) For 4961'TYPE(C_PTR)' and procedure pointers, the pointer itself is passed such 4962that it can be modified without affecting the caller. 4963 4964 For Boolean ('LOGICAL') arguments, please note that GCC expects only 4965the integer value 0 and 1. If a GNU Fortran 'LOGICAL' variable contains 4966another integer value, the result is undefined. As some other Fortran 4967compilers use -1 for '.TRUE.', extra care has to be taken - such as 4968passing the value as 'INTEGER'. (The same value restriction also 4969applies to other front ends of GCC, e.g. to GCC's C99 compiler for 4970'_Bool' or GCC's Ada compiler for 'Boolean'.) 4971 4972 For arguments of 'CHARACTER' type, the character length is passed as 4973a hidden argument at the end of the argument list. For deferred-length 4974strings, the value is passed by reference, otherwise by value. The 4975character length has the C type 'size_t' (or 'INTEGER(kind=C_SIZE_T)' in 4976Fortran). Note that this is different to older versions of the GNU 4977Fortran compiler, where the type of the hidden character length argument 4978was a C 'int'. In order to retain compatibility with older versions, 4979one can e.g. for the following Fortran procedure 4980 4981 subroutine fstrlen (s, a) 4982 character(len=*) :: s 4983 integer :: a 4984 print*, len(s) 4985 end subroutine fstrlen 4986 4987 define the corresponding C prototype as follows: 4988 4989 #if __GNUC__ > 7 4990 typedef size_t fortran_charlen_t; 4991 #else 4992 typedef int fortran_charlen_t; 4993 #endif 4994 4995 void fstrlen_ (char*, int*, fortran_charlen_t); 4996 4997 In order to avoid such compiler-specific details, for new code it is 4998instead recommended to use the ISO_C_BINDING feature. 4999 5000 Note with C binding, 'CHARACTER(len=1)' result variables are returned 5001according to the platform ABI and no hidden length argument is used for 5002dummy arguments; with 'VALUE', those variables are passed by value. 5003 5004 For 'OPTIONAL' dummy arguments, an absent argument is denoted by a 5005NULL pointer, except for scalar dummy arguments of type 'INTEGER', 5006'LOGICAL', 'REAL' and 'COMPLEX' which have the 'VALUE' attribute. For 5007those, a hidden Boolean argument ('logical(kind=C_bool),value') is used 5008to indicate whether the argument is present. 5009 5010 Arguments which are assumed-shape, assumed-rank or deferred-rank 5011arrays or, with '-fcoarray=lib', allocatable scalar coarrays use an 5012array descriptor. All other arrays pass the address of the first 5013element of the array. With '-fcoarray=lib', the token and the offset 5014belonging to nonallocatable coarrays dummy arguments are passed as 5015hidden argument along the character length hidden arguments. The token 5016is an oparque pointer identifying the coarray and the offset is a 5017passed-by-value integer of kind 'C_PTRDIFF_T', denoting the byte offset 5018between the base address of the coarray and the passed scalar or first 5019element of the passed array. 5020 5021 The arguments are passed in the following order 5022 * Result variable, when the function result is passed by reference 5023 * Character length of the function result, if it is a of type 5024 'CHARACTER' and no C binding is used 5025 * The arguments in the order in which they appear in the Fortran 5026 declaration 5027 * The the present status for optional arguments with value attribute, 5028 which are internally passed by value 5029 * The character length and/or coarray token and offset for the first 5030 argument which is a 'CHARACTER' or a nonallocatable coarray dummy 5031 argument, followed by the hidden arguments of the next dummy 5032 argument of such a type 5033 5034 5035File: gfortran.info, Node: Coarray Programming, Next: Intrinsic Procedures, Prev: Mixed-Language Programming, Up: Top 5036 50378 Coarray Programming 5038********************* 5039 5040* Menu: 5041 5042* Type and enum ABI Documentation:: 5043* Function ABI Documentation:: 5044 5045 5046File: gfortran.info, Node: Type and enum ABI Documentation, Next: Function ABI Documentation, Up: Coarray Programming 5047 50488.1 Type and enum ABI Documentation 5049=================================== 5050 5051* Menu: 5052 5053* caf_token_t:: 5054* caf_register_t:: 5055* caf_deregister_t:: 5056* caf_reference_t:: 5057* caf_team_t:: 5058 5059 5060File: gfortran.info, Node: caf_token_t, Next: caf_register_t, Up: Type and enum ABI Documentation 5061 50628.1.1 'caf_token_t' 5063------------------- 5064 5065Typedef of type 'void *' on the compiler side. Can be any data type on 5066the library side. 5067 5068 5069File: gfortran.info, Node: caf_register_t, Next: caf_deregister_t, Prev: caf_token_t, Up: Type and enum ABI Documentation 5070 50718.1.2 'caf_register_t' 5072---------------------- 5073 5074Indicates which kind of coarray variable should be registered. 5075 5076typedef enum caf_register_t { 5077 CAF_REGTYPE_COARRAY_STATIC, 5078 CAF_REGTYPE_COARRAY_ALLOC, 5079 CAF_REGTYPE_LOCK_STATIC, 5080 CAF_REGTYPE_LOCK_ALLOC, 5081 CAF_REGTYPE_CRITICAL, 5082 CAF_REGTYPE_EVENT_STATIC, 5083 CAF_REGTYPE_EVENT_ALLOC, 5084 CAF_REGTYPE_COARRAY_ALLOC_REGISTER_ONLY, 5085 CAF_REGTYPE_COARRAY_ALLOC_ALLOCATE_ONLY 5086} 5087caf_register_t; 5088 5089 The values 'CAF_REGTYPE_COARRAY_ALLOC_REGISTER_ONLY' and 5090'CAF_REGTYPE_COARRAY_ALLOC_ALLOCATE_ONLY' are for allocatable components 5091in derived type coarrays only. The first one sets up the token without 5092allocating memory for allocatable component. The latter one only 5093allocates the memory for an allocatable component in a derived type 5094coarray. The token needs to be setup previously by the REGISTER_ONLY. 5095This allows to have allocatable components un-allocated on some images. 5096The status whether an allocatable component is allocated on a remote 5097image can be queried by '_caf_is_present' which used internally by the 5098'ALLOCATED' intrinsic. 5099 5100 5101File: gfortran.info, Node: caf_deregister_t, Next: caf_reference_t, Prev: caf_register_t, Up: Type and enum ABI Documentation 5102 51038.1.3 'caf_deregister_t' 5104------------------------ 5105 5106typedef enum caf_deregister_t { 5107 CAF_DEREGTYPE_COARRAY_DEREGISTER, 5108 CAF_DEREGTYPE_COARRAY_DEALLOCATE_ONLY 5109} 5110caf_deregister_t; 5111 5112 Allows to specifiy the type of deregistration of a coarray object. 5113The 'CAF_DEREGTYPE_COARRAY_DEALLOCATE_ONLY' flag is only allowed for 5114allocatable components in derived type coarrays. 5115 5116 5117File: gfortran.info, Node: caf_reference_t, Next: caf_team_t, Prev: caf_deregister_t, Up: Type and enum ABI Documentation 5118 51198.1.4 'caf_reference_t' 5120----------------------- 5121 5122The structure used for implementing arbitrary reference chains. A 5123'CAF_REFERENCE_T' allows to specify a component reference or any kind of 5124array reference of any rank supported by gfortran. For array references 5125all kinds as known by the compiler/Fortran standard are supported 5126indicated by a 'MODE'. 5127 5128typedef enum caf_ref_type_t { 5129 /* Reference a component of a derived type, either regular one or an 5130 allocatable or pointer type. For regular ones idx in caf_reference_t is 5131 set to -1. */ 5132 CAF_REF_COMPONENT, 5133 /* Reference an allocatable array. */ 5134 CAF_REF_ARRAY, 5135 /* Reference a non-allocatable/non-pointer array. I.e., the coarray object 5136 has no array descriptor associated and the addressing is done 5137 completely using the ref. */ 5138 CAF_REF_STATIC_ARRAY 5139} caf_ref_type_t; 5140 5141typedef enum caf_array_ref_t { 5142 /* No array ref. This terminates the array ref. */ 5143 CAF_ARR_REF_NONE = 0, 5144 /* Reference array elements given by a vector. Only for this mode 5145 caf_reference_t.u.a.dim[i].v is valid. */ 5146 CAF_ARR_REF_VECTOR, 5147 /* A full array ref (:). */ 5148 CAF_ARR_REF_FULL, 5149 /* Reference a range on elements given by start, end and stride. */ 5150 CAF_ARR_REF_RANGE, 5151 /* Only a single item is referenced given in the start member. */ 5152 CAF_ARR_REF_SINGLE, 5153 /* An array ref of the kind (i:), where i is an arbitrary valid index in the 5154 array. The index i is given in the start member. */ 5155 CAF_ARR_REF_OPEN_END, 5156 /* An array ref of the kind (:i), where the lower bound of the array ref 5157 is given by the remote side. The index i is given in the end member. */ 5158 CAF_ARR_REF_OPEN_START 5159} caf_array_ref_t; 5160 5161/* References to remote components of a derived type. */ 5162typedef struct caf_reference_t { 5163 /* A pointer to the next ref or NULL. */ 5164 struct caf_reference_t *next; 5165 /* The type of the reference. */ 5166 /* caf_ref_type_t, replaced by int to allow specification in fortran FE. */ 5167 int type; 5168 /* The size of an item referenced in bytes. I.e. in an array ref this is 5169 the factor to advance the array pointer with to get to the next item. 5170 For component refs this gives just the size of the element referenced. */ 5171 size_t item_size; 5172 union { 5173 struct { 5174 /* The offset (in bytes) of the component in the derived type. 5175 Unused for allocatable or pointer components. */ 5176 ptrdiff_t offset; 5177 /* The offset (in bytes) to the caf_token associated with this 5178 component. NULL, when not allocatable/pointer ref. */ 5179 ptrdiff_t caf_token_offset; 5180 } c; 5181 struct { 5182 /* The mode of the array ref. See CAF_ARR_REF_*. */ 5183 /* caf_array_ref_t, replaced by unsigend char to allow specification in 5184 fortran FE. */ 5185 unsigned char mode[GFC_MAX_DIMENSIONS]; 5186 /* The type of a static array. Unset for array's with descriptors. */ 5187 int static_array_type; 5188 /* Subscript refs (s) or vector refs (v). */ 5189 union { 5190 struct { 5191 /* The start and end boundary of the ref and the stride. */ 5192 index_type start, end, stride; 5193 } s; 5194 struct { 5195 /* nvec entries of kind giving the elements to reference. */ 5196 void *vector; 5197 /* The number of entries in vector. */ 5198 size_t nvec; 5199 /* The integer kind used for the elements in vector. */ 5200 int kind; 5201 } v; 5202 } dim[GFC_MAX_DIMENSIONS]; 5203 } a; 5204 } u; 5205} caf_reference_t; 5206 5207 The references make up a single linked list of reference operations. 5208The 'NEXT' member links to the next reference or NULL to indicate the 5209end of the chain. Component and array refs can be arbitrarly mixed as 5210long as they comply to the Fortran standard. 5211 5212 _NOTES_ The member 'STATIC_ARRAY_TYPE' is used only when the 'TYPE' 5213is 'CAF_REF_STATIC_ARRAY'. The member gives the type of the data 5214referenced. Because no array descriptor is available for a 5215descriptor-less array and type conversion still needs to take place the 5216type is transported here. 5217 5218 At the moment 'CAF_ARR_REF_VECTOR' is not implemented in the front 5219end for descriptor-less arrays. The library caf_single has untested 5220support for it. 5221 5222 5223File: gfortran.info, Node: caf_team_t, Prev: caf_reference_t, Up: Type and enum ABI Documentation 5224 52258.1.5 'caf_team_t' 5226------------------ 5227 5228Opaque pointer to represent a team-handle. This type is a stand-in for 5229the future implementation of teams. It is about to change without 5230further notice. 5231 5232 5233File: gfortran.info, Node: Function ABI Documentation, Prev: Type and enum ABI Documentation, Up: Coarray Programming 5234 52358.2 Function ABI Documentation 5236============================== 5237 5238* Menu: 5239 5240* _gfortran_caf_init:: Initialiation function 5241* _gfortran_caf_finish:: Finalization function 5242* _gfortran_caf_this_image:: Querying the image number 5243* _gfortran_caf_num_images:: Querying the maximal number of images 5244* _gfortran_caf_image_status :: Query the status of an image 5245* _gfortran_caf_failed_images :: Get an array of the indexes of the failed images 5246* _gfortran_caf_stopped_images :: Get an array of the indexes of the stopped images 5247* _gfortran_caf_register:: Registering coarrays 5248* _gfortran_caf_deregister:: Deregistering coarrays 5249* _gfortran_caf_is_present:: Query whether an allocatable or pointer component in a derived type coarray is allocated 5250* _gfortran_caf_send:: Sending data from a local image to a remote image 5251* _gfortran_caf_get:: Getting data from a remote image 5252* _gfortran_caf_sendget:: Sending data between remote images 5253* _gfortran_caf_send_by_ref:: Sending data from a local image to a remote image using enhanced references 5254* _gfortran_caf_get_by_ref:: Getting data from a remote image using enhanced references 5255* _gfortran_caf_sendget_by_ref:: Sending data between remote images using enhanced references 5256* _gfortran_caf_lock:: Locking a lock variable 5257* _gfortran_caf_unlock:: Unlocking a lock variable 5258* _gfortran_caf_event_post:: Post an event 5259* _gfortran_caf_event_wait:: Wait that an event occurred 5260* _gfortran_caf_event_query:: Query event count 5261* _gfortran_caf_sync_all:: All-image barrier 5262* _gfortran_caf_sync_images:: Barrier for selected images 5263* _gfortran_caf_sync_memory:: Wait for completion of segment-memory operations 5264* _gfortran_caf_error_stop:: Error termination with exit code 5265* _gfortran_caf_error_stop_str:: Error termination with string 5266* _gfortran_caf_fail_image :: Mark the image failed and end its execution 5267* _gfortran_caf_atomic_define:: Atomic variable assignment 5268* _gfortran_caf_atomic_ref:: Atomic variable reference 5269* _gfortran_caf_atomic_cas:: Atomic compare and swap 5270* _gfortran_caf_atomic_op:: Atomic operation 5271* _gfortran_caf_co_broadcast:: Sending data to all images 5272* _gfortran_caf_co_max:: Collective maximum reduction 5273* _gfortran_caf_co_min:: Collective minimum reduction 5274* _gfortran_caf_co_sum:: Collective summing reduction 5275* _gfortran_caf_co_reduce:: Generic collective reduction 5276 5277 5278File: gfortran.info, Node: _gfortran_caf_init, Next: _gfortran_caf_finish, Up: Function ABI Documentation 5279 52808.2.1 '_gfortran_caf_init' -- Initialiation function 5281---------------------------------------------------- 5282 5283_Description_: 5284 This function is called at startup of the program before the 5285 Fortran main program, if the latter has been compiled with 5286 '-fcoarray=lib'. It takes as arguments the command-line arguments 5287 of the program. It is permitted to pass two 'NULL' pointers as 5288 argument; if non-'NULL', the library is permitted to modify the 5289 arguments. 5290 5291_Syntax_: 5292 'void _gfortran_caf_init (int *argc, char ***argv)' 5293 5294_Arguments_: 5295 ARGC intent(inout) An integer pointer with the number 5296 of arguments passed to the program or 'NULL'. 5297 ARGV intent(inout) A pointer to an array of strings 5298 with the command-line arguments or 'NULL'. 5299 5300_NOTES_ 5301 The function is modelled after the initialization function of the 5302 Message Passing Interface (MPI) specification. Due to the way 5303 coarray registration works, it might not be the first call to the 5304 library. If the main program is not written in Fortran and only a 5305 library uses coarrays, it can happen that this function is never 5306 called. Therefore, it is recommended that the library does not 5307 rely on the passed arguments and whether the call has been done. 5308 5309 5310File: gfortran.info, Node: _gfortran_caf_finish, Next: _gfortran_caf_this_image, Prev: _gfortran_caf_init, Up: Function ABI Documentation 5311 53128.2.2 '_gfortran_caf_finish' -- Finalization function 5313----------------------------------------------------- 5314 5315_Description_: 5316 This function is called at the end of the Fortran main program, if 5317 it has been compiled with the '-fcoarray=lib' option. 5318 5319_Syntax_: 5320 'void _gfortran_caf_finish (void)' 5321 5322_NOTES_ 5323 For non-Fortran programs, it is recommended to call the function at 5324 the end of the main program. To ensure that the shutdown is also 5325 performed for programs where this function is not explicitly 5326 invoked, for instance non-Fortran programs or calls to the system's 5327 exit() function, the library can use a destructor function. Note 5328 that programs can also be terminated using the STOP and ERROR STOP 5329 statements; those use different library calls. 5330 5331 5332File: gfortran.info, Node: _gfortran_caf_this_image, Next: _gfortran_caf_num_images, Prev: _gfortran_caf_finish, Up: Function ABI Documentation 5333 53348.2.3 '_gfortran_caf_this_image' -- Querying the image number 5335------------------------------------------------------------- 5336 5337_Description_: 5338 This function returns the current image number, which is a positive 5339 number. 5340 5341_Syntax_: 5342 'int _gfortran_caf_this_image (int distance)' 5343 5344_Arguments_: 5345 DISTANCE As specified for the 'this_image' intrinsic in 5346 TS18508. Shall be a non-negative number. 5347 5348_NOTES_ 5349 If the Fortran intrinsic 'this_image' is invoked without an 5350 argument, which is the only permitted form in Fortran 2008, GCC 5351 passes '0' as first argument. 5352 5353 5354File: gfortran.info, Node: _gfortran_caf_num_images, Next: _gfortran_caf_image_status, Prev: _gfortran_caf_this_image, Up: Function ABI Documentation 5355 53568.2.4 '_gfortran_caf_num_images' -- Querying the maximal number of images 5357------------------------------------------------------------------------- 5358 5359_Description_: 5360 This function returns the number of images in the current team, if 5361 DISTANCE is 0 or the number of images in the parent team at the 5362 specified distance. If failed is -1, the function returns the 5363 number of all images at the specified distance; if it is 0, the 5364 function returns the number of nonfailed images, and if it is 1, it 5365 returns the number of failed images. 5366 5367_Syntax_: 5368 'int _gfortran_caf_num_images(int distance, int failed)' 5369 5370_Arguments_: 5371 DISTANCE the distance from this image to the ancestor. 5372 Shall be positive. 5373 FAILED shall be -1, 0, or 1 5374 5375_NOTES_ 5376 This function follows TS18508. If the num_image intrinsic has no 5377 arguments, then the compiler passes 'distance=0' and 'failed=-1' to 5378 the function. 5379 5380 5381File: gfortran.info, Node: _gfortran_caf_image_status, Next: _gfortran_caf_failed_images, Prev: _gfortran_caf_num_images, Up: Function ABI Documentation 5382 53838.2.5 '_gfortran_caf_image_status' -- Query the status of an image 5384------------------------------------------------------------------ 5385 5386_Description_: 5387 Get the status of the image given by the id IMAGE of the team given 5388 by TEAM. Valid results are zero, for image is ok, 5389 'STAT_STOPPED_IMAGE' from the ISO_FORTRAN_ENV module to indicate 5390 that the image has been stopped and 'STAT_FAILED_IMAGE' also from 5391 ISO_FORTRAN_ENV to indicate that the image has executed a 'FAIL 5392 IMAGE' statement. 5393 5394_Syntax_: 5395 'int _gfortran_caf_image_status (int image, caf_team_t * team)' 5396 5397_Arguments_: 5398 IMAGE the positive scalar id of the image in the 5399 current TEAM. 5400 TEAM optional; team on the which the inquiry is to be 5401 performed. 5402 5403_NOTES_ 5404 This function follows TS18508. Because team-functionality is not 5405 yet implemented a null-pointer is passed for the TEAM argument at 5406 the moment. 5407 5408 5409File: gfortran.info, Node: _gfortran_caf_failed_images, Next: _gfortran_caf_stopped_images, Prev: _gfortran_caf_image_status, Up: Function ABI Documentation 5410 54118.2.6 '_gfortran_caf_failed_images' -- Get an array of the indexes of the failed images 5412--------------------------------------------------------------------------------------- 5413 5414_Description_: 5415 Get an array of image indexes in the current TEAM that have failed. 5416 The array is sorted ascendingly. When TEAM is not provided the 5417 current team is to be used. When KIND is provided then the 5418 resulting array is of that integer kind else it is of default 5419 integer kind. The returns an unallocated size zero array when no 5420 images have failed. 5421 5422_Syntax_: 5423 'int _gfortran_caf_failed_images (caf_team_t * team, int * kind)' 5424 5425_Arguments_: 5426 TEAM optional; team on the which the inquiry is to be 5427 performed. 5428 IMAGE optional; the kind of the resulting integer 5429 array. 5430 5431_NOTES_ 5432 This function follows TS18508. Because team-functionality is not 5433 yet implemented a null-pointer is passed for the TEAM argument at 5434 the moment. 5435 5436 5437File: gfortran.info, Node: _gfortran_caf_stopped_images, Next: _gfortran_caf_register, Prev: _gfortran_caf_failed_images, Up: Function ABI Documentation 5438 54398.2.7 '_gfortran_caf_stopped_images' -- Get an array of the indexes of the stopped images 5440----------------------------------------------------------------------------------------- 5441 5442_Description_: 5443 Get an array of image indexes in the current TEAM that have 5444 stopped. The array is sorted ascendingly. When TEAM is not 5445 provided the current team is to be used. When KIND is provided 5446 then the resulting array is of that integer kind else it is of 5447 default integer kind. The returns an unallocated size zero array 5448 when no images have failed. 5449 5450_Syntax_: 5451 'int _gfortran_caf_stopped_images (caf_team_t * team, int * kind)' 5452 5453_Arguments_: 5454 TEAM optional; team on the which the inquiry is to be 5455 performed. 5456 IMAGE optional; the kind of the resulting integer 5457 array. 5458 5459_NOTES_ 5460 This function follows TS18508. Because team-functionality is not 5461 yet implemented a null-pointer is passed for the TEAM argument at 5462 the moment. 5463 5464 5465File: gfortran.info, Node: _gfortran_caf_register, Next: _gfortran_caf_deregister, Prev: _gfortran_caf_stopped_images, Up: Function ABI Documentation 5466 54678.2.8 '_gfortran_caf_register' -- Registering coarrays 5468------------------------------------------------------ 5469 5470_Description_: 5471 Registers memory for a coarray and creates a token to identify the 5472 coarray. The routine is called for both coarrays with 'SAVE' 5473 attribute and using an explicit 'ALLOCATE' statement. If an error 5474 occurs and STAT is a 'NULL' pointer, the function shall abort with 5475 printing an error message and starting the error termination. If 5476 no error occurs and STAT is present, it shall be set to zero. 5477 Otherwise, it shall be set to a positive value and, if not-'NULL', 5478 ERRMSG shall be set to a string describing the failure. The 5479 routine shall register the memory provided in the 'DATA'-component 5480 of the array descriptor DESC, when that component is non-'NULL', 5481 else it shall allocate sufficient memory and provide a pointer to 5482 it in the 'DATA'-component of DESC. The array descriptor has rank 5483 zero, when a scalar object is to be registered and the array 5484 descriptor may be invalid after the call to 5485 '_gfortran_caf_register'. When an array is to be allocated the 5486 descriptor persists. 5487 5488 For 'CAF_REGTYPE_COARRAY_STATIC' and 'CAF_REGTYPE_COARRAY_ALLOC', 5489 the passed size is the byte size requested. For 5490 'CAF_REGTYPE_LOCK_STATIC', 'CAF_REGTYPE_LOCK_ALLOC' and 5491 'CAF_REGTYPE_CRITICAL' it is the array size or one for a scalar. 5492 5493 When 'CAF_REGTYPE_COARRAY_ALLOC_REGISTER_ONLY' is used, then only a 5494 token for an allocatable or pointer component is created. The 5495 'SIZE' parameter is not used then. On the contrary when 5496 'CAF_REGTYPE_COARRAY_ALLOC_ALLOCATE_ONLY' is specified, then the 5497 TOKEN needs to be registered by a previous call with regtype 5498 'CAF_REGTYPE_COARRAY_ALLOC_REGISTER_ONLY' and either the memory 5499 specified in the DESC's data-ptr is registered or allocate when the 5500 data-ptr is 'NULL'. 5501 5502_Syntax_: 5503 'void caf_register (size_t size, caf_register_t type, caf_token_t 5504 *token, gfc_descriptor_t *desc, int *stat, char *errmsg, size_t 5505 errmsg_len)' 5506 5507_Arguments_: 5508 SIZE For normal coarrays, the byte size of the 5509 coarray to be allocated; for lock types and 5510 event types, the number of elements. 5511 TYPE one of the caf_register_t types. 5512 TOKEN intent(out) An opaque pointer identifying the 5513 coarray. 5514 DESC intent(inout) The (pseudo) array descriptor. 5515 STAT intent(out) For allocatable coarrays, stores the 5516 STAT=; may be 'NULL' 5517 ERRMSG intent(out) When an error occurs, this will be 5518 set to an error message; may be 'NULL' 5519 ERRMSG_LEN the buffer size of errmsg. 5520 5521_NOTES_ 5522 Nonallocatable coarrays have to be registered prior use from remote 5523 images. In order to guarantee this, they have to be registered 5524 before the main program. This can be achieved by creating 5525 constructor functions. That is what GCC does such that also for 5526 nonallocatable coarrays the memory is allocated and no static 5527 memory is used. The token permits to identify the coarray; to the 5528 processor, the token is a nonaliasing pointer. The library can, 5529 for instance, store the base address of the coarray in the token, 5530 some handle or a more complicated struct. The library may also 5531 store the array descriptor DESC when its rank is non-zero. 5532 5533 For lock types, the value shall only be used for checking the 5534 allocation status. Note that for critical blocks, the locking is 5535 only required on one image; in the locking statement, the processor 5536 shall always pass an image index of one for critical-block lock 5537 variables ('CAF_REGTYPE_CRITICAL'). For lock types and 5538 critical-block variables, the initial value shall be unlocked (or, 5539 respecitively, not in critical section) such as the value false; 5540 for event types, the initial state should be no event, e.g. zero. 5541 5542 5543File: gfortran.info, Node: _gfortran_caf_deregister, Next: _gfortran_caf_is_present, Prev: _gfortran_caf_register, Up: Function ABI Documentation 5544 55458.2.9 '_gfortran_caf_deregister' -- Deregistering coarrays 5546---------------------------------------------------------- 5547 5548_Description_: 5549 Called to free or deregister the memory of a coarray; the processor 5550 calls this function for automatic and explicit deallocation. In 5551 case of an error, this function shall fail with an error message, 5552 unless the STAT variable is not null. The library is only expected 5553 to free memory it allocated itself during a call to 5554 '_gfortran_caf_register'. 5555 5556_Syntax_: 5557 'void caf_deregister (caf_token_t *token, caf_deregister_t type, 5558 int *stat, char *errmsg, size_t errmsg_len)' 5559 5560_Arguments_: 5561 TOKEN the token to free. 5562 TYPE the type of action to take for the coarray. A 5563 'CAF_DEREGTYPE_COARRAY_DEALLOCATE_ONLY' is 5564 allowed only for allocatable or pointer 5565 components of derived type coarrays. The action 5566 only deallocates the local memory without 5567 deleting the token. 5568 STAT intent(out) Stores the STAT=; may be NULL 5569 ERRMSG intent(out) When an error occurs, this will be 5570 set to an error message; may be NULL 5571 ERRMSG_LEN the buffer size of errmsg. 5572 5573_NOTES_ 5574 For nonalloatable coarrays this function is never called. If a 5575 cleanup is required, it has to be handled via the finish, stop and 5576 error stop functions, and via destructors. 5577 5578 5579File: gfortran.info, Node: _gfortran_caf_is_present, Next: _gfortran_caf_send, Prev: _gfortran_caf_deregister, Up: Function ABI Documentation 5580 55818.2.10 '_gfortran_caf_is_present' -- Query whether an allocatable or pointer component in a derived type coarray is allocated 5582----------------------------------------------------------------------------------------------------------------------------- 5583 5584_Description_: 5585 Used to query the coarray library whether an allocatable component 5586 in a derived type coarray is allocated on a remote image. 5587 5588_Syntax_: 5589 'void _gfortran_caf_is_present (caf_token_t token, int image_index, 5590 gfc_reference_t *ref)' 5591 5592_Arguments_: 5593 TOKEN An opaque pointer identifying the coarray. 5594 IMAGE_INDEX The ID of the remote image; must be a positive 5595 number. 5596 REF A chain of references to address the allocatable 5597 or pointer component in the derived type 5598 coarray. The object reference needs to be a 5599 scalar or a full array reference, respectively. 5600 5601 5602File: gfortran.info, Node: _gfortran_caf_send, Next: _gfortran_caf_get, Prev: _gfortran_caf_is_present, Up: Function ABI Documentation 5603 56048.2.11 '_gfortran_caf_send' -- Sending data from a local image to a remote image 5605-------------------------------------------------------------------------------- 5606 5607_Description_: 5608 Called to send a scalar, an array section or a whole array from a 5609 local to a remote image identified by the image_index. 5610 5611_Syntax_: 5612 'void _gfortran_caf_send (caf_token_t token, size_t offset, int 5613 image_index, gfc_descriptor_t *dest, caf_vector_t *dst_vector, 5614 gfc_descriptor_t *src, int dst_kind, int src_kind, bool 5615 may_require_tmp, int *stat)' 5616 5617_Arguments_: 5618 TOKEN intent(in) An opaque pointer identifying the 5619 coarray. 5620 OFFSET intent(in) By which amount of bytes the actual 5621 data is shifted compared to the base address of 5622 the coarray. 5623 IMAGE_INDEX intent(in) The ID of the remote image; must be a 5624 positive number. 5625 DEST intent(in) Array descriptor for the remote image 5626 for the bounds and the size. The 'base_addr' 5627 shall not be accessed. 5628 DST_VECTOR intent(in) If not NULL, it contains the vector 5629 subscript of the destination array; the values 5630 are relative to the dimension triplet of the 5631 dest argument. 5632 SRC intent(in) Array descriptor of the local array 5633 to be transferred to the remote image 5634 DST_KIND intent(in) Kind of the destination argument 5635 SRC_KIND intent(in) Kind of the source argument 5636 MAY_REQUIRE_TMPintent(in) The variable is 'false' when it is 5637 known at compile time that the DEST and SRC 5638 either cannot overlap or overlap (fully or 5639 partially) such that walking SRC and DEST in 5640 element wise element order (honoring the stride 5641 value) will not lead to wrong results. 5642 Otherwise, the value is 'true'. 5643 STAT intent(out) when non-NULL give the result of the 5644 operation, i.e., zero on success and non-zero on 5645 error. When NULL and an error occurs, then an 5646 error message is printed and the program is 5647 terminated. 5648 5649_NOTES_ 5650 It is permitted to have IMAGE_INDEX equal the current image; the 5651 memory of the send-to and the send-from might (partially) overlap 5652 in that case. The implementation has to take care that it handles 5653 this case, e.g. using 'memmove' which handles (partially) 5654 overlapping memory. If MAY_REQUIRE_TMP is true, the library might 5655 additionally create a temporary variable, unless additional checks 5656 show that this is not required (e.g. because walking backward is 5657 possible or because both arrays are contiguous and 'memmove' takes 5658 care of overlap issues). 5659 5660 Note that the assignment of a scalar to an array is permitted. In 5661 addition, the library has to handle numeric-type conversion and for 5662 strings, padding and different character kinds. 5663 5664 5665File: gfortran.info, Node: _gfortran_caf_get, Next: _gfortran_caf_sendget, Prev: _gfortran_caf_send, Up: Function ABI Documentation 5666 56678.2.12 '_gfortran_caf_get' -- Getting data from a remote image 5668-------------------------------------------------------------- 5669 5670_Description_: 5671 Called to get an array section or a whole array from a remote, 5672 image identified by the image_index. 5673 5674_Syntax_: 5675 'void _gfortran_caf_get (caf_token_t token, size_t offset, int 5676 image_index, gfc_descriptor_t *src, caf_vector_t *src_vector, 5677 gfc_descriptor_t *dest, int src_kind, int dst_kind, bool 5678 may_require_tmp, int *stat)' 5679 5680_Arguments_: 5681 TOKEN intent(in) An opaque pointer identifying the 5682 coarray. 5683 OFFSET intent(in) By which amount of bytes the actual 5684 data is shifted compared to the base address of 5685 the coarray. 5686 IMAGE_INDEX intent(in) The ID of the remote image; must be a 5687 positive number. 5688 DEST intent(out) Array descriptor of the local array 5689 to store the data retrieved from the remote 5690 image 5691 SRC intent(in) Array descriptor for the remote image 5692 for the bounds and the size. The 'base_addr' 5693 shall not be accessed. 5694 SRC_VECTOR intent(in) If not NULL, it contains the vector 5695 subscript of the source array; the values are 5696 relative to the dimension triplet of the SRC 5697 argument. 5698 DST_KIND intent(in) Kind of the destination argument 5699 SRC_KIND intent(in) Kind of the source argument 5700 MAY_REQUIRE_TMPintent(in) The variable is 'false' when it is 5701 known at compile time that the DEST and SRC 5702 either cannot overlap or overlap (fully or 5703 partially) such that walking SRC and DEST in 5704 element wise element order (honoring the stride 5705 value) will not lead to wrong results. 5706 Otherwise, the value is 'true'. 5707 STAT intent(out) When non-NULL give the result of the 5708 operation, i.e., zero on success and non-zero on 5709 error. When NULL and an error occurs, then an 5710 error message is printed and the program is 5711 terminated. 5712 5713_NOTES_ 5714 It is permitted to have IMAGE_INDEX equal the current image; the 5715 memory of the send-to and the send-from might (partially) overlap 5716 in that case. The implementation has to take care that it handles 5717 this case, e.g. using 'memmove' which handles (partially) 5718 overlapping memory. If MAY_REQUIRE_TMP is true, the library might 5719 additionally create a temporary variable, unless additional checks 5720 show that this is not required (e.g. because walking backward is 5721 possible or because both arrays are contiguous and 'memmove' takes 5722 care of overlap issues). 5723 5724 Note that the library has to handle numeric-type conversion and for 5725 strings, padding and different character kinds. 5726 5727 5728File: gfortran.info, Node: _gfortran_caf_sendget, Next: _gfortran_caf_send_by_ref, Prev: _gfortran_caf_get, Up: Function ABI Documentation 5729 57308.2.13 '_gfortran_caf_sendget' -- Sending data between remote images 5731-------------------------------------------------------------------- 5732 5733_Description_: 5734 Called to send a scalar, an array section or a whole array from a 5735 remote image identified by the SRC_IMAGE_INDEX to a remote image 5736 identified by the DST_IMAGE_INDEX. 5737 5738_Syntax_: 5739 'void _gfortran_caf_sendget (caf_token_t dst_token, size_t 5740 dst_offset, int dst_image_index, gfc_descriptor_t *dest, 5741 caf_vector_t *dst_vector, caf_token_t src_token, size_t src_offset, 5742 int src_image_index, gfc_descriptor_t *src, caf_vector_t 5743 *src_vector, int dst_kind, int src_kind, bool may_require_tmp, int 5744 *stat)' 5745 5746_Arguments_: 5747 DST_TOKEN intent(in) An opaque pointer identifying the 5748 destination coarray. 5749 DST_OFFSET intent(in) By which amount of bytes the actual 5750 data is shifted compared to the base address of 5751 the destination coarray. 5752 DST_IMAGE_INDEXintent(in) The ID of the destination remote 5753 image; must be a positive number. 5754 DEST intent(in) Array descriptor for the destination 5755 remote image for the bounds and the size. The 5756 'base_addr' shall not be accessed. 5757 DST_VECTOR intent(int) If not NULL, it contains the vector 5758 subscript of the destination array; the values 5759 are relative to the dimension triplet of the 5760 DEST argument. 5761 SRC_TOKEN intent(in) An opaque pointer identifying the 5762 source coarray. 5763 SRC_OFFSET intent(in) By which amount of bytes the actual 5764 data is shifted compared to the base address of 5765 the source coarray. 5766 SRC_IMAGE_INDEXintent(in) The ID of the source remote image; 5767 must be a positive number. 5768 SRC intent(in) Array descriptor of the local array 5769 to be transferred to the remote image. 5770 SRC_VECTOR intent(in) Array descriptor of the local array 5771 to be transferred to the remote image 5772 DST_KIND intent(in) Kind of the destination argument 5773 SRC_KIND intent(in) Kind of the source argument 5774 MAY_REQUIRE_TMPintent(in) The variable is 'false' when it is 5775 known at compile time that the DEST and SRC 5776 either cannot overlap or overlap (fully or 5777 partially) such that walking SRC and DEST in 5778 element wise element order (honoring the stride 5779 value) will not lead to wrong results. 5780 Otherwise, the value is 'true'. 5781 STAT intent(out) when non-NULL give the result of the 5782 operation, i.e., zero on success and non-zero on 5783 error. When NULL and an error occurs, then an 5784 error message is printed and the program is 5785 terminated. 5786 5787_NOTES_ 5788 It is permitted to have the same image index for both 5789 SRC_IMAGE_INDEX and DST_IMAGE_INDEX; the memory of the send-to and 5790 the send-from might (partially) overlap in that case. The 5791 implementation has to take care that it handles this case, e.g. 5792 using 'memmove' which handles (partially) overlapping memory. If 5793 MAY_REQUIRE_TMP is true, the library might additionally create a 5794 temporary variable, unless additional checks show that this is not 5795 required (e.g. because walking backward is possible or because 5796 both arrays are contiguous and 'memmove' takes care of overlap 5797 issues). 5798 5799 Note that the assignment of a scalar to an array is permitted. In 5800 addition, the library has to handle numeric-type conversion and for 5801 strings, padding and different character kinds. 5802 5803 5804File: gfortran.info, Node: _gfortran_caf_send_by_ref, Next: _gfortran_caf_get_by_ref, Prev: _gfortran_caf_sendget, Up: Function ABI Documentation 5805 58068.2.14 '_gfortran_caf_send_by_ref' -- Sending data from a local image to a remote image with enhanced referencing options 5807------------------------------------------------------------------------------------------------------------------------- 5808 5809_Description_: 5810 Called to send a scalar, an array section or a whole array from a 5811 local to a remote image identified by the IMAGE_INDEX. 5812 5813_Syntax_: 5814 'void _gfortran_caf_send_by_ref (caf_token_t token, int 5815 image_index, gfc_descriptor_t *src, caf_reference_t *refs, int 5816 dst_kind, int src_kind, bool may_require_tmp, bool 5817 dst_reallocatable, int *stat, int dst_type)' 5818 5819_Arguments_: 5820 TOKEN intent(in) An opaque pointer identifying the 5821 coarray. 5822 IMAGE_INDEX intent(in) The ID of the remote image; must be a 5823 positive number. 5824 SRC intent(in) Array descriptor of the local array 5825 to be transferred to the remote image 5826 REFS intent(in) The references on the remote array to 5827 store the data given by src. Guaranteed to have 5828 at least one entry. 5829 DST_KIND intent(in) Kind of the destination argument 5830 SRC_KIND intent(in) Kind of the source argument 5831 MAY_REQUIRE_TMPintent(in) The variable is 'false' when it is 5832 known at compile time that the DEST and SRC 5833 either cannot overlap or overlap (fully or 5834 partially) such that walking SRC and DEST in 5835 element wise element order (honoring the stride 5836 value) will not lead to wrong results. 5837 Otherwise, the value is 'true'. 5838 DST_REALLOCATABLEintent(in) Set when the destination is of 5839 allocatable or pointer type and the refs will 5840 allow reallocation, i.e., the ref is a full 5841 array or component ref. 5842 STAT intent(out) When non-'NULL' give the result of 5843 the operation, i.e., zero on success and 5844 non-zero on error. When 'NULL' and an error 5845 occurs, then an error message is printed and the 5846 program is terminated. 5847 DST_TYPE intent(in) Give the type of the destination. 5848 When the destination is not an array, than the 5849 precise type, e.g. of a component in a derived 5850 type, is not known, but provided here. 5851 5852_NOTES_ 5853 It is permitted to have IMAGE_INDEX equal the current image; the 5854 memory of the send-to and the send-from might (partially) overlap 5855 in that case. The implementation has to take care that it handles 5856 this case, e.g. using 'memmove' which handles (partially) 5857 overlapping memory. If MAY_REQUIRE_TMP is true, the library might 5858 additionally create a temporary variable, unless additional checks 5859 show that this is not required (e.g. because walking backward is 5860 possible or because both arrays are contiguous and 'memmove' takes 5861 care of overlap issues). 5862 5863 Note that the assignment of a scalar to an array is permitted. In 5864 addition, the library has to handle numeric-type conversion and for 5865 strings, padding and different character kinds. 5866 5867 Because of the more complicated references possible some operations 5868 may be unsupported by certain libraries. The library is expected 5869 to issue a precise error message why the operation is not 5870 permitted. 5871 5872 5873File: gfortran.info, Node: _gfortran_caf_get_by_ref, Next: _gfortran_caf_sendget_by_ref, Prev: _gfortran_caf_send_by_ref, Up: Function ABI Documentation 5874 58758.2.15 '_gfortran_caf_get_by_ref' -- Getting data from a remote image using enhanced references 5876----------------------------------------------------------------------------------------------- 5877 5878_Description_: 5879 Called to get a scalar, an array section or a whole array from a 5880 remote image identified by the IMAGE_INDEX. 5881 5882_Syntax_: 5883 'void _gfortran_caf_get_by_ref (caf_token_t token, int image_index, 5884 caf_reference_t *refs, gfc_descriptor_t *dst, int dst_kind, int 5885 src_kind, bool may_require_tmp, bool dst_reallocatable, int *stat, 5886 int src_type)' 5887 5888_Arguments_: 5889 TOKEN intent(in) An opaque pointer identifying the 5890 coarray. 5891 IMAGE_INDEX intent(in) The ID of the remote image; must be a 5892 positive number. 5893 REFS intent(in) The references to apply to the remote 5894 structure to get the data. 5895 DST intent(in) Array descriptor of the local array 5896 to store the data transferred from the remote 5897 image. May be reallocated where needed and when 5898 DST_REALLOCATABLE allows it. 5899 DST_KIND intent(in) Kind of the destination argument 5900 SRC_KIND intent(in) Kind of the source argument 5901 MAY_REQUIRE_TMPintent(in) The variable is 'false' when it is 5902 known at compile time that the DEST and SRC 5903 either cannot overlap or overlap (fully or 5904 partially) such that walking SRC and DEST in 5905 element wise element order (honoring the stride 5906 value) will not lead to wrong results. 5907 Otherwise, the value is 'true'. 5908 DST_REALLOCATABLEintent(in) Set when DST is of allocatable or 5909 pointer type and its refs allow reallocation, 5910 i.e., the full array or a component is 5911 referenced. 5912 STAT intent(out) When non-'NULL' give the result of 5913 the operation, i.e., zero on success and 5914 non-zero on error. When 'NULL' and an error 5915 occurs, then an error message is printed and the 5916 program is terminated. 5917 SRC_TYPE intent(in) Give the type of the source. When 5918 the source is not an array, than the precise 5919 type, e.g. of a component in a derived type, is 5920 not known, but provided here. 5921 5922_NOTES_ 5923 It is permitted to have 'image_index' equal the current image; the 5924 memory of the send-to and the send-from might (partially) overlap 5925 in that case. The implementation has to take care that it handles 5926 this case, e.g. using 'memmove' which handles (partially) 5927 overlapping memory. If MAY_REQUIRE_TMP is true, the library might 5928 additionally create a temporary variable, unless additional checks 5929 show that this is not required (e.g. because walking backward is 5930 possible or because both arrays are contiguous and 'memmove' takes 5931 care of overlap issues). 5932 5933 Note that the library has to handle numeric-type conversion and for 5934 strings, padding and different character kinds. 5935 5936 Because of the more complicated references possible some operations 5937 may be unsupported by certain libraries. The library is expected 5938 to issue a precise error message why the operation is not 5939 permitted. 5940 5941 5942File: gfortran.info, Node: _gfortran_caf_sendget_by_ref, Next: _gfortran_caf_lock, Prev: _gfortran_caf_get_by_ref, Up: Function ABI Documentation 5943 59448.2.16 '_gfortran_caf_sendget_by_ref' -- Sending data between remote images using enhanced references on both sides 5945------------------------------------------------------------------------------------------------------------------- 5946 5947_Description_: 5948 Called to send a scalar, an array section or a whole array from a 5949 remote image identified by the SRC_IMAGE_INDEX to a remote image 5950 identified by the DST_IMAGE_INDEX. 5951 5952_Syntax_: 5953 'void _gfortran_caf_sendget_by_ref (caf_token_t dst_token, int 5954 dst_image_index, caf_reference_t *dst_refs, caf_token_t src_token, 5955 int src_image_index, caf_reference_t *src_refs, int dst_kind, int 5956 src_kind, bool may_require_tmp, int *dst_stat, int *src_stat, int 5957 dst_type, int src_type)' 5958 5959_Arguments_: 5960 DST_TOKEN intent(in) An opaque pointer identifying the 5961 destination coarray. 5962 DST_IMAGE_INDEXintent(in) The ID of the destination remote 5963 image; must be a positive number. 5964 DST_REFS intent(in) The references on the remote array to 5965 store the data given by the source. Guaranteed 5966 to have at least one entry. 5967 SRC_TOKEN intent(in) An opaque pointer identifying the 5968 source coarray. 5969 SRC_IMAGE_INDEXintent(in) The ID of the source remote image; 5970 must be a positive number. 5971 SRC_REFS intent(in) The references to apply to the remote 5972 structure to get the data. 5973 DST_KIND intent(in) Kind of the destination argument 5974 SRC_KIND intent(in) Kind of the source argument 5975 MAY_REQUIRE_TMPintent(in) The variable is 'false' when it is 5976 known at compile time that the DEST and SRC 5977 either cannot overlap or overlap (fully or 5978 partially) such that walking SRC and DEST in 5979 element wise element order (honoring the stride 5980 value) will not lead to wrong results. 5981 Otherwise, the value is 'true'. 5982 DST_STAT intent(out) when non-'NULL' give the result of 5983 the send-operation, i.e., zero on success and 5984 non-zero on error. When 'NULL' and an error 5985 occurs, then an error message is printed and the 5986 program is terminated. 5987 SRC_STAT intent(out) When non-'NULL' give the result of 5988 the get-operation, i.e., zero on success and 5989 non-zero on error. When 'NULL' and an error 5990 occurs, then an error message is printed and the 5991 program is terminated. 5992 DST_TYPE intent(in) Give the type of the destination. 5993 When the destination is not an array, than the 5994 precise type, e.g. of a component in a derived 5995 type, is not known, but provided here. 5996 SRC_TYPE intent(in) Give the type of the source. When 5997 the source is not an array, than the precise 5998 type, e.g. of a component in a derived type, is 5999 not known, but provided here. 6000 6001_NOTES_ 6002 It is permitted to have the same image index for both 6003 SRC_IMAGE_INDEX and DST_IMAGE_INDEX; the memory of the send-to and 6004 the send-from might (partially) overlap in that case. The 6005 implementation has to take care that it handles this case, e.g. 6006 using 'memmove' which handles (partially) overlapping memory. If 6007 MAY_REQUIRE_TMP is true, the library might additionally create a 6008 temporary variable, unless additional checks show that this is not 6009 required (e.g. because walking backward is possible or because 6010 both arrays are contiguous and 'memmove' takes care of overlap 6011 issues). 6012 6013 Note that the assignment of a scalar to an array is permitted. In 6014 addition, the library has to handle numeric-type conversion and for 6015 strings, padding and different character kinds. 6016 6017 Because of the more complicated references possible some operations 6018 may be unsupported by certain libraries. The library is expected 6019 to issue a precise error message why the operation is not 6020 permitted. 6021 6022 6023File: gfortran.info, Node: _gfortran_caf_lock, Next: _gfortran_caf_unlock, Prev: _gfortran_caf_sendget_by_ref, Up: Function ABI Documentation 6024 60258.2.17 '_gfortran_caf_lock' -- Locking a lock variable 6026------------------------------------------------------ 6027 6028_Description_: 6029 Acquire a lock on the given image on a scalar locking variable or 6030 for the given array element for an array-valued variable. If the 6031 AQUIRED_LOCK is 'NULL', the function returns after having obtained 6032 the lock. If it is non-'NULL', then ACQUIRED_LOCK is assigned the 6033 value true (one) when the lock could be obtained and false (zero) 6034 otherwise. Locking a lock variable which has already been locked 6035 by the same image is an error. 6036 6037_Syntax_: 6038 'void _gfortran_caf_lock (caf_token_t token, size_t index, int 6039 image_index, int *aquired_lock, int *stat, char *errmsg, size_t 6040 errmsg_len)' 6041 6042_Arguments_: 6043 TOKEN intent(in) An opaque pointer identifying the 6044 coarray. 6045 INDEX intent(in) Array index; first array index is 0. 6046 For scalars, it is always 0. 6047 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6048 positive number. 6049 AQUIRED_LOCKintent(out) If not NULL, it returns whether lock 6050 could be obtained. 6051 STAT intent(out) Stores the STAT=; may be NULL. 6052 ERRMSG intent(out) When an error occurs, this will be 6053 set to an error message; may be NULL. 6054 ERRMSG_LEN intent(in) the buffer size of errmsg 6055 6056_NOTES_ 6057 This function is also called for critical blocks; for those, the 6058 array index is always zero and the image index is one. Libraries 6059 are permitted to use other images for critical-block locking 6060 variables. 6061 6062 6063File: gfortran.info, Node: _gfortran_caf_unlock, Next: _gfortran_caf_event_post, Prev: _gfortran_caf_lock, Up: Function ABI Documentation 6064 60658.2.18 '_gfortran_caf_lock' -- Unlocking a lock variable 6066-------------------------------------------------------- 6067 6068_Description_: 6069 Release a lock on the given image on a scalar locking variable or 6070 for the given array element for an array-valued variable. 6071 Unlocking a lock variable which is unlocked or has been locked by a 6072 different image is an error. 6073 6074_Syntax_: 6075 'void _gfortran_caf_unlock (caf_token_t token, size_t index, int 6076 image_index, int *stat, char *errmsg, size_t errmsg_len)' 6077 6078_Arguments_: 6079 TOKEN intent(in) An opaque pointer identifying the 6080 coarray. 6081 INDEX intent(in) Array index; first array index is 0. 6082 For scalars, it is always 0. 6083 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6084 positive number. 6085 STAT intent(out) For allocatable coarrays, stores the 6086 STAT=; may be NULL. 6087 ERRMSG intent(out) When an error occurs, this will be 6088 set to an error message; may be NULL. 6089 ERRMSG_LEN intent(in) the buffer size of errmsg 6090 6091_NOTES_ 6092 This function is also called for critical block; for those, the 6093 array index is always zero and the image index is one. Libraries 6094 are permitted to use other images for critical-block locking 6095 variables. 6096 6097 6098File: gfortran.info, Node: _gfortran_caf_event_post, Next: _gfortran_caf_event_wait, Prev: _gfortran_caf_unlock, Up: Function ABI Documentation 6099 61008.2.19 '_gfortran_caf_event_post' -- Post an event 6101-------------------------------------------------- 6102 6103_Description_: 6104 Increment the event count of the specified event variable. 6105 6106_Syntax_: 6107 'void _gfortran_caf_event_post (caf_token_t token, size_t index, 6108 int image_index, int *stat, char *errmsg, size_t errmsg_len)' 6109 6110_Arguments_: 6111 TOKEN intent(in) An opaque pointer identifying the 6112 coarray. 6113 INDEX intent(in) Array index; first array index is 0. 6114 For scalars, it is always 0. 6115 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6116 positive number; zero indicates the current 6117 image, when accessed noncoindexed. 6118 STAT intent(out) Stores the STAT=; may be NULL. 6119 ERRMSG intent(out) When an error occurs, this will be 6120 set to an error message; may be NULL. 6121 ERRMSG_LEN intent(in) the buffer size of errmsg 6122 6123_NOTES_ 6124 This acts like an atomic add of one to the remote image's event 6125 variable. The statement is an image-control statement but does not 6126 imply sync memory. Still, all preceeding push communications of 6127 this image to the specified remote image have to be completed 6128 before 'event_wait' on the remote image returns. 6129 6130 6131File: gfortran.info, Node: _gfortran_caf_event_wait, Next: _gfortran_caf_event_query, Prev: _gfortran_caf_event_post, Up: Function ABI Documentation 6132 61338.2.20 '_gfortran_caf_event_wait' -- Wait that an event occurred 6134---------------------------------------------------------------- 6135 6136_Description_: 6137 Wait until the event count has reached at least the specified 6138 UNTIL_COUNT; if so, atomically decrement the event variable by this 6139 amount and return. 6140 6141_Syntax_: 6142 'void _gfortran_caf_event_wait (caf_token_t token, size_t index, 6143 int until_count, int *stat, char *errmsg, size_t errmsg_len)' 6144 6145_Arguments_: 6146 TOKEN intent(in) An opaque pointer identifying the 6147 coarray. 6148 INDEX intent(in) Array index; first array index is 0. 6149 For scalars, it is always 0. 6150 UNTIL_COUNT intent(in) The number of events which have to be 6151 available before the function returns. 6152 STAT intent(out) Stores the STAT=; may be NULL. 6153 ERRMSG intent(out) When an error occurs, this will be 6154 set to an error message; may be NULL. 6155 ERRMSG_LEN intent(in) the buffer size of errmsg 6156 6157_NOTES_ 6158 This function only operates on a local coarray. It acts like a 6159 loop checking atomically the value of the event variable, breaking 6160 if the value is greater or equal the requested number of counts. 6161 Before the function returns, the event variable has to be 6162 decremented by the requested UNTIL_COUNT value. A possible 6163 implementation would be a busy loop for a certain number of spins 6164 (possibly depending on the number of threads relative to the number 6165 of available cores) followed by another waiting strategy such as a 6166 sleeping wait (possibly with an increasing number of sleep time) 6167 or, if possible, a futex wait. 6168 6169 The statement is an image-control statement but does not imply sync 6170 memory. Still, all preceeding push communications of this image to 6171 the specified remote image have to be completed before 'event_wait' 6172 on the remote image returns. 6173 6174 6175File: gfortran.info, Node: _gfortran_caf_event_query, Next: _gfortran_caf_sync_all, Prev: _gfortran_caf_event_wait, Up: Function ABI Documentation 6176 61778.2.21 '_gfortran_caf_event_query' -- Query event count 6178------------------------------------------------------- 6179 6180_Description_: 6181 Return the event count of the specified event variable. 6182 6183_Syntax_: 6184 'void _gfortran_caf_event_query (caf_token_t token, size_t index, 6185 int image_index, int *count, int *stat)' 6186 6187_Arguments_: 6188 TOKEN intent(in) An opaque pointer identifying the 6189 coarray. 6190 INDEX intent(in) Array index; first array index is 0. 6191 For scalars, it is always 0. 6192 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6193 positive number; zero indicates the current 6194 image when accessed noncoindexed. 6195 COUNT intent(out) The number of events currently 6196 posted to the event variable. 6197 STAT intent(out) Stores the STAT=; may be NULL. 6198 6199_NOTES_ 6200 The typical use is to check the local event variable to only call 6201 'event_wait' when the data is available. However, a coindexed 6202 variable is permitted; there is no ordering or synchronization 6203 implied. It acts like an atomic fetch of the value of the event 6204 variable. 6205 6206 6207File: gfortran.info, Node: _gfortran_caf_sync_all, Next: _gfortran_caf_sync_images, Prev: _gfortran_caf_event_query, Up: Function ABI Documentation 6208 62098.2.22 '_gfortran_caf_sync_all' -- All-image barrier 6210---------------------------------------------------- 6211 6212_Description_: 6213 Synchronization of all images in the current team; the program only 6214 continues on a given image after this function has been called on 6215 all images of the current team. Additionally, it ensures that all 6216 pending data transfers of previous segment have completed. 6217 6218_Syntax_: 6219 'void _gfortran_caf_sync_all (int *stat, char *errmsg, size_t 6220 errmsg_len)' 6221 6222_Arguments_: 6223 STAT intent(out) Stores the status STAT= and may be 6224 NULL. 6225 ERRMSG intent(out) When an error occurs, this will be 6226 set to an error message; may be NULL. 6227 ERRMSG_LEN intent(in) the buffer size of errmsg 6228 6229 6230File: gfortran.info, Node: _gfortran_caf_sync_images, Next: _gfortran_caf_sync_memory, Prev: _gfortran_caf_sync_all, Up: Function ABI Documentation 6231 62328.2.23 '_gfortran_caf_sync_images' -- Barrier for selected images 6233----------------------------------------------------------------- 6234 6235_Description_: 6236 Synchronization between the specified images; the program only 6237 continues on a given image after this function has been called on 6238 all images specified for that image. Note that one image can wait 6239 for all other images in the current team (e.g. via 'sync 6240 images(*)') while those only wait for that specific image. 6241 Additionally, 'sync images' ensures that all pending data transfers 6242 of previous segments have completed. 6243 6244_Syntax_: 6245 'void _gfortran_caf_sync_images (int count, int images[], int 6246 *stat, char *errmsg, size_t errmsg_len)' 6247 6248_Arguments_: 6249 COUNT intent(in) The number of images which are 6250 provided in the next argument. For a zero-sized 6251 array, the value is zero. For 'sync images 6252 (*)', the value is -1. 6253 IMAGES intent(in) An array with the images provided by 6254 the user. If COUNT is zero, a NULL pointer is 6255 passed. 6256 STAT intent(out) Stores the status STAT= and may be 6257 NULL. 6258 ERRMSG intent(out) When an error occurs, this will be 6259 set to an error message; may be NULL. 6260 ERRMSG_LEN intent(in) the buffer size of errmsg 6261 6262 6263File: gfortran.info, Node: _gfortran_caf_sync_memory, Next: _gfortran_caf_error_stop, Prev: _gfortran_caf_sync_images, Up: Function ABI Documentation 6264 62658.2.24 '_gfortran_caf_sync_memory' -- Wait for completion of segment-memory operations 6266-------------------------------------------------------------------------------------- 6267 6268_Description_: 6269 Acts as optimization barrier between different segments. It also 6270 ensures that all pending memory operations of this image have been 6271 completed. 6272 6273_Syntax_: 6274 'void _gfortran_caf_sync_memory (int *stat, char *errmsg, size_t 6275 errmsg_len)' 6276 6277_Arguments_: 6278 STAT intent(out) Stores the status STAT= and may be 6279 NULL. 6280 ERRMSG intent(out) When an error occurs, this will be 6281 set to an error message; may be NULL. 6282 ERRMSG_LEN intent(in) the buffer size of errmsg 6283 6284_NOTE_ A simple implementation could be 6285 '__asm__ __volatile__ ("":::"memory")' to prevent code movements. 6286 6287 6288File: gfortran.info, Node: _gfortran_caf_error_stop, Next: _gfortran_caf_error_stop_str, Prev: _gfortran_caf_sync_memory, Up: Function ABI Documentation 6289 62908.2.25 '_gfortran_caf_error_stop' -- Error termination with exit code 6291--------------------------------------------------------------------- 6292 6293_Description_: 6294 Invoked for an 'ERROR STOP' statement which has an integer 6295 argument. The function should terminate the program with the 6296 specified exit code. 6297 6298_Syntax_: 6299 'void _gfortran_caf_error_stop (int error)' 6300 6301_Arguments_: 6302 ERROR intent(in) The exit status to be used. 6303 6304 6305File: gfortran.info, Node: _gfortran_caf_error_stop_str, Next: _gfortran_caf_fail_image, Prev: _gfortran_caf_error_stop, Up: Function ABI Documentation 6306 63078.2.26 '_gfortran_caf_error_stop_str' -- Error termination with string 6308---------------------------------------------------------------------- 6309 6310_Description_: 6311 Invoked for an 'ERROR STOP' statement which has a string as 6312 argument. The function should terminate the program with a 6313 nonzero-exit code. 6314 6315_Syntax_: 6316 'void _gfortran_caf_error_stop (const char *string, size_t len)' 6317 6318_Arguments_: 6319 STRING intent(in) the error message (not zero 6320 terminated) 6321 LEN intent(in) the length of the string 6322 6323 6324File: gfortran.info, Node: _gfortran_caf_fail_image, Next: _gfortran_caf_atomic_define, Prev: _gfortran_caf_error_stop_str, Up: Function ABI Documentation 6325 63268.2.27 '_gfortran_caf_fail_image' -- Mark the image failed and end its execution 6327-------------------------------------------------------------------------------- 6328 6329_Description_: 6330 Invoked for an 'FAIL IMAGE' statement. The function should 6331 terminate the current image. 6332 6333_Syntax_: 6334 'void _gfortran_caf_fail_image ()' 6335 6336_NOTES_ 6337 This function follows TS18508. 6338 6339 6340File: gfortran.info, Node: _gfortran_caf_atomic_define, Next: _gfortran_caf_atomic_ref, Prev: _gfortran_caf_fail_image, Up: Function ABI Documentation 6341 63428.2.28 '_gfortran_caf_atomic_define' -- Atomic variable assignment 6343------------------------------------------------------------------ 6344 6345_Description_: 6346 Assign atomically a value to an integer or logical variable. 6347 6348_Syntax_: 6349 'void _gfortran_caf_atomic_define (caf_token_t token, size_t 6350 offset, int image_index, void *value, int *stat, int type, int 6351 kind)' 6352 6353_Arguments_: 6354 TOKEN intent(in) An opaque pointer identifying the 6355 coarray. 6356 OFFSET intent(in) By which amount of bytes the actual 6357 data is shifted compared to the base address of 6358 the coarray. 6359 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6360 positive number; zero indicates the current 6361 image when used noncoindexed. 6362 VALUE intent(in) the value to be assigned, passed by 6363 reference 6364 STAT intent(out) Stores the status STAT= and may be 6365 NULL. 6366 TYPE intent(in) The data type, i.e. 'BT_INTEGER' (1) 6367 or 'BT_LOGICAL' (2). 6368 KIND intent(in) The kind value (only 4; always 'int') 6369 6370 6371File: gfortran.info, Node: _gfortran_caf_atomic_ref, Next: _gfortran_caf_atomic_cas, Prev: _gfortran_caf_atomic_define, Up: Function ABI Documentation 6372 63738.2.29 '_gfortran_caf_atomic_ref' -- Atomic variable reference 6374-------------------------------------------------------------- 6375 6376_Description_: 6377 Reference atomically a value of a kind-4 integer or logical 6378 variable. 6379 6380_Syntax_: 6381 'void _gfortran_caf_atomic_ref (caf_token_t token, size_t offset, 6382 int image_index, void *value, int *stat, int type, int kind)' 6383 6384_Arguments_: 6385 TOKEN intent(in) An opaque pointer identifying the 6386 coarray. 6387 OFFSET intent(in) By which amount of bytes the actual 6388 data is shifted compared to the base address of 6389 the coarray. 6390 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6391 positive number; zero indicates the current 6392 image when used noncoindexed. 6393 VALUE intent(out) The variable assigned the atomically 6394 referenced variable. 6395 STAT intent(out) Stores the status STAT= and may be 6396 NULL. 6397 TYPE the data type, i.e. 'BT_INTEGER' (1) or 6398 'BT_LOGICAL' (2). 6399 KIND The kind value (only 4; always 'int') 6400 6401 6402File: gfortran.info, Node: _gfortran_caf_atomic_cas, Next: _gfortran_caf_atomic_op, Prev: _gfortran_caf_atomic_ref, Up: Function ABI Documentation 6403 64048.2.30 '_gfortran_caf_atomic_cas' -- Atomic compare and swap 6405------------------------------------------------------------ 6406 6407_Description_: 6408 Atomic compare and swap of a kind-4 integer or logical variable. 6409 Assigns atomically the specified value to the atomic variable, if 6410 the latter has the value specified by the passed condition value. 6411 6412_Syntax_: 6413 'void _gfortran_caf_atomic_cas (caf_token_t token, size_t offset, 6414 int image_index, void *old, void *compare, void *new_val, int 6415 *stat, int type, int kind)' 6416 6417_Arguments_: 6418 TOKEN intent(in) An opaque pointer identifying the 6419 coarray. 6420 OFFSET intent(in) By which amount of bytes the actual 6421 data is shifted compared to the base address of 6422 the coarray. 6423 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6424 positive number; zero indicates the current 6425 image when used noncoindexed. 6426 OLD intent(out) The value which the atomic variable 6427 had just before the cas operation. 6428 COMPARE intent(in) The value used for comparision. 6429 NEW_VAL intent(in) The new value for the atomic 6430 variable, assigned to the atomic variable, if 6431 'compare' equals the value of the atomic 6432 variable. 6433 STAT intent(out) Stores the status STAT= and may be 6434 NULL. 6435 TYPE intent(in) the data type, i.e. 'BT_INTEGER' (1) 6436 or 'BT_LOGICAL' (2). 6437 KIND intent(in) The kind value (only 4; always 'int') 6438 6439 6440File: gfortran.info, Node: _gfortran_caf_atomic_op, Next: _gfortran_caf_co_broadcast, Prev: _gfortran_caf_atomic_cas, Up: Function ABI Documentation 6441 64428.2.31 '_gfortran_caf_atomic_op' -- Atomic operation 6443---------------------------------------------------- 6444 6445_Description_: 6446 Apply an operation atomically to an atomic integer or logical 6447 variable. After the operation, OLD contains the value just before 6448 the operation, which, respectively, adds (GFC_CAF_ATOMIC_ADD) 6449 atomically the 'value' to the atomic integer variable or does a 6450 bitwise AND, OR or exclusive OR between the atomic variable and 6451 VALUE; the result is then stored in the atomic variable. 6452 6453_Syntax_: 6454 'void _gfortran_caf_atomic_op (int op, caf_token_t token, size_t 6455 offset, int image_index, void *value, void *old, int *stat, int 6456 type, int kind)' 6457 6458_Arguments_: 6459 OP intent(in) the operation to be performed; 6460 possible values 'GFC_CAF_ATOMIC_ADD' (1), 6461 'GFC_CAF_ATOMIC_AND' (2), 'GFC_CAF_ATOMIC_OR' 6462 (3), 'GFC_CAF_ATOMIC_XOR' (4). 6463 TOKEN intent(in) An opaque pointer identifying the 6464 coarray. 6465 OFFSET intent(in) By which amount of bytes the actual 6466 data is shifted compared to the base address of 6467 the coarray. 6468 IMAGE_INDEX intent(in) The ID of the remote image; must be a 6469 positive number; zero indicates the current 6470 image when used noncoindexed. 6471 OLD intent(out) The value which the atomic variable 6472 had just before the atomic operation. 6473 VAL intent(in) The new value for the atomic 6474 variable, assigned to the atomic variable, if 6475 'compare' equals the value of the atomic 6476 variable. 6477 STAT intent(out) Stores the status STAT= and may be 6478 NULL. 6479 TYPE intent(in) the data type, i.e. 'BT_INTEGER' (1) 6480 or 'BT_LOGICAL' (2) 6481 KIND intent(in) the kind value (only 4; always 'int') 6482 6483 6484File: gfortran.info, Node: _gfortran_caf_co_broadcast, Next: _gfortran_caf_co_max, Prev: _gfortran_caf_atomic_op, Up: Function ABI Documentation 6485 64868.2.32 '_gfortran_caf_co_broadcast' -- Sending data to all images 6487----------------------------------------------------------------- 6488 6489_Description_: 6490 Distribute a value from a given image to all other images in the 6491 team. Has to be called collectively. 6492 6493_Syntax_: 6494 'void _gfortran_caf_co_broadcast (gfc_descriptor_t *a, int 6495 source_image, int *stat, char *errmsg, size_t errmsg_len)' 6496 6497_Arguments_: 6498 A intent(inout) An array descriptor with the data 6499 to be broadcasted (on SOURCE_IMAGE) or to be 6500 received (other images). 6501 SOURCE_IMAGEintent(in) The ID of the image from which the 6502 data should be broadcasted. 6503 STAT intent(out) Stores the status STAT= and may be 6504 NULL. 6505 ERRMSG intent(out) When an error occurs, this will be 6506 set to an error message; may be NULL. 6507 ERRMSG_LEN intent(in) the buffer size of errmsg. 6508 6509 6510File: gfortran.info, Node: _gfortran_caf_co_max, Next: _gfortran_caf_co_min, Prev: _gfortran_caf_co_broadcast, Up: Function ABI Documentation 6511 65128.2.33 '_gfortran_caf_co_max' -- Collective maximum reduction 6513------------------------------------------------------------- 6514 6515_Description_: 6516 Calculates for each array element of the variable A the maximum 6517 value for that element in the current team; if RESULT_IMAGE has the 6518 value 0, the result shall be stored on all images, otherwise, only 6519 on the specified image. This function operates on numeric values 6520 and character strings. 6521 6522_Syntax_: 6523 'void _gfortran_caf_co_max (gfc_descriptor_t *a, int result_image, 6524 int *stat, char *errmsg, int a_len, size_t errmsg_len)' 6525 6526_Arguments_: 6527 A intent(inout) An array descriptor for the data 6528 to be processed. On the destination image(s) 6529 the result overwrites the old content. 6530 RESULT_IMAGEintent(in) The ID of the image to which the 6531 reduced value should be copied to; if zero, it 6532 has to be copied to all images. 6533 STAT intent(out) Stores the status STAT= and may be 6534 NULL. 6535 ERRMSG intent(out) When an error occurs, this will be 6536 set to an error message; may be NULL. 6537 A_LEN intent(in) the string length of argument A 6538 ERRMSG_LEN intent(in) the buffer size of errmsg 6539 6540_NOTES_ 6541 If RESULT_IMAGE is nonzero, the data in the array descriptor A on 6542 all images except of the specified one become undefined; hence, the 6543 library may make use of this. 6544 6545 6546File: gfortran.info, Node: _gfortran_caf_co_min, Next: _gfortran_caf_co_sum, Prev: _gfortran_caf_co_max, Up: Function ABI Documentation 6547 65488.2.34 '_gfortran_caf_co_min' -- Collective minimum reduction 6549------------------------------------------------------------- 6550 6551_Description_: 6552 Calculates for each array element of the variable A the minimum 6553 value for that element in the current team; if RESULT_IMAGE has the 6554 value 0, the result shall be stored on all images, otherwise, only 6555 on the specified image. This function operates on numeric values 6556 and character strings. 6557 6558_Syntax_: 6559 'void _gfortran_caf_co_min (gfc_descriptor_t *a, int result_image, 6560 int *stat, char *errmsg, int a_len, size_t errmsg_len)' 6561 6562_Arguments_: 6563 A intent(inout) An array descriptor for the data 6564 to be processed. On the destination image(s) 6565 the result overwrites the old content. 6566 RESULT_IMAGEintent(in) The ID of the image to which the 6567 reduced value should be copied to; if zero, it 6568 has to be copied to all images. 6569 STAT intent(out) Stores the status STAT= and may be 6570 NULL. 6571 ERRMSG intent(out) When an error occurs, this will be 6572 set to an error message; may be NULL. 6573 A_LEN intent(in) the string length of argument A 6574 ERRMSG_LEN intent(in) the buffer size of errmsg 6575 6576_NOTES_ 6577 If RESULT_IMAGE is nonzero, the data in the array descriptor A on 6578 all images except of the specified one become undefined; hence, the 6579 library may make use of this. 6580 6581 6582File: gfortran.info, Node: _gfortran_caf_co_sum, Next: _gfortran_caf_co_reduce, Prev: _gfortran_caf_co_min, Up: Function ABI Documentation 6583 65848.2.35 '_gfortran_caf_co_sum' -- Collective summing reduction 6585------------------------------------------------------------- 6586 6587_Description_: 6588 Calculates for each array element of the variable A the sum of all 6589 values for that element in the current team; if RESULT_IMAGE has 6590 the value 0, the result shall be stored on all images, otherwise, 6591 only on the specified image. This function operates on numeric 6592 values only. 6593 6594_Syntax_: 6595 'void _gfortran_caf_co_sum (gfc_descriptor_t *a, int result_image, 6596 int *stat, char *errmsg, size_t errmsg_len)' 6597 6598_Arguments_: 6599 A intent(inout) An array descriptor with the data 6600 to be processed. On the destination image(s) 6601 the result overwrites the old content. 6602 RESULT_IMAGEintent(in) The ID of the image to which the 6603 reduced value should be copied to; if zero, it 6604 has to be copied to all images. 6605 STAT intent(out) Stores the status STAT= and may be 6606 NULL. 6607 ERRMSG intent(out) When an error occurs, this will be 6608 set to an error message; may be NULL. 6609 ERRMSG_LEN intent(in) the buffer size of errmsg 6610 6611_NOTES_ 6612 If RESULT_IMAGE is nonzero, the data in the array descriptor A on 6613 all images except of the specified one become undefined; hence, the 6614 library may make use of this. 6615 6616 6617File: gfortran.info, Node: _gfortran_caf_co_reduce, Prev: _gfortran_caf_co_sum, Up: Function ABI Documentation 6618 66198.2.36 '_gfortran_caf_co_reduce' -- Generic collective reduction 6620---------------------------------------------------------------- 6621 6622_Description_: 6623 Calculates for each array element of the variable A the reduction 6624 value for that element in the current team; if RESULT_IMAGE has the 6625 value 0, the result shall be stored on all images, otherwise, only 6626 on the specified image. The OPR is a pure function doing a 6627 mathematically commutative and associative operation. 6628 6629 The OPR_FLAGS denote the following; the values are bitwise ored. 6630 'GFC_CAF_BYREF' (1) if the result should be returned by reference; 6631 'GFC_CAF_HIDDENLEN' (2) whether the result and argument string 6632 lengths shall be specified as hidden arguments; 'GFC_CAF_ARG_VALUE' 6633 (4) whether the arguments shall be passed by value, 6634 'GFC_CAF_ARG_DESC' (8) whether the arguments shall be passed by 6635 descriptor. 6636 6637_Syntax_: 6638 'void _gfortran_caf_co_reduce (gfc_descriptor_t *a, void * (*opr) 6639 (void *, void *), int opr_flags, int result_image, int *stat, char 6640 *errmsg, int a_len, size_t errmsg_len)' 6641 6642_Arguments_: 6643 A intent(inout) An array descriptor with the data 6644 to be processed. On the destination image(s) 6645 the result overwrites the old content. 6646 OPR intent(in) Function pointer to the reduction 6647 function 6648 OPR_FLAGS intent(in) Flags regarding the reduction 6649 function 6650 RESULT_IMAGEintent(in) The ID of the image to which the 6651 reduced value should be copied to; if zero, it 6652 has to be copied to all images. 6653 STAT intent(out) Stores the status STAT= and may be 6654 NULL. 6655 ERRMSG intent(out) When an error occurs, this will be 6656 set to an error message; may be NULL. 6657 A_LEN intent(in) the string length of argument A 6658 ERRMSG_LEN intent(in) the buffer size of errmsg 6659 6660_NOTES_ 6661 If RESULT_IMAGE is nonzero, the data in the array descriptor A on 6662 all images except of the specified one become undefined; hence, the 6663 library may make use of this. 6664 6665 For character arguments, the result is passed as first argument, 6666 followed by the result string length, next come the two string 6667 arguments, followed by the two hidden string length arguments. 6668 With C binding, there are no hidden arguments and by-reference 6669 passing and either only a single character is passed or an array 6670 descriptor. 6671 6672 6673File: gfortran.info, Node: Intrinsic Procedures, Next: Intrinsic Modules, Prev: Coarray Programming, Up: Top 6674 66759 Intrinsic Procedures 6676********************** 6677 6678* Menu: 6679 6680* Introduction: Introduction to Intrinsics 6681* 'ABORT': ABORT, Abort the program 6682* 'ABS': ABS, Absolute value 6683* 'ACCESS': ACCESS, Checks file access modes 6684* 'ACHAR': ACHAR, Character in ASCII collating sequence 6685* 'ACOS': ACOS, Arccosine function 6686* 'ACOSD': ACOSD, Arccosine function, degrees 6687* 'ACOSH': ACOSH, Inverse hyperbolic cosine function 6688* 'ADJUSTL': ADJUSTL, Left adjust a string 6689* 'ADJUSTR': ADJUSTR, Right adjust a string 6690* 'AIMAG': AIMAG, Imaginary part of complex number 6691* 'AINT': AINT, Truncate to a whole number 6692* 'ALARM': ALARM, Set an alarm clock 6693* 'ALL': ALL, Determine if all values are true 6694* 'ALLOCATED': ALLOCATED, Status of allocatable entity 6695* 'AND': AND, Bitwise logical AND 6696* 'ANINT': ANINT, Nearest whole number 6697* 'ANY': ANY, Determine if any values are true 6698* 'ASIN': ASIN, Arcsine function 6699* 'ASIND': ASIND, Arcsine function, degrees 6700* 'ASINH': ASINH, Inverse hyperbolic sine function 6701* 'ASSOCIATED': ASSOCIATED, Status of a pointer or pointer/target pair 6702* 'ATAN': ATAN, Arctangent function 6703* 'ATAND': ATAND, Arctangent function, degrees 6704* 'ATAN2': ATAN2, Arctangent function 6705* 'ATAN2D': ATAN2D, Arctangent function, degrees 6706* 'ATANH': ATANH, Inverse hyperbolic tangent function 6707* 'ATOMIC_ADD': ATOMIC_ADD, Atomic ADD operation 6708* 'ATOMIC_AND': ATOMIC_AND, Atomic bitwise AND operation 6709* 'ATOMIC_CAS': ATOMIC_CAS, Atomic compare and swap 6710* 'ATOMIC_DEFINE': ATOMIC_DEFINE, Setting a variable atomically 6711* 'ATOMIC_FETCH_ADD': ATOMIC_FETCH_ADD, Atomic ADD operation with prior fetch 6712* 'ATOMIC_FETCH_AND': ATOMIC_FETCH_AND, Atomic bitwise AND operation with prior fetch 6713* 'ATOMIC_FETCH_OR': ATOMIC_FETCH_OR, Atomic bitwise OR operation with prior fetch 6714* 'ATOMIC_FETCH_XOR': ATOMIC_FETCH_XOR, Atomic bitwise XOR operation with prior fetch 6715* 'ATOMIC_OR': ATOMIC_OR, Atomic bitwise OR operation 6716* 'ATOMIC_REF': ATOMIC_REF, Obtaining the value of a variable atomically 6717* 'ATOMIC_XOR': ATOMIC_XOR, Atomic bitwise OR operation 6718* 'BACKTRACE': BACKTRACE, Show a backtrace 6719* 'BESSEL_J0': BESSEL_J0, Bessel function of the first kind of order 0 6720* 'BESSEL_J1': BESSEL_J1, Bessel function of the first kind of order 1 6721* 'BESSEL_JN': BESSEL_JN, Bessel function of the first kind 6722* 'BESSEL_Y0': BESSEL_Y0, Bessel function of the second kind of order 0 6723* 'BESSEL_Y1': BESSEL_Y1, Bessel function of the second kind of order 1 6724* 'BESSEL_YN': BESSEL_YN, Bessel function of the second kind 6725* 'BGE': BGE, Bitwise greater than or equal to 6726* 'BGT': BGT, Bitwise greater than 6727* 'BIT_SIZE': BIT_SIZE, Bit size inquiry function 6728* 'BLE': BLE, Bitwise less than or equal to 6729* 'BLT': BLT, Bitwise less than 6730* 'BTEST': BTEST, Bit test function 6731* 'C_ASSOCIATED': C_ASSOCIATED, Status of a C pointer 6732* 'C_F_POINTER': C_F_POINTER, Convert C into Fortran pointer 6733* 'C_F_PROCPOINTER': C_F_PROCPOINTER, Convert C into Fortran procedure pointer 6734* 'C_FUNLOC': C_FUNLOC, Obtain the C address of a procedure 6735* 'C_LOC': C_LOC, Obtain the C address of an object 6736* 'C_SIZEOF': C_SIZEOF, Size in bytes of an expression 6737* 'CEILING': CEILING, Integer ceiling function 6738* 'CHAR': CHAR, Integer-to-character conversion function 6739* 'CHDIR': CHDIR, Change working directory 6740* 'CHMOD': CHMOD, Change access permissions of files 6741* 'CMPLX': CMPLX, Complex conversion function 6742* 'CO_BROADCAST': CO_BROADCAST, Copy a value to all images the current set of images 6743* 'CO_MAX': CO_MAX, Maximal value on the current set of images 6744* 'CO_MIN': CO_MIN, Minimal value on the current set of images 6745* 'CO_REDUCE': CO_REDUCE, Reduction of values on the current set of images 6746* 'CO_SUM': CO_SUM, Sum of values on the current set of images 6747* 'COMMAND_ARGUMENT_COUNT': COMMAND_ARGUMENT_COUNT, Get number of command line arguments 6748* 'COMPILER_OPTIONS': COMPILER_OPTIONS, Options passed to the compiler 6749* 'COMPILER_VERSION': COMPILER_VERSION, Compiler version string 6750* 'COMPLEX': COMPLEX, Complex conversion function 6751* 'CONJG': CONJG, Complex conjugate function 6752* 'COS': COS, Cosine function 6753* 'COSD': COSD, Cosine function, degrees 6754* 'COSH': COSH, Hyperbolic cosine function 6755* 'COTAN': COTAN, Cotangent function 6756* 'COTAND': COTAND, Cotangent function, degrees 6757* 'COUNT': COUNT, Count occurrences of TRUE in an array 6758* 'CPU_TIME': CPU_TIME, CPU time subroutine 6759* 'CSHIFT': CSHIFT, Circular shift elements of an array 6760* 'CTIME': CTIME, Subroutine (or function) to convert a time into a string 6761* 'DATE_AND_TIME': DATE_AND_TIME, Date and time subroutine 6762* 'DBLE': DBLE, Double precision conversion function 6763* 'DCMPLX': DCMPLX, Double complex conversion function 6764* 'DIGITS': DIGITS, Significant digits function 6765* 'DIM': DIM, Positive difference 6766* 'DOT_PRODUCT': DOT_PRODUCT, Dot product function 6767* 'DPROD': DPROD, Double product function 6768* 'DREAL': DREAL, Double real part function 6769* 'DSHIFTL': DSHIFTL, Combined left shift 6770* 'DSHIFTR': DSHIFTR, Combined right shift 6771* 'DTIME': DTIME, Execution time subroutine (or function) 6772* 'EOSHIFT': EOSHIFT, End-off shift elements of an array 6773* 'EPSILON': EPSILON, Epsilon function 6774* 'ERF': ERF, Error function 6775* 'ERFC': ERFC, Complementary error function 6776* 'ERFC_SCALED': ERFC_SCALED, Exponentially-scaled complementary error function 6777* 'ETIME': ETIME, Execution time subroutine (or function) 6778* 'EVENT_QUERY': EVENT_QUERY, Query whether a coarray event has occurred 6779* 'EXECUTE_COMMAND_LINE': EXECUTE_COMMAND_LINE, Execute a shell command 6780* 'EXIT': EXIT, Exit the program with status. 6781* 'EXP': EXP, Exponential function 6782* 'EXPONENT': EXPONENT, Exponent function 6783* 'EXTENDS_TYPE_OF': EXTENDS_TYPE_OF, Query dynamic type for extension 6784* 'FDATE': FDATE, Subroutine (or function) to get the current time as a string 6785* 'FGET': FGET, Read a single character in stream mode from stdin 6786* 'FGETC': FGETC, Read a single character in stream mode 6787* 'FLOOR': FLOOR, Integer floor function 6788* 'FLUSH': FLUSH, Flush I/O unit(s) 6789* 'FNUM': FNUM, File number function 6790* 'FPUT': FPUT, Write a single character in stream mode to stdout 6791* 'FPUTC': FPUTC, Write a single character in stream mode 6792* 'FRACTION': FRACTION, Fractional part of the model representation 6793* 'FREE': FREE, Memory de-allocation subroutine 6794* 'FSEEK': FSEEK, Low level file positioning subroutine 6795* 'FSTAT': FSTAT, Get file status 6796* 'FTELL': FTELL, Current stream position 6797* 'GAMMA': GAMMA, Gamma function 6798* 'GERROR': GERROR, Get last system error message 6799* 'GETARG': GETARG, Get command line arguments 6800* 'GET_COMMAND': GET_COMMAND, Get the entire command line 6801* 'GET_COMMAND_ARGUMENT': GET_COMMAND_ARGUMENT, Get command line arguments 6802* 'GETCWD': GETCWD, Get current working directory 6803* 'GETENV': GETENV, Get an environmental variable 6804* 'GET_ENVIRONMENT_VARIABLE': GET_ENVIRONMENT_VARIABLE, Get an environmental variable 6805* 'GETGID': GETGID, Group ID function 6806* 'GETLOG': GETLOG, Get login name 6807* 'GETPID': GETPID, Process ID function 6808* 'GETUID': GETUID, User ID function 6809* 'GMTIME': GMTIME, Convert time to GMT info 6810* 'HOSTNM': HOSTNM, Get system host name 6811* 'HUGE': HUGE, Largest number of a kind 6812* 'HYPOT': HYPOT, Euclidean distance function 6813* 'IACHAR': IACHAR, Code in ASCII collating sequence 6814* 'IALL': IALL, Bitwise AND of array elements 6815* 'IAND': IAND, Bitwise logical and 6816* 'IANY': IANY, Bitwise OR of array elements 6817* 'IARGC': IARGC, Get the number of command line arguments 6818* 'IBCLR': IBCLR, Clear bit 6819* 'IBITS': IBITS, Bit extraction 6820* 'IBSET': IBSET, Set bit 6821* 'ICHAR': ICHAR, Character-to-integer conversion function 6822* 'IDATE': IDATE, Current local time (day/month/year) 6823* 'IEOR': IEOR, Bitwise logical exclusive or 6824* 'IERRNO': IERRNO, Function to get the last system error number 6825* 'IMAGE_INDEX': IMAGE_INDEX, Cosubscript to image index conversion 6826* 'INDEX': INDEX intrinsic, Position of a substring within a string 6827* 'INT': INT, Convert to integer type 6828* 'INT2': INT2, Convert to 16-bit integer type 6829* 'INT8': INT8, Convert to 64-bit integer type 6830* 'IOR': IOR, Bitwise logical or 6831* 'IPARITY': IPARITY, Bitwise XOR of array elements 6832* 'IRAND': IRAND, Integer pseudo-random number 6833* 'IS_IOSTAT_END': IS_IOSTAT_END, Test for end-of-file value 6834* 'IS_IOSTAT_EOR': IS_IOSTAT_EOR, Test for end-of-record value 6835* 'ISATTY': ISATTY, Whether a unit is a terminal device 6836* 'ISHFT': ISHFT, Shift bits 6837* 'ISHFTC': ISHFTC, Shift bits circularly 6838* 'ISNAN': ISNAN, Tests for a NaN 6839* 'ITIME': ITIME, Current local time (hour/minutes/seconds) 6840* 'KILL': KILL, Send a signal to a process 6841* 'KIND': KIND, Kind of an entity 6842* 'LBOUND': LBOUND, Lower dimension bounds of an array 6843* 'LCOBOUND': LCOBOUND, Lower codimension bounds of an array 6844* 'LEADZ': LEADZ, Number of leading zero bits of an integer 6845* 'LEN': LEN, Length of a character entity 6846* 'LEN_TRIM': LEN_TRIM, Length of a character entity without trailing blank characters 6847* 'LGE': LGE, Lexical greater than or equal 6848* 'LGT': LGT, Lexical greater than 6849* 'LINK': LINK, Create a hard link 6850* 'LLE': LLE, Lexical less than or equal 6851* 'LLT': LLT, Lexical less than 6852* 'LNBLNK': LNBLNK, Index of the last non-blank character in a string 6853* 'LOC': LOC, Returns the address of a variable 6854* 'LOG': LOG, Logarithm function 6855* 'LOG10': LOG10, Base 10 logarithm function 6856* 'LOG_GAMMA': LOG_GAMMA, Logarithm of the Gamma function 6857* 'LOGICAL': LOGICAL, Convert to logical type 6858* 'LONG': LONG, Convert to integer type 6859* 'LSHIFT': LSHIFT, Left shift bits 6860* 'LSTAT': LSTAT, Get file status 6861* 'LTIME': LTIME, Convert time to local time info 6862* 'MALLOC': MALLOC, Dynamic memory allocation function 6863* 'MASKL': MASKL, Left justified mask 6864* 'MASKR': MASKR, Right justified mask 6865* 'MATMUL': MATMUL, matrix multiplication 6866* 'MAX': MAX, Maximum value of an argument list 6867* 'MAXEXPONENT': MAXEXPONENT, Maximum exponent of a real kind 6868* 'MAXLOC': MAXLOC, Location of the maximum value within an array 6869* 'MAXVAL': MAXVAL, Maximum value of an array 6870* 'MCLOCK': MCLOCK, Time function 6871* 'MCLOCK8': MCLOCK8, Time function (64-bit) 6872* 'MERGE': MERGE, Merge arrays 6873* 'MERGE_BITS': MERGE_BITS, Merge of bits under mask 6874* 'MIN': MIN, Minimum value of an argument list 6875* 'MINEXPONENT': MINEXPONENT, Minimum exponent of a real kind 6876* 'MINLOC': MINLOC, Location of the minimum value within an array 6877* 'MINVAL': MINVAL, Minimum value of an array 6878* 'MOD': MOD, Remainder function 6879* 'MODULO': MODULO, Modulo function 6880* 'MOVE_ALLOC': MOVE_ALLOC, Move allocation from one object to another 6881* 'MVBITS': MVBITS, Move bits from one integer to another 6882* 'NEAREST': NEAREST, Nearest representable number 6883* 'NEW_LINE': NEW_LINE, New line character 6884* 'NINT': NINT, Nearest whole number 6885* 'NORM2': NORM2, Euclidean vector norm 6886* 'NOT': NOT, Logical negation 6887* 'NULL': NULL, Function that returns an disassociated pointer 6888* 'NUM_IMAGES': NUM_IMAGES, Number of images 6889* 'OR': OR, Bitwise logical OR 6890* 'PACK': PACK, Pack an array into an array of rank one 6891* 'PARITY': PARITY, Reduction with exclusive OR 6892* 'PERROR': PERROR, Print system error message 6893* 'POPCNT': POPCNT, Number of bits set 6894* 'POPPAR': POPPAR, Parity of the number of bits set 6895* 'PRECISION': PRECISION, Decimal precision of a real kind 6896* 'PRESENT': PRESENT, Determine whether an optional dummy argument is specified 6897* 'PRODUCT': PRODUCT, Product of array elements 6898* 'RADIX': RADIX, Base of a data model 6899* 'RAN': RAN, Real pseudo-random number 6900* 'RAND': RAND, Real pseudo-random number 6901* 'RANDOM_NUMBER': RANDOM_NUMBER, Pseudo-random number 6902* 'RANDOM_SEED': RANDOM_SEED, Initialize a pseudo-random number sequence 6903* 'RANGE': RANGE, Decimal exponent range 6904* 'RANK' : RANK, Rank of a data object 6905* 'REAL': REAL, Convert to real type 6906* 'RENAME': RENAME, Rename a file 6907* 'REPEAT': REPEAT, Repeated string concatenation 6908* 'RESHAPE': RESHAPE, Function to reshape an array 6909* 'RRSPACING': RRSPACING, Reciprocal of the relative spacing 6910* 'RSHIFT': RSHIFT, Right shift bits 6911* 'SAME_TYPE_AS': SAME_TYPE_AS, Query dynamic types for equality 6912* 'SCALE': SCALE, Scale a real value 6913* 'SCAN': SCAN, Scan a string for the presence of a set of characters 6914* 'SECNDS': SECNDS, Time function 6915* 'SECOND': SECOND, CPU time function 6916* 'SELECTED_CHAR_KIND': SELECTED_CHAR_KIND, Choose character kind 6917* 'SELECTED_INT_KIND': SELECTED_INT_KIND, Choose integer kind 6918* 'SELECTED_REAL_KIND': SELECTED_REAL_KIND, Choose real kind 6919* 'SET_EXPONENT': SET_EXPONENT, Set the exponent of the model 6920* 'SHAPE': SHAPE, Determine the shape of an array 6921* 'SHIFTA': SHIFTA, Right shift with fill 6922* 'SHIFTL': SHIFTL, Left shift 6923* 'SHIFTR': SHIFTR, Right shift 6924* 'SIGN': SIGN, Sign copying function 6925* 'SIGNAL': SIGNAL, Signal handling subroutine (or function) 6926* 'SIN': SIN, Sine function 6927* 'SIND': SIND, Sine function, degrees 6928* 'SINH': SINH, Hyperbolic sine function 6929* 'SIZE': SIZE, Function to determine the size of an array 6930* 'SIZEOF': SIZEOF, Determine the size in bytes of an expression 6931* 'SLEEP': SLEEP, Sleep for the specified number of seconds 6932* 'SPACING': SPACING, Smallest distance between two numbers of a given type 6933* 'SPREAD': SPREAD, Add a dimension to an array 6934* 'SQRT': SQRT, Square-root function 6935* 'SRAND': SRAND, Reinitialize the random number generator 6936* 'STAT': STAT, Get file status 6937* 'STORAGE_SIZE': STORAGE_SIZE, Storage size in bits 6938* 'SUM': SUM, Sum of array elements 6939* 'SYMLNK': SYMLNK, Create a symbolic link 6940* 'SYSTEM': SYSTEM, Execute a shell command 6941* 'SYSTEM_CLOCK': SYSTEM_CLOCK, Time function 6942* 'TAN': TAN, Tangent function 6943* 'TAND': TAND, Tangent function, degrees 6944* 'TANH': TANH, Hyperbolic tangent function 6945* 'THIS_IMAGE': THIS_IMAGE, Cosubscript index of this image 6946* 'TIME': TIME, Time function 6947* 'TIME8': TIME8, Time function (64-bit) 6948* 'TINY': TINY, Smallest positive number of a real kind 6949* 'TRAILZ': TRAILZ, Number of trailing zero bits of an integer 6950* 'TRANSFER': TRANSFER, Transfer bit patterns 6951* 'TRANSPOSE': TRANSPOSE, Transpose an array of rank two 6952* 'TRIM': TRIM, Remove trailing blank characters of a string 6953* 'TTYNAM': TTYNAM, Get the name of a terminal device. 6954* 'UBOUND': UBOUND, Upper dimension bounds of an array 6955* 'UCOBOUND': UCOBOUND, Upper codimension bounds of an array 6956* 'UMASK': UMASK, Set the file creation mask 6957* 'UNLINK': UNLINK, Remove a file from the file system 6958* 'UNPACK': UNPACK, Unpack an array of rank one into an array 6959* 'VERIFY': VERIFY, Scan a string for the absence of a set of characters 6960* 'XOR': XOR, Bitwise logical exclusive or 6961 6962 6963File: gfortran.info, Node: Introduction to Intrinsics, Next: ABORT, Up: Intrinsic Procedures 6964 69659.1 Introduction to intrinsic procedures 6966======================================== 6967 6968The intrinsic procedures provided by GNU Fortran include all of the 6969intrinsic procedures required by the Fortran 95 standard, a set of 6970intrinsic procedures for backwards compatibility with G77, and a 6971selection of intrinsic procedures from the Fortran 2003 and Fortran 2008 6972standards. Any conflict between a description here and a description in 6973either the Fortran 95 standard, the Fortran 2003 standard or the Fortran 69742008 standard is unintentional, and the standard(s) should be considered 6975authoritative. 6976 6977 The enumeration of the 'KIND' type parameter is processor defined in 6978the Fortran 95 standard. GNU Fortran defines the default integer type 6979and default real type by 'INTEGER(KIND=4)' and 'REAL(KIND=4)', 6980respectively. The standard mandates that both data types shall have 6981another kind, which have more precision. On typical target 6982architectures supported by 'gfortran', this kind type parameter is 6983'KIND=8'. Hence, 'REAL(KIND=8)' and 'DOUBLE PRECISION' are equivalent. 6984In the description of generic intrinsic procedures, the kind type 6985parameter will be specified by 'KIND=*', and in the description of 6986specific names for an intrinsic procedure the kind type parameter will 6987be explicitly given (e.g., 'REAL(KIND=4)' or 'REAL(KIND=8)'). Finally, 6988for brevity the optional 'KIND=' syntax will be omitted. 6989 6990 Many of the intrinsic procedures take one or more optional arguments. 6991This document follows the convention used in the Fortran 95 standard, 6992and denotes such arguments by square brackets. 6993 6994 GNU Fortran offers the '-std=f95' and '-std=gnu' options, which can 6995be used to restrict the set of intrinsic procedures to a given standard. 6996By default, 'gfortran' sets the '-std=gnu' option, and so all intrinsic 6997procedures described here are accepted. There is one caveat. For a 6998select group of intrinsic procedures, 'g77' implemented both a function 6999and a subroutine. Both classes have been implemented in 'gfortran' for 7000backwards compatibility with 'g77'. It is noted here that these 7001functions and subroutines cannot be intermixed in a given subprogram. 7002In the descriptions that follow, the applicable standard for each 7003intrinsic procedure is noted. 7004 7005 7006File: gfortran.info, Node: ABORT, Next: ABS, Prev: Introduction to Intrinsics, Up: Intrinsic Procedures 7007 70089.2 'ABORT' -- Abort the program 7009================================ 7010 7011_Description_: 7012 'ABORT' causes immediate termination of the program. On operating 7013 systems that support a core dump, 'ABORT' will produce a core dump. 7014 It will also print a backtrace, unless '-fno-backtrace' is given. 7015 7016_Standard_: 7017 GNU extension 7018 7019_Class_: 7020 Subroutine 7021 7022_Syntax_: 7023 'CALL ABORT' 7024 7025_Return value_: 7026 Does not return. 7027 7028_Example_: 7029 program test_abort 7030 integer :: i = 1, j = 2 7031 if (i /= j) call abort 7032 end program test_abort 7033 7034_See also_: 7035 *note EXIT::, *note KILL::, *note BACKTRACE:: 7036 7037 7038File: gfortran.info, Node: ABS, Next: ACCESS, Prev: ABORT, Up: Intrinsic Procedures 7039 70409.3 'ABS' -- Absolute value 7041=========================== 7042 7043_Description_: 7044 'ABS(A)' computes the absolute value of 'A'. 7045 7046_Standard_: 7047 Fortran 77 and later, has overloads that are GNU extensions 7048 7049_Class_: 7050 Elemental function 7051 7052_Syntax_: 7053 'RESULT = ABS(A)' 7054 7055_Arguments_: 7056 A The type of the argument shall be an 'INTEGER', 7057 'REAL', or 'COMPLEX'. 7058 7059_Return value_: 7060 The return value is of the same type and kind as the argument 7061 except the return value is 'REAL' for a 'COMPLEX' argument. 7062 7063_Example_: 7064 program test_abs 7065 integer :: i = -1 7066 real :: x = -1.e0 7067 complex :: z = (-1.e0,0.e0) 7068 i = abs(i) 7069 x = abs(x) 7070 x = abs(z) 7071 end program test_abs 7072 7073_Specific names_: 7074 Name Argument Return type Standard 7075 'ABS(A)' 'REAL(4) A' 'REAL(4)' Fortran 77 and 7076 later 7077 'CABS(A)' 'COMPLEX(4) 'REAL(4)' Fortran 77 and 7078 A' later 7079 'DABS(A)' 'REAL(8) A' 'REAL(8)' Fortran 77 and 7080 later 7081 'IABS(A)' 'INTEGER(4) 'INTEGER(4)' Fortran 77 and 7082 A' later 7083 'BABS(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 7084 A' 7085 'IIABS(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 7086 A' 7087 'JIABS(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 7088 A' 7089 'KIABS(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 7090 A' 7091 'ZABS(A)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 7092 A' 7093 'CDABS(A)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 7094 A' 7095 7096 7097File: gfortran.info, Node: ACCESS, Next: ACHAR, Prev: ABS, Up: Intrinsic Procedures 7098 70999.4 'ACCESS' -- Checks file access modes 7100======================================== 7101 7102_Description_: 7103 'ACCESS(NAME, MODE)' checks whether the file NAME exists, is 7104 readable, writable or executable. Except for the executable check, 7105 'ACCESS' can be replaced by Fortran 95's 'INQUIRE'. 7106 7107_Standard_: 7108 GNU extension 7109 7110_Class_: 7111 Inquiry function 7112 7113_Syntax_: 7114 'RESULT = ACCESS(NAME, MODE)' 7115 7116_Arguments_: 7117 NAME Scalar 'CHARACTER' of default kind with the file 7118 name. Tailing blank are ignored unless the 7119 character 'achar(0)' is present, then all 7120 characters up to and excluding 'achar(0)' are 7121 used as file name. 7122 MODE Scalar 'CHARACTER' of default kind with the file 7123 access mode, may be any concatenation of '"r"' 7124 (readable), '"w"' (writable) and '"x"' 7125 (executable), or '" "' to check for existence. 7126 7127_Return value_: 7128 Returns a scalar 'INTEGER', which is '0' if the file is accessible 7129 in the given mode; otherwise or if an invalid argument has been 7130 given for 'MODE' the value '1' is returned. 7131 7132_Example_: 7133 program access_test 7134 implicit none 7135 character(len=*), parameter :: file = 'test.dat' 7136 character(len=*), parameter :: file2 = 'test.dat '//achar(0) 7137 if(access(file,' ') == 0) print *, trim(file),' is exists' 7138 if(access(file,'r') == 0) print *, trim(file),' is readable' 7139 if(access(file,'w') == 0) print *, trim(file),' is writable' 7140 if(access(file,'x') == 0) print *, trim(file),' is executable' 7141 if(access(file2,'rwx') == 0) & 7142 print *, trim(file2),' is readable, writable and executable' 7143 end program access_test 7144_Specific names_: 7145_See also_: 7146 7147 7148File: gfortran.info, Node: ACHAR, Next: ACOS, Prev: ACCESS, Up: Intrinsic Procedures 7149 71509.5 'ACHAR' -- Character in ASCII collating sequence 7151==================================================== 7152 7153_Description_: 7154 'ACHAR(I)' returns the character located at position 'I' in the 7155 ASCII collating sequence. 7156 7157_Standard_: 7158 Fortran 77 and later, with KIND argument Fortran 2003 and later 7159 7160_Class_: 7161 Elemental function 7162 7163_Syntax_: 7164 'RESULT = ACHAR(I [, KIND])' 7165 7166_Arguments_: 7167 I The type shall be 'INTEGER'. 7168 KIND (Optional) An 'INTEGER' initialization 7169 expression indicating the kind parameter of the 7170 result. 7171 7172_Return value_: 7173 The return value is of type 'CHARACTER' with a length of one. If 7174 the KIND argument is present, the return value is of the specified 7175 kind and of the default kind otherwise. 7176 7177_Example_: 7178 program test_achar 7179 character c 7180 c = achar(32) 7181 end program test_achar 7182 7183_Note_: 7184 See *note ICHAR:: for a discussion of converting between numerical 7185 values and formatted string representations. 7186 7187_See also_: 7188 *note CHAR::, *note IACHAR::, *note ICHAR:: 7189 7190 7191File: gfortran.info, Node: ACOS, Next: ACOSD, Prev: ACHAR, Up: Intrinsic Procedures 7192 71939.6 'ACOS' -- Arccosine function 7194================================ 7195 7196_Description_: 7197 'ACOS(X)' computes the arccosine of X (inverse of 'COS(X)'). 7198 7199_Standard_: 7200 Fortran 77 and later, for a complex argument Fortran 2008 or later 7201 7202_Class_: 7203 Elemental function 7204 7205_Syntax_: 7206 'RESULT = ACOS(X)' 7207 7208_Arguments_: 7209 X The type shall either be 'REAL' with a magnitude 7210 that is less than or equal to one - or the type 7211 shall be 'COMPLEX'. 7212 7213_Return value_: 7214 The return value is of the same type and kind as X. The real part 7215 of the result is in radians and lies in the range 0 \leq \Re 7216 \acos(x) \leq \pi. 7217 7218_Example_: 7219 program test_acos 7220 real(8) :: x = 0.866_8 7221 x = acos(x) 7222 end program test_acos 7223 7224_Specific names_: 7225 Name Argument Return type Standard 7226 'ACOS(X)' 'REAL(4) X' 'REAL(4)' Fortran 77 and 7227 later 7228 'DACOS(X)' 'REAL(8) X' 'REAL(8)' Fortran 77 and 7229 later 7230 7231_See also_: 7232 Inverse function: *note COS:: Degrees function: *note ACOSD:: 7233 7234 7235File: gfortran.info, Node: ACOSD, Next: ACOSH, Prev: ACOS, Up: Intrinsic Procedures 7236 72379.7 'ACOSD' -- Arccosine function, degrees 7238========================================== 7239 7240_Description_: 7241 'ACOSD(X)' computes the arccosine of X in degrees (inverse of 7242 'COSD(X)'). 7243 7244 This function is for compatibility only and should be avoided in 7245 favor of standard constructs wherever possible. 7246 7247_Standard_: 7248 GNU Extension, enabled with '-fdec-math' 7249 7250_Class_: 7251 Elemental function 7252 7253_Syntax_: 7254 'RESULT = ACOSD(X)' 7255 7256_Arguments_: 7257 X The type shall either be 'REAL' with a magnitude 7258 that is less than or equal to one - or the type 7259 shall be 'COMPLEX'. 7260 7261_Return value_: 7262 The return value is of the same type and kind as X. The real part 7263 of the result is in degrees and lies in the range 0 \leq \Re 7264 \acos(x) \leq 180. 7265 7266_Example_: 7267 program test_acosd 7268 real(8) :: x = 0.866_8 7269 x = acosd(x) 7270 end program test_acosd 7271 7272_Specific names_: 7273 Name Argument Return type Standard 7274 'ACOSD(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 7275 'DACOSD(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 7276 7277_See also_: 7278 Inverse function: *note COSD:: Radians function: *note ACOS:: 7279 7280 7281File: gfortran.info, Node: ACOSH, Next: ADJUSTL, Prev: ACOSD, Up: Intrinsic Procedures 7282 72839.8 'ACOSH' -- Inverse hyperbolic cosine function 7284================================================= 7285 7286_Description_: 7287 'ACOSH(X)' computes the inverse hyperbolic cosine of X. 7288 7289_Standard_: 7290 Fortran 2008 and later 7291 7292_Class_: 7293 Elemental function 7294 7295_Syntax_: 7296 'RESULT = ACOSH(X)' 7297 7298_Arguments_: 7299 X The type shall be 'REAL' or 'COMPLEX'. 7300 7301_Return value_: 7302 The return value has the same type and kind as X. If X is complex, 7303 the imaginary part of the result is in radians and lies between 0 7304 \leq \Im \acosh(x) \leq \pi. 7305 7306_Example_: 7307 PROGRAM test_acosh 7308 REAL(8), DIMENSION(3) :: x = (/ 1.0, 2.0, 3.0 /) 7309 WRITE (*,*) ACOSH(x) 7310 END PROGRAM 7311 7312_Specific names_: 7313 Name Argument Return type Standard 7314 'DACOSH(X)' 'REAL(8) X' 'REAL(8)' GNU extension 7315 7316_See also_: 7317 Inverse function: *note COSH:: 7318 7319 7320File: gfortran.info, Node: ADJUSTL, Next: ADJUSTR, Prev: ACOSH, Up: Intrinsic Procedures 7321 73229.9 'ADJUSTL' -- Left adjust a string 7323===================================== 7324 7325_Description_: 7326 'ADJUSTL(STRING)' will left adjust a string by removing leading 7327 spaces. Spaces are inserted at the end of the string as needed. 7328 7329_Standard_: 7330 Fortran 90 and later 7331 7332_Class_: 7333 Elemental function 7334 7335_Syntax_: 7336 'RESULT = ADJUSTL(STRING)' 7337 7338_Arguments_: 7339 STRING The type shall be 'CHARACTER'. 7340 7341_Return value_: 7342 The return value is of type 'CHARACTER' and of the same kind as 7343 STRING where leading spaces are removed and the same number of 7344 spaces are inserted on the end of STRING. 7345 7346_Example_: 7347 program test_adjustl 7348 character(len=20) :: str = ' gfortran' 7349 str = adjustl(str) 7350 print *, str 7351 end program test_adjustl 7352 7353_See also_: 7354 *note ADJUSTR::, *note TRIM:: 7355 7356 7357File: gfortran.info, Node: ADJUSTR, Next: AIMAG, Prev: ADJUSTL, Up: Intrinsic Procedures 7358 73599.10 'ADJUSTR' -- Right adjust a string 7360======================================= 7361 7362_Description_: 7363 'ADJUSTR(STRING)' will right adjust a string by removing trailing 7364 spaces. Spaces are inserted at the start of the string as needed. 7365 7366_Standard_: 7367 Fortran 95 and later 7368 7369_Class_: 7370 Elemental function 7371 7372_Syntax_: 7373 'RESULT = ADJUSTR(STRING)' 7374 7375_Arguments_: 7376 STR The type shall be 'CHARACTER'. 7377 7378_Return value_: 7379 The return value is of type 'CHARACTER' and of the same kind as 7380 STRING where trailing spaces are removed and the same number of 7381 spaces are inserted at the start of STRING. 7382 7383_Example_: 7384 program test_adjustr 7385 character(len=20) :: str = 'gfortran' 7386 str = adjustr(str) 7387 print *, str 7388 end program test_adjustr 7389 7390_See also_: 7391 *note ADJUSTL::, *note TRIM:: 7392 7393 7394File: gfortran.info, Node: AIMAG, Next: AINT, Prev: ADJUSTR, Up: Intrinsic Procedures 7395 73969.11 'AIMAG' -- Imaginary part of complex number 7397================================================ 7398 7399_Description_: 7400 'AIMAG(Z)' yields the imaginary part of complex argument 'Z'. The 7401 'IMAG(Z)' and 'IMAGPART(Z)' intrinsic functions are provided for 7402 compatibility with 'g77', and their use in new code is strongly 7403 discouraged. 7404 7405_Standard_: 7406 Fortran 77 and later, has overloads that are GNU extensions 7407 7408_Class_: 7409 Elemental function 7410 7411_Syntax_: 7412 'RESULT = AIMAG(Z)' 7413 7414_Arguments_: 7415 Z The type of the argument shall be 'COMPLEX'. 7416 7417_Return value_: 7418 The return value is of type 'REAL' with the kind type parameter of 7419 the argument. 7420 7421_Example_: 7422 program test_aimag 7423 complex(4) z4 7424 complex(8) z8 7425 z4 = cmplx(1.e0_4, 0.e0_4) 7426 z8 = cmplx(0.e0_8, 1.e0_8) 7427 print *, aimag(z4), dimag(z8) 7428 end program test_aimag 7429 7430_Specific names_: 7431 Name Argument Return type Standard 7432 'AIMAG(Z)' 'COMPLEX Z' 'REAL' GNU extension 7433 'DIMAG(Z)' 'COMPLEX(8) 'REAL(8)' GNU extension 7434 Z' 7435 'IMAG(Z)' 'COMPLEX Z' 'REAL' GNU extension 7436 'IMAGPART(Z)' 'COMPLEX Z' 'REAL' GNU extension 7437 7438 7439File: gfortran.info, Node: AINT, Next: ALARM, Prev: AIMAG, Up: Intrinsic Procedures 7440 74419.12 'AINT' -- Truncate to a whole number 7442========================================= 7443 7444_Description_: 7445 'AINT(A [, KIND])' truncates its argument to a whole number. 7446 7447_Standard_: 7448 Fortran 77 and later 7449 7450_Class_: 7451 Elemental function 7452 7453_Syntax_: 7454 'RESULT = AINT(A [, KIND])' 7455 7456_Arguments_: 7457 A The type of the argument shall be 'REAL'. 7458 KIND (Optional) An 'INTEGER' initialization 7459 expression indicating the kind parameter of the 7460 result. 7461 7462_Return value_: 7463 The return value is of type 'REAL' with the kind type parameter of 7464 the argument if the optional KIND is absent; otherwise, the kind 7465 type parameter will be given by KIND. If the magnitude of X is 7466 less than one, 'AINT(X)' returns zero. If the magnitude is equal 7467 to or greater than one then it returns the largest whole number 7468 that does not exceed its magnitude. The sign is the same as the 7469 sign of X. 7470 7471_Example_: 7472 program test_aint 7473 real(4) x4 7474 real(8) x8 7475 x4 = 1.234E0_4 7476 x8 = 4.321_8 7477 print *, aint(x4), dint(x8) 7478 x8 = aint(x4,8) 7479 end program test_aint 7480 7481_Specific names_: 7482 Name Argument Return type Standard 7483 'AINT(A)' 'REAL(4) A' 'REAL(4)' Fortran 77 and 7484 later 7485 'DINT(A)' 'REAL(8) A' 'REAL(8)' Fortran 77 and 7486 later 7487 7488 7489File: gfortran.info, Node: ALARM, Next: ALL, Prev: AINT, Up: Intrinsic Procedures 7490 74919.13 'ALARM' -- Execute a routine after a given delay 7492===================================================== 7493 7494_Description_: 7495 'ALARM(SECONDS, HANDLER [, STATUS])' causes external subroutine 7496 HANDLER to be executed after a delay of SECONDS by using 'alarm(2)' 7497 to set up a signal and 'signal(2)' to catch it. If STATUS is 7498 supplied, it will be returned with the number of seconds remaining 7499 until any previously scheduled alarm was due to be delivered, or 7500 zero if there was no previously scheduled alarm. 7501 7502_Standard_: 7503 GNU extension 7504 7505_Class_: 7506 Subroutine 7507 7508_Syntax_: 7509 'CALL ALARM(SECONDS, HANDLER [, STATUS])' 7510 7511_Arguments_: 7512 SECONDS The type of the argument shall be a scalar 7513 'INTEGER'. It is 'INTENT(IN)'. 7514 HANDLER Signal handler ('INTEGER FUNCTION' or 7515 'SUBROUTINE') or dummy/global 'INTEGER' scalar. 7516 The scalar values may be either 'SIG_IGN=1' to 7517 ignore the alarm generated or 'SIG_DFL=0' to set 7518 the default action. It is 'INTENT(IN)'. 7519 STATUS (Optional) STATUS shall be a scalar variable of 7520 the default 'INTEGER' kind. It is 7521 'INTENT(OUT)'. 7522 7523_Example_: 7524 program test_alarm 7525 external handler_print 7526 integer i 7527 call alarm (3, handler_print, i) 7528 print *, i 7529 call sleep(10) 7530 end program test_alarm 7531 This will cause the external routine HANDLER_PRINT to be called 7532 after 3 seconds. 7533 7534 7535File: gfortran.info, Node: ALL, Next: ALLOCATED, Prev: ALARM, Up: Intrinsic Procedures 7536 75379.14 'ALL' -- All values in MASK along DIM are true 7538=================================================== 7539 7540_Description_: 7541 'ALL(MASK [, DIM])' determines if all the values are true in MASK 7542 in the array along dimension DIM. 7543 7544_Standard_: 7545 Fortran 95 and later 7546 7547_Class_: 7548 Transformational function 7549 7550_Syntax_: 7551 'RESULT = ALL(MASK [, DIM])' 7552 7553_Arguments_: 7554 MASK The type of the argument shall be 'LOGICAL' and 7555 it shall not be scalar. 7556 DIM (Optional) DIM shall be a scalar integer with a 7557 value that lies between one and the rank of 7558 MASK. 7559 7560_Return value_: 7561 'ALL(MASK)' returns a scalar value of type 'LOGICAL' where the kind 7562 type parameter is the same as the kind type parameter of MASK. If 7563 DIM is present, then 'ALL(MASK, DIM)' returns an array with the 7564 rank of MASK minus 1. The shape is determined from the shape of 7565 MASK where the DIM dimension is elided. 7566 7567 (A) 7568 'ALL(MASK)' is true if all elements of MASK are true. It also 7569 is true if MASK has zero size; otherwise, it is false. 7570 (B) 7571 If the rank of MASK is one, then 'ALL(MASK,DIM)' is equivalent 7572 to 'ALL(MASK)'. If the rank is greater than one, then 7573 'ALL(MASK,DIM)' is determined by applying 'ALL' to the array 7574 sections. 7575 7576_Example_: 7577 program test_all 7578 logical l 7579 l = all((/.true., .true., .true./)) 7580 print *, l 7581 call section 7582 contains 7583 subroutine section 7584 integer a(2,3), b(2,3) 7585 a = 1 7586 b = 1 7587 b(2,2) = 2 7588 print *, all(a .eq. b, 1) 7589 print *, all(a .eq. b, 2) 7590 end subroutine section 7591 end program test_all 7592 7593 7594File: gfortran.info, Node: ALLOCATED, Next: AND, Prev: ALL, Up: Intrinsic Procedures 7595 75969.15 'ALLOCATED' -- Status of an allocatable entity 7597=================================================== 7598 7599_Description_: 7600 'ALLOCATED(ARRAY)' and 'ALLOCATED(SCALAR)' check the allocation 7601 status of ARRAY and SCALAR, respectively. 7602 7603_Standard_: 7604 Fortran 95 and later. Note, the 'SCALAR=' keyword and allocatable 7605 scalar entities are available in Fortran 2003 and later. 7606 7607_Class_: 7608 Inquiry function 7609 7610_Syntax_: 7611 'RESULT = ALLOCATED(ARRAY)' 7612 'RESULT = ALLOCATED(SCALAR)' 7613 7614_Arguments_: 7615 ARRAY The argument shall be an 'ALLOCATABLE' array. 7616 SCALAR The argument shall be an 'ALLOCATABLE' scalar. 7617 7618_Return value_: 7619 The return value is a scalar 'LOGICAL' with the default logical 7620 kind type parameter. If the argument is allocated, then the result 7621 is '.TRUE.'; otherwise, it returns '.FALSE.' 7622 7623_Example_: 7624 program test_allocated 7625 integer :: i = 4 7626 real(4), allocatable :: x(:) 7627 if (.not. allocated(x)) allocate(x(i)) 7628 end program test_allocated 7629 7630 7631File: gfortran.info, Node: AND, Next: ANINT, Prev: ALLOCATED, Up: Intrinsic Procedures 7632 76339.16 'AND' -- Bitwise logical AND 7634================================= 7635 7636_Description_: 7637 Bitwise logical 'AND'. 7638 7639 This intrinsic routine is provided for backwards compatibility with 7640 GNU Fortran 77. For integer arguments, programmers should consider 7641 the use of the *note IAND:: intrinsic defined by the Fortran 7642 standard. 7643 7644_Standard_: 7645 GNU extension 7646 7647_Class_: 7648 Function 7649 7650_Syntax_: 7651 'RESULT = AND(I, J)' 7652 7653_Arguments_: 7654 I The type shall be either a scalar 'INTEGER' type 7655 or a scalar 'LOGICAL' type. 7656 J The type shall be the same as the type of I. 7657 7658_Return value_: 7659 The return type is either a scalar 'INTEGER' or a scalar 'LOGICAL'. 7660 If the kind type parameters differ, then the smaller kind type is 7661 implicitly converted to larger kind, and the return has the larger 7662 kind. 7663 7664_Example_: 7665 PROGRAM test_and 7666 LOGICAL :: T = .TRUE., F = .FALSE. 7667 INTEGER :: a, b 7668 DATA a / Z'F' /, b / Z'3' / 7669 7670 WRITE (*,*) AND(T, T), AND(T, F), AND(F, T), AND(F, F) 7671 WRITE (*,*) AND(a, b) 7672 END PROGRAM 7673 7674_See also_: 7675 Fortran 95 elemental function: *note IAND:: 7676 7677 7678File: gfortran.info, Node: ANINT, Next: ANY, Prev: AND, Up: Intrinsic Procedures 7679 76809.17 'ANINT' -- Nearest whole number 7681==================================== 7682 7683_Description_: 7684 'ANINT(A [, KIND])' rounds its argument to the nearest whole 7685 number. 7686 7687_Standard_: 7688 Fortran 77 and later 7689 7690_Class_: 7691 Elemental function 7692 7693_Syntax_: 7694 'RESULT = ANINT(A [, KIND])' 7695 7696_Arguments_: 7697 A The type of the argument shall be 'REAL'. 7698 KIND (Optional) An 'INTEGER' initialization 7699 expression indicating the kind parameter of the 7700 result. 7701 7702_Return value_: 7703 The return value is of type real with the kind type parameter of 7704 the argument if the optional KIND is absent; otherwise, the kind 7705 type parameter will be given by KIND. If A is greater than zero, 7706 'ANINT(A)' returns 'AINT(X+0.5)'. If A is less than or equal to 7707 zero then it returns 'AINT(X-0.5)'. 7708 7709_Example_: 7710 program test_anint 7711 real(4) x4 7712 real(8) x8 7713 x4 = 1.234E0_4 7714 x8 = 4.321_8 7715 print *, anint(x4), dnint(x8) 7716 x8 = anint(x4,8) 7717 end program test_anint 7718 7719_Specific names_: 7720 Name Argument Return type Standard 7721 'AINT(A)' 'REAL(4) A' 'REAL(4)' Fortran 77 and 7722 later 7723 'DNINT(A)' 'REAL(8) A' 'REAL(8)' Fortran 77 and 7724 later 7725 7726 7727File: gfortran.info, Node: ANY, Next: ASIN, Prev: ANINT, Up: Intrinsic Procedures 7728 77299.18 'ANY' -- Any value in MASK along DIM is true 7730================================================= 7731 7732_Description_: 7733 'ANY(MASK [, DIM])' determines if any of the values in the logical 7734 array MASK along dimension DIM are '.TRUE.'. 7735 7736_Standard_: 7737 Fortran 95 and later 7738 7739_Class_: 7740 Transformational function 7741 7742_Syntax_: 7743 'RESULT = ANY(MASK [, DIM])' 7744 7745_Arguments_: 7746 MASK The type of the argument shall be 'LOGICAL' and 7747 it shall not be scalar. 7748 DIM (Optional) DIM shall be a scalar integer with a 7749 value that lies between one and the rank of 7750 MASK. 7751 7752_Return value_: 7753 'ANY(MASK)' returns a scalar value of type 'LOGICAL' where the kind 7754 type parameter is the same as the kind type parameter of MASK. If 7755 DIM is present, then 'ANY(MASK, DIM)' returns an array with the 7756 rank of MASK minus 1. The shape is determined from the shape of 7757 MASK where the DIM dimension is elided. 7758 7759 (A) 7760 'ANY(MASK)' is true if any element of MASK is true; otherwise, 7761 it is false. It also is false if MASK has zero size. 7762 (B) 7763 If the rank of MASK is one, then 'ANY(MASK,DIM)' is equivalent 7764 to 'ANY(MASK)'. If the rank is greater than one, then 7765 'ANY(MASK,DIM)' is determined by applying 'ANY' to the array 7766 sections. 7767 7768_Example_: 7769 program test_any 7770 logical l 7771 l = any((/.true., .true., .true./)) 7772 print *, l 7773 call section 7774 contains 7775 subroutine section 7776 integer a(2,3), b(2,3) 7777 a = 1 7778 b = 1 7779 b(2,2) = 2 7780 print *, any(a .eq. b, 1) 7781 print *, any(a .eq. b, 2) 7782 end subroutine section 7783 end program test_any 7784 7785 7786File: gfortran.info, Node: ASIN, Next: ASIND, Prev: ANY, Up: Intrinsic Procedures 7787 77889.19 'ASIN' -- Arcsine function 7789=============================== 7790 7791_Description_: 7792 'ASIN(X)' computes the arcsine of its X (inverse of 'SIN(X)'). 7793 7794_Standard_: 7795 Fortran 77 and later, for a complex argument Fortran 2008 or later 7796 7797_Class_: 7798 Elemental function 7799 7800_Syntax_: 7801 'RESULT = ASIN(X)' 7802 7803_Arguments_: 7804 X The type shall be either 'REAL' and a magnitude 7805 that is less than or equal to one - or be 7806 'COMPLEX'. 7807 7808_Return value_: 7809 The return value is of the same type and kind as X. The real part 7810 of the result is in radians and lies in the range -\pi/2 \leq \Re 7811 \asin(x) \leq \pi/2. 7812 7813_Example_: 7814 program test_asin 7815 real(8) :: x = 0.866_8 7816 x = asin(x) 7817 end program test_asin 7818 7819_Specific names_: 7820 Name Argument Return type Standard 7821 'ASIN(X)' 'REAL(4) X' 'REAL(4)' Fortran 77 and 7822 later 7823 'DASIN(X)' 'REAL(8) X' 'REAL(8)' Fortran 77 and 7824 later 7825 7826_See also_: 7827 Inverse function: *note SIN:: Degrees function: *note ASIND:: 7828 7829 7830File: gfortran.info, Node: ASIND, Next: ASINH, Prev: ASIN, Up: Intrinsic Procedures 7831 78329.20 'ASIND' -- Arcsine function, degrees 7833========================================= 7834 7835_Description_: 7836 'ASIND(X)' computes the arcsine of its X in degrees (inverse of 7837 'SIND(X)'). 7838 7839 This function is for compatibility only and should be avoided in 7840 favor of standard constructs wherever possible. 7841 7842_Standard_: 7843 GNU Extension, enabled with '-fdec-math'. 7844 7845_Class_: 7846 Elemental function 7847 7848_Syntax_: 7849 'RESULT = ASIND(X)' 7850 7851_Arguments_: 7852 X The type shall be either 'REAL' and a magnitude 7853 that is less than or equal to one - or be 7854 'COMPLEX'. 7855 7856_Return value_: 7857 The return value is of the same type and kind as X. The real part 7858 of the result is in degrees and lies in the range -90 \leq \Re 7859 \asin(x) \leq 90. 7860 7861_Example_: 7862 program test_asind 7863 real(8) :: x = 0.866_8 7864 x = asind(x) 7865 end program test_asind 7866 7867_Specific names_: 7868 Name Argument Return type Standard 7869 'ASIND(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 7870 'DASIND(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 7871 7872_See also_: 7873 Inverse function: *note SIND:: Radians function: *note ASIN:: 7874 7875 7876File: gfortran.info, Node: ASINH, Next: ASSOCIATED, Prev: ASIND, Up: Intrinsic Procedures 7877 78789.21 'ASINH' -- Inverse hyperbolic sine function 7879================================================ 7880 7881_Description_: 7882 'ASINH(X)' computes the inverse hyperbolic sine of X. 7883 7884_Standard_: 7885 Fortran 2008 and later 7886 7887_Class_: 7888 Elemental function 7889 7890_Syntax_: 7891 'RESULT = ASINH(X)' 7892 7893_Arguments_: 7894 X The type shall be 'REAL' or 'COMPLEX'. 7895 7896_Return value_: 7897 The return value is of the same type and kind as X. If X is 7898 complex, the imaginary part of the result is in radians and lies 7899 between -\pi/2 \leq \Im \asinh(x) \leq \pi/2. 7900 7901_Example_: 7902 PROGRAM test_asinh 7903 REAL(8), DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /) 7904 WRITE (*,*) ASINH(x) 7905 END PROGRAM 7906 7907_Specific names_: 7908 Name Argument Return type Standard 7909 'DASINH(X)' 'REAL(8) X' 'REAL(8)' GNU extension. 7910 7911_See also_: 7912 Inverse function: *note SINH:: 7913 7914 7915File: gfortran.info, Node: ASSOCIATED, Next: ATAN, Prev: ASINH, Up: Intrinsic Procedures 7916 79179.22 'ASSOCIATED' -- Status of a pointer or pointer/target pair 7918=============================================================== 7919 7920_Description_: 7921 'ASSOCIATED(POINTER [, TARGET])' determines the status of the 7922 pointer POINTER or if POINTER is associated with the target TARGET. 7923 7924_Standard_: 7925 Fortran 95 and later 7926 7927_Class_: 7928 Inquiry function 7929 7930_Syntax_: 7931 'RESULT = ASSOCIATED(POINTER [, TARGET])' 7932 7933_Arguments_: 7934 POINTER POINTER shall have the 'POINTER' attribute and 7935 it can be of any type. 7936 TARGET (Optional) TARGET shall be a pointer or a 7937 target. It must have the same type, kind type 7938 parameter, and array rank as POINTER. 7939 The association status of neither POINTER nor TARGET shall be 7940 undefined. 7941 7942_Return value_: 7943 'ASSOCIATED(POINTER)' returns a scalar value of type 'LOGICAL(4)'. 7944 There are several cases: 7945 (A) When the optional TARGET is not present then 7946 'ASSOCIATED(POINTER)' is true if POINTER is associated with a 7947 target; otherwise, it returns false. 7948 (B) If TARGET is present and a scalar target, the result is true if 7949 TARGET is not a zero-sized storage sequence and the target 7950 associated with POINTER occupies the same storage units. If 7951 POINTER is disassociated, the result is false. 7952 (C) If TARGET is present and an array target, the result is true if 7953 TARGET and POINTER have the same shape, are not zero-sized 7954 arrays, are arrays whose elements are not zero-sized storage 7955 sequences, and TARGET and POINTER occupy the same storage 7956 units in array element order. As in case(B), the result is 7957 false, if POINTER is disassociated. 7958 (D) If TARGET is present and an scalar pointer, the result is true 7959 if TARGET is associated with POINTER, the target associated 7960 with TARGET are not zero-sized storage sequences and occupy 7961 the same storage units. The result is false, if either TARGET 7962 or POINTER is disassociated. 7963 (E) If TARGET is present and an array pointer, the result is true if 7964 target associated with POINTER and the target associated with 7965 TARGET have the same shape, are not zero-sized arrays, are 7966 arrays whose elements are not zero-sized storage sequences, 7967 and TARGET and POINTER occupy the same storage units in array 7968 element order. The result is false, if either TARGET or 7969 POINTER is disassociated. 7970 7971_Example_: 7972 program test_associated 7973 implicit none 7974 real, target :: tgt(2) = (/1., 2./) 7975 real, pointer :: ptr(:) 7976 ptr => tgt 7977 if (associated(ptr) .eqv. .false.) call abort 7978 if (associated(ptr,tgt) .eqv. .false.) call abort 7979 end program test_associated 7980 7981_See also_: 7982 *note NULL:: 7983 7984 7985File: gfortran.info, Node: ATAN, Next: ATAND, Prev: ASSOCIATED, Up: Intrinsic Procedures 7986 79879.23 'ATAN' -- Arctangent function 7988================================== 7989 7990_Description_: 7991 'ATAN(X)' computes the arctangent of X. 7992 7993_Standard_: 7994 Fortran 77 and later, for a complex argument and for two arguments 7995 Fortran 2008 or later 7996 7997_Class_: 7998 Elemental function 7999 8000_Syntax_: 8001 'RESULT = ATAN(X)' 8002 'RESULT = ATAN(Y, X)' 8003 8004_Arguments_: 8005 X The type shall be 'REAL' or 'COMPLEX'; if Y is 8006 present, X shall be REAL. 8007 Y shall 8008 be of the 8009 same type 8010 and kind 8011 as X. 8012 8013_Return value_: 8014 The return value is of the same type and kind as X. If Y is 8015 present, the result is identical to 'ATAN2(Y,X)'. Otherwise, it 8016 the arcus tangent of X, where the real part of the result is in 8017 radians and lies in the range -\pi/2 \leq \Re \atan(x) \leq \pi/2. 8018 8019_Example_: 8020 program test_atan 8021 real(8) :: x = 2.866_8 8022 x = atan(x) 8023 end program test_atan 8024 8025_Specific names_: 8026 Name Argument Return type Standard 8027 'ATAN(X)' 'REAL(4) X' 'REAL(4)' Fortran 77 and 8028 later 8029 'DATAN(X)' 'REAL(8) X' 'REAL(8)' Fortran 77 and 8030 later 8031 8032_See also_: 8033 Inverse function: *note TAN:: Degrees function: *note ATAND:: 8034 8035 8036File: gfortran.info, Node: ATAND, Next: ATAN2, Prev: ATAN, Up: Intrinsic Procedures 8037 80389.24 'ATAND' -- Arctangent function, degrees 8039============================================ 8040 8041_Description_: 8042 'ATAND(X)' computes the arctangent of X in degrees (inverse of 8043 *note TAND::). 8044 8045 This function is for compatibility only and should be avoided in 8046 favor of standard constructs wherever possible. 8047 8048_Standard_: 8049 GNU Extension, enabled with '-fdec-math'. 8050 8051_Class_: 8052 Elemental function 8053 8054_Syntax_: 8055 'RESULT = ATAND(X)' 8056 'RESULT = ATAND(Y, X)' 8057 8058_Arguments_: 8059 X The type shall be 'REAL' or 'COMPLEX'; if Y is 8060 present, X shall be REAL. 8061 Y shall 8062 be of the 8063 same type 8064 and kind 8065 as X. 8066 8067_Return value_: 8068 The return value is of the same type and kind as X. If Y is 8069 present, the result is identical to 'ATAND2(Y,X)'. Otherwise, it 8070 is the arcus tangent of X, where the real part of the result is in 8071 degrees and lies in the range -90 \leq \Re \atand(x) \leq 90. 8072 8073_Example_: 8074 program test_atand 8075 real(8) :: x = 2.866_8 8076 x = atand(x) 8077 end program test_atand 8078 8079_Specific names_: 8080 Name Argument Return type Standard 8081 'ATAND(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 8082 'DATAND(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 8083 8084_See also_: 8085 Inverse function: *note TAND:: Radians function: *note ATAN:: 8086 8087 8088File: gfortran.info, Node: ATAN2, Next: ATAN2D, Prev: ATAND, Up: Intrinsic Procedures 8089 80909.25 'ATAN2' -- Arctangent function 8091=================================== 8092 8093_Description_: 8094 'ATAN2(Y, X)' computes the principal value of the argument function 8095 of the complex number X + i Y. This function can be used to 8096 transform from Cartesian into polar coordinates and allows to 8097 determine the angle in the correct quadrant. 8098 8099_Standard_: 8100 Fortran 77 and later 8101 8102_Class_: 8103 Elemental function 8104 8105_Syntax_: 8106 'RESULT = ATAN2(Y, X)' 8107 8108_Arguments_: 8109 Y The type shall be 'REAL'. 8110 X The type and kind type parameter shall be the 8111 same as Y. If Y is zero, then X must be 8112 nonzero. 8113 8114_Return value_: 8115 The return value has the same type and kind type parameter as Y. 8116 It is the principal value of the complex number X + i Y. If X is 8117 nonzero, then it lies in the range -\pi \le \atan (x) \leq \pi. 8118 The sign is positive if Y is positive. If Y is zero, then the 8119 return value is zero if X is strictly positive, \pi if X is 8120 negative and Y is positive zero (or the processor does not handle 8121 signed zeros), and -\pi if X is negative and Y is negative zero. 8122 Finally, if X is zero, then the magnitude of the result is \pi/2. 8123 8124_Example_: 8125 program test_atan2 8126 real(4) :: x = 1.e0_4, y = 0.5e0_4 8127 x = atan2(y,x) 8128 end program test_atan2 8129 8130_Specific names_: 8131 Name Argument Return type Standard 8132 'ATAN2(X, 'REAL(4) X, 'REAL(4)' Fortran 77 and 8133 Y)' Y' later 8134 'DATAN2(X, 'REAL(8) X, 'REAL(8)' Fortran 77 and 8135 Y)' Y' later 8136 8137_See also_: 8138 Alias: *note ATAN:: Degrees function: *note ATAN2D:: 8139 8140 8141File: gfortran.info, Node: ATAN2D, Next: ATANH, Prev: ATAN2, Up: Intrinsic Procedures 8142 81439.26 'ATAN2D' -- Arctangent function, degrees 8144============================================= 8145 8146_Description_: 8147 'ATAN2D(Y, X)' computes the principal value of the argument 8148 function of the complex number X + i Y in degrees. This function 8149 can be used to transform from Cartesian into polar coordinates and 8150 allows to determine the angle in the correct quadrant. 8151 8152 This function is for compatibility only and should be avoided in 8153 favor of standard constructs wherever possible. 8154 8155_Standard_: 8156 GNU Extension, enabled with '-fdec-math'. 8157 8158_Class_: 8159 Elemental function 8160 8161_Syntax_: 8162 'RESULT = ATAN2D(Y, X)' 8163 8164_Arguments_: 8165 Y The type shall be 'REAL'. 8166 X The type and kind type parameter shall be the 8167 same as Y. If Y is zero, then X must be 8168 nonzero. 8169 8170_Return value_: 8171 The return value has the same type and kind type parameter as Y. 8172 It is the principal value of the complex number X + i Y. If X is 8173 nonzero, then it lies in the range -180 \le \atan (x) \leq 180. 8174 The sign is positive if Y is positive. If Y is zero, then the 8175 return value is zero if X is strictly positive, 180 if X is 8176 negative and Y is positive zero (or the processor does not handle 8177 signed zeros), and -180 if X is negative and Y is negative zero. 8178 Finally, if X is zero, then the magnitude of the result is 90. 8179 8180_Example_: 8181 program test_atan2d 8182 real(4) :: x = 1.e0_4, y = 0.5e0_4 8183 x = atan2d(y,x) 8184 end program test_atan2d 8185 8186_Specific names_: 8187 Name Argument Return type Standard 8188 'ATAN2D(X, 'REAL(4) X, 'REAL(4)' GNU Extension 8189 Y)' Y' 8190 'DATAN2D(X, 'REAL(8) X, 'REAL(8)' GNU Extension 8191 Y)' Y' 8192 8193_See also_: 8194 Alias: *note ATAND:: Radians function: *note ATAN2:: 8195 8196 8197File: gfortran.info, Node: ATANH, Next: ATOMIC_ADD, Prev: ATAN2D, Up: Intrinsic Procedures 8198 81999.27 'ATANH' -- Inverse hyperbolic tangent function 8200=================================================== 8201 8202_Description_: 8203 'ATANH(X)' computes the inverse hyperbolic tangent of X. 8204 8205_Standard_: 8206 Fortran 2008 and later 8207 8208_Class_: 8209 Elemental function 8210 8211_Syntax_: 8212 'RESULT = ATANH(X)' 8213 8214_Arguments_: 8215 X The type shall be 'REAL' or 'COMPLEX'. 8216 8217_Return value_: 8218 The return value has same type and kind as X. If X is complex, the 8219 imaginary part of the result is in radians and lies between -\pi/2 8220 \leq \Im \atanh(x) \leq \pi/2. 8221 8222_Example_: 8223 PROGRAM test_atanh 8224 REAL, DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /) 8225 WRITE (*,*) ATANH(x) 8226 END PROGRAM 8227 8228_Specific names_: 8229 Name Argument Return type Standard 8230 'DATANH(X)' 'REAL(8) X' 'REAL(8)' GNU extension 8231 8232_See also_: 8233 Inverse function: *note TANH:: 8234 8235 8236File: gfortran.info, Node: ATOMIC_ADD, Next: ATOMIC_AND, Prev: ATANH, Up: Intrinsic Procedures 8237 82389.28 'ATOMIC_ADD' -- Atomic ADD operation 8239========================================= 8240 8241_Description_: 8242 'ATOMIC_ADD(ATOM, VALUE)' atomically adds the value of VAR to the 8243 variable ATOM. When STAT is present and the invocation was 8244 successful, it is assigned the value 0. If it is present and the 8245 invocation has failed, it is assigned a positive value; in 8246 particular, for a coindexed ATOM, if the remote image has stopped, 8247 it is assigned the value of 'ISO_FORTRAN_ENV''s 8248 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8249 'STAT_FAILED_IMAGE'. 8250 8251_Standard_: 8252 TS 18508 or later 8253 8254_Class_: 8255 Atomic subroutine 8256 8257_Syntax_: 8258 'CALL ATOMIC_ADD (ATOM, VALUE [, STAT])' 8259 8260_Arguments_: 8261 ATOM Scalar coarray or coindexed variable of integer 8262 type with 'ATOMIC_INT_KIND' kind. 8263 VALUE Scalar of the same type as ATOM. If the kind is 8264 different, the value is converted to the kind of 8265 ATOM. 8266 STAT (optional) Scalar default-kind integer variable. 8267 8268_Example_: 8269 program atomic 8270 use iso_fortran_env 8271 integer(atomic_int_kind) :: atom[*] 8272 call atomic_add (atom[1], this_image()) 8273 end program atomic 8274 8275_See also_: 8276 *note ATOMIC_DEFINE::, *note ATOMIC_FETCH_ADD::, *note 8277 ISO_FORTRAN_ENV::, *note ATOMIC_AND::, *note ATOMIC_OR::, *note 8278 ATOMIC_XOR:: 8279 8280 8281File: gfortran.info, Node: ATOMIC_AND, Next: ATOMIC_CAS, Prev: ATOMIC_ADD, Up: Intrinsic Procedures 8282 82839.29 'ATOMIC_AND' -- Atomic bitwise AND operation 8284================================================= 8285 8286_Description_: 8287 'ATOMIC_AND(ATOM, VALUE)' atomically defines ATOM with the bitwise 8288 AND between the values of ATOM and VALUE. When STAT is present and 8289 the invocation was successful, it is assigned the value 0. If it 8290 is present and the invocation has failed, it is assigned a positive 8291 value; in particular, for a coindexed ATOM, if the remote image has 8292 stopped, it is assigned the value of 'ISO_FORTRAN_ENV''s 8293 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8294 'STAT_FAILED_IMAGE'. 8295 8296_Standard_: 8297 TS 18508 or later 8298 8299_Class_: 8300 Atomic subroutine 8301 8302_Syntax_: 8303 'CALL ATOMIC_AND (ATOM, VALUE [, STAT])' 8304 8305_Arguments_: 8306 ATOM Scalar coarray or coindexed variable of integer 8307 type with 'ATOMIC_INT_KIND' kind. 8308 VALUE Scalar of the same type as ATOM. If the kind is 8309 different, the value is converted to the kind of 8310 ATOM. 8311 STAT (optional) Scalar default-kind integer variable. 8312 8313_Example_: 8314 program atomic 8315 use iso_fortran_env 8316 integer(atomic_int_kind) :: atom[*] 8317 call atomic_and (atom[1], int(b'10100011101')) 8318 end program atomic 8319 8320_See also_: 8321 *note ATOMIC_DEFINE::, *note ATOMIC_FETCH_AND::, *note 8322 ISO_FORTRAN_ENV::, *note ATOMIC_ADD::, *note ATOMIC_OR::, *note 8323 ATOMIC_XOR:: 8324 8325 8326File: gfortran.info, Node: ATOMIC_CAS, Next: ATOMIC_DEFINE, Prev: ATOMIC_AND, Up: Intrinsic Procedures 8327 83289.30 'ATOMIC_CAS' -- Atomic compare and swap 8329============================================ 8330 8331_Description_: 8332 'ATOMIC_CAS' compares the variable ATOM with the value of COMPARE; 8333 if the value is the same, ATOM is set to the value of NEW. 8334 Additionally, OLD is set to the value of ATOM that was used for the 8335 comparison. When STAT is present and the invocation was 8336 successful, it is assigned the value 0. If it is present and the 8337 invocation has failed, it is assigned a positive value; in 8338 particular, for a coindexed ATOM, if the remote image has stopped, 8339 it is assigned the value of 'ISO_FORTRAN_ENV''s 8340 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8341 'STAT_FAILED_IMAGE'. 8342 8343_Standard_: 8344 TS 18508 or later 8345 8346_Class_: 8347 Atomic subroutine 8348 8349_Syntax_: 8350 'CALL ATOMIC_CAS (ATOM, OLD, COMPARE, NEW [, STAT])' 8351 8352_Arguments_: 8353 ATOM Scalar coarray or coindexed variable of either 8354 integer type with 'ATOMIC_INT_KIND' kind or 8355 logical type with 'ATOMIC_LOGICAL_KIND' kind. 8356 OLD Scalar of the same type and kind as ATOM. 8357 COMPARE Scalar variable of the same type and kind as 8358 ATOM. 8359 NEW Scalar variable of the same type as ATOM. If 8360 kind is different, the value is converted to the 8361 kind of ATOM. 8362 STAT (optional) Scalar default-kind integer variable. 8363 8364_Example_: 8365 program atomic 8366 use iso_fortran_env 8367 logical(atomic_logical_kind) :: atom[*], prev 8368 call atomic_cas (atom[1], prev, .false., .true.)) 8369 end program atomic 8370 8371_See also_: 8372 *note ATOMIC_DEFINE::, *note ATOMIC_REF::, *note ISO_FORTRAN_ENV:: 8373 8374 8375File: gfortran.info, Node: ATOMIC_DEFINE, Next: ATOMIC_FETCH_ADD, Prev: ATOMIC_CAS, Up: Intrinsic Procedures 8376 83779.31 'ATOMIC_DEFINE' -- Setting a variable atomically 8378===================================================== 8379 8380_Description_: 8381 'ATOMIC_DEFINE(ATOM, VALUE)' defines the variable ATOM with the 8382 value VALUE atomically. When STAT is present and the invocation 8383 was successful, it is assigned the value 0. If it is present and 8384 the invocation has failed, it is assigned a positive value; in 8385 particular, for a coindexed ATOM, if the remote image has stopped, 8386 it is assigned the value of 'ISO_FORTRAN_ENV''s 8387 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8388 'STAT_FAILED_IMAGE'. 8389 8390_Standard_: 8391 Fortran 2008 and later; with STAT, TS 18508 or later 8392 8393_Class_: 8394 Atomic subroutine 8395 8396_Syntax_: 8397 'CALL ATOMIC_DEFINE (ATOM, VALUE [, STAT])' 8398 8399_Arguments_: 8400 ATOM Scalar coarray or coindexed variable of either 8401 integer type with 'ATOMIC_INT_KIND' kind or 8402 logical type with 'ATOMIC_LOGICAL_KIND' kind. 8403 8404 VALUE Scalar of the same type as ATOM. If the kind is 8405 different, the value is converted to the kind of 8406 ATOM. 8407 STAT (optional) Scalar default-kind integer variable. 8408 8409_Example_: 8410 program atomic 8411 use iso_fortran_env 8412 integer(atomic_int_kind) :: atom[*] 8413 call atomic_define (atom[1], this_image()) 8414 end program atomic 8415 8416_See also_: 8417 *note ATOMIC_REF::, *note ATOMIC_CAS::, *note ISO_FORTRAN_ENV::, 8418 *note ATOMIC_ADD::, *note ATOMIC_AND::, *note ATOMIC_OR::, *note 8419 ATOMIC_XOR:: 8420 8421 8422File: gfortran.info, Node: ATOMIC_FETCH_ADD, Next: ATOMIC_FETCH_AND, Prev: ATOMIC_DEFINE, Up: Intrinsic Procedures 8423 84249.32 'ATOMIC_FETCH_ADD' -- Atomic ADD operation with prior fetch 8425================================================================ 8426 8427_Description_: 8428 'ATOMIC_FETCH_ADD(ATOM, VALUE, OLD)' atomically stores the value of 8429 ATOM in OLD and adds the value of VAR to the variable ATOM. When 8430 STAT is present and the invocation was successful, it is assigned 8431 the value 0. If it is present and the invocation has failed, it is 8432 assigned a positive value; in particular, for a coindexed ATOM, if 8433 the remote image has stopped, it is assigned the value of 8434 'ISO_FORTRAN_ENV''s 'STAT_STOPPED_IMAGE' and if the remote image 8435 has failed, the value 'STAT_FAILED_IMAGE'. 8436 8437_Standard_: 8438 TS 18508 or later 8439 8440_Class_: 8441 Atomic subroutine 8442 8443_Syntax_: 8444 'CALL ATOMIC_FETCH_ADD (ATOM, VALUE, old [, STAT])' 8445 8446_Arguments_: 8447 ATOM Scalar coarray or coindexed variable of integer 8448 type with 'ATOMIC_INT_KIND' kind. 8449 'ATOMIC_LOGICAL_KIND' kind. 8450 8451 VALUE Scalar of the same type as ATOM. If the kind is 8452 different, the value is converted to the kind of 8453 ATOM. 8454 OLD Scalar of the same type and kind as ATOM. 8455 STAT (optional) Scalar default-kind integer variable. 8456 8457_Example_: 8458 program atomic 8459 use iso_fortran_env 8460 integer(atomic_int_kind) :: atom[*], old 8461 call atomic_add (atom[1], this_image(), old) 8462 end program atomic 8463 8464_See also_: 8465 *note ATOMIC_DEFINE::, *note ATOMIC_ADD::, *note ISO_FORTRAN_ENV::, 8466 *note ATOMIC_FETCH_AND::, *note ATOMIC_FETCH_OR::, *note 8467 ATOMIC_FETCH_XOR:: 8468 8469 8470File: gfortran.info, Node: ATOMIC_FETCH_AND, Next: ATOMIC_FETCH_OR, Prev: ATOMIC_FETCH_ADD, Up: Intrinsic Procedures 8471 84729.33 'ATOMIC_FETCH_AND' -- Atomic bitwise AND operation with prior fetch 8473======================================================================== 8474 8475_Description_: 8476 'ATOMIC_AND(ATOM, VALUE)' atomically stores the value of ATOM in 8477 OLD and defines ATOM with the bitwise AND between the values of 8478 ATOM and VALUE. When STAT is present and the invocation was 8479 successful, it is assigned the value 0. If it is present and the 8480 invocation has failed, it is assigned a positive value; in 8481 particular, for a coindexed ATOM, if the remote image has stopped, 8482 it is assigned the value of 'ISO_FORTRAN_ENV''s 8483 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8484 'STAT_FAILED_IMAGE'. 8485 8486_Standard_: 8487 TS 18508 or later 8488 8489_Class_: 8490 Atomic subroutine 8491 8492_Syntax_: 8493 'CALL ATOMIC_FETCH_AND (ATOM, VALUE, OLD [, STAT])' 8494 8495_Arguments_: 8496 ATOM Scalar coarray or coindexed variable of integer 8497 type with 'ATOMIC_INT_KIND' kind. 8498 VALUE Scalar of the same type as ATOM. If the kind is 8499 different, the value is converted to the kind of 8500 ATOM. 8501 OLD Scalar of the same type and kind as ATOM. 8502 STAT (optional) Scalar default-kind integer variable. 8503 8504_Example_: 8505 program atomic 8506 use iso_fortran_env 8507 integer(atomic_int_kind) :: atom[*], old 8508 call atomic_fetch_and (atom[1], int(b'10100011101'), old) 8509 end program atomic 8510 8511_See also_: 8512 *note ATOMIC_DEFINE::, *note ATOMIC_AND::, *note ISO_FORTRAN_ENV::, 8513 *note ATOMIC_FETCH_ADD::, *note ATOMIC_FETCH_OR::, *note 8514 ATOMIC_FETCH_XOR:: 8515 8516 8517File: gfortran.info, Node: ATOMIC_FETCH_OR, Next: ATOMIC_FETCH_XOR, Prev: ATOMIC_FETCH_AND, Up: Intrinsic Procedures 8518 85199.34 'ATOMIC_FETCH_OR' -- Atomic bitwise OR operation with prior fetch 8520====================================================================== 8521 8522_Description_: 8523 'ATOMIC_OR(ATOM, VALUE)' atomically stores the value of ATOM in OLD 8524 and defines ATOM with the bitwise OR between the values of ATOM and 8525 VALUE. When STAT is present and the invocation was successful, it 8526 is assigned the value 0. If it is present and the invocation has 8527 failed, it is assigned a positive value; in particular, for a 8528 coindexed ATOM, if the remote image has stopped, it is assigned the 8529 value of 'ISO_FORTRAN_ENV''s 'STAT_STOPPED_IMAGE' and if the remote 8530 image has failed, the value 'STAT_FAILED_IMAGE'. 8531 8532_Standard_: 8533 TS 18508 or later 8534 8535_Class_: 8536 Atomic subroutine 8537 8538_Syntax_: 8539 'CALL ATOMIC_FETCH_OR (ATOM, VALUE, OLD [, STAT])' 8540 8541_Arguments_: 8542 ATOM Scalar coarray or coindexed variable of integer 8543 type with 'ATOMIC_INT_KIND' kind. 8544 VALUE Scalar of the same type as ATOM. If the kind is 8545 different, the value is converted to the kind of 8546 ATOM. 8547 OLD Scalar of the same type and kind as ATOM. 8548 STAT (optional) Scalar default-kind integer variable. 8549 8550_Example_: 8551 program atomic 8552 use iso_fortran_env 8553 integer(atomic_int_kind) :: atom[*], old 8554 call atomic_fetch_or (atom[1], int(b'10100011101'), old) 8555 end program atomic 8556 8557_See also_: 8558 *note ATOMIC_DEFINE::, *note ATOMIC_OR::, *note ISO_FORTRAN_ENV::, 8559 *note ATOMIC_FETCH_ADD::, *note ATOMIC_FETCH_AND::, *note 8560 ATOMIC_FETCH_XOR:: 8561 8562 8563File: gfortran.info, Node: ATOMIC_FETCH_XOR, Next: ATOMIC_OR, Prev: ATOMIC_FETCH_OR, Up: Intrinsic Procedures 8564 85659.35 'ATOMIC_FETCH_XOR' -- Atomic bitwise XOR operation with prior fetch 8566======================================================================== 8567 8568_Description_: 8569 'ATOMIC_XOR(ATOM, VALUE)' atomically stores the value of ATOM in 8570 OLD and defines ATOM with the bitwise XOR between the values of 8571 ATOM and VALUE. When STAT is present and the invocation was 8572 successful, it is assigned the value 0. If it is present and the 8573 invocation has failed, it is assigned a positive value; in 8574 particular, for a coindexed ATOM, if the remote image has stopped, 8575 it is assigned the value of 'ISO_FORTRAN_ENV''s 8576 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8577 'STAT_FAILED_IMAGE'. 8578 8579_Standard_: 8580 TS 18508 or later 8581 8582_Class_: 8583 Atomic subroutine 8584 8585_Syntax_: 8586 'CALL ATOMIC_FETCH_XOR (ATOM, VALUE, OLD [, STAT])' 8587 8588_Arguments_: 8589 ATOM Scalar coarray or coindexed variable of integer 8590 type with 'ATOMIC_INT_KIND' kind. 8591 VALUE Scalar of the same type as ATOM. If the kind is 8592 different, the value is converted to the kind of 8593 ATOM. 8594 OLD Scalar of the same type and kind as ATOM. 8595 STAT (optional) Scalar default-kind integer variable. 8596 8597_Example_: 8598 program atomic 8599 use iso_fortran_env 8600 integer(atomic_int_kind) :: atom[*], old 8601 call atomic_fetch_xor (atom[1], int(b'10100011101'), old) 8602 end program atomic 8603 8604_See also_: 8605 *note ATOMIC_DEFINE::, *note ATOMIC_XOR::, *note ISO_FORTRAN_ENV::, 8606 *note ATOMIC_FETCH_ADD::, *note ATOMIC_FETCH_AND::, *note 8607 ATOMIC_FETCH_OR:: 8608 8609 8610File: gfortran.info, Node: ATOMIC_OR, Next: ATOMIC_REF, Prev: ATOMIC_FETCH_XOR, Up: Intrinsic Procedures 8611 86129.36 'ATOMIC_OR' -- Atomic bitwise OR operation 8613=============================================== 8614 8615_Description_: 8616 'ATOMIC_OR(ATOM, VALUE)' atomically defines ATOM with the bitwise 8617 AND between the values of ATOM and VALUE. When STAT is present and 8618 the invocation was successful, it is assigned the value 0. If it 8619 is present and the invocation has failed, it is assigned a positive 8620 value; in particular, for a coindexed ATOM, if the remote image has 8621 stopped, it is assigned the value of 'ISO_FORTRAN_ENV''s 8622 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8623 'STAT_FAILED_IMAGE'. 8624 8625_Standard_: 8626 TS 18508 or later 8627 8628_Class_: 8629 Atomic subroutine 8630 8631_Syntax_: 8632 'CALL ATOMIC_OR (ATOM, VALUE [, STAT])' 8633 8634_Arguments_: 8635 ATOM Scalar coarray or coindexed variable of integer 8636 type with 'ATOMIC_INT_KIND' kind. 8637 VALUE Scalar of the same type as ATOM. If the kind is 8638 different, the value is converted to the kind of 8639 ATOM. 8640 STAT (optional) Scalar default-kind integer variable. 8641 8642_Example_: 8643 program atomic 8644 use iso_fortran_env 8645 integer(atomic_int_kind) :: atom[*] 8646 call atomic_or (atom[1], int(b'10100011101')) 8647 end program atomic 8648 8649_See also_: 8650 *note ATOMIC_DEFINE::, *note ATOMIC_FETCH_OR::, *note 8651 ISO_FORTRAN_ENV::, *note ATOMIC_ADD::, *note ATOMIC_OR::, *note 8652 ATOMIC_XOR:: 8653 8654 8655File: gfortran.info, Node: ATOMIC_REF, Next: ATOMIC_XOR, Prev: ATOMIC_OR, Up: Intrinsic Procedures 8656 86579.37 'ATOMIC_REF' -- Obtaining the value of a variable atomically 8658================================================================= 8659 8660_Description_: 8661 'ATOMIC_DEFINE(ATOM, VALUE)' atomically assigns the value of the 8662 variable ATOM to VALUE. When STAT is present and the invocation 8663 was successful, it is assigned the value 0. If it is present and 8664 the invocation has failed, it is assigned a positive value; in 8665 particular, for a coindexed ATOM, if the remote image has stopped, 8666 it is assigned the value of 'ISO_FORTRAN_ENV''s 8667 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8668 'STAT_FAILED_IMAGE'. 8669 8670_Standard_: 8671 Fortran 2008 and later; with STAT, TS 18508 or later 8672 8673_Class_: 8674 Atomic subroutine 8675 8676_Syntax_: 8677 'CALL ATOMIC_REF(VALUE, ATOM [, STAT])' 8678 8679_Arguments_: 8680 VALUE Scalar of the same type as ATOM. If the kind is 8681 different, the value is converted to the kind of 8682 ATOM. 8683 ATOM Scalar coarray or coindexed variable of either 8684 integer type with 'ATOMIC_INT_KIND' kind or 8685 logical type with 'ATOMIC_LOGICAL_KIND' kind. 8686 STAT (optional) Scalar default-kind integer variable. 8687 8688_Example_: 8689 program atomic 8690 use iso_fortran_env 8691 logical(atomic_logical_kind) :: atom[*] 8692 logical :: val 8693 call atomic_ref (atom, .false.) 8694 ! ... 8695 call atomic_ref (atom, val) 8696 if (val) then 8697 print *, "Obtained" 8698 end if 8699 end program atomic 8700 8701_See also_: 8702 *note ATOMIC_DEFINE::, *note ATOMIC_CAS::, *note ISO_FORTRAN_ENV::, 8703 *note ATOMIC_FETCH_ADD::, *note ATOMIC_FETCH_AND::, *note 8704 ATOMIC_FETCH_OR::, *note ATOMIC_FETCH_XOR:: 8705 8706 8707File: gfortran.info, Node: ATOMIC_XOR, Next: BACKTRACE, Prev: ATOMIC_REF, Up: Intrinsic Procedures 8708 87099.38 'ATOMIC_XOR' -- Atomic bitwise OR operation 8710================================================ 8711 8712_Description_: 8713 'ATOMIC_AND(ATOM, VALUE)' atomically defines ATOM with the bitwise 8714 XOR between the values of ATOM and VALUE. When STAT is present and 8715 the invocation was successful, it is assigned the value 0. If it 8716 is present and the invocation has failed, it is assigned a positive 8717 value; in particular, for a coindexed ATOM, if the remote image has 8718 stopped, it is assigned the value of 'ISO_FORTRAN_ENV''s 8719 'STAT_STOPPED_IMAGE' and if the remote image has failed, the value 8720 'STAT_FAILED_IMAGE'. 8721 8722_Standard_: 8723 TS 18508 or later 8724 8725_Class_: 8726 Atomic subroutine 8727 8728_Syntax_: 8729 'CALL ATOMIC_XOR (ATOM, VALUE [, STAT])' 8730 8731_Arguments_: 8732 ATOM Scalar coarray or coindexed variable of integer 8733 type with 'ATOMIC_INT_KIND' kind. 8734 VALUE Scalar of the same type as ATOM. If the kind is 8735 different, the value is converted to the kind of 8736 ATOM. 8737 STAT (optional) Scalar default-kind integer variable. 8738 8739_Example_: 8740 program atomic 8741 use iso_fortran_env 8742 integer(atomic_int_kind) :: atom[*] 8743 call atomic_xor (atom[1], int(b'10100011101')) 8744 end program atomic 8745 8746_See also_: 8747 *note ATOMIC_DEFINE::, *note ATOMIC_FETCH_XOR::, *note 8748 ISO_FORTRAN_ENV::, *note ATOMIC_ADD::, *note ATOMIC_OR::, *note 8749 ATOMIC_XOR:: 8750 8751 8752File: gfortran.info, Node: BACKTRACE, Next: BESSEL_J0, Prev: ATOMIC_XOR, Up: Intrinsic Procedures 8753 87549.39 'BACKTRACE' -- Show a backtrace 8755==================================== 8756 8757_Description_: 8758 'BACKTRACE' shows a backtrace at an arbitrary place in user code. 8759 Program execution continues normally afterwards. The backtrace 8760 information is printed to the unit corresponding to 'ERROR_UNIT' in 8761 'ISO_FORTRAN_ENV'. 8762 8763_Standard_: 8764 GNU Extension 8765 8766_Class_: 8767 Subroutine 8768 8769_Syntax_: 8770 'CALL BACKTRACE' 8771 8772_Arguments_: 8773 None 8774 8775_See also_: 8776 *note ABORT:: 8777 8778 8779File: gfortran.info, Node: BESSEL_J0, Next: BESSEL_J1, Prev: BACKTRACE, Up: Intrinsic Procedures 8780 87819.40 'BESSEL_J0' -- Bessel function of the first kind of order 0 8782================================================================ 8783 8784_Description_: 8785 'BESSEL_J0(X)' computes the Bessel function of the first kind of 8786 order 0 of X. This function is available under the name 'BESJ0' as 8787 a GNU extension. 8788 8789_Standard_: 8790 Fortran 2008 and later 8791 8792_Class_: 8793 Elemental function 8794 8795_Syntax_: 8796 'RESULT = BESSEL_J0(X)' 8797 8798_Arguments_: 8799 X The type shall be 'REAL'. 8800 8801_Return value_: 8802 The return value is of type 'REAL' and lies in the range - 8803 0.4027... \leq Bessel (0,x) \leq 1. It has the same kind as X. 8804 8805_Example_: 8806 program test_besj0 8807 real(8) :: x = 0.0_8 8808 x = bessel_j0(x) 8809 end program test_besj0 8810 8811_Specific names_: 8812 Name Argument Return type Standard 8813 'DBESJ0(X)' 'REAL(8) X' 'REAL(8)' GNU extension 8814 8815 8816File: gfortran.info, Node: BESSEL_J1, Next: BESSEL_JN, Prev: BESSEL_J0, Up: Intrinsic Procedures 8817 88189.41 'BESSEL_J1' -- Bessel function of the first kind of order 1 8819================================================================ 8820 8821_Description_: 8822 'BESSEL_J1(X)' computes the Bessel function of the first kind of 8823 order 1 of X. This function is available under the name 'BESJ1' as 8824 a GNU extension. 8825 8826_Standard_: 8827 Fortran 2008 8828 8829_Class_: 8830 Elemental function 8831 8832_Syntax_: 8833 'RESULT = BESSEL_J1(X)' 8834 8835_Arguments_: 8836 X The type shall be 'REAL'. 8837 8838_Return value_: 8839 The return value is of type 'REAL' and lies in the range - 8840 0.5818... \leq Bessel (0,x) \leq 0.5818 . It has the same kind as 8841 X. 8842 8843_Example_: 8844 program test_besj1 8845 real(8) :: x = 1.0_8 8846 x = bessel_j1(x) 8847 end program test_besj1 8848 8849_Specific names_: 8850 Name Argument Return type Standard 8851 'DBESJ1(X)' 'REAL(8) X' 'REAL(8)' GNU extension 8852 8853 8854File: gfortran.info, Node: BESSEL_JN, Next: BESSEL_Y0, Prev: BESSEL_J1, Up: Intrinsic Procedures 8855 88569.42 'BESSEL_JN' -- Bessel function of the first kind 8857===================================================== 8858 8859_Description_: 8860 'BESSEL_JN(N, X)' computes the Bessel function of the first kind of 8861 order N of X. This function is available under the name 'BESJN' as 8862 a GNU extension. If N and X are arrays, their ranks and shapes 8863 shall conform. 8864 8865 'BESSEL_JN(N1, N2, X)' returns an array with the Bessel functions 8866 of the first kind of the orders N1 to N2. 8867 8868_Standard_: 8869 Fortran 2008 and later, negative N is allowed as GNU extension 8870 8871_Class_: 8872 Elemental function, except for the transformational function 8873 'BESSEL_JN(N1, N2, X)' 8874 8875_Syntax_: 8876 'RESULT = BESSEL_JN(N, X)' 8877 'RESULT = BESSEL_JN(N1, N2, X)' 8878 8879_Arguments_: 8880 N Shall be a scalar or an array of type 'INTEGER'. 8881 N1 Shall be a non-negative scalar of type 8882 'INTEGER'. 8883 N2 Shall be a non-negative scalar of type 8884 'INTEGER'. 8885 X Shall be a scalar or an array of type 'REAL'; 8886 for 'BESSEL_JN(N1, N2, X)' it shall be scalar. 8887 8888_Return value_: 8889 The return value is a scalar of type 'REAL'. It has the same kind 8890 as X. 8891 8892_Note_: 8893 The transformational function uses a recurrence algorithm which 8894 might, for some values of X, lead to different results than calls 8895 to the elemental function. 8896 8897_Example_: 8898 program test_besjn 8899 real(8) :: x = 1.0_8 8900 x = bessel_jn(5,x) 8901 end program test_besjn 8902 8903_Specific names_: 8904 Name Argument Return type Standard 8905 'DBESJN(N, 'INTEGER N' 'REAL(8)' GNU extension 8906 X)' 8907 'REAL(8) X' 8908 8909 8910File: gfortran.info, Node: BESSEL_Y0, Next: BESSEL_Y1, Prev: BESSEL_JN, Up: Intrinsic Procedures 8911 89129.43 'BESSEL_Y0' -- Bessel function of the second kind of order 0 8913================================================================= 8914 8915_Description_: 8916 'BESSEL_Y0(X)' computes the Bessel function of the second kind of 8917 order 0 of X. This function is available under the name 'BESY0' as 8918 a GNU extension. 8919 8920_Standard_: 8921 Fortran 2008 and later 8922 8923_Class_: 8924 Elemental function 8925 8926_Syntax_: 8927 'RESULT = BESSEL_Y0(X)' 8928 8929_Arguments_: 8930 X The type shall be 'REAL'. 8931 8932_Return value_: 8933 The return value is of type 'REAL'. It has the same kind as X. 8934 8935_Example_: 8936 program test_besy0 8937 real(8) :: x = 0.0_8 8938 x = bessel_y0(x) 8939 end program test_besy0 8940 8941_Specific names_: 8942 Name Argument Return type Standard 8943 'DBESY0(X)' 'REAL(8) X' 'REAL(8)' GNU extension 8944 8945 8946File: gfortran.info, Node: BESSEL_Y1, Next: BESSEL_YN, Prev: BESSEL_Y0, Up: Intrinsic Procedures 8947 89489.44 'BESSEL_Y1' -- Bessel function of the second kind of order 1 8949================================================================= 8950 8951_Description_: 8952 'BESSEL_Y1(X)' computes the Bessel function of the second kind of 8953 order 1 of X. This function is available under the name 'BESY1' as 8954 a GNU extension. 8955 8956_Standard_: 8957 Fortran 2008 and later 8958 8959_Class_: 8960 Elemental function 8961 8962_Syntax_: 8963 'RESULT = BESSEL_Y1(X)' 8964 8965_Arguments_: 8966 X The type shall be 'REAL'. 8967 8968_Return value_: 8969 The return value is of type 'REAL'. It has the same kind as X. 8970 8971_Example_: 8972 program test_besy1 8973 real(8) :: x = 1.0_8 8974 x = bessel_y1(x) 8975 end program test_besy1 8976 8977_Specific names_: 8978 Name Argument Return type Standard 8979 'DBESY1(X)' 'REAL(8) X' 'REAL(8)' GNU extension 8980 8981 8982File: gfortran.info, Node: BESSEL_YN, Next: BGE, Prev: BESSEL_Y1, Up: Intrinsic Procedures 8983 89849.45 'BESSEL_YN' -- Bessel function of the second kind 8985====================================================== 8986 8987_Description_: 8988 'BESSEL_YN(N, X)' computes the Bessel function of the second kind 8989 of order N of X. This function is available under the name 'BESYN' 8990 as a GNU extension. If N and X are arrays, their ranks and shapes 8991 shall conform. 8992 8993 'BESSEL_YN(N1, N2, X)' returns an array with the Bessel functions 8994 of the first kind of the orders N1 to N2. 8995 8996_Standard_: 8997 Fortran 2008 and later, negative N is allowed as GNU extension 8998 8999_Class_: 9000 Elemental function, except for the transformational function 9001 'BESSEL_YN(N1, N2, X)' 9002 9003_Syntax_: 9004 'RESULT = BESSEL_YN(N, X)' 9005 'RESULT = BESSEL_YN(N1, N2, X)' 9006 9007_Arguments_: 9008 N Shall be a scalar or an array of type 'INTEGER' 9009 . 9010 N1 Shall be a non-negative scalar of type 9011 'INTEGER'. 9012 N2 Shall be a non-negative scalar of type 9013 'INTEGER'. 9014 X Shall be a scalar or an array of type 'REAL'; 9015 for 'BESSEL_YN(N1, N2, X)' it shall be scalar. 9016 9017_Return value_: 9018 The return value is a scalar of type 'REAL'. It has the same kind 9019 as X. 9020 9021_Note_: 9022 The transformational function uses a recurrence algorithm which 9023 might, for some values of X, lead to different results than calls 9024 to the elemental function. 9025 9026_Example_: 9027 program test_besyn 9028 real(8) :: x = 1.0_8 9029 x = bessel_yn(5,x) 9030 end program test_besyn 9031 9032_Specific names_: 9033 Name Argument Return type Standard 9034 'DBESYN(N,X)' 'INTEGER N' 'REAL(8)' GNU extension 9035 'REAL(8) X' 9036 9037 9038File: gfortran.info, Node: BGE, Next: BGT, Prev: BESSEL_YN, Up: Intrinsic Procedures 9039 90409.46 'BGE' -- Bitwise greater than or equal to 9041============================================== 9042 9043_Description_: 9044 Determines whether an integral is a bitwise greater than or equal 9045 to another. 9046 9047_Standard_: 9048 Fortran 2008 and later 9049 9050_Class_: 9051 Elemental function 9052 9053_Syntax_: 9054 'RESULT = BGE(I, J)' 9055 9056_Arguments_: 9057 I Shall be of 'INTEGER' type. 9058 J Shall be of 'INTEGER' type, and of the same kind 9059 as I. 9060 9061_Return value_: 9062 The return value is of type 'LOGICAL' and of the default kind. 9063 9064_See also_: 9065 *note BGT::, *note BLE::, *note BLT:: 9066 9067 9068File: gfortran.info, Node: BGT, Next: BIT_SIZE, Prev: BGE, Up: Intrinsic Procedures 9069 90709.47 'BGT' -- Bitwise greater than 9071================================== 9072 9073_Description_: 9074 Determines whether an integral is a bitwise greater than another. 9075 9076_Standard_: 9077 Fortran 2008 and later 9078 9079_Class_: 9080 Elemental function 9081 9082_Syntax_: 9083 'RESULT = BGT(I, J)' 9084 9085_Arguments_: 9086 I Shall be of 'INTEGER' type. 9087 J Shall be of 'INTEGER' type, and of the same kind 9088 as I. 9089 9090_Return value_: 9091 The return value is of type 'LOGICAL' and of the default kind. 9092 9093_See also_: 9094 *note BGE::, *note BLE::, *note BLT:: 9095 9096 9097File: gfortran.info, Node: BIT_SIZE, Next: BLE, Prev: BGT, Up: Intrinsic Procedures 9098 90999.48 'BIT_SIZE' -- Bit size inquiry function 9100============================================ 9101 9102_Description_: 9103 'BIT_SIZE(I)' returns the number of bits (integer precision plus 9104 sign bit) represented by the type of I. The result of 9105 'BIT_SIZE(I)' is independent of the actual value of I. 9106 9107_Standard_: 9108 Fortran 95 and later 9109 9110_Class_: 9111 Inquiry function 9112 9113_Syntax_: 9114 'RESULT = BIT_SIZE(I)' 9115 9116_Arguments_: 9117 I The type shall be 'INTEGER'. 9118 9119_Return value_: 9120 The return value is of type 'INTEGER' 9121 9122_Example_: 9123 program test_bit_size 9124 integer :: i = 123 9125 integer :: size 9126 size = bit_size(i) 9127 print *, size 9128 end program test_bit_size 9129 9130 9131File: gfortran.info, Node: BLE, Next: BLT, Prev: BIT_SIZE, Up: Intrinsic Procedures 9132 91339.49 'BLE' -- Bitwise less than or equal to 9134=========================================== 9135 9136_Description_: 9137 Determines whether an integral is a bitwise less than or equal to 9138 another. 9139 9140_Standard_: 9141 Fortran 2008 and later 9142 9143_Class_: 9144 Elemental function 9145 9146_Syntax_: 9147 'RESULT = BLE(I, J)' 9148 9149_Arguments_: 9150 I Shall be of 'INTEGER' type. 9151 J Shall be of 'INTEGER' type, and of the same kind 9152 as I. 9153 9154_Return value_: 9155 The return value is of type 'LOGICAL' and of the default kind. 9156 9157_See also_: 9158 *note BGT::, *note BGE::, *note BLT:: 9159 9160 9161File: gfortran.info, Node: BLT, Next: BTEST, Prev: BLE, Up: Intrinsic Procedures 9162 91639.50 'BLT' -- Bitwise less than 9164=============================== 9165 9166_Description_: 9167 Determines whether an integral is a bitwise less than another. 9168 9169_Standard_: 9170 Fortran 2008 and later 9171 9172_Class_: 9173 Elemental function 9174 9175_Syntax_: 9176 'RESULT = BLT(I, J)' 9177 9178_Arguments_: 9179 I Shall be of 'INTEGER' type. 9180 J Shall be of 'INTEGER' type, and of the same kind 9181 as I. 9182 9183_Return value_: 9184 The return value is of type 'LOGICAL' and of the default kind. 9185 9186_See also_: 9187 *note BGE::, *note BGT::, *note BLE:: 9188 9189 9190File: gfortran.info, Node: BTEST, Next: C_ASSOCIATED, Prev: BLT, Up: Intrinsic Procedures 9191 91929.51 'BTEST' -- Bit test function 9193================================= 9194 9195_Description_: 9196 'BTEST(I,POS)' returns logical '.TRUE.' if the bit at POS in I is 9197 set. The counting of the bits starts at 0. 9198 9199_Standard_: 9200 Fortran 95 and later, has overloads that are GNU extensions 9201 9202_Class_: 9203 Elemental function 9204 9205_Syntax_: 9206 'RESULT = BTEST(I, POS)' 9207 9208_Arguments_: 9209 I The type shall be 'INTEGER'. 9210 POS The type shall be 'INTEGER'. 9211 9212_Return value_: 9213 The return value is of type 'LOGICAL' 9214 9215_Example_: 9216 program test_btest 9217 integer :: i = 32768 + 1024 + 64 9218 integer :: pos 9219 logical :: bool 9220 do pos=0,16 9221 bool = btest(i, pos) 9222 print *, pos, bool 9223 end do 9224 end program test_btest 9225 9226_Specific names_: 9227 Name Argument Return type Standard 9228 'BTEST(I,POS)' 'INTEGER 'LOGICAL' F95 and later 9229 I,POS' 9230 'BBTEST(I,POS)''INTEGER(1) 'LOGICAL(1)' GNU extension 9231 I,POS' 9232 'BITEST(I,POS)''INTEGER(2) 'LOGICAL(2)' GNU extension 9233 I,POS' 9234 'BJTEST(I,POS)''INTEGER(4) 'LOGICAL(4)' GNU extension 9235 I,POS' 9236 'BKTEST(I,POS)''INTEGER(8) 'LOGICAL(8)' GNU extension 9237 I,POS' 9238 9239 9240File: gfortran.info, Node: C_ASSOCIATED, Next: C_F_POINTER, Prev: BTEST, Up: Intrinsic Procedures 9241 92429.52 'C_ASSOCIATED' -- Status of a C pointer 9243============================================ 9244 9245_Description_: 9246 'C_ASSOCIATED(c_ptr_1[, c_ptr_2])' determines the status of the C 9247 pointer C_PTR_1 or if C_PTR_1 is associated with the target 9248 C_PTR_2. 9249 9250_Standard_: 9251 Fortran 2003 and later 9252 9253_Class_: 9254 Inquiry function 9255 9256_Syntax_: 9257 'RESULT = C_ASSOCIATED(c_ptr_1[, c_ptr_2])' 9258 9259_Arguments_: 9260 C_PTR_1 Scalar of the type 'C_PTR' or 'C_FUNPTR'. 9261 C_PTR_2 (Optional) Scalar of the same type as C_PTR_1. 9262 9263_Return value_: 9264 The return value is of type 'LOGICAL'; it is '.false.' if either 9265 C_PTR_1 is a C NULL pointer or if C_PTR1 and C_PTR_2 point to 9266 different addresses. 9267 9268_Example_: 9269 subroutine association_test(a,b) 9270 use iso_c_binding, only: c_associated, c_loc, c_ptr 9271 implicit none 9272 real, pointer :: a 9273 type(c_ptr) :: b 9274 if(c_associated(b, c_loc(a))) & 9275 stop 'b and a do not point to same target' 9276 end subroutine association_test 9277 9278_See also_: 9279 *note C_LOC::, *note C_FUNLOC:: 9280 9281 9282File: gfortran.info, Node: C_F_POINTER, Next: C_F_PROCPOINTER, Prev: C_ASSOCIATED, Up: Intrinsic Procedures 9283 92849.53 'C_F_POINTER' -- Convert C into Fortran pointer 9285==================================================== 9286 9287_Description_: 9288 'C_F_POINTER(CPTR, FPTR[, SHAPE])' assigns the target of the C 9289 pointer CPTR to the Fortran pointer FPTR and specifies its shape. 9290 9291_Standard_: 9292 Fortran 2003 and later 9293 9294_Class_: 9295 Subroutine 9296 9297_Syntax_: 9298 'CALL C_F_POINTER(CPTR, FPTR[, SHAPE])' 9299 9300_Arguments_: 9301 CPTR scalar of the type 'C_PTR'. It is 'INTENT(IN)'. 9302 FPTR pointer interoperable with CPTR. It is 9303 'INTENT(OUT)'. 9304 SHAPE (Optional) Rank-one array of type 'INTEGER' with 9305 'INTENT(IN)'. It shall be present if and only 9306 if FPTR is an array. The size must be equal to 9307 the rank of FPTR. 9308 9309_Example_: 9310 program main 9311 use iso_c_binding 9312 implicit none 9313 interface 9314 subroutine my_routine(p) bind(c,name='myC_func') 9315 import :: c_ptr 9316 type(c_ptr), intent(out) :: p 9317 end subroutine 9318 end interface 9319 type(c_ptr) :: cptr 9320 real,pointer :: a(:) 9321 call my_routine(cptr) 9322 call c_f_pointer(cptr, a, [12]) 9323 end program main 9324 9325_See also_: 9326 *note C_LOC::, *note C_F_PROCPOINTER:: 9327 9328 9329File: gfortran.info, Node: C_F_PROCPOINTER, Next: C_FUNLOC, Prev: C_F_POINTER, Up: Intrinsic Procedures 9330 93319.54 'C_F_PROCPOINTER' -- Convert C into Fortran procedure pointer 9332================================================================== 9333 9334_Description_: 9335 'C_F_PROCPOINTER(CPTR, FPTR)' Assign the target of the C function 9336 pointer CPTR to the Fortran procedure pointer FPTR. 9337 9338_Standard_: 9339 Fortran 2003 and later 9340 9341_Class_: 9342 Subroutine 9343 9344_Syntax_: 9345 'CALL C_F_PROCPOINTER(cptr, fptr)' 9346 9347_Arguments_: 9348 CPTR scalar of the type 'C_FUNPTR'. It is 9349 'INTENT(IN)'. 9350 FPTR procedure pointer interoperable with CPTR. It 9351 is 'INTENT(OUT)'. 9352 9353_Example_: 9354 program main 9355 use iso_c_binding 9356 implicit none 9357 abstract interface 9358 function func(a) 9359 import :: c_float 9360 real(c_float), intent(in) :: a 9361 real(c_float) :: func 9362 end function 9363 end interface 9364 interface 9365 function getIterFunc() bind(c,name="getIterFunc") 9366 import :: c_funptr 9367 type(c_funptr) :: getIterFunc 9368 end function 9369 end interface 9370 type(c_funptr) :: cfunptr 9371 procedure(func), pointer :: myFunc 9372 cfunptr = getIterFunc() 9373 call c_f_procpointer(cfunptr, myFunc) 9374 end program main 9375 9376_See also_: 9377 *note C_LOC::, *note C_F_POINTER:: 9378 9379 9380File: gfortran.info, Node: C_FUNLOC, Next: C_LOC, Prev: C_F_PROCPOINTER, Up: Intrinsic Procedures 9381 93829.55 'C_FUNLOC' -- Obtain the C address of a procedure 9383====================================================== 9384 9385_Description_: 9386 'C_FUNLOC(x)' determines the C address of the argument. 9387 9388_Standard_: 9389 Fortran 2003 and later 9390 9391_Class_: 9392 Inquiry function 9393 9394_Syntax_: 9395 'RESULT = C_FUNLOC(x)' 9396 9397_Arguments_: 9398 X Interoperable function or pointer to such 9399 function. 9400 9401_Return value_: 9402 The return value is of type 'C_FUNPTR' and contains the C address 9403 of the argument. 9404 9405_Example_: 9406 module x 9407 use iso_c_binding 9408 implicit none 9409 contains 9410 subroutine sub(a) bind(c) 9411 real(c_float) :: a 9412 a = sqrt(a)+5.0 9413 end subroutine sub 9414 end module x 9415 program main 9416 use iso_c_binding 9417 use x 9418 implicit none 9419 interface 9420 subroutine my_routine(p) bind(c,name='myC_func') 9421 import :: c_funptr 9422 type(c_funptr), intent(in) :: p 9423 end subroutine 9424 end interface 9425 call my_routine(c_funloc(sub)) 9426 end program main 9427 9428_See also_: 9429 *note C_ASSOCIATED::, *note C_LOC::, *note C_F_POINTER::, *note 9430 C_F_PROCPOINTER:: 9431 9432 9433File: gfortran.info, Node: C_LOC, Next: C_SIZEOF, Prev: C_FUNLOC, Up: Intrinsic Procedures 9434 94359.56 'C_LOC' -- Obtain the C address of an object 9436================================================= 9437 9438_Description_: 9439 'C_LOC(X)' determines the C address of the argument. 9440 9441_Standard_: 9442 Fortran 2003 and later 9443 9444_Class_: 9445 Inquiry function 9446 9447_Syntax_: 9448 'RESULT = C_LOC(X)' 9449 9450_Arguments_: 9451 X Shall have either the POINTER or TARGET attribute. 9452 It shall not be a coindexed object. It shall either 9453 be a variable with interoperable type and kind type 9454 parameters, or be a scalar, nonpolymorphic variable 9455 with no length type parameters. 9456 9457 9458_Return value_: 9459 The return value is of type 'C_PTR' and contains the C address of 9460 the argument. 9461 9462_Example_: 9463 subroutine association_test(a,b) 9464 use iso_c_binding, only: c_associated, c_loc, c_ptr 9465 implicit none 9466 real, pointer :: a 9467 type(c_ptr) :: b 9468 if(c_associated(b, c_loc(a))) & 9469 stop 'b and a do not point to same target' 9470 end subroutine association_test 9471 9472_See also_: 9473 *note C_ASSOCIATED::, *note C_FUNLOC::, *note C_F_POINTER::, *note 9474 C_F_PROCPOINTER:: 9475 9476 9477File: gfortran.info, Node: C_SIZEOF, Next: CEILING, Prev: C_LOC, Up: Intrinsic Procedures 9478 94799.57 'C_SIZEOF' -- Size in bytes of an expression 9480================================================= 9481 9482_Description_: 9483 'C_SIZEOF(X)' calculates the number of bytes of storage the 9484 expression 'X' occupies. 9485 9486_Standard_: 9487 Fortran 2008 9488 9489_Class_: 9490 Inquiry function of the module 'ISO_C_BINDING' 9491 9492_Syntax_: 9493 'N = C_SIZEOF(X)' 9494 9495_Arguments_: 9496 X The argument shall be an interoperable data 9497 entity. 9498 9499_Return value_: 9500 The return value is of type integer and of the system-dependent 9501 kind 'C_SIZE_T' (from the 'ISO_C_BINDING' module). Its value is 9502 the number of bytes occupied by the argument. If the argument has 9503 the 'POINTER' attribute, the number of bytes of the storage area 9504 pointed to is returned. If the argument is of a derived type with 9505 'POINTER' or 'ALLOCATABLE' components, the return value does not 9506 account for the sizes of the data pointed to by these components. 9507 9508_Example_: 9509 use iso_c_binding 9510 integer(c_int) :: i 9511 real(c_float) :: r, s(5) 9512 print *, (c_sizeof(s)/c_sizeof(r) == 5) 9513 end 9514 The example will print '.TRUE.' unless you are using a platform 9515 where default 'REAL' variables are unusually padded. 9516 9517_See also_: 9518 *note SIZEOF::, *note STORAGE_SIZE:: 9519 9520 9521File: gfortran.info, Node: CEILING, Next: CHAR, Prev: C_SIZEOF, Up: Intrinsic Procedures 9522 95239.58 'CEILING' -- Integer ceiling function 9524========================================== 9525 9526_Description_: 9527 'CEILING(A)' returns the least integer greater than or equal to A. 9528 9529_Standard_: 9530 Fortran 95 and later 9531 9532_Class_: 9533 Elemental function 9534 9535_Syntax_: 9536 'RESULT = CEILING(A [, KIND])' 9537 9538_Arguments_: 9539 A The type shall be 'REAL'. 9540 KIND (Optional) An 'INTEGER' initialization 9541 expression indicating the kind parameter of the 9542 result. 9543 9544_Return value_: 9545 The return value is of type 'INTEGER(KIND)' if KIND is present and 9546 a default-kind 'INTEGER' otherwise. 9547 9548_Example_: 9549 program test_ceiling 9550 real :: x = 63.29 9551 real :: y = -63.59 9552 print *, ceiling(x) ! returns 64 9553 print *, ceiling(y) ! returns -63 9554 end program test_ceiling 9555 9556_See also_: 9557 *note FLOOR::, *note NINT:: 9558 9559 9560File: gfortran.info, Node: CHAR, Next: CHDIR, Prev: CEILING, Up: Intrinsic Procedures 9561 95629.59 'CHAR' -- Character conversion function 9563============================================ 9564 9565_Description_: 9566 'CHAR(I [, KIND])' returns the character represented by the integer 9567 I. 9568 9569_Standard_: 9570 Fortran 77 and later 9571 9572_Class_: 9573 Elemental function 9574 9575_Syntax_: 9576 'RESULT = CHAR(I [, KIND])' 9577 9578_Arguments_: 9579 I The type shall be 'INTEGER'. 9580 KIND (Optional) An 'INTEGER' initialization 9581 expression indicating the kind parameter of the 9582 result. 9583 9584_Return value_: 9585 The return value is of type 'CHARACTER(1)' 9586 9587_Example_: 9588 program test_char 9589 integer :: i = 74 9590 character(1) :: c 9591 c = char(i) 9592 print *, i, c ! returns 'J' 9593 end program test_char 9594 9595_Specific names_: 9596 Name Argument Return type Standard 9597 'CHAR(I)' 'INTEGER I' 'CHARACTER(LEN=1)'F77 and later 9598 9599_Note_: 9600 See *note ICHAR:: for a discussion of converting between numerical 9601 values and formatted string representations. 9602 9603_See also_: 9604 *note ACHAR::, *note IACHAR::, *note ICHAR:: 9605 9606 9607File: gfortran.info, Node: CHDIR, Next: CHMOD, Prev: CHAR, Up: Intrinsic Procedures 9608 96099.60 'CHDIR' -- Change working directory 9610======================================== 9611 9612_Description_: 9613 Change current working directory to a specified path. 9614 9615 This intrinsic is provided in both subroutine and function forms; 9616 however, only one form can be used in any given program unit. 9617 9618_Standard_: 9619 GNU extension 9620 9621_Class_: 9622 Subroutine, function 9623 9624_Syntax_: 9625 'CALL CHDIR(NAME [, STATUS])' 9626 'STATUS = CHDIR(NAME)' 9627 9628_Arguments_: 9629 NAME The type shall be 'CHARACTER' of default kind 9630 and shall specify a valid path within the file 9631 system. 9632 STATUS (Optional) 'INTEGER' status flag of the default 9633 kind. Returns 0 on success, and a system 9634 specific and nonzero error code otherwise. 9635 9636_Example_: 9637 PROGRAM test_chdir 9638 CHARACTER(len=255) :: path 9639 CALL getcwd(path) 9640 WRITE(*,*) TRIM(path) 9641 CALL chdir("/tmp") 9642 CALL getcwd(path) 9643 WRITE(*,*) TRIM(path) 9644 END PROGRAM 9645 9646_See also_: 9647 *note GETCWD:: 9648 9649 9650File: gfortran.info, Node: CHMOD, Next: CMPLX, Prev: CHDIR, Up: Intrinsic Procedures 9651 96529.61 'CHMOD' -- Change access permissions of files 9653================================================== 9654 9655_Description_: 9656 'CHMOD' changes the permissions of a file. 9657 9658 This intrinsic is provided in both subroutine and function forms; 9659 however, only one form can be used in any given program unit. 9660 9661_Standard_: 9662 GNU extension 9663 9664_Class_: 9665 Subroutine, function 9666 9667_Syntax_: 9668 'CALL CHMOD(NAME, MODE[, STATUS])' 9669 'STATUS = CHMOD(NAME, MODE)' 9670 9671_Arguments_: 9672 9673 NAME Scalar 'CHARACTER' of default kind with the file 9674 name. Trailing blanks are ignored unless the 9675 character 'achar(0)' is present, then all 9676 characters up to and excluding 'achar(0)' are 9677 used as the file name. 9678 9679 MODE Scalar 'CHARACTER' of default kind giving the 9680 file permission. MODE uses the same syntax as 9681 the 'chmod' utility as defined by the POSIX 9682 standard. The argument shall either be a string 9683 of a nonnegative octal number or a symbolic 9684 mode. 9685 9686 STATUS (optional) scalar 'INTEGER', which is '0' on 9687 success and nonzero otherwise. 9688 9689_Return value_: 9690 In either syntax, STATUS is set to '0' on success and nonzero 9691 otherwise. 9692 9693_Example_: 9694 'CHMOD' as subroutine 9695 program chmod_test 9696 implicit none 9697 integer :: status 9698 call chmod('test.dat','u+x',status) 9699 print *, 'Status: ', status 9700 end program chmod_test 9701 'CHMOD' as function: 9702 program chmod_test 9703 implicit none 9704 integer :: status 9705 status = chmod('test.dat','u+x') 9706 print *, 'Status: ', status 9707 end program chmod_test 9708 9709 9710File: gfortran.info, Node: CMPLX, Next: CO_BROADCAST, Prev: CHMOD, Up: Intrinsic Procedures 9711 97129.62 'CMPLX' -- Complex conversion function 9713=========================================== 9714 9715_Description_: 9716 'CMPLX(X [, Y [, KIND]])' returns a complex number where X is 9717 converted to the real component. If Y is present it is converted 9718 to the imaginary component. If Y is not present then the imaginary 9719 component is set to 0.0. If X is complex then Y must not be 9720 present. 9721 9722_Standard_: 9723 Fortran 77 and later 9724 9725_Class_: 9726 Elemental function 9727 9728_Syntax_: 9729 'RESULT = CMPLX(X [, Y [, KIND]])' 9730 9731_Arguments_: 9732 X The type may be 'INTEGER', 'REAL', or 'COMPLEX'. 9733 Y (Optional; only allowed if X is not 'COMPLEX'.) 9734 May be 'INTEGER' or 'REAL'. 9735 KIND (Optional) An 'INTEGER' initialization 9736 expression indicating the kind parameter of the 9737 result. 9738 9739_Return value_: 9740 The return value is of 'COMPLEX' type, with a kind equal to KIND if 9741 it is specified. If KIND is not specified, the result is of the 9742 default 'COMPLEX' kind, regardless of the kinds of X and Y. 9743 9744_Example_: 9745 program test_cmplx 9746 integer :: i = 42 9747 real :: x = 3.14 9748 complex :: z 9749 z = cmplx(i, x) 9750 print *, z, cmplx(x) 9751 end program test_cmplx 9752 9753_See also_: 9754 *note COMPLEX:: 9755 9756 9757File: gfortran.info, Node: CO_BROADCAST, Next: CO_MAX, Prev: CMPLX, Up: Intrinsic Procedures 9758 97599.63 'CO_BROADCAST' -- Copy a value to all images the current set of images 9760=========================================================================== 9761 9762_Description_: 9763 'CO_BROADCAST' copies the value of argument A on the image with 9764 image index 'SOURCE_IMAGE' to all images in the current team. A 9765 becomes defined as if by intrinsic assignment. If the execution 9766 was successful and STAT is present, it is assigned the value zero. 9767 If the execution failed, STAT gets assigned a nonzero value and, if 9768 present, ERRMSG gets assigned a value describing the occurred 9769 error. 9770 9771_Standard_: 9772 Technical Specification (TS) 18508 or later 9773 9774_Class_: 9775 Collective subroutine 9776 9777_Syntax_: 9778 'CALL CO_BROADCAST(A, SOURCE_IMAGE [, STAT, ERRMSG])' 9779 9780_Arguments_: 9781 A INTENT(INOUT) argument; shall have the same 9782 dynamic type and type paramters on all images of 9783 the current team. If it is an array, it shall 9784 have the same shape on all images. 9785 SOURCE_IMAGEa scalar integer expression. It shall have the 9786 same the same value on all images and refer to 9787 an image of the current team. 9788 STAT (optional) a scalar integer variable 9789 ERRMSG (optional) a scalar character variable 9790 9791_Example_: 9792 program test 9793 integer :: val(3) 9794 if (this_image() == 1) then 9795 val = [1, 5, 3] 9796 end if 9797 call co_broadcast (val, source_image=1) 9798 print *, this_image, ":", val 9799 end program test 9800 9801_See also_: 9802 *note CO_MAX::, *note CO_MIN::, *note CO_SUM::, *note CO_REDUCE:: 9803 9804 9805File: gfortran.info, Node: CO_MAX, Next: CO_MIN, Prev: CO_BROADCAST, Up: Intrinsic Procedures 9806 98079.64 'CO_MAX' -- Maximal value on the current set of images 9808=========================================================== 9809 9810_Description_: 9811 'CO_MAX' determines element-wise the maximal value of A on all 9812 images of the current team. If RESULT_IMAGE is present, the 9813 maximum values are returned in A on the specified image only and 9814 the value of A on the other images become undefined. If 9815 RESULT_IMAGE is not present, the value is returned on all images. 9816 If the execution was successful and STAT is present, it is assigned 9817 the value zero. If the execution failed, STAT gets assigned a 9818 nonzero value and, if present, ERRMSG gets assigned a value 9819 describing the occurred error. 9820 9821_Standard_: 9822 Technical Specification (TS) 18508 or later 9823 9824_Class_: 9825 Collective subroutine 9826 9827_Syntax_: 9828 'CALL CO_MAX(A [, RESULT_IMAGE, STAT, ERRMSG])' 9829 9830_Arguments_: 9831 A shall be an integer, real or character variable, 9832 which has the same type and type parameters on 9833 all images of the team. 9834 RESULT_IMAGE(optional) a scalar integer expression; if 9835 present, it shall have the same the same value 9836 on all images and refer to an image of the 9837 current team. 9838 STAT (optional) a scalar integer variable 9839 ERRMSG (optional) a scalar character variable 9840 9841_Example_: 9842 program test 9843 integer :: val 9844 val = this_image () 9845 call co_max (val, result_image=1) 9846 if (this_image() == 1) then 9847 write(*,*) "Maximal value", val ! prints num_images() 9848 end if 9849 end program test 9850 9851_See also_: 9852 *note CO_MIN::, *note CO_SUM::, *note CO_REDUCE::, *note 9853 CO_BROADCAST:: 9854 9855 9856File: gfortran.info, Node: CO_MIN, Next: CO_REDUCE, Prev: CO_MAX, Up: Intrinsic Procedures 9857 98589.65 'CO_MIN' -- Minimal value on the current set of images 9859=========================================================== 9860 9861_Description_: 9862 'CO_MIN' determines element-wise the minimal value of A on all 9863 images of the current team. If RESULT_IMAGE is present, the 9864 minimal values are returned in A on the specified image only and 9865 the value of A on the other images become undefined. If 9866 RESULT_IMAGE is not present, the value is returned on all images. 9867 If the execution was successful and STAT is present, it is assigned 9868 the value zero. If the execution failed, STAT gets assigned a 9869 nonzero value and, if present, ERRMSG gets assigned a value 9870 describing the occurred error. 9871 9872_Standard_: 9873 Technical Specification (TS) 18508 or later 9874 9875_Class_: 9876 Collective subroutine 9877 9878_Syntax_: 9879 'CALL CO_MIN(A [, RESULT_IMAGE, STAT, ERRMSG])' 9880 9881_Arguments_: 9882 A shall be an integer, real or character variable, 9883 which has the same type and type parameters on 9884 all images of the team. 9885 RESULT_IMAGE(optional) a scalar integer expression; if 9886 present, it shall have the same the same value 9887 on all images and refer to an image of the 9888 current team. 9889 STAT (optional) a scalar integer variable 9890 ERRMSG (optional) a scalar character variable 9891 9892_Example_: 9893 program test 9894 integer :: val 9895 val = this_image () 9896 call co_min (val, result_image=1) 9897 if (this_image() == 1) then 9898 write(*,*) "Minimal value", val ! prints 1 9899 end if 9900 end program test 9901 9902_See also_: 9903 *note CO_MAX::, *note CO_SUM::, *note CO_REDUCE::, *note 9904 CO_BROADCAST:: 9905 9906 9907File: gfortran.info, Node: CO_REDUCE, Next: CO_SUM, Prev: CO_MIN, Up: Intrinsic Procedures 9908 99099.66 'CO_REDUCE' -- Reduction of values on the current set of images 9910==================================================================== 9911 9912_Description_: 9913 'CO_REDUCE' determines element-wise the reduction of the value of A 9914 on all images of the current team. The pure function passed as 9915 OPERATOR is used to pairwise reduce the values of A by passing 9916 either the value of A of different images or the result values of 9917 such a reduction as argument. If A is an array, the deduction is 9918 done element wise. If RESULT_IMAGE is present, the result values 9919 are returned in A on the specified image only and the value of A on 9920 the other images become undefined. If RESULT_IMAGE is not present, 9921 the value is returned on all images. If the execution was 9922 successful and STAT is present, it is assigned the value zero. If 9923 the execution failed, STAT gets assigned a nonzero value and, if 9924 present, ERRMSG gets assigned a value describing the occurred 9925 error. 9926 9927_Standard_: 9928 Technical Specification (TS) 18508 or later 9929 9930_Class_: 9931 Collective subroutine 9932 9933_Syntax_: 9934 'CALL CO_REDUCE(A, OPERATOR, [, RESULT_IMAGE, STAT, ERRMSG])' 9935 9936_Arguments_: 9937 A is an 'INTENT(INOUT)' argument and shall be 9938 nonpolymorphic. If it is allocatable, it shall 9939 be allocated; if it is a pointer, it shall be 9940 associated. A shall have the same type and type 9941 parameters on all images of the team; if it is 9942 an array, it shall have the same shape on all 9943 images. 9944 OPERATOR pure function with two scalar nonallocatable 9945 arguments, which shall be nonpolymorphic and 9946 have the same type and type parameters as A. 9947 The function shall return a nonallocatable 9948 scalar of the same type and type parameters as 9949 A. The function shall be the same on all images 9950 and with regards to the arguments mathematically 9951 commutative and associative. Note that OPERATOR 9952 may not be an elemental function, unless it is 9953 an intrisic function. 9954 RESULT_IMAGE(optional) a scalar integer expression; if 9955 present, it shall have the same the same value 9956 on all images and refer to an image of the 9957 current team. 9958 STAT (optional) a scalar integer variable 9959 ERRMSG (optional) a scalar character variable 9960 9961_Example_: 9962 program test 9963 integer :: val 9964 val = this_image () 9965 call co_reduce (val, result_image=1, operator=myprod) 9966 if (this_image() == 1) then 9967 write(*,*) "Product value", val ! prints num_images() factorial 9968 end if 9969 contains 9970 pure function myprod(a, b) 9971 integer, value :: a, b 9972 integer :: myprod 9973 myprod = a * b 9974 end function myprod 9975 end program test 9976 9977_Note_: 9978 While the rules permit in principle an intrinsic function, none of 9979 the intrinsics in the standard fulfill the criteria of having a 9980 specific function, which takes two arguments of the same type and 9981 returning that type as result. 9982 9983_See also_: 9984 *note CO_MIN::, *note CO_MAX::, *note CO_SUM::, *note 9985 CO_BROADCAST:: 9986 9987 9988File: gfortran.info, Node: CO_SUM, Next: COMMAND_ARGUMENT_COUNT, Prev: CO_REDUCE, Up: Intrinsic Procedures 9989 99909.67 'CO_SUM' -- Sum of values on the current set of images 9991=========================================================== 9992 9993_Description_: 9994 'CO_SUM' sums up the values of each element of A on all images of 9995 the current team. If RESULT_IMAGE is present, the summed-up values 9996 are returned in A on the specified image only and the value of A on 9997 the other images become undefined. If RESULT_IMAGE is not present, 9998 the value is returned on all images. If the execution was 9999 successful and STAT is present, it is assigned the value zero. If 10000 the execution failed, STAT gets assigned a nonzero value and, if 10001 present, ERRMSG gets assigned a value describing the occurred 10002 error. 10003 10004_Standard_: 10005 Technical Specification (TS) 18508 or later 10006 10007_Class_: 10008 Collective subroutine 10009 10010_Syntax_: 10011 'CALL CO_MIN(A [, RESULT_IMAGE, STAT, ERRMSG])' 10012 10013_Arguments_: 10014 A shall be an integer, real or complex variable, 10015 which has the same type and type parameters on 10016 all images of the team. 10017 RESULT_IMAGE(optional) a scalar integer expression; if 10018 present, it shall have the same the same value 10019 on all images and refer to an image of the 10020 current team. 10021 STAT (optional) a scalar integer variable 10022 ERRMSG (optional) a scalar character variable 10023 10024_Example_: 10025 program test 10026 integer :: val 10027 val = this_image () 10028 call co_sum (val, result_image=1) 10029 if (this_image() == 1) then 10030 write(*,*) "The sum is ", val ! prints (n**2 + n)/2, with n = num_images() 10031 end if 10032 end program test 10033 10034_See also_: 10035 *note CO_MAX::, *note CO_MIN::, *note CO_REDUCE::, *note 10036 CO_BROADCAST:: 10037 10038 10039File: gfortran.info, Node: COMMAND_ARGUMENT_COUNT, Next: COMPILER_OPTIONS, Prev: CO_SUM, Up: Intrinsic Procedures 10040 100419.68 'COMMAND_ARGUMENT_COUNT' -- Get number of command line arguments 10042===================================================================== 10043 10044_Description_: 10045 'COMMAND_ARGUMENT_COUNT' returns the number of arguments passed on 10046 the command line when the containing program was invoked. 10047 10048_Standard_: 10049 Fortran 2003 and later 10050 10051_Class_: 10052 Inquiry function 10053 10054_Syntax_: 10055 'RESULT = COMMAND_ARGUMENT_COUNT()' 10056 10057_Arguments_: 10058 None 10059 10060_Return value_: 10061 The return value is an 'INTEGER' of default kind. 10062 10063_Example_: 10064 program test_command_argument_count 10065 integer :: count 10066 count = command_argument_count() 10067 print *, count 10068 end program test_command_argument_count 10069 10070_See also_: 10071 *note GET_COMMAND::, *note GET_COMMAND_ARGUMENT:: 10072 10073 10074File: gfortran.info, Node: COMPILER_OPTIONS, Next: COMPILER_VERSION, Prev: COMMAND_ARGUMENT_COUNT, Up: Intrinsic Procedures 10075 100769.69 'COMPILER_OPTIONS' -- Options passed to the compiler 10077========================================================= 10078 10079_Description_: 10080 'COMPILER_OPTIONS' returns a string with the options used for 10081 compiling. 10082 10083_Standard_: 10084 Fortran 2008 10085 10086_Class_: 10087 Inquiry function of the module 'ISO_FORTRAN_ENV' 10088 10089_Syntax_: 10090 'STR = COMPILER_OPTIONS()' 10091 10092_Arguments_: 10093 None. 10094 10095_Return value_: 10096 The return value is a default-kind string with system-dependent 10097 length. It contains the compiler flags used to compile the file, 10098 which called the 'COMPILER_OPTIONS' intrinsic. 10099 10100_Example_: 10101 use iso_fortran_env 10102 print '(4a)', 'This file was compiled by ', & 10103 compiler_version(), ' using the options ', & 10104 compiler_options() 10105 end 10106 10107_See also_: 10108 *note COMPILER_VERSION::, *note ISO_FORTRAN_ENV:: 10109 10110 10111File: gfortran.info, Node: COMPILER_VERSION, Next: COMPLEX, Prev: COMPILER_OPTIONS, Up: Intrinsic Procedures 10112 101139.70 'COMPILER_VERSION' -- Compiler version string 10114================================================== 10115 10116_Description_: 10117 'COMPILER_VERSION' returns a string with the name and the version 10118 of the compiler. 10119 10120_Standard_: 10121 Fortran 2008 10122 10123_Class_: 10124 Inquiry function of the module 'ISO_FORTRAN_ENV' 10125 10126_Syntax_: 10127 'STR = COMPILER_VERSION()' 10128 10129_Arguments_: 10130 None. 10131 10132_Return value_: 10133 The return value is a default-kind string with system-dependent 10134 length. It contains the name of the compiler and its version 10135 number. 10136 10137_Example_: 10138 use iso_fortran_env 10139 print '(4a)', 'This file was compiled by ', & 10140 compiler_version(), ' using the options ', & 10141 compiler_options() 10142 end 10143 10144_See also_: 10145 *note COMPILER_OPTIONS::, *note ISO_FORTRAN_ENV:: 10146 10147 10148File: gfortran.info, Node: COMPLEX, Next: CONJG, Prev: COMPILER_VERSION, Up: Intrinsic Procedures 10149 101509.71 'COMPLEX' -- Complex conversion function 10151============================================= 10152 10153_Description_: 10154 'COMPLEX(X, Y)' returns a complex number where X is converted to 10155 the real component and Y is converted to the imaginary component. 10156 10157_Standard_: 10158 GNU extension 10159 10160_Class_: 10161 Elemental function 10162 10163_Syntax_: 10164 'RESULT = COMPLEX(X, Y)' 10165 10166_Arguments_: 10167 X The type may be 'INTEGER' or 'REAL'. 10168 Y The type may be 'INTEGER' or 'REAL'. 10169 10170_Return value_: 10171 If X and Y are both of 'INTEGER' type, then the return value is of 10172 default 'COMPLEX' type. 10173 10174 If X and Y are of 'REAL' type, or one is of 'REAL' type and one is 10175 of 'INTEGER' type, then the return value is of 'COMPLEX' type with 10176 a kind equal to that of the 'REAL' argument with the highest 10177 precision. 10178 10179_Example_: 10180 program test_complex 10181 integer :: i = 42 10182 real :: x = 3.14 10183 print *, complex(i, x) 10184 end program test_complex 10185 10186_See also_: 10187 *note CMPLX:: 10188 10189 10190File: gfortran.info, Node: CONJG, Next: COS, Prev: COMPLEX, Up: Intrinsic Procedures 10191 101929.72 'CONJG' -- Complex conjugate function 10193========================================== 10194 10195_Description_: 10196 'CONJG(Z)' returns the conjugate of Z. If Z is '(x, y)' then the 10197 result is '(x, -y)' 10198 10199_Standard_: 10200 Fortran 77 and later, has overloads that are GNU extensions 10201 10202_Class_: 10203 Elemental function 10204 10205_Syntax_: 10206 'Z = CONJG(Z)' 10207 10208_Arguments_: 10209 Z The type shall be 'COMPLEX'. 10210 10211_Return value_: 10212 The return value is of type 'COMPLEX'. 10213 10214_Example_: 10215 program test_conjg 10216 complex :: z = (2.0, 3.0) 10217 complex(8) :: dz = (2.71_8, -3.14_8) 10218 z= conjg(z) 10219 print *, z 10220 dz = dconjg(dz) 10221 print *, dz 10222 end program test_conjg 10223 10224_Specific names_: 10225 Name Argument Return type Standard 10226 'CONJG(Z)' 'COMPLEX Z' 'COMPLEX' GNU extension 10227 'DCONJG(Z)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 10228 Z' 10229 10230 10231File: gfortran.info, Node: COS, Next: COSD, Prev: CONJG, Up: Intrinsic Procedures 10232 102339.73 'COS' -- Cosine function 10234============================= 10235 10236_Description_: 10237 'COS(X)' computes the cosine of X. 10238 10239_Standard_: 10240 Fortran 77 and later, has overloads that are GNU extensions 10241 10242_Class_: 10243 Elemental function 10244 10245_Syntax_: 10246 'RESULT = COS(X)' 10247 10248_Arguments_: 10249 X The type shall be 'REAL' or 'COMPLEX'. 10250 10251_Return value_: 10252 The return value is of the same type and kind as X. The real part 10253 of the result is in radians. If X is of the type 'REAL', the 10254 return value lies in the range -1 \leq \cos (x) \leq 1. 10255 10256_Example_: 10257 program test_cos 10258 real :: x = 0.0 10259 x = cos(x) 10260 end program test_cos 10261 10262_Specific names_: 10263 Name Argument Return type Standard 10264 'COS(X)' 'REAL(4) X' 'REAL(4)' Fortran 77 and 10265 later 10266 'DCOS(X)' 'REAL(8) X' 'REAL(8)' Fortran 77 and 10267 later 10268 'CCOS(X)' 'COMPLEX(4) 'COMPLEX(4)' Fortran 77 and 10269 X' later 10270 'ZCOS(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 10271 X' 10272 'CDCOS(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 10273 X' 10274 10275_See also_: 10276 Inverse function: *note ACOS:: Degrees function: *note COSD:: 10277 10278 10279File: gfortran.info, Node: COSD, Next: COSH, Prev: COS, Up: Intrinsic Procedures 10280 102819.74 'COSD' -- Cosine function, degrees 10282======================================= 10283 10284_Description_: 10285 'COSD(X)' computes the cosine of X in degrees. 10286 10287 This function is for compatibility only and should be avoided in 10288 favor of standard constructs wherever possible. 10289 10290_Standard_: 10291 GNU Extension, enabled with '-fdec-math'. 10292 10293_Class_: 10294 Elemental function 10295 10296_Syntax_: 10297 'RESULT = COSD(X)' 10298 10299_Arguments_: 10300 X The type shall be 'REAL' or 'COMPLEX'. 10301 10302_Return value_: 10303 The return value is of the same type and kind as X. The real part 10304 of the result is in degrees. If X is of the type 'REAL', the 10305 return value lies in the range -1 \leq \cosd (x) \leq 1. 10306 10307_Example_: 10308 program test_cosd 10309 real :: x = 0.0 10310 x = cosd(x) 10311 end program test_cosd 10312 10313_Specific names_: 10314 Name Argument Return type Standard 10315 'COSD(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 10316 'DCOSD(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 10317 'CCOSD(X)' 'COMPLEX(4) 'COMPLEX(4)' GNU Extension 10318 X' 10319 'ZCOSD(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 10320 X' 10321 'CDCOSD(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 10322 X' 10323 10324_See also_: 10325 Inverse function: *note ACOSD:: Radians function: *note COS:: 10326 10327 10328File: gfortran.info, Node: COSH, Next: COTAN, Prev: COSD, Up: Intrinsic Procedures 10329 103309.75 'COSH' -- Hyperbolic cosine function 10331========================================= 10332 10333_Description_: 10334 'COSH(X)' computes the hyperbolic cosine of X. 10335 10336_Standard_: 10337 Fortran 77 and later, for a complex argument Fortran 2008 or later 10338 10339_Class_: 10340 Elemental function 10341 10342_Syntax_: 10343 'X = COSH(X)' 10344 10345_Arguments_: 10346 X The type shall be 'REAL' or 'COMPLEX'. 10347 10348_Return value_: 10349 The return value has same type and kind as X. If X is complex, the 10350 imaginary part of the result is in radians. If X is 'REAL', the 10351 return value has a lower bound of one, \cosh (x) \geq 1. 10352 10353_Example_: 10354 program test_cosh 10355 real(8) :: x = 1.0_8 10356 x = cosh(x) 10357 end program test_cosh 10358 10359_Specific names_: 10360 Name Argument Return type Standard 10361 'COSH(X)' 'REAL(4) X' 'REAL(4)' Fortran 77 and 10362 later 10363 'DCOSH(X)' 'REAL(8) X' 'REAL(8)' Fortran 77 and 10364 later 10365 10366_See also_: 10367 Inverse function: *note ACOSH:: 10368 10369 10370File: gfortran.info, Node: COTAN, Next: COTAND, Prev: COSH, Up: Intrinsic Procedures 10371 103729.76 'COTAN' -- Cotangent function 10373================================== 10374 10375_Description_: 10376 'COTAN(X)' computes the cotangent of X. Equivalent to 'COS(x)' 10377 divided by 'SIN(x)', or '1 / TAN(x)'. 10378 10379 This function is for compatibility only and should be avoided in 10380 favor of standard constructs wherever possible. 10381 10382_Standard_: 10383 GNU Extension, enabled with '-fdec-math'. 10384 10385_Class_: 10386 Elemental function 10387 10388_Syntax_: 10389 'RESULT = COTAN(X)' 10390 10391_Arguments_: 10392 X The type shall be 'REAL' or 'COMPLEX'. 10393 10394_Return value_: 10395 The return value has same type and kind as X, and its value is in 10396 radians. 10397 10398_Example_: 10399 program test_cotan 10400 real(8) :: x = 0.165_8 10401 x = cotan(x) 10402 end program test_cotan 10403 10404_Specific names_: 10405 Name Argument Return type Standard 10406 'COTAN(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 10407 'DCOTAN(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 10408 10409_See also_: 10410 Converse function: *note TAN:: Degrees function: *note COTAND:: 10411 10412 10413File: gfortran.info, Node: COTAND, Next: COUNT, Prev: COTAN, Up: Intrinsic Procedures 10414 104159.77 'COTAND' -- Cotangent function, degrees 10416============================================ 10417 10418_Description_: 10419 'COTAND(X)' computes the cotangent of X in degrees. Equivalent to 10420 'COSD(x)' divided by 'SIND(x)', or '1 / TAND(x)'. 10421 10422_Standard_: 10423 GNU Extension, enabled with '-fdec-math'. 10424 10425 This function is for compatibility only and should be avoided in 10426 favor of standard constructs wherever possible. 10427 10428_Class_: 10429 Elemental function 10430 10431_Syntax_: 10432 'RESULT = COTAND(X)' 10433 10434_Arguments_: 10435 X The type shall be 'REAL' or 'COMPLEX'. 10436 10437_Return value_: 10438 The return value has same type and kind as X, and its value is in 10439 degrees. 10440 10441_Example_: 10442 program test_cotand 10443 real(8) :: x = 0.165_8 10444 x = cotand(x) 10445 end program test_cotand 10446 10447_Specific names_: 10448 Name Argument Return type Standard 10449 'COTAND(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 10450 'DCOTAND(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 10451 10452_See also_: 10453 Converse function: *note TAND:: Radians function: *note COTAN:: 10454 10455 10456File: gfortran.info, Node: COUNT, Next: CPU_TIME, Prev: COTAND, Up: Intrinsic Procedures 10457 104589.78 'COUNT' -- Count function 10459============================== 10460 10461_Description_: 10462 10463 Counts the number of '.TRUE.' elements in a logical MASK, or, if 10464 the DIM argument is supplied, counts the number of elements along 10465 each row of the array in the DIM direction. If the array has zero 10466 size, or all of the elements of MASK are '.FALSE.', then the result 10467 is '0'. 10468 10469_Standard_: 10470 Fortran 95 and later, with KIND argument Fortran 2003 and later 10471 10472_Class_: 10473 Transformational function 10474 10475_Syntax_: 10476 'RESULT = COUNT(MASK [, DIM, KIND])' 10477 10478_Arguments_: 10479 MASK The type shall be 'LOGICAL'. 10480 DIM (Optional) The type shall be 'INTEGER'. 10481 KIND (Optional) An 'INTEGER' initialization 10482 expression indicating the kind parameter of the 10483 result. 10484 10485_Return value_: 10486 The return value is of type 'INTEGER' and of kind KIND. If KIND is 10487 absent, the return value is of default integer kind. If DIM is 10488 present, the result is an array with a rank one less than the rank 10489 of ARRAY, and a size corresponding to the shape of ARRAY with the 10490 DIM dimension removed. 10491 10492_Example_: 10493 program test_count 10494 integer, dimension(2,3) :: a, b 10495 logical, dimension(2,3) :: mask 10496 a = reshape( (/ 1, 2, 3, 4, 5, 6 /), (/ 2, 3 /)) 10497 b = reshape( (/ 0, 7, 3, 4, 5, 8 /), (/ 2, 3 /)) 10498 print '(3i3)', a(1,:) 10499 print '(3i3)', a(2,:) 10500 print * 10501 print '(3i3)', b(1,:) 10502 print '(3i3)', b(2,:) 10503 print * 10504 mask = a.ne.b 10505 print '(3l3)', mask(1,:) 10506 print '(3l3)', mask(2,:) 10507 print * 10508 print '(3i3)', count(mask) 10509 print * 10510 print '(3i3)', count(mask, 1) 10511 print * 10512 print '(3i3)', count(mask, 2) 10513 end program test_count 10514 10515 10516File: gfortran.info, Node: CPU_TIME, Next: CSHIFT, Prev: COUNT, Up: Intrinsic Procedures 10517 105189.79 'CPU_TIME' -- CPU elapsed time in seconds 10519============================================== 10520 10521_Description_: 10522 Returns a 'REAL' value representing the elapsed CPU time in 10523 seconds. This is useful for testing segments of code to determine 10524 execution time. 10525 10526 If a time source is available, time will be reported with 10527 microsecond resolution. If no time source is available, TIME is 10528 set to '-1.0'. 10529 10530 Note that TIME may contain a, system dependent, arbitrary offset 10531 and may not start with '0.0'. For 'CPU_TIME', the absolute value 10532 is meaningless, only differences between subsequent calls to this 10533 subroutine, as shown in the example below, should be used. 10534 10535_Standard_: 10536 Fortran 95 and later 10537 10538_Class_: 10539 Subroutine 10540 10541_Syntax_: 10542 'CALL CPU_TIME(TIME)' 10543 10544_Arguments_: 10545 TIME The type shall be 'REAL' with 'INTENT(OUT)'. 10546 10547_Return value_: 10548 None 10549 10550_Example_: 10551 program test_cpu_time 10552 real :: start, finish 10553 call cpu_time(start) 10554 ! put code to test here 10555 call cpu_time(finish) 10556 print '("Time = ",f6.3," seconds.")',finish-start 10557 end program test_cpu_time 10558 10559_See also_: 10560 *note SYSTEM_CLOCK::, *note DATE_AND_TIME:: 10561 10562 10563File: gfortran.info, Node: CSHIFT, Next: CTIME, Prev: CPU_TIME, Up: Intrinsic Procedures 10564 105659.80 'CSHIFT' -- Circular shift elements of an array 10566==================================================== 10567 10568_Description_: 10569 'CSHIFT(ARRAY, SHIFT [, DIM])' performs a circular shift on 10570 elements of ARRAY along the dimension of DIM. If DIM is omitted it 10571 is taken to be '1'. DIM is a scalar of type 'INTEGER' in the range 10572 of 1 \leq DIM \leq n) where n is the rank of ARRAY. If the rank of 10573 ARRAY is one, then all elements of ARRAY are shifted by SHIFT 10574 places. If rank is greater than one, then all complete rank one 10575 sections of ARRAY along the given dimension are shifted. Elements 10576 shifted out one end of each rank one section are shifted back in 10577 the other end. 10578 10579_Standard_: 10580 Fortran 95 and later 10581 10582_Class_: 10583 Transformational function 10584 10585_Syntax_: 10586 'RESULT = CSHIFT(ARRAY, SHIFT [, DIM])' 10587 10588_Arguments_: 10589 ARRAY Shall be an array of any type. 10590 SHIFT The type shall be 'INTEGER'. 10591 DIM The type shall be 'INTEGER'. 10592 10593_Return value_: 10594 Returns an array of same type and rank as the ARRAY argument. 10595 10596_Example_: 10597 program test_cshift 10598 integer, dimension(3,3) :: a 10599 a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /)) 10600 print '(3i3)', a(1,:) 10601 print '(3i3)', a(2,:) 10602 print '(3i3)', a(3,:) 10603 a = cshift(a, SHIFT=(/1, 2, -1/), DIM=2) 10604 print * 10605 print '(3i3)', a(1,:) 10606 print '(3i3)', a(2,:) 10607 print '(3i3)', a(3,:) 10608 end program test_cshift 10609 10610 10611File: gfortran.info, Node: CTIME, Next: DATE_AND_TIME, Prev: CSHIFT, Up: Intrinsic Procedures 10612 106139.81 'CTIME' -- Convert a time into a string 10614============================================ 10615 10616_Description_: 10617 'CTIME' converts a system time value, such as returned by *note 10618 TIME8::, to a string. The output will be of the form 'Sat Aug 19 10619 18:13:14 1995'. 10620 10621 This intrinsic is provided in both subroutine and function forms; 10622 however, only one form can be used in any given program unit. 10623 10624_Standard_: 10625 GNU extension 10626 10627_Class_: 10628 Subroutine, function 10629 10630_Syntax_: 10631 'CALL CTIME(TIME, RESULT)'. 10632 'RESULT = CTIME(TIME)'. 10633 10634_Arguments_: 10635 TIME The type shall be of type 'INTEGER'. 10636 RESULT The type shall be of type 'CHARACTER' and of 10637 default kind. It is an 'INTENT(OUT)' argument. 10638 If the length of this variable is too short for 10639 the time and date string to fit completely, it 10640 will be blank on procedure return. 10641 10642_Return value_: 10643 The converted date and time as a string. 10644 10645_Example_: 10646 program test_ctime 10647 integer(8) :: i 10648 character(len=30) :: date 10649 i = time8() 10650 10651 ! Do something, main part of the program 10652 10653 call ctime(i,date) 10654 print *, 'Program was started on ', date 10655 end program test_ctime 10656 10657_See Also_: 10658 *note DATE_AND_TIME::, *note GMTIME::, *note LTIME::, *note TIME::, 10659 *note TIME8:: 10660 10661 10662File: gfortran.info, Node: DATE_AND_TIME, Next: DBLE, Prev: CTIME, Up: Intrinsic Procedures 10663 106649.82 'DATE_AND_TIME' -- Date and time subroutine 10665================================================ 10666 10667_Description_: 10668 'DATE_AND_TIME(DATE, TIME, ZONE, VALUES)' gets the corresponding 10669 date and time information from the real-time system clock. DATE is 10670 'INTENT(OUT)' and has form ccyymmdd. TIME is 'INTENT(OUT)' and has 10671 form hhmmss.sss. ZONE is 'INTENT(OUT)' and has form (+-)hhmm, 10672 representing the difference with respect to Coordinated Universal 10673 Time (UTC). Unavailable time and date parameters return blanks. 10674 10675 VALUES is 'INTENT(OUT)' and provides the following: 10676 10677 'VALUE(1)': The year 10678 'VALUE(2)': The month 10679 'VALUE(3)': The day of the month 10680 'VALUE(4)': Time difference with UTC in 10681 minutes 10682 'VALUE(5)': The hour of the day 10683 'VALUE(6)': The minutes of the hour 10684 'VALUE(7)': The seconds of the minute 10685 'VALUE(8)': The milliseconds of the 10686 second 10687 10688_Standard_: 10689 Fortran 95 and later 10690 10691_Class_: 10692 Subroutine 10693 10694_Syntax_: 10695 'CALL DATE_AND_TIME([DATE, TIME, ZONE, VALUES])' 10696 10697_Arguments_: 10698 DATE (Optional) The type shall be 'CHARACTER(LEN=8)' 10699 or larger, and of default kind. 10700 TIME (Optional) The type shall be 'CHARACTER(LEN=10)' 10701 or larger, and of default kind. 10702 ZONE (Optional) The type shall be 'CHARACTER(LEN=5)' 10703 or larger, and of default kind. 10704 VALUES (Optional) The type shall be 'INTEGER(8)'. 10705 10706_Return value_: 10707 None 10708 10709_Example_: 10710 program test_time_and_date 10711 character(8) :: date 10712 character(10) :: time 10713 character(5) :: zone 10714 integer,dimension(8) :: values 10715 ! using keyword arguments 10716 call date_and_time(date,time,zone,values) 10717 call date_and_time(DATE=date,ZONE=zone) 10718 call date_and_time(TIME=time) 10719 call date_and_time(VALUES=values) 10720 print '(a,2x,a,2x,a)', date, time, zone 10721 print '(8i5)', values 10722 end program test_time_and_date 10723 10724_See also_: 10725 *note CPU_TIME::, *note SYSTEM_CLOCK:: 10726 10727 10728File: gfortran.info, Node: DBLE, Next: DCMPLX, Prev: DATE_AND_TIME, Up: Intrinsic Procedures 10729 107309.83 'DBLE' -- Double conversion function 10731========================================= 10732 10733_Description_: 10734 'DBLE(A)' Converts A to double precision real type. 10735 10736_Standard_: 10737 Fortran 77 and later 10738 10739_Class_: 10740 Elemental function 10741 10742_Syntax_: 10743 'RESULT = DBLE(A)' 10744 10745_Arguments_: 10746 A The type shall be 'INTEGER', 'REAL', or 10747 'COMPLEX'. 10748 10749_Return value_: 10750 The return value is of type double precision real. 10751 10752_Example_: 10753 program test_dble 10754 real :: x = 2.18 10755 integer :: i = 5 10756 complex :: z = (2.3,1.14) 10757 print *, dble(x), dble(i), dble(z) 10758 end program test_dble 10759 10760_See also_: 10761 *note REAL:: 10762 10763 10764File: gfortran.info, Node: DCMPLX, Next: DIGITS, Prev: DBLE, Up: Intrinsic Procedures 10765 107669.84 'DCMPLX' -- Double complex conversion function 10767=================================================== 10768 10769_Description_: 10770 'DCMPLX(X [,Y])' returns a double complex number where X is 10771 converted to the real component. If Y is present it is converted 10772 to the imaginary component. If Y is not present then the imaginary 10773 component is set to 0.0. If X is complex then Y must not be 10774 present. 10775 10776_Standard_: 10777 GNU extension 10778 10779_Class_: 10780 Elemental function 10781 10782_Syntax_: 10783 'RESULT = DCMPLX(X [, Y])' 10784 10785_Arguments_: 10786 X The type may be 'INTEGER', 'REAL', or 'COMPLEX'. 10787 Y (Optional if X is not 'COMPLEX'.) May be 10788 'INTEGER' or 'REAL'. 10789 10790_Return value_: 10791 The return value is of type 'COMPLEX(8)' 10792 10793_Example_: 10794 program test_dcmplx 10795 integer :: i = 42 10796 real :: x = 3.14 10797 complex :: z 10798 z = cmplx(i, x) 10799 print *, dcmplx(i) 10800 print *, dcmplx(x) 10801 print *, dcmplx(z) 10802 print *, dcmplx(x,i) 10803 end program test_dcmplx 10804 10805 10806File: gfortran.info, Node: DIGITS, Next: DIM, Prev: DCMPLX, Up: Intrinsic Procedures 10807 108089.85 'DIGITS' -- Significant binary digits function 10809=================================================== 10810 10811_Description_: 10812 'DIGITS(X)' returns the number of significant binary digits of the 10813 internal model representation of X. For example, on a system using 10814 a 32-bit floating point representation, a default real number would 10815 likely return 24. 10816 10817_Standard_: 10818 Fortran 95 and later 10819 10820_Class_: 10821 Inquiry function 10822 10823_Syntax_: 10824 'RESULT = DIGITS(X)' 10825 10826_Arguments_: 10827 X The type may be 'INTEGER' or 'REAL'. 10828 10829_Return value_: 10830 The return value is of type 'INTEGER'. 10831 10832_Example_: 10833 program test_digits 10834 integer :: i = 12345 10835 real :: x = 3.143 10836 real(8) :: y = 2.33 10837 print *, digits(i) 10838 print *, digits(x) 10839 print *, digits(y) 10840 end program test_digits 10841 10842 10843File: gfortran.info, Node: DIM, Next: DOT_PRODUCT, Prev: DIGITS, Up: Intrinsic Procedures 10844 108459.86 'DIM' -- Positive difference 10846================================= 10847 10848_Description_: 10849 'DIM(X,Y)' returns the difference 'X-Y' if the result is positive; 10850 otherwise returns zero. 10851 10852_Standard_: 10853 Fortran 77 and later 10854 10855_Class_: 10856 Elemental function 10857 10858_Syntax_: 10859 'RESULT = DIM(X, Y)' 10860 10861_Arguments_: 10862 X The type shall be 'INTEGER' or 'REAL' 10863 Y The type shall be the same type and kind as X. 10864 10865_Return value_: 10866 The return value is of type 'INTEGER' or 'REAL'. 10867 10868_Example_: 10869 program test_dim 10870 integer :: i 10871 real(8) :: x 10872 i = dim(4, 15) 10873 x = dim(4.345_8, 2.111_8) 10874 print *, i 10875 print *, x 10876 end program test_dim 10877 10878_Specific names_: 10879 Name Argument Return type Standard 10880 'DIM(X,Y)' 'REAL(4) X, 'REAL(4)' Fortran 77 and 10881 Y' later 10882 'IDIM(X,Y)' 'INTEGER(4) 'INTEGER(4)' Fortran 77 and 10883 X, Y' later 10884 'DDIM(X,Y)' 'REAL(8) X, 'REAL(8)' Fortran 77 and 10885 Y' later 10886 10887 10888File: gfortran.info, Node: DOT_PRODUCT, Next: DPROD, Prev: DIM, Up: Intrinsic Procedures 10889 108909.87 'DOT_PRODUCT' -- Dot product function 10891========================================== 10892 10893_Description_: 10894 'DOT_PRODUCT(VECTOR_A, VECTOR_B)' computes the dot product 10895 multiplication of two vectors VECTOR_A and VECTOR_B. The two 10896 vectors may be either numeric or logical and must be arrays of rank 10897 one and of equal size. If the vectors are 'INTEGER' or 'REAL', the 10898 result is 'SUM(VECTOR_A*VECTOR_B)'. If the vectors are 'COMPLEX', 10899 the result is 'SUM(CONJG(VECTOR_A)*VECTOR_B)'. If the vectors are 10900 'LOGICAL', the result is 'ANY(VECTOR_A .AND. VECTOR_B)'. 10901 10902_Standard_: 10903 Fortran 95 and later 10904 10905_Class_: 10906 Transformational function 10907 10908_Syntax_: 10909 'RESULT = DOT_PRODUCT(VECTOR_A, VECTOR_B)' 10910 10911_Arguments_: 10912 VECTOR_A The type shall be numeric or 'LOGICAL', rank 1. 10913 VECTOR_B The type shall be numeric if VECTOR_A is of 10914 numeric type or 'LOGICAL' if VECTOR_A is of type 10915 'LOGICAL'. VECTOR_B shall be a rank-one array. 10916 10917_Return value_: 10918 If the arguments are numeric, the return value is a scalar of 10919 numeric type, 'INTEGER', 'REAL', or 'COMPLEX'. If the arguments 10920 are 'LOGICAL', the return value is '.TRUE.' or '.FALSE.'. 10921 10922_Example_: 10923 program test_dot_prod 10924 integer, dimension(3) :: a, b 10925 a = (/ 1, 2, 3 /) 10926 b = (/ 4, 5, 6 /) 10927 print '(3i3)', a 10928 print * 10929 print '(3i3)', b 10930 print * 10931 print *, dot_product(a,b) 10932 end program test_dot_prod 10933 10934 10935File: gfortran.info, Node: DPROD, Next: DREAL, Prev: DOT_PRODUCT, Up: Intrinsic Procedures 10936 109379.88 'DPROD' -- Double product function 10938======================================= 10939 10940_Description_: 10941 'DPROD(X,Y)' returns the product 'X*Y'. 10942 10943_Standard_: 10944 Fortran 77 and later 10945 10946_Class_: 10947 Elemental function 10948 10949_Syntax_: 10950 'RESULT = DPROD(X, Y)' 10951 10952_Arguments_: 10953 X The type shall be 'REAL'. 10954 Y The type shall be 'REAL'. 10955 10956_Return value_: 10957 The return value is of type 'REAL(8)'. 10958 10959_Example_: 10960 program test_dprod 10961 real :: x = 5.2 10962 real :: y = 2.3 10963 real(8) :: d 10964 d = dprod(x,y) 10965 print *, d 10966 end program test_dprod 10967 10968_Specific names_: 10969 Name Argument Return type Standard 10970 'DPROD(X,Y)' 'REAL(4) X, 'REAL(8)' Fortran 77 and 10971 Y' later 10972 10973 10974File: gfortran.info, Node: DREAL, Next: DSHIFTL, Prev: DPROD, Up: Intrinsic Procedures 10975 109769.89 'DREAL' -- Double real part function 10977========================================= 10978 10979_Description_: 10980 'DREAL(Z)' returns the real part of complex variable Z. 10981 10982_Standard_: 10983 GNU extension 10984 10985_Class_: 10986 Elemental function 10987 10988_Syntax_: 10989 'RESULT = DREAL(A)' 10990 10991_Arguments_: 10992 A The type shall be 'COMPLEX(8)'. 10993 10994_Return value_: 10995 The return value is of type 'REAL(8)'. 10996 10997_Example_: 10998 program test_dreal 10999 complex(8) :: z = (1.3_8,7.2_8) 11000 print *, dreal(z) 11001 end program test_dreal 11002 11003_See also_: 11004 *note AIMAG:: 11005 11006 11007File: gfortran.info, Node: DSHIFTL, Next: DSHIFTR, Prev: DREAL, Up: Intrinsic Procedures 11008 110099.90 'DSHIFTL' -- Combined left shift 11010===================================== 11011 11012_Description_: 11013 'DSHIFTL(I, J, SHIFT)' combines bits of I and J. The rightmost 11014 SHIFT bits of the result are the leftmost SHIFT bits of J, and the 11015 remaining bits are the rightmost bits of I. 11016 11017_Standard_: 11018 Fortran 2008 and later 11019 11020_Class_: 11021 Elemental function 11022 11023_Syntax_: 11024 'RESULT = DSHIFTL(I, J, SHIFT)' 11025 11026_Arguments_: 11027 I Shall be of type 'INTEGER' or a BOZ constant. 11028 J Shall be of type 'INTEGER' or a BOZ constant. 11029 If both I and J have integer type, then they 11030 shall have the same kind type parameter. I and 11031 J shall not both be BOZ constants. 11032 SHIFT Shall be of type 'INTEGER'. It shall be 11033 nonnegative. If I is not a BOZ constant, then 11034 SHIFT shall be less than or equal to 11035 'BIT_SIZE(I)'; otherwise, SHIFT shall be less 11036 than or equal to 'BIT_SIZE(J)'. 11037 11038_Return value_: 11039 If either I or J is a BOZ constant, it is first converted as if by 11040 the intrinsic function 'INT' to an integer type with the kind type 11041 parameter of the other. 11042 11043_See also_: 11044 *note DSHIFTR:: 11045 11046 11047File: gfortran.info, Node: DSHIFTR, Next: DTIME, Prev: DSHIFTL, Up: Intrinsic Procedures 11048 110499.91 'DSHIFTR' -- Combined right shift 11050====================================== 11051 11052_Description_: 11053 'DSHIFTR(I, J, SHIFT)' combines bits of I and J. The leftmost 11054 SHIFT bits of the result are the rightmost SHIFT bits of I, and the 11055 remaining bits are the leftmost bits of J. 11056 11057_Standard_: 11058 Fortran 2008 and later 11059 11060_Class_: 11061 Elemental function 11062 11063_Syntax_: 11064 'RESULT = DSHIFTR(I, J, SHIFT)' 11065 11066_Arguments_: 11067 I Shall be of type 'INTEGER' or a BOZ constant. 11068 J Shall be of type 'INTEGER' or a BOZ constant. 11069 If both I and J have integer type, then they 11070 shall have the same kind type parameter. I and 11071 J shall not both be BOZ constants. 11072 SHIFT Shall be of type 'INTEGER'. It shall be 11073 nonnegative. If I is not a BOZ constant, then 11074 SHIFT shall be less than or equal to 11075 'BIT_SIZE(I)'; otherwise, SHIFT shall be less 11076 than or equal to 'BIT_SIZE(J)'. 11077 11078_Return value_: 11079 If either I or J is a BOZ constant, it is first converted as if by 11080 the intrinsic function 'INT' to an integer type with the kind type 11081 parameter of the other. 11082 11083_See also_: 11084 *note DSHIFTL:: 11085 11086 11087File: gfortran.info, Node: DTIME, Next: EOSHIFT, Prev: DSHIFTR, Up: Intrinsic Procedures 11088 110899.92 'DTIME' -- Execution time subroutine (or function) 11090======================================================= 11091 11092_Description_: 11093 'DTIME(VALUES, TIME)' initially returns the number of seconds of 11094 runtime since the start of the process's execution in TIME. VALUES 11095 returns the user and system components of this time in 'VALUES(1)' 11096 and 'VALUES(2)' respectively. TIME is equal to 'VALUES(1) + 11097 VALUES(2)'. 11098 11099 Subsequent invocations of 'DTIME' return values accumulated since 11100 the previous invocation. 11101 11102 On some systems, the underlying timings are represented using types 11103 with sufficiently small limits that overflows (wrap around) are 11104 possible, such as 32-bit types. Therefore, the values returned by 11105 this intrinsic might be, or become, negative, or numerically less 11106 than previous values, during a single run of the compiled program. 11107 11108 Please note, that this implementation is thread safe if used within 11109 OpenMP directives, i.e., its state will be consistent while called 11110 from multiple threads. However, if 'DTIME' is called from multiple 11111 threads, the result is still the time since the last invocation. 11112 This may not give the intended results. If possible, use 11113 'CPU_TIME' instead. 11114 11115 This intrinsic is provided in both subroutine and function forms; 11116 however, only one form can be used in any given program unit. 11117 11118 VALUES and TIME are 'INTENT(OUT)' and provide the following: 11119 11120 'VALUES(1)': User time in seconds. 11121 'VALUES(2)': System time in seconds. 11122 'TIME': Run time since start in 11123 seconds. 11124 11125_Standard_: 11126 GNU extension 11127 11128_Class_: 11129 Subroutine, function 11130 11131_Syntax_: 11132 'CALL DTIME(VALUES, TIME)'. 11133 'TIME = DTIME(VALUES)', (not recommended). 11134 11135_Arguments_: 11136 VALUES The type shall be 'REAL(4), DIMENSION(2)'. 11137 TIME The type shall be 'REAL(4)'. 11138 11139_Return value_: 11140 Elapsed time in seconds since the last invocation or since the 11141 start of program execution if not called before. 11142 11143_Example_: 11144 program test_dtime 11145 integer(8) :: i, j 11146 real, dimension(2) :: tarray 11147 real :: result 11148 call dtime(tarray, result) 11149 print *, result 11150 print *, tarray(1) 11151 print *, tarray(2) 11152 do i=1,100000000 ! Just a delay 11153 j = i * i - i 11154 end do 11155 call dtime(tarray, result) 11156 print *, result 11157 print *, tarray(1) 11158 print *, tarray(2) 11159 end program test_dtime 11160 11161_See also_: 11162 *note CPU_TIME:: 11163 11164 11165File: gfortran.info, Node: EOSHIFT, Next: EPSILON, Prev: DTIME, Up: Intrinsic Procedures 11166 111679.93 'EOSHIFT' -- End-off shift elements of an array 11168==================================================== 11169 11170_Description_: 11171 'EOSHIFT(ARRAY, SHIFT[, BOUNDARY, DIM])' performs an end-off shift 11172 on elements of ARRAY along the dimension of DIM. If DIM is omitted 11173 it is taken to be '1'. DIM is a scalar of type 'INTEGER' in the 11174 range of 1 \leq DIM \leq n) where n is the rank of ARRAY. If the 11175 rank of ARRAY is one, then all elements of ARRAY are shifted by 11176 SHIFT places. If rank is greater than one, then all complete rank 11177 one sections of ARRAY along the given dimension are shifted. 11178 Elements shifted out one end of each rank one section are dropped. 11179 If BOUNDARY is present then the corresponding value of from 11180 BOUNDARY is copied back in the other end. If BOUNDARY is not 11181 present then the following are copied in depending on the type of 11182 ARRAY. 11183 11184 _Array _Boundary Value_ 11185 Type_ 11186 Numeric 0 of the type and kind of ARRAY. 11187 Logical '.FALSE.'. 11188 Character(LEN)LEN blanks. 11189 11190_Standard_: 11191 Fortran 95 and later 11192 11193_Class_: 11194 Transformational function 11195 11196_Syntax_: 11197 'RESULT = EOSHIFT(ARRAY, SHIFT [, BOUNDARY, DIM])' 11198 11199_Arguments_: 11200 ARRAY May be any type, not scalar. 11201 SHIFT The type shall be 'INTEGER'. 11202 BOUNDARY Same type as ARRAY. 11203 DIM The type shall be 'INTEGER'. 11204 11205_Return value_: 11206 Returns an array of same type and rank as the ARRAY argument. 11207 11208_Example_: 11209 program test_eoshift 11210 integer, dimension(3,3) :: a 11211 a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /)) 11212 print '(3i3)', a(1,:) 11213 print '(3i3)', a(2,:) 11214 print '(3i3)', a(3,:) 11215 a = EOSHIFT(a, SHIFT=(/1, 2, 1/), BOUNDARY=-5, DIM=2) 11216 print * 11217 print '(3i3)', a(1,:) 11218 print '(3i3)', a(2,:) 11219 print '(3i3)', a(3,:) 11220 end program test_eoshift 11221 11222 11223File: gfortran.info, Node: EPSILON, Next: ERF, Prev: EOSHIFT, Up: Intrinsic Procedures 11224 112259.94 'EPSILON' -- Epsilon function 11226================================== 11227 11228_Description_: 11229 'EPSILON(X)' returns the smallest number E of the same kind as X 11230 such that 1 + E > 1. 11231 11232_Standard_: 11233 Fortran 95 and later 11234 11235_Class_: 11236 Inquiry function 11237 11238_Syntax_: 11239 'RESULT = EPSILON(X)' 11240 11241_Arguments_: 11242 X The type shall be 'REAL'. 11243 11244_Return value_: 11245 The return value is of same type as the argument. 11246 11247_Example_: 11248 program test_epsilon 11249 real :: x = 3.143 11250 real(8) :: y = 2.33 11251 print *, EPSILON(x) 11252 print *, EPSILON(y) 11253 end program test_epsilon 11254 11255 11256File: gfortran.info, Node: ERF, Next: ERFC, Prev: EPSILON, Up: Intrinsic Procedures 11257 112589.95 'ERF' -- Error function 11259============================ 11260 11261_Description_: 11262 'ERF(X)' computes the error function of X. 11263 11264_Standard_: 11265 Fortran 2008 and later 11266 11267_Class_: 11268 Elemental function 11269 11270_Syntax_: 11271 'RESULT = ERF(X)' 11272 11273_Arguments_: 11274 X The type shall be 'REAL'. 11275 11276_Return value_: 11277 The return value is of type 'REAL', of the same kind as X and lies 11278 in the range -1 \leq erf (x) \leq 1 . 11279 11280_Example_: 11281 program test_erf 11282 real(8) :: x = 0.17_8 11283 x = erf(x) 11284 end program test_erf 11285 11286_Specific names_: 11287 Name Argument Return type Standard 11288 'DERF(X)' 'REAL(8) X' 'REAL(8)' GNU extension 11289 11290 11291File: gfortran.info, Node: ERFC, Next: ERFC_SCALED, Prev: ERF, Up: Intrinsic Procedures 11292 112939.96 'ERFC' -- Error function 11294============================= 11295 11296_Description_: 11297 'ERFC(X)' computes the complementary error function of X. 11298 11299_Standard_: 11300 Fortran 2008 and later 11301 11302_Class_: 11303 Elemental function 11304 11305_Syntax_: 11306 'RESULT = ERFC(X)' 11307 11308_Arguments_: 11309 X The type shall be 'REAL'. 11310 11311_Return value_: 11312 The return value is of type 'REAL' and of the same kind as X. It 11313 lies in the range 0 \leq erfc (x) \leq 2 . 11314 11315_Example_: 11316 program test_erfc 11317 real(8) :: x = 0.17_8 11318 x = erfc(x) 11319 end program test_erfc 11320 11321_Specific names_: 11322 Name Argument Return type Standard 11323 'DERFC(X)' 'REAL(8) X' 'REAL(8)' GNU extension 11324 11325 11326File: gfortran.info, Node: ERFC_SCALED, Next: ETIME, Prev: ERFC, Up: Intrinsic Procedures 11327 113289.97 'ERFC_SCALED' -- Error function 11329==================================== 11330 11331_Description_: 11332 'ERFC_SCALED(X)' computes the exponentially-scaled complementary 11333 error function of X. 11334 11335_Standard_: 11336 Fortran 2008 and later 11337 11338_Class_: 11339 Elemental function 11340 11341_Syntax_: 11342 'RESULT = ERFC_SCALED(X)' 11343 11344_Arguments_: 11345 X The type shall be 'REAL'. 11346 11347_Return value_: 11348 The return value is of type 'REAL' and of the same kind as X. 11349 11350_Example_: 11351 program test_erfc_scaled 11352 real(8) :: x = 0.17_8 11353 x = erfc_scaled(x) 11354 end program test_erfc_scaled 11355 11356 11357File: gfortran.info, Node: ETIME, Next: EVENT_QUERY, Prev: ERFC_SCALED, Up: Intrinsic Procedures 11358 113599.98 'ETIME' -- Execution time subroutine (or function) 11360======================================================= 11361 11362_Description_: 11363 'ETIME(VALUES, TIME)' returns the number of seconds of runtime 11364 since the start of the process's execution in TIME. VALUES returns 11365 the user and system components of this time in 'VALUES(1)' and 11366 'VALUES(2)' respectively. TIME is equal to 'VALUES(1) + 11367 VALUES(2)'. 11368 11369 On some systems, the underlying timings are represented using types 11370 with sufficiently small limits that overflows (wrap around) are 11371 possible, such as 32-bit types. Therefore, the values returned by 11372 this intrinsic might be, or become, negative, or numerically less 11373 than previous values, during a single run of the compiled program. 11374 11375 This intrinsic is provided in both subroutine and function forms; 11376 however, only one form can be used in any given program unit. 11377 11378 VALUES and TIME are 'INTENT(OUT)' and provide the following: 11379 11380 'VALUES(1)': User time in seconds. 11381 'VALUES(2)': System time in seconds. 11382 'TIME': Run time since start in seconds. 11383 11384_Standard_: 11385 GNU extension 11386 11387_Class_: 11388 Subroutine, function 11389 11390_Syntax_: 11391 'CALL ETIME(VALUES, TIME)'. 11392 'TIME = ETIME(VALUES)', (not recommended). 11393 11394_Arguments_: 11395 VALUES The type shall be 'REAL(4), DIMENSION(2)'. 11396 TIME The type shall be 'REAL(4)'. 11397 11398_Return value_: 11399 Elapsed time in seconds since the start of program execution. 11400 11401_Example_: 11402 program test_etime 11403 integer(8) :: i, j 11404 real, dimension(2) :: tarray 11405 real :: result 11406 call ETIME(tarray, result) 11407 print *, result 11408 print *, tarray(1) 11409 print *, tarray(2) 11410 do i=1,100000000 ! Just a delay 11411 j = i * i - i 11412 end do 11413 call ETIME(tarray, result) 11414 print *, result 11415 print *, tarray(1) 11416 print *, tarray(2) 11417 end program test_etime 11418 11419_See also_: 11420 *note CPU_TIME:: 11421 11422 11423File: gfortran.info, Node: EVENT_QUERY, Next: EXECUTE_COMMAND_LINE, Prev: ETIME, Up: Intrinsic Procedures 11424 114259.99 'EVENT_QUERY' -- Query whether a coarray event has occurred 11426================================================================ 11427 11428_Description_: 11429 'EVENT_QUERY' assignes the number of events to COUNT which have 11430 been posted to the EVENT variable and not yet been removed by 11431 calling 'EVENT WAIT'. When STAT is present and the invocation was 11432 successful, it is assigned the value 0. If it is present and the 11433 invocation has failed, it is assigned a positive value and COUNT is 11434 assigned the value -1. 11435 11436_Standard_: 11437 TS 18508 or later 11438 11439_Class_: 11440 subroutine 11441 11442_Syntax_: 11443 'CALL EVENT_QUERY (EVENT, COUNT [, STAT])' 11444 11445_Arguments_: 11446 EVENT (intent(IN)) Scalar of type 'EVENT_TYPE', 11447 defined in 'ISO_FORTRAN_ENV'; shall not be 11448 coindexed. 11449 COUNT (intent(out))Scalar integer with at least the 11450 precision of default integer. 11451 STAT (optional) Scalar default-kind integer variable. 11452 11453_Example_: 11454 program atomic 11455 use iso_fortran_env 11456 implicit none 11457 type(event_type) :: event_value_has_been_set[*] 11458 integer :: cnt 11459 if (this_image() == 1) then 11460 call event_query (event_value_has_been_set, cnt) 11461 if (cnt > 0) write(*,*) "Value has been set" 11462 elseif (this_image() == 2) then 11463 event post (event_value_has_been_set[1]) 11464 end if 11465 end program atomic 11466 11467 11468File: gfortran.info, Node: EXECUTE_COMMAND_LINE, Next: EXIT, Prev: EVENT_QUERY, Up: Intrinsic Procedures 11469 114709.100 'EXECUTE_COMMAND_LINE' -- Execute a shell command 11471======================================================= 11472 11473_Description_: 11474 'EXECUTE_COMMAND_LINE' runs a shell command, synchronously or 11475 asynchronously. 11476 11477 The 'COMMAND' argument is passed to the shell and executed, using 11478 the C library's 'system' call. (The shell is 'sh' on Unix systems, 11479 and 'cmd.exe' on Windows.) If 'WAIT' is present and has the value 11480 false, the execution of the command is asynchronous if the system 11481 supports it; otherwise, the command is executed synchronously. 11482 11483 The three last arguments allow the user to get status information. 11484 After synchronous execution, 'EXITSTAT' contains the integer exit 11485 code of the command, as returned by 'system'. 'CMDSTAT' is set to 11486 zero if the command line was executed (whatever its exit status 11487 was). 'CMDMSG' is assigned an error message if an error has 11488 occurred. 11489 11490 Note that the 'system' function need not be thread-safe. It is the 11491 responsibility of the user to ensure that 'system' is not called 11492 concurrently. 11493 11494_Standard_: 11495 Fortran 2008 and later 11496 11497_Class_: 11498 Subroutine 11499 11500_Syntax_: 11501 'CALL EXECUTE_COMMAND_LINE(COMMAND [, WAIT, EXITSTAT, CMDSTAT, 11502 CMDMSG ])' 11503 11504_Arguments_: 11505 COMMAND Shall be a default 'CHARACTER' scalar. 11506 WAIT (Optional) Shall be a default 'LOGICAL' scalar. 11507 EXITSTAT (Optional) Shall be an 'INTEGER' of the default 11508 kind. 11509 CMDSTAT (Optional) Shall be an 'INTEGER' of the default 11510 kind. 11511 CMDMSG (Optional) Shall be an 'CHARACTER' scalar of the 11512 default kind. 11513 11514_Example_: 11515 program test_exec 11516 integer :: i 11517 11518 call execute_command_line ("external_prog.exe", exitstat=i) 11519 print *, "Exit status of external_prog.exe was ", i 11520 11521 call execute_command_line ("reindex_files.exe", wait=.false.) 11522 print *, "Now reindexing files in the background" 11523 11524 end program test_exec 11525 11526_Note_: 11527 11528 Because this intrinsic is implemented in terms of the 'system' 11529 function call, its behavior with respect to signaling is processor 11530 dependent. In particular, on POSIX-compliant systems, the SIGINT 11531 and SIGQUIT signals will be ignored, and the SIGCHLD will be 11532 blocked. As such, if the parent process is terminated, the child 11533 process might not be terminated alongside. 11534 11535_See also_: 11536 *note SYSTEM:: 11537 11538 11539File: gfortran.info, Node: EXIT, Next: EXP, Prev: EXECUTE_COMMAND_LINE, Up: Intrinsic Procedures 11540 115419.101 'EXIT' -- Exit the program with status. 11542============================================= 11543 11544_Description_: 11545 'EXIT' causes immediate termination of the program with status. If 11546 status is omitted it returns the canonical _success_ for the 11547 system. All Fortran I/O units are closed. 11548 11549_Standard_: 11550 GNU extension 11551 11552_Class_: 11553 Subroutine 11554 11555_Syntax_: 11556 'CALL EXIT([STATUS])' 11557 11558_Arguments_: 11559 STATUS Shall be an 'INTEGER' of the default kind. 11560 11561_Return value_: 11562 'STATUS' is passed to the parent process on exit. 11563 11564_Example_: 11565 program test_exit 11566 integer :: STATUS = 0 11567 print *, 'This program is going to exit.' 11568 call EXIT(STATUS) 11569 end program test_exit 11570 11571_See also_: 11572 *note ABORT::, *note KILL:: 11573 11574 11575File: gfortran.info, Node: EXP, Next: EXPONENT, Prev: EXIT, Up: Intrinsic Procedures 11576 115779.102 'EXP' -- Exponential function 11578=================================== 11579 11580_Description_: 11581 'EXP(X)' computes the base e exponential of X. 11582 11583_Standard_: 11584 Fortran 77 and later, has overloads that are GNU extensions 11585 11586_Class_: 11587 Elemental function 11588 11589_Syntax_: 11590 'RESULT = EXP(X)' 11591 11592_Arguments_: 11593 X The type shall be 'REAL' or 'COMPLEX'. 11594 11595_Return value_: 11596 The return value has same type and kind as X. 11597 11598_Example_: 11599 program test_exp 11600 real :: x = 1.0 11601 x = exp(x) 11602 end program test_exp 11603 11604_Specific names_: 11605 Name Argument Return type Standard 11606 'EXP(X)' 'REAL(4) X' 'REAL(4)' Fortran 77 and 11607 later 11608 'DEXP(X)' 'REAL(8) X' 'REAL(8)' Fortran 77 and 11609 later 11610 'CEXP(X)' 'COMPLEX(4) 'COMPLEX(4)' Fortran 77 and 11611 X' later 11612 'ZEXP(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 11613 X' 11614 'CDEXP(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 11615 X' 11616 11617 11618File: gfortran.info, Node: EXPONENT, Next: EXTENDS_TYPE_OF, Prev: EXP, Up: Intrinsic Procedures 11619 116209.103 'EXPONENT' -- Exponent function 11621===================================== 11622 11623_Description_: 11624 'EXPONENT(X)' returns the value of the exponent part of X. If X is 11625 zero the value returned is zero. 11626 11627_Standard_: 11628 Fortran 95 and later 11629 11630_Class_: 11631 Elemental function 11632 11633_Syntax_: 11634 'RESULT = EXPONENT(X)' 11635 11636_Arguments_: 11637 X The type shall be 'REAL'. 11638 11639_Return value_: 11640 The return value is of type default 'INTEGER'. 11641 11642_Example_: 11643 program test_exponent 11644 real :: x = 1.0 11645 integer :: i 11646 i = exponent(x) 11647 print *, i 11648 print *, exponent(0.0) 11649 end program test_exponent 11650 11651 11652File: gfortran.info, Node: EXTENDS_TYPE_OF, Next: FDATE, Prev: EXPONENT, Up: Intrinsic Procedures 11653 116549.104 'EXTENDS_TYPE_OF' -- Query dynamic type for extension 11655=========================================================== 11656 11657_Description_: 11658 Query dynamic type for extension. 11659 11660_Standard_: 11661 Fortran 2003 and later 11662 11663_Class_: 11664 Inquiry function 11665 11666_Syntax_: 11667 'RESULT = EXTENDS_TYPE_OF(A, MOLD)' 11668 11669_Arguments_: 11670 A Shall be an object of extensible declared type 11671 or unlimited polymorphic. 11672 MOLD Shall be an object of extensible declared type 11673 or unlimited polymorphic. 11674 11675_Return value_: 11676 The return value is a scalar of type default logical. It is true 11677 if and only if the dynamic type of A is an extension type of the 11678 dynamic type of MOLD. 11679 11680_See also_: 11681 *note SAME_TYPE_AS:: 11682 11683 11684File: gfortran.info, Node: FDATE, Next: FGET, Prev: EXTENDS_TYPE_OF, Up: Intrinsic Procedures 11685 116869.105 'FDATE' -- Get the current time as a string 11687================================================= 11688 11689_Description_: 11690 'FDATE(DATE)' returns the current date (using the same format as 11691 *note CTIME::) in DATE. It is equivalent to 'CALL CTIME(DATE, 11692 TIME())'. 11693 11694 This intrinsic is provided in both subroutine and function forms; 11695 however, only one form can be used in any given program unit. 11696 11697_Standard_: 11698 GNU extension 11699 11700_Class_: 11701 Subroutine, function 11702 11703_Syntax_: 11704 'CALL FDATE(DATE)'. 11705 'DATE = FDATE()'. 11706 11707_Arguments_: 11708 DATE The type shall be of type 'CHARACTER' of the 11709 default kind. It is an 'INTENT(OUT)' argument. 11710 If the length of this variable is too short for 11711 the date and time string to fit completely, it 11712 will be blank on procedure return. 11713 11714_Return value_: 11715 The current date and time as a string. 11716 11717_Example_: 11718 program test_fdate 11719 integer(8) :: i, j 11720 character(len=30) :: date 11721 call fdate(date) 11722 print *, 'Program started on ', date 11723 do i = 1, 100000000 ! Just a delay 11724 j = i * i - i 11725 end do 11726 call fdate(date) 11727 print *, 'Program ended on ', date 11728 end program test_fdate 11729 11730_See also_: 11731 *note DATE_AND_TIME::, *note CTIME:: 11732 11733 11734File: gfortran.info, Node: FGET, Next: FGETC, Prev: FDATE, Up: Intrinsic Procedures 11735 117369.106 'FGET' -- Read a single character in stream mode from stdin 11737================================================================= 11738 11739_Description_: 11740 Read a single character in stream mode from stdin by bypassing 11741 normal formatted output. Stream I/O should not be mixed with 11742 normal record-oriented (formatted or unformatted) I/O on the same 11743 unit; the results are unpredictable. 11744 11745 This intrinsic is provided in both subroutine and function forms; 11746 however, only one form can be used in any given program unit. 11747 11748 Note that the 'FGET' intrinsic is provided for backwards 11749 compatibility with 'g77'. GNU Fortran provides the Fortran 2003 11750 Stream facility. Programmers should consider the use of new stream 11751 IO feature in new code for future portability. See also *note 11752 Fortran 2003 status::. 11753 11754_Standard_: 11755 GNU extension 11756 11757_Class_: 11758 Subroutine, function 11759 11760_Syntax_: 11761 'CALL FGET(C [, STATUS])' 11762 'STATUS = FGET(C)' 11763 11764_Arguments_: 11765 C The type shall be 'CHARACTER' and of default 11766 kind. 11767 STATUS (Optional) status flag of type 'INTEGER'. 11768 Returns 0 on success, -1 on end-of-file, and a 11769 system specific positive error code otherwise. 11770 11771_Example_: 11772 PROGRAM test_fget 11773 INTEGER, PARAMETER :: strlen = 100 11774 INTEGER :: status, i = 1 11775 CHARACTER(len=strlen) :: str = "" 11776 11777 WRITE (*,*) 'Enter text:' 11778 DO 11779 CALL fget(str(i:i), status) 11780 if (status /= 0 .OR. i > strlen) exit 11781 i = i + 1 11782 END DO 11783 WRITE (*,*) TRIM(str) 11784 END PROGRAM 11785 11786_See also_: 11787 *note FGETC::, *note FPUT::, *note FPUTC:: 11788 11789 11790File: gfortran.info, Node: FGETC, Next: FLOOR, Prev: FGET, Up: Intrinsic Procedures 11791 117929.107 'FGETC' -- Read a single character in stream mode 11793======================================================= 11794 11795_Description_: 11796 Read a single character in stream mode by bypassing normal 11797 formatted output. Stream I/O should not be mixed with normal 11798 record-oriented (formatted or unformatted) I/O on the same unit; 11799 the results are unpredictable. 11800 11801 This intrinsic is provided in both subroutine and function forms; 11802 however, only one form can be used in any given program unit. 11803 11804 Note that the 'FGET' intrinsic is provided for backwards 11805 compatibility with 'g77'. GNU Fortran provides the Fortran 2003 11806 Stream facility. Programmers should consider the use of new stream 11807 IO feature in new code for future portability. See also *note 11808 Fortran 2003 status::. 11809 11810_Standard_: 11811 GNU extension 11812 11813_Class_: 11814 Subroutine, function 11815 11816_Syntax_: 11817 'CALL FGETC(UNIT, C [, STATUS])' 11818 'STATUS = FGETC(UNIT, C)' 11819 11820_Arguments_: 11821 UNIT The type shall be 'INTEGER'. 11822 C The type shall be 'CHARACTER' and of default 11823 kind. 11824 STATUS (Optional) status flag of type 'INTEGER'. 11825 Returns 0 on success, -1 on end-of-file and a 11826 system specific positive error code otherwise. 11827 11828_Example_: 11829 PROGRAM test_fgetc 11830 INTEGER :: fd = 42, status 11831 CHARACTER :: c 11832 11833 OPEN(UNIT=fd, FILE="/etc/passwd", ACTION="READ", STATUS = "OLD") 11834 DO 11835 CALL fgetc(fd, c, status) 11836 IF (status /= 0) EXIT 11837 call fput(c) 11838 END DO 11839 CLOSE(UNIT=fd) 11840 END PROGRAM 11841 11842_See also_: 11843 *note FGET::, *note FPUT::, *note FPUTC:: 11844 11845 11846File: gfortran.info, Node: FLOOR, Next: FLUSH, Prev: FGETC, Up: Intrinsic Procedures 11847 118489.108 'FLOOR' -- Integer floor function 11849======================================= 11850 11851_Description_: 11852 'FLOOR(A)' returns the greatest integer less than or equal to X. 11853 11854_Standard_: 11855 Fortran 95 and later 11856 11857_Class_: 11858 Elemental function 11859 11860_Syntax_: 11861 'RESULT = FLOOR(A [, KIND])' 11862 11863_Arguments_: 11864 A The type shall be 'REAL'. 11865 KIND (Optional) An 'INTEGER' initialization 11866 expression indicating the kind parameter of the 11867 result. 11868 11869_Return value_: 11870 The return value is of type 'INTEGER(KIND)' if KIND is present and 11871 of default-kind 'INTEGER' otherwise. 11872 11873_Example_: 11874 program test_floor 11875 real :: x = 63.29 11876 real :: y = -63.59 11877 print *, floor(x) ! returns 63 11878 print *, floor(y) ! returns -64 11879 end program test_floor 11880 11881_See also_: 11882 *note CEILING::, *note NINT:: 11883 11884 11885File: gfortran.info, Node: FLUSH, Next: FNUM, Prev: FLOOR, Up: Intrinsic Procedures 11886 118879.109 'FLUSH' -- Flush I/O unit(s) 11888================================== 11889 11890_Description_: 11891 Flushes Fortran unit(s) currently open for output. Without the 11892 optional argument, all units are flushed, otherwise just the unit 11893 specified. 11894 11895_Standard_: 11896 GNU extension 11897 11898_Class_: 11899 Subroutine 11900 11901_Syntax_: 11902 'CALL FLUSH(UNIT)' 11903 11904_Arguments_: 11905 UNIT (Optional) The type shall be 'INTEGER'. 11906 11907_Note_: 11908 Beginning with the Fortran 2003 standard, there is a 'FLUSH' 11909 statement that should be preferred over the 'FLUSH' intrinsic. 11910 11911 The 'FLUSH' intrinsic and the Fortran 2003 'FLUSH' statement have 11912 identical effect: they flush the runtime library's I/O buffer so 11913 that the data becomes visible to other processes. This does not 11914 guarantee that the data is committed to disk. 11915 11916 On POSIX systems, you can request that all data is transferred to 11917 the storage device by calling the 'fsync' function, with the POSIX 11918 file descriptor of the I/O unit as argument (retrieved with GNU 11919 intrinsic 'FNUM'). The following example shows how: 11920 11921 ! Declare the interface for POSIX fsync function 11922 interface 11923 function fsync (fd) bind(c,name="fsync") 11924 use iso_c_binding, only: c_int 11925 integer(c_int), value :: fd 11926 integer(c_int) :: fsync 11927 end function fsync 11928 end interface 11929 11930 ! Variable declaration 11931 integer :: ret 11932 11933 ! Opening unit 10 11934 open (10,file="foo") 11935 11936 ! ... 11937 ! Perform I/O on unit 10 11938 ! ... 11939 11940 ! Flush and sync 11941 flush(10) 11942 ret = fsync(fnum(10)) 11943 11944 ! Handle possible error 11945 if (ret /= 0) stop "Error calling FSYNC" 11946 11947 11948File: gfortran.info, Node: FNUM, Next: FPUT, Prev: FLUSH, Up: Intrinsic Procedures 11949 119509.110 'FNUM' -- File number function 11951==================================== 11952 11953_Description_: 11954 'FNUM(UNIT)' returns the POSIX file descriptor number corresponding 11955 to the open Fortran I/O unit 'UNIT'. 11956 11957_Standard_: 11958 GNU extension 11959 11960_Class_: 11961 Function 11962 11963_Syntax_: 11964 'RESULT = FNUM(UNIT)' 11965 11966_Arguments_: 11967 UNIT The type shall be 'INTEGER'. 11968 11969_Return value_: 11970 The return value is of type 'INTEGER' 11971 11972_Example_: 11973 program test_fnum 11974 integer :: i 11975 open (unit=10, status = "scratch") 11976 i = fnum(10) 11977 print *, i 11978 close (10) 11979 end program test_fnum 11980 11981 11982File: gfortran.info, Node: FPUT, Next: FPUTC, Prev: FNUM, Up: Intrinsic Procedures 11983 119849.111 'FPUT' -- Write a single character in stream mode to stdout 11985================================================================= 11986 11987_Description_: 11988 Write a single character in stream mode to stdout by bypassing 11989 normal formatted output. Stream I/O should not be mixed with 11990 normal record-oriented (formatted or unformatted) I/O on the same 11991 unit; the results are unpredictable. 11992 11993 This intrinsic is provided in both subroutine and function forms; 11994 however, only one form can be used in any given program unit. 11995 11996 Note that the 'FGET' intrinsic is provided for backwards 11997 compatibility with 'g77'. GNU Fortran provides the Fortran 2003 11998 Stream facility. Programmers should consider the use of new stream 11999 IO feature in new code for future portability. See also *note 12000 Fortran 2003 status::. 12001 12002_Standard_: 12003 GNU extension 12004 12005_Class_: 12006 Subroutine, function 12007 12008_Syntax_: 12009 'CALL FPUT(C [, STATUS])' 12010 'STATUS = FPUT(C)' 12011 12012_Arguments_: 12013 C The type shall be 'CHARACTER' and of default 12014 kind. 12015 STATUS (Optional) status flag of type 'INTEGER'. 12016 Returns 0 on success, -1 on end-of-file and a 12017 system specific positive error code otherwise. 12018 12019_Example_: 12020 PROGRAM test_fput 12021 CHARACTER(len=10) :: str = "gfortran" 12022 INTEGER :: i 12023 DO i = 1, len_trim(str) 12024 CALL fput(str(i:i)) 12025 END DO 12026 END PROGRAM 12027 12028_See also_: 12029 *note FPUTC::, *note FGET::, *note FGETC:: 12030 12031 12032File: gfortran.info, Node: FPUTC, Next: FRACTION, Prev: FPUT, Up: Intrinsic Procedures 12033 120349.112 'FPUTC' -- Write a single character in stream mode 12035======================================================== 12036 12037_Description_: 12038 Write a single character in stream mode by bypassing normal 12039 formatted output. Stream I/O should not be mixed with normal 12040 record-oriented (formatted or unformatted) I/O on the same unit; 12041 the results are unpredictable. 12042 12043 This intrinsic is provided in both subroutine and function forms; 12044 however, only one form can be used in any given program unit. 12045 12046 Note that the 'FGET' intrinsic is provided for backwards 12047 compatibility with 'g77'. GNU Fortran provides the Fortran 2003 12048 Stream facility. Programmers should consider the use of new stream 12049 IO feature in new code for future portability. See also *note 12050 Fortran 2003 status::. 12051 12052_Standard_: 12053 GNU extension 12054 12055_Class_: 12056 Subroutine, function 12057 12058_Syntax_: 12059 'CALL FPUTC(UNIT, C [, STATUS])' 12060 'STATUS = FPUTC(UNIT, C)' 12061 12062_Arguments_: 12063 UNIT The type shall be 'INTEGER'. 12064 C The type shall be 'CHARACTER' and of default 12065 kind. 12066 STATUS (Optional) status flag of type 'INTEGER'. 12067 Returns 0 on success, -1 on end-of-file and a 12068 system specific positive error code otherwise. 12069 12070_Example_: 12071 PROGRAM test_fputc 12072 CHARACTER(len=10) :: str = "gfortran" 12073 INTEGER :: fd = 42, i 12074 12075 OPEN(UNIT = fd, FILE = "out", ACTION = "WRITE", STATUS="NEW") 12076 DO i = 1, len_trim(str) 12077 CALL fputc(fd, str(i:i)) 12078 END DO 12079 CLOSE(fd) 12080 END PROGRAM 12081 12082_See also_: 12083 *note FPUT::, *note FGET::, *note FGETC:: 12084 12085 12086File: gfortran.info, Node: FRACTION, Next: FREE, Prev: FPUTC, Up: Intrinsic Procedures 12087 120889.113 'FRACTION' -- Fractional part of the model representation 12089=============================================================== 12090 12091_Description_: 12092 'FRACTION(X)' returns the fractional part of the model 12093 representation of 'X'. 12094 12095_Standard_: 12096 Fortran 95 and later 12097 12098_Class_: 12099 Elemental function 12100 12101_Syntax_: 12102 'Y = FRACTION(X)' 12103 12104_Arguments_: 12105 X The type of the argument shall be a 'REAL'. 12106 12107_Return value_: 12108 The return value is of the same type and kind as the argument. The 12109 fractional part of the model representation of 'X' is returned; it 12110 is 'X * RADIX(X)**(-EXPONENT(X))'. 12111 12112_Example_: 12113 program test_fraction 12114 real :: x 12115 x = 178.1387e-4 12116 print *, fraction(x), x * radix(x)**(-exponent(x)) 12117 end program test_fraction 12118 12119 12120File: gfortran.info, Node: FREE, Next: FSEEK, Prev: FRACTION, Up: Intrinsic Procedures 12121 121229.114 'FREE' -- Frees memory 12123============================ 12124 12125_Description_: 12126 Frees memory previously allocated by 'MALLOC'. The 'FREE' 12127 intrinsic is an extension intended to be used with Cray pointers, 12128 and is provided in GNU Fortran to allow user to compile legacy 12129 code. For new code using Fortran 95 pointers, the memory 12130 de-allocation intrinsic is 'DEALLOCATE'. 12131 12132_Standard_: 12133 GNU extension 12134 12135_Class_: 12136 Subroutine 12137 12138_Syntax_: 12139 'CALL FREE(PTR)' 12140 12141_Arguments_: 12142 PTR The type shall be 'INTEGER'. It represents the 12143 location of the memory that should be 12144 de-allocated. 12145 12146_Return value_: 12147 None 12148 12149_Example_: 12150 See 'MALLOC' for an example. 12151 12152_See also_: 12153 *note MALLOC:: 12154 12155 12156File: gfortran.info, Node: FSEEK, Next: FSTAT, Prev: FREE, Up: Intrinsic Procedures 12157 121589.115 'FSEEK' -- Low level file positioning subroutine 12159====================================================== 12160 12161_Description_: 12162 Moves UNIT to the specified OFFSET. If WHENCE is set to 0, the 12163 OFFSET is taken as an absolute value 'SEEK_SET', if set to 1, 12164 OFFSET is taken to be relative to the current position 'SEEK_CUR', 12165 and if set to 2 relative to the end of the file 'SEEK_END'. On 12166 error, STATUS is set to a nonzero value. If STATUS the seek fails 12167 silently. 12168 12169 This intrinsic routine is not fully backwards compatible with 12170 'g77'. In 'g77', the 'FSEEK' takes a statement label instead of a 12171 STATUS variable. If FSEEK is used in old code, change 12172 CALL FSEEK(UNIT, OFFSET, WHENCE, *label) 12173 to 12174 INTEGER :: status 12175 CALL FSEEK(UNIT, OFFSET, WHENCE, status) 12176 IF (status /= 0) GOTO label 12177 12178 Please note that GNU Fortran provides the Fortran 2003 Stream 12179 facility. Programmers should consider the use of new stream IO 12180 feature in new code for future portability. See also *note Fortran 12181 2003 status::. 12182 12183_Standard_: 12184 GNU extension 12185 12186_Class_: 12187 Subroutine 12188 12189_Syntax_: 12190 'CALL FSEEK(UNIT, OFFSET, WHENCE[, STATUS])' 12191 12192_Arguments_: 12193 UNIT Shall be a scalar of type 'INTEGER'. 12194 OFFSET Shall be a scalar of type 'INTEGER'. 12195 WHENCE Shall be a scalar of type 'INTEGER'. Its value 12196 shall be either 0, 1 or 2. 12197 STATUS (Optional) shall be a scalar of type 12198 'INTEGER(4)'. 12199 12200_Example_: 12201 PROGRAM test_fseek 12202 INTEGER, PARAMETER :: SEEK_SET = 0, SEEK_CUR = 1, SEEK_END = 2 12203 INTEGER :: fd, offset, ierr 12204 12205 ierr = 0 12206 offset = 5 12207 fd = 10 12208 12209 OPEN(UNIT=fd, FILE="fseek.test") 12210 CALL FSEEK(fd, offset, SEEK_SET, ierr) ! move to OFFSET 12211 print *, FTELL(fd), ierr 12212 12213 CALL FSEEK(fd, 0, SEEK_END, ierr) ! move to end 12214 print *, FTELL(fd), ierr 12215 12216 CALL FSEEK(fd, 0, SEEK_SET, ierr) ! move to beginning 12217 print *, FTELL(fd), ierr 12218 12219 CLOSE(UNIT=fd) 12220 END PROGRAM 12221 12222_See also_: 12223 *note FTELL:: 12224 12225 12226File: gfortran.info, Node: FSTAT, Next: FTELL, Prev: FSEEK, Up: Intrinsic Procedures 12227 122289.116 'FSTAT' -- Get file status 12229================================ 12230 12231_Description_: 12232 'FSTAT' is identical to *note STAT::, except that information about 12233 an already opened file is obtained. 12234 12235 The elements in 'VALUES' are the same as described by *note STAT::. 12236 12237 This intrinsic is provided in both subroutine and function forms; 12238 however, only one form can be used in any given program unit. 12239 12240_Standard_: 12241 GNU extension 12242 12243_Class_: 12244 Subroutine, function 12245 12246_Syntax_: 12247 'CALL FSTAT(UNIT, VALUES [, STATUS])' 12248 'STATUS = FSTAT(UNIT, VALUES)' 12249 12250_Arguments_: 12251 UNIT An open I/O unit number of type 'INTEGER'. 12252 VALUES The type shall be 'INTEGER(4), DIMENSION(13)'. 12253 STATUS (Optional) status flag of type 'INTEGER(4)'. 12254 Returns 0 on success and a system specific error 12255 code otherwise. 12256 12257_Example_: 12258 See *note STAT:: for an example. 12259 12260_See also_: 12261 To stat a link: *note LSTAT::, to stat a file: *note STAT:: 12262 12263 12264File: gfortran.info, Node: FTELL, Next: GAMMA, Prev: FSTAT, Up: Intrinsic Procedures 12265 122669.117 'FTELL' -- Current stream position 12267======================================== 12268 12269_Description_: 12270 Retrieves the current position within an open file. 12271 12272 This intrinsic is provided in both subroutine and function forms; 12273 however, only one form can be used in any given program unit. 12274 12275_Standard_: 12276 GNU extension 12277 12278_Class_: 12279 Subroutine, function 12280 12281_Syntax_: 12282 'CALL FTELL(UNIT, OFFSET)' 12283 'OFFSET = FTELL(UNIT)' 12284 12285_Arguments_: 12286 OFFSET Shall of type 'INTEGER'. 12287 UNIT Shall of type 'INTEGER'. 12288 12289_Return value_: 12290 In either syntax, OFFSET is set to the current offset of unit 12291 number UNIT, or to -1 if the unit is not currently open. 12292 12293_Example_: 12294 PROGRAM test_ftell 12295 INTEGER :: i 12296 OPEN(10, FILE="temp.dat") 12297 CALL ftell(10,i) 12298 WRITE(*,*) i 12299 END PROGRAM 12300 12301_See also_: 12302 *note FSEEK:: 12303 12304 12305File: gfortran.info, Node: GAMMA, Next: GERROR, Prev: FTELL, Up: Intrinsic Procedures 12306 123079.118 'GAMMA' -- Gamma function 12308=============================== 12309 12310_Description_: 12311 'GAMMA(X)' computes Gamma (\Gamma) of X. For positive, integer 12312 values of X the Gamma function simplifies to the factorial function 12313 \Gamma(x)=(x-1)!. 12314 12315_Standard_: 12316 Fortran 2008 and later 12317 12318_Class_: 12319 Elemental function 12320 12321_Syntax_: 12322 'X = GAMMA(X)' 12323 12324_Arguments_: 12325 X Shall be of type 'REAL' and neither zero nor a 12326 negative integer. 12327 12328_Return value_: 12329 The return value is of type 'REAL' of the same kind as X. 12330 12331_Example_: 12332 program test_gamma 12333 real :: x = 1.0 12334 x = gamma(x) ! returns 1.0 12335 end program test_gamma 12336 12337_Specific names_: 12338 Name Argument Return type Standard 12339 'GAMMA(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 12340 'DGAMMA(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 12341 12342_See also_: 12343 Logarithm of the Gamma function: *note LOG_GAMMA:: 12344 12345 12346File: gfortran.info, Node: GERROR, Next: GETARG, Prev: GAMMA, Up: Intrinsic Procedures 12347 123489.119 'GERROR' -- Get last system error message 12349=============================================== 12350 12351_Description_: 12352 Returns the system error message corresponding to the last system 12353 error. This resembles the functionality of 'strerror(3)' in C. 12354 12355_Standard_: 12356 GNU extension 12357 12358_Class_: 12359 Subroutine 12360 12361_Syntax_: 12362 'CALL GERROR(RESULT)' 12363 12364_Arguments_: 12365 RESULT Shall of type 'CHARACTER' and of default 12366 12367_Example_: 12368 PROGRAM test_gerror 12369 CHARACTER(len=100) :: msg 12370 CALL gerror(msg) 12371 WRITE(*,*) msg 12372 END PROGRAM 12373 12374_See also_: 12375 *note IERRNO::, *note PERROR:: 12376 12377 12378File: gfortran.info, Node: GETARG, Next: GET_COMMAND, Prev: GERROR, Up: Intrinsic Procedures 12379 123809.120 'GETARG' -- Get command line arguments 12381============================================ 12382 12383_Description_: 12384 Retrieve the POS-th argument that was passed on the command line 12385 when the containing program was invoked. 12386 12387 This intrinsic routine is provided for backwards compatibility with 12388 GNU Fortran 77. In new code, programmers should consider the use 12389 of the *note GET_COMMAND_ARGUMENT:: intrinsic defined by the 12390 Fortran 2003 standard. 12391 12392_Standard_: 12393 GNU extension 12394 12395_Class_: 12396 Subroutine 12397 12398_Syntax_: 12399 'CALL GETARG(POS, VALUE)' 12400 12401_Arguments_: 12402 POS Shall be of type 'INTEGER' and not wider than 12403 the default integer kind; POS \geq 0 12404 VALUE Shall be of type 'CHARACTER' and of default 12405 kind. 12406 VALUE Shall be of type 'CHARACTER'. 12407 12408_Return value_: 12409 After 'GETARG' returns, the VALUE argument holds the POSth command 12410 line argument. If VALUE can not hold the argument, it is truncated 12411 to fit the length of VALUE. If there are less than POS arguments 12412 specified at the command line, VALUE will be filled with blanks. 12413 If POS = 0, VALUE is set to the name of the program (on systems 12414 that support this feature). 12415 12416_Example_: 12417 PROGRAM test_getarg 12418 INTEGER :: i 12419 CHARACTER(len=32) :: arg 12420 12421 DO i = 1, iargc() 12422 CALL getarg(i, arg) 12423 WRITE (*,*) arg 12424 END DO 12425 END PROGRAM 12426 12427_See also_: 12428 GNU Fortran 77 compatibility function: *note IARGC:: 12429 12430 Fortran 2003 functions and subroutines: *note GET_COMMAND::, *note 12431 GET_COMMAND_ARGUMENT::, *note COMMAND_ARGUMENT_COUNT:: 12432 12433 12434File: gfortran.info, Node: GET_COMMAND, Next: GET_COMMAND_ARGUMENT, Prev: GETARG, Up: Intrinsic Procedures 12435 124369.121 'GET_COMMAND' -- Get the entire command line 12437================================================== 12438 12439_Description_: 12440 Retrieve the entire command line that was used to invoke the 12441 program. 12442 12443_Standard_: 12444 Fortran 2003 and later 12445 12446_Class_: 12447 Subroutine 12448 12449_Syntax_: 12450 'CALL GET_COMMAND([COMMAND, LENGTH, STATUS])' 12451 12452_Arguments_: 12453 COMMAND (Optional) shall be of type 'CHARACTER' and of 12454 default kind. 12455 LENGTH (Optional) Shall be of type 'INTEGER' and of 12456 default kind. 12457 STATUS (Optional) Shall be of type 'INTEGER' and of 12458 default kind. 12459 12460_Return value_: 12461 If COMMAND is present, stores the entire command line that was used 12462 to invoke the program in COMMAND. If LENGTH is present, it is 12463 assigned the length of the command line. If STATUS is present, it 12464 is assigned 0 upon success of the command, -1 if COMMAND is too 12465 short to store the command line, or a positive value in case of an 12466 error. 12467 12468_Example_: 12469 PROGRAM test_get_command 12470 CHARACTER(len=255) :: cmd 12471 CALL get_command(cmd) 12472 WRITE (*,*) TRIM(cmd) 12473 END PROGRAM 12474 12475_See also_: 12476 *note GET_COMMAND_ARGUMENT::, *note COMMAND_ARGUMENT_COUNT:: 12477 12478 12479File: gfortran.info, Node: GET_COMMAND_ARGUMENT, Next: GETCWD, Prev: GET_COMMAND, Up: Intrinsic Procedures 12480 124819.122 'GET_COMMAND_ARGUMENT' -- Get command line arguments 12482========================================================== 12483 12484_Description_: 12485 Retrieve the NUMBER-th argument that was passed on the command line 12486 when the containing program was invoked. 12487 12488_Standard_: 12489 Fortran 2003 and later 12490 12491_Class_: 12492 Subroutine 12493 12494_Syntax_: 12495 'CALL GET_COMMAND_ARGUMENT(NUMBER [, VALUE, LENGTH, STATUS])' 12496 12497_Arguments_: 12498 NUMBER Shall be a scalar of type 'INTEGER' and of 12499 default kind, NUMBER \geq 0 12500 VALUE (Optional) Shall be a scalar of type 'CHARACTER' 12501 and of default kind. 12502 LENGTH (Optional) Shall be a scalar of type 'INTEGER' 12503 and of default kind. 12504 STATUS (Optional) Shall be a scalar of type 'INTEGER' 12505 and of default kind. 12506 12507_Return value_: 12508 After 'GET_COMMAND_ARGUMENT' returns, the VALUE argument holds the 12509 NUMBER-th command line argument. If VALUE can not hold the 12510 argument, it is truncated to fit the length of VALUE. If there are 12511 less than NUMBER arguments specified at the command line, VALUE 12512 will be filled with blanks. If NUMBER = 0, VALUE is set to the 12513 name of the program (on systems that support this feature). The 12514 LENGTH argument contains the length of the NUMBER-th command line 12515 argument. If the argument retrieval fails, STATUS is a positive 12516 number; if VALUE contains a truncated command line argument, STATUS 12517 is -1; and otherwise the STATUS is zero. 12518 12519_Example_: 12520 PROGRAM test_get_command_argument 12521 INTEGER :: i 12522 CHARACTER(len=32) :: arg 12523 12524 i = 0 12525 DO 12526 CALL get_command_argument(i, arg) 12527 IF (LEN_TRIM(arg) == 0) EXIT 12528 12529 WRITE (*,*) TRIM(arg) 12530 i = i+1 12531 END DO 12532 END PROGRAM 12533 12534_See also_: 12535 *note GET_COMMAND::, *note COMMAND_ARGUMENT_COUNT:: 12536 12537 12538File: gfortran.info, Node: GETCWD, Next: GETENV, Prev: GET_COMMAND_ARGUMENT, Up: Intrinsic Procedures 12539 125409.123 'GETCWD' -- Get current working directory 12541=============================================== 12542 12543_Description_: 12544 Get current working directory. 12545 12546 This intrinsic is provided in both subroutine and function forms; 12547 however, only one form can be used in any given program unit. 12548 12549_Standard_: 12550 GNU extension 12551 12552_Class_: 12553 Subroutine, function 12554 12555_Syntax_: 12556 'CALL GETCWD(C [, STATUS])' 12557 'STATUS = GETCWD(C)' 12558 12559_Arguments_: 12560 C The type shall be 'CHARACTER' and of default 12561 kind. 12562 STATUS (Optional) status flag. Returns 0 on success, a 12563 system specific and nonzero error code 12564 otherwise. 12565 12566_Example_: 12567 PROGRAM test_getcwd 12568 CHARACTER(len=255) :: cwd 12569 CALL getcwd(cwd) 12570 WRITE(*,*) TRIM(cwd) 12571 END PROGRAM 12572 12573_See also_: 12574 *note CHDIR:: 12575 12576 12577File: gfortran.info, Node: GETENV, Next: GET_ENVIRONMENT_VARIABLE, Prev: GETCWD, Up: Intrinsic Procedures 12578 125799.124 'GETENV' -- Get an environmental variable 12580=============================================== 12581 12582_Description_: 12583 Get the VALUE of the environmental variable NAME. 12584 12585 This intrinsic routine is provided for backwards compatibility with 12586 GNU Fortran 77. In new code, programmers should consider the use 12587 of the *note GET_ENVIRONMENT_VARIABLE:: intrinsic defined by the 12588 Fortran 2003 standard. 12589 12590 Note that 'GETENV' need not be thread-safe. It is the 12591 responsibility of the user to ensure that the environment is not 12592 being updated concurrently with a call to the 'GETENV' intrinsic. 12593 12594_Standard_: 12595 GNU extension 12596 12597_Class_: 12598 Subroutine 12599 12600_Syntax_: 12601 'CALL GETENV(NAME, VALUE)' 12602 12603_Arguments_: 12604 NAME Shall be of type 'CHARACTER' and of default 12605 kind. 12606 VALUE Shall be of type 'CHARACTER' and of default 12607 kind. 12608 12609_Return value_: 12610 Stores the value of NAME in VALUE. If VALUE is not large enough to 12611 hold the data, it is truncated. If NAME is not set, VALUE will be 12612 filled with blanks. 12613 12614_Example_: 12615 PROGRAM test_getenv 12616 CHARACTER(len=255) :: homedir 12617 CALL getenv("HOME", homedir) 12618 WRITE (*,*) TRIM(homedir) 12619 END PROGRAM 12620 12621_See also_: 12622 *note GET_ENVIRONMENT_VARIABLE:: 12623 12624 12625File: gfortran.info, Node: GET_ENVIRONMENT_VARIABLE, Next: GETGID, Prev: GETENV, Up: Intrinsic Procedures 12626 126279.125 'GET_ENVIRONMENT_VARIABLE' -- Get an environmental variable 12628================================================================= 12629 12630_Description_: 12631 Get the VALUE of the environmental variable NAME. 12632 12633 Note that 'GET_ENVIRONMENT_VARIABLE' need not be thread-safe. It 12634 is the responsibility of the user to ensure that the environment is 12635 not being updated concurrently with a call to the 12636 'GET_ENVIRONMENT_VARIABLE' intrinsic. 12637 12638_Standard_: 12639 Fortran 2003 and later 12640 12641_Class_: 12642 Subroutine 12643 12644_Syntax_: 12645 'CALL GET_ENVIRONMENT_VARIABLE(NAME[, VALUE, LENGTH, STATUS, 12646 TRIM_NAME)' 12647 12648_Arguments_: 12649 NAME Shall be a scalar of type 'CHARACTER' and of 12650 default kind. 12651 VALUE (Optional) Shall be a scalar of type 'CHARACTER' 12652 and of default kind. 12653 LENGTH (Optional) Shall be a scalar of type 'INTEGER' 12654 and of default kind. 12655 STATUS (Optional) Shall be a scalar of type 'INTEGER' 12656 and of default kind. 12657 TRIM_NAME (Optional) Shall be a scalar of type 'LOGICAL' 12658 and of default kind. 12659 12660_Return value_: 12661 Stores the value of NAME in VALUE. If VALUE is not large enough to 12662 hold the data, it is truncated. If NAME is not set, VALUE will be 12663 filled with blanks. Argument LENGTH contains the length needed for 12664 storing the environment variable NAME or zero if it is not present. 12665 STATUS is -1 if VALUE is present but too short for the environment 12666 variable; it is 1 if the environment variable does not exist and 2 12667 if the processor does not support environment variables; in all 12668 other cases STATUS is zero. If TRIM_NAME is present with the value 12669 '.FALSE.', the trailing blanks in NAME are significant; otherwise 12670 they are not part of the environment variable name. 12671 12672_Example_: 12673 PROGRAM test_getenv 12674 CHARACTER(len=255) :: homedir 12675 CALL get_environment_variable("HOME", homedir) 12676 WRITE (*,*) TRIM(homedir) 12677 END PROGRAM 12678 12679 12680File: gfortran.info, Node: GETGID, Next: GETLOG, Prev: GET_ENVIRONMENT_VARIABLE, Up: Intrinsic Procedures 12681 126829.126 'GETGID' -- Group ID function 12683=================================== 12684 12685_Description_: 12686 Returns the numerical group ID of the current process. 12687 12688_Standard_: 12689 GNU extension 12690 12691_Class_: 12692 Function 12693 12694_Syntax_: 12695 'RESULT = GETGID()' 12696 12697_Return value_: 12698 The return value of 'GETGID' is an 'INTEGER' of the default kind. 12699 12700_Example_: 12701 See 'GETPID' for an example. 12702 12703_See also_: 12704 *note GETPID::, *note GETUID:: 12705 12706 12707File: gfortran.info, Node: GETLOG, Next: GETPID, Prev: GETGID, Up: Intrinsic Procedures 12708 127099.127 'GETLOG' -- Get login name 12710================================ 12711 12712_Description_: 12713 Gets the username under which the program is running. 12714 12715_Standard_: 12716 GNU extension 12717 12718_Class_: 12719 Subroutine 12720 12721_Syntax_: 12722 'CALL GETLOG(C)' 12723 12724_Arguments_: 12725 C Shall be of type 'CHARACTER' and of default 12726 kind. 12727 12728_Return value_: 12729 Stores the current user name in LOGIN. (On systems where POSIX 12730 functions 'geteuid' and 'getpwuid' are not available, and the 12731 'getlogin' function is not implemented either, this will return a 12732 blank string.) 12733 12734_Example_: 12735 PROGRAM TEST_GETLOG 12736 CHARACTER(32) :: login 12737 CALL GETLOG(login) 12738 WRITE(*,*) login 12739 END PROGRAM 12740 12741_See also_: 12742 *note GETUID:: 12743 12744 12745File: gfortran.info, Node: GETPID, Next: GETUID, Prev: GETLOG, Up: Intrinsic Procedures 12746 127479.128 'GETPID' -- Process ID function 12748===================================== 12749 12750_Description_: 12751 Returns the numerical process identifier of the current process. 12752 12753_Standard_: 12754 GNU extension 12755 12756_Class_: 12757 Function 12758 12759_Syntax_: 12760 'RESULT = GETPID()' 12761 12762_Return value_: 12763 The return value of 'GETPID' is an 'INTEGER' of the default kind. 12764 12765_Example_: 12766 program info 12767 print *, "The current process ID is ", getpid() 12768 print *, "Your numerical user ID is ", getuid() 12769 print *, "Your numerical group ID is ", getgid() 12770 end program info 12771 12772_See also_: 12773 *note GETGID::, *note GETUID:: 12774 12775 12776File: gfortran.info, Node: GETUID, Next: GMTIME, Prev: GETPID, Up: Intrinsic Procedures 12777 127789.129 'GETUID' -- User ID function 12779================================== 12780 12781_Description_: 12782 Returns the numerical user ID of the current process. 12783 12784_Standard_: 12785 GNU extension 12786 12787_Class_: 12788 Function 12789 12790_Syntax_: 12791 'RESULT = GETUID()' 12792 12793_Return value_: 12794 The return value of 'GETUID' is an 'INTEGER' of the default kind. 12795 12796_Example_: 12797 See 'GETPID' for an example. 12798 12799_See also_: 12800 *note GETPID::, *note GETLOG:: 12801 12802 12803File: gfortran.info, Node: GMTIME, Next: HOSTNM, Prev: GETUID, Up: Intrinsic Procedures 12804 128059.130 'GMTIME' -- Convert time to GMT info 12806========================================== 12807 12808_Description_: 12809 Given a system time value TIME (as provided by the *note TIME:: 12810 intrinsic), fills VALUES with values extracted from it appropriate 12811 to the UTC time zone (Universal Coordinated Time, also known in 12812 some countries as GMT, Greenwich Mean Time), using 'gmtime(3)'. 12813 12814 This intrinsic routine is provided for backwards compatibility with 12815 GNU Fortran 77. In new code, programmers should consider the use 12816 of the *note DATE_AND_TIME:: intrinsic defined by the Fortran 95 12817 standard. 12818 12819_Standard_: 12820 GNU extension 12821 12822_Class_: 12823 Subroutine 12824 12825_Syntax_: 12826 'CALL GMTIME(TIME, VALUES)' 12827 12828_Arguments_: 12829 TIME An 'INTEGER' scalar expression corresponding to 12830 a system time, with 'INTENT(IN)'. 12831 VALUES A default 'INTEGER' array with 9 elements, with 12832 'INTENT(OUT)'. 12833 12834_Return value_: 12835 The elements of VALUES are assigned as follows: 12836 1. Seconds after the minute, range 0-59 or 0-61 to allow for leap 12837 seconds 12838 2. Minutes after the hour, range 0-59 12839 3. Hours past midnight, range 0-23 12840 4. Day of month, range 1-31 12841 5. Number of months since January, range 0-11 12842 6. Years since 1900 12843 7. Number of days since Sunday, range 0-6 12844 8. Days since January 1, range 0-365 12845 9. Daylight savings indicator: positive if daylight savings is in 12846 effect, zero if not, and negative if the information is not 12847 available. 12848 12849_See also_: 12850 *note DATE_AND_TIME::, *note CTIME::, *note LTIME::, *note TIME::, 12851 *note TIME8:: 12852 12853 12854File: gfortran.info, Node: HOSTNM, Next: HUGE, Prev: GMTIME, Up: Intrinsic Procedures 12855 128569.131 'HOSTNM' -- Get system host name 12857====================================== 12858 12859_Description_: 12860 Retrieves the host name of the system on which the program is 12861 running. 12862 12863 This intrinsic is provided in both subroutine and function forms; 12864 however, only one form can be used in any given program unit. 12865 12866_Standard_: 12867 GNU extension 12868 12869_Class_: 12870 Subroutine, function 12871 12872_Syntax_: 12873 'CALL HOSTNM(C [, STATUS])' 12874 'STATUS = HOSTNM(NAME)' 12875 12876_Arguments_: 12877 C Shall of type 'CHARACTER' and of default kind. 12878 STATUS (Optional) status flag of type 'INTEGER'. 12879 Returns 0 on success, or a system specific error 12880 code otherwise. 12881 12882_Return value_: 12883 In either syntax, NAME is set to the current hostname if it can be 12884 obtained, or to a blank string otherwise. 12885 12886 12887File: gfortran.info, Node: HUGE, Next: HYPOT, Prev: HOSTNM, Up: Intrinsic Procedures 12888 128899.132 'HUGE' -- Largest number of a kind 12890======================================== 12891 12892_Description_: 12893 'HUGE(X)' returns the largest number that is not an infinity in the 12894 model of the type of 'X'. 12895 12896_Standard_: 12897 Fortran 95 and later 12898 12899_Class_: 12900 Inquiry function 12901 12902_Syntax_: 12903 'RESULT = HUGE(X)' 12904 12905_Arguments_: 12906 X Shall be of type 'REAL' or 'INTEGER'. 12907 12908_Return value_: 12909 The return value is of the same type and kind as X 12910 12911_Example_: 12912 program test_huge_tiny 12913 print *, huge(0), huge(0.0), huge(0.0d0) 12914 print *, tiny(0.0), tiny(0.0d0) 12915 end program test_huge_tiny 12916 12917 12918File: gfortran.info, Node: HYPOT, Next: IACHAR, Prev: HUGE, Up: Intrinsic Procedures 12919 129209.133 'HYPOT' -- Euclidean distance function 12921============================================ 12922 12923_Description_: 12924 'HYPOT(X,Y)' is the Euclidean distance function. It is equal to 12925 \sqrt{X^2 + Y^2}, without undue underflow or overflow. 12926 12927_Standard_: 12928 Fortran 2008 and later 12929 12930_Class_: 12931 Elemental function 12932 12933_Syntax_: 12934 'RESULT = HYPOT(X, Y)' 12935 12936_Arguments_: 12937 X The type shall be 'REAL'. 12938 Y The type and kind type parameter shall be the 12939 same as X. 12940 12941_Return value_: 12942 The return value has the same type and kind type parameter as X. 12943 12944_Example_: 12945 program test_hypot 12946 real(4) :: x = 1.e0_4, y = 0.5e0_4 12947 x = hypot(x,y) 12948 end program test_hypot 12949 12950 12951File: gfortran.info, Node: IACHAR, Next: IALL, Prev: HYPOT, Up: Intrinsic Procedures 12952 129539.134 'IACHAR' -- Code in ASCII collating sequence 12954================================================== 12955 12956_Description_: 12957 'IACHAR(C)' returns the code for the ASCII character in the first 12958 character position of 'C'. 12959 12960_Standard_: 12961 Fortran 95 and later, with KIND argument Fortran 2003 and later 12962 12963_Class_: 12964 Elemental function 12965 12966_Syntax_: 12967 'RESULT = IACHAR(C [, KIND])' 12968 12969_Arguments_: 12970 C Shall be a scalar 'CHARACTER', with 'INTENT(IN)' 12971 KIND (Optional) An 'INTEGER' initialization 12972 expression indicating the kind parameter of the 12973 result. 12974 12975_Return value_: 12976 The return value is of type 'INTEGER' and of kind KIND. If KIND is 12977 absent, the return value is of default integer kind. 12978 12979_Example_: 12980 program test_iachar 12981 integer i 12982 i = iachar(' ') 12983 end program test_iachar 12984 12985_Note_: 12986 See *note ICHAR:: for a discussion of converting between numerical 12987 values and formatted string representations. 12988 12989_See also_: 12990 *note ACHAR::, *note CHAR::, *note ICHAR:: 12991 12992 12993File: gfortran.info, Node: IALL, Next: IAND, Prev: IACHAR, Up: Intrinsic Procedures 12994 129959.135 'IALL' -- Bitwise AND of array elements 12996============================================= 12997 12998_Description_: 12999 Reduces with bitwise AND the elements of ARRAY along dimension DIM 13000 if the corresponding element in MASK is 'TRUE'. 13001 13002_Standard_: 13003 Fortran 2008 and later 13004 13005_Class_: 13006 Transformational function 13007 13008_Syntax_: 13009 'RESULT = IALL(ARRAY[, MASK])' 13010 'RESULT = IALL(ARRAY, DIM[, MASK])' 13011 13012_Arguments_: 13013 ARRAY Shall be an array of type 'INTEGER' 13014 DIM (Optional) shall be a scalar of type 'INTEGER' 13015 with a value in the range from 1 to n, where n 13016 equals the rank of ARRAY. 13017 MASK (Optional) shall be of type 'LOGICAL' and either 13018 be a scalar or an array of the same shape as 13019 ARRAY. 13020 13021_Return value_: 13022 The result is of the same type as ARRAY. 13023 13024 If DIM is absent, a scalar with the bitwise ALL of all elements in 13025 ARRAY is returned. Otherwise, an array of rank n-1, where n equals 13026 the rank of ARRAY, and a shape similar to that of ARRAY with 13027 dimension DIM dropped is returned. 13028 13029_Example_: 13030 PROGRAM test_iall 13031 INTEGER(1) :: a(2) 13032 13033 a(1) = b'00100100' 13034 a(2) = b'01101010' 13035 13036 ! prints 00100000 13037 PRINT '(b8.8)', IALL(a) 13038 END PROGRAM 13039 13040_See also_: 13041 *note IANY::, *note IPARITY::, *note IAND:: 13042 13043 13044File: gfortran.info, Node: IAND, Next: IANY, Prev: IALL, Up: Intrinsic Procedures 13045 130469.136 'IAND' -- Bitwise logical and 13047=================================== 13048 13049_Description_: 13050 Bitwise logical 'AND'. 13051 13052_Standard_: 13053 Fortran 95 and later, has overloads that are GNU extensions 13054 13055_Class_: 13056 Elemental function 13057 13058_Syntax_: 13059 'RESULT = IAND(I, J)' 13060 13061_Arguments_: 13062 I The type shall be 'INTEGER'. 13063 J The type shall be 'INTEGER', of the same kind as 13064 I. (As a GNU extension, different kinds are 13065 also permitted.) 13066 13067_Return value_: 13068 The return type is 'INTEGER', of the same kind as the arguments. 13069 (If the argument kinds differ, it is of the same kind as the larger 13070 argument.) 13071 13072_Example_: 13073 PROGRAM test_iand 13074 INTEGER :: a, b 13075 DATA a / Z'F' /, b / Z'3' / 13076 WRITE (*,*) IAND(a, b) 13077 END PROGRAM 13078 13079_Specific names_: 13080 Name Argument Return type Standard 13081 'IAND(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 13082 later 13083 'BIAND(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 13084 A' 13085 'IIAND(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 13086 A' 13087 'JIAND(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 13088 A' 13089 'KIAND(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 13090 A' 13091 13092_See also_: 13093 *note IOR::, *note IEOR::, *note IBITS::, *note IBSET::, *note 13094 IBCLR::, *note NOT:: 13095 13096 13097File: gfortran.info, Node: IANY, Next: IARGC, Prev: IAND, Up: Intrinsic Procedures 13098 130999.137 'IANY' -- Bitwise OR of array elements 13100============================================ 13101 13102_Description_: 13103 Reduces with bitwise OR (inclusive or) the elements of ARRAY along 13104 dimension DIM if the corresponding element in MASK is 'TRUE'. 13105 13106_Standard_: 13107 Fortran 2008 and later 13108 13109_Class_: 13110 Transformational function 13111 13112_Syntax_: 13113 'RESULT = IANY(ARRAY[, MASK])' 13114 'RESULT = IANY(ARRAY, DIM[, MASK])' 13115 13116_Arguments_: 13117 ARRAY Shall be an array of type 'INTEGER' 13118 DIM (Optional) shall be a scalar of type 'INTEGER' 13119 with a value in the range from 1 to n, where n 13120 equals the rank of ARRAY. 13121 MASK (Optional) shall be of type 'LOGICAL' and either 13122 be a scalar or an array of the same shape as 13123 ARRAY. 13124 13125_Return value_: 13126 The result is of the same type as ARRAY. 13127 13128 If DIM is absent, a scalar with the bitwise OR of all elements in 13129 ARRAY is returned. Otherwise, an array of rank n-1, where n equals 13130 the rank of ARRAY, and a shape similar to that of ARRAY with 13131 dimension DIM dropped is returned. 13132 13133_Example_: 13134 PROGRAM test_iany 13135 INTEGER(1) :: a(2) 13136 13137 a(1) = b'00100100' 13138 a(2) = b'01101010' 13139 13140 ! prints 01101110 13141 PRINT '(b8.8)', IANY(a) 13142 END PROGRAM 13143 13144_See also_: 13145 *note IPARITY::, *note IALL::, *note IOR:: 13146 13147 13148File: gfortran.info, Node: IARGC, Next: IBCLR, Prev: IANY, Up: Intrinsic Procedures 13149 131509.138 'IARGC' -- Get the number of command line arguments 13151========================================================= 13152 13153_Description_: 13154 'IARGC' returns the number of arguments passed on the command line 13155 when the containing program was invoked. 13156 13157 This intrinsic routine is provided for backwards compatibility with 13158 GNU Fortran 77. In new code, programmers should consider the use 13159 of the *note COMMAND_ARGUMENT_COUNT:: intrinsic defined by the 13160 Fortran 2003 standard. 13161 13162_Standard_: 13163 GNU extension 13164 13165_Class_: 13166 Function 13167 13168_Syntax_: 13169 'RESULT = IARGC()' 13170 13171_Arguments_: 13172 None. 13173 13174_Return value_: 13175 The number of command line arguments, type 'INTEGER(4)'. 13176 13177_Example_: 13178 See *note GETARG:: 13179 13180_See also_: 13181 GNU Fortran 77 compatibility subroutine: *note GETARG:: 13182 13183 Fortran 2003 functions and subroutines: *note GET_COMMAND::, *note 13184 GET_COMMAND_ARGUMENT::, *note COMMAND_ARGUMENT_COUNT:: 13185 13186 13187File: gfortran.info, Node: IBCLR, Next: IBITS, Prev: IARGC, Up: Intrinsic Procedures 13188 131899.139 'IBCLR' -- Clear bit 13190========================== 13191 13192_Description_: 13193 'IBCLR' returns the value of I with the bit at position POS set to 13194 zero. 13195 13196_Standard_: 13197 Fortran 95 and later, has overloads that are GNU extensions 13198 13199_Class_: 13200 Elemental function 13201 13202_Syntax_: 13203 'RESULT = IBCLR(I, POS)' 13204 13205_Arguments_: 13206 I The type shall be 'INTEGER'. 13207 POS The type shall be 'INTEGER'. 13208 13209_Return value_: 13210 The return value is of type 'INTEGER' and of the same kind as I. 13211 13212_Specific names_: 13213 Name Argument Return type Standard 13214 'IBCLR(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 13215 later 13216 'BBCLR(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 13217 A' 13218 'IIBCLR(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 13219 A' 13220 'JIBCLR(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 13221 A' 13222 'KIBCLR(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 13223 A' 13224 13225_See also_: 13226 *note IBITS::, *note IBSET::, *note IAND::, *note IOR::, *note 13227 IEOR::, *note MVBITS:: 13228 13229 13230File: gfortran.info, Node: IBITS, Next: IBSET, Prev: IBCLR, Up: Intrinsic Procedures 13231 132329.140 'IBITS' -- Bit extraction 13233=============================== 13234 13235_Description_: 13236 'IBITS' extracts a field of length LEN from I, starting from bit 13237 position POS and extending left for LEN bits. The result is 13238 right-justified and the remaining bits are zeroed. The value of 13239 'POS+LEN' must be less than or equal to the value 'BIT_SIZE(I)'. 13240 13241_Standard_: 13242 Fortran 95 and later, has overloads that are GNU extensions 13243 13244_Class_: 13245 Elemental function 13246 13247_Syntax_: 13248 'RESULT = IBITS(I, POS, LEN)' 13249 13250_Arguments_: 13251 I The type shall be 'INTEGER'. 13252 POS The type shall be 'INTEGER'. 13253 LEN The type shall be 'INTEGER'. 13254 13255_Return value_: 13256 The return value is of type 'INTEGER' and of the same kind as I. 13257 13258_Specific names_: 13259 Name Argument Return type Standard 13260 'IBITS(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 13261 later 13262 'BBITS(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 13263 A' 13264 'IIBITS(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 13265 A' 13266 'JIBITS(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 13267 A' 13268 'KIBITS(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 13269 A' 13270 13271_See also_: 13272 *note BIT_SIZE::, *note IBCLR::, *note IBSET::, *note IAND::, *note 13273 IOR::, *note IEOR:: 13274 13275 13276File: gfortran.info, Node: IBSET, Next: ICHAR, Prev: IBITS, Up: Intrinsic Procedures 13277 132789.141 'IBSET' -- Set bit 13279======================== 13280 13281_Description_: 13282 'IBSET' returns the value of I with the bit at position POS set to 13283 one. 13284 13285_Standard_: 13286 Fortran 95 and later, has overloads that are GNU extensions 13287 13288_Class_: 13289 Elemental function 13290 13291_Syntax_: 13292 'RESULT = IBSET(I, POS)' 13293 13294_Arguments_: 13295 I The type shall be 'INTEGER'. 13296 POS The type shall be 'INTEGER'. 13297 13298_Return value_: 13299 The return value is of type 'INTEGER' and of the same kind as I. 13300 13301_Specific names_: 13302 Name Argument Return type Standard 13303 'IBSET(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 13304 later 13305 'BBSET(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 13306 A' 13307 'IIBSET(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 13308 A' 13309 'JIBSET(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 13310 A' 13311 'KIBSET(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 13312 A' 13313 13314_See also_: 13315 *note IBCLR::, *note IBITS::, *note IAND::, *note IOR::, *note 13316 IEOR::, *note MVBITS:: 13317 13318 13319File: gfortran.info, Node: ICHAR, Next: IDATE, Prev: IBSET, Up: Intrinsic Procedures 13320 133219.142 'ICHAR' -- Character-to-integer conversion function 13322========================================================= 13323 13324_Description_: 13325 'ICHAR(C)' returns the code for the character in the first 13326 character position of 'C' in the system's native character set. 13327 The correspondence between characters and their codes is not 13328 necessarily the same across different GNU Fortran implementations. 13329 13330_Standard_: 13331 Fortran 95 and later, with KIND argument Fortran 2003 and later 13332 13333_Class_: 13334 Elemental function 13335 13336_Syntax_: 13337 'RESULT = ICHAR(C [, KIND])' 13338 13339_Arguments_: 13340 C Shall be a scalar 'CHARACTER', with 'INTENT(IN)' 13341 KIND (Optional) An 'INTEGER' initialization 13342 expression indicating the kind parameter of the 13343 result. 13344 13345_Return value_: 13346 The return value is of type 'INTEGER' and of kind KIND. If KIND is 13347 absent, the return value is of default integer kind. 13348 13349_Example_: 13350 program test_ichar 13351 integer i 13352 i = ichar(' ') 13353 end program test_ichar 13354 13355_Specific names_: 13356 Name Argument Return type Standard 13357 'ICHAR(C)' 'CHARACTER 'INTEGER(4)' Fortran 77 and 13358 C' later 13359 13360_Note_: 13361 No intrinsic exists to convert between a numeric value and a 13362 formatted character string representation - for instance, given the 13363 'CHARACTER' value ''154'', obtaining an 'INTEGER' or 'REAL' value 13364 with the value 154, or vice versa. Instead, this functionality is 13365 provided by internal-file I/O, as in the following example: 13366 program read_val 13367 integer value 13368 character(len=10) string, string2 13369 string = '154' 13370 13371 ! Convert a string to a numeric value 13372 read (string,'(I10)') value 13373 print *, value 13374 13375 ! Convert a value to a formatted string 13376 write (string2,'(I10)') value 13377 print *, string2 13378 end program read_val 13379 13380_See also_: 13381 *note ACHAR::, *note CHAR::, *note IACHAR:: 13382 13383 13384File: gfortran.info, Node: IDATE, Next: IEOR, Prev: ICHAR, Up: Intrinsic Procedures 13385 133869.143 'IDATE' -- Get current local time subroutine (day/month/year) 13387=================================================================== 13388 13389_Description_: 13390 'IDATE(VALUES)' Fills VALUES with the numerical values at the 13391 current local time. The day (in the range 1-31), month (in the 13392 range 1-12), and year appear in elements 1, 2, and 3 of VALUES, 13393 respectively. The year has four significant digits. 13394 13395 This intrinsic routine is provided for backwards compatibility with 13396 GNU Fortran 77. In new code, programmers should consider the use 13397 of the *note DATE_AND_TIME:: intrinsic defined by the Fortran 95 13398 standard. 13399 13400_Standard_: 13401 GNU extension 13402 13403_Class_: 13404 Subroutine 13405 13406_Syntax_: 13407 'CALL IDATE(VALUES)' 13408 13409_Arguments_: 13410 VALUES The type shall be 'INTEGER, DIMENSION(3)' and 13411 the kind shall be the default integer kind. 13412 13413_Return value_: 13414 Does not return anything. 13415 13416_Example_: 13417 program test_idate 13418 integer, dimension(3) :: tarray 13419 call idate(tarray) 13420 print *, tarray(1) 13421 print *, tarray(2) 13422 print *, tarray(3) 13423 end program test_idate 13424 13425_See also_: 13426 *note DATE_AND_TIME:: 13427 13428 13429File: gfortran.info, Node: IEOR, Next: IERRNO, Prev: IDATE, Up: Intrinsic Procedures 13430 134319.144 'IEOR' -- Bitwise logical exclusive or 13432============================================ 13433 13434_Description_: 13435 'IEOR' returns the bitwise Boolean exclusive-OR of I and J. 13436 13437_Standard_: 13438 Fortran 95 and later, has overloads that are GNU extensions 13439 13440_Class_: 13441 Elemental function 13442 13443_Syntax_: 13444 'RESULT = IEOR(I, J)' 13445 13446_Arguments_: 13447 I The type shall be 'INTEGER'. 13448 J The type shall be 'INTEGER', of the same kind as 13449 I. (As a GNU extension, different kinds are 13450 also permitted.) 13451 13452_Return value_: 13453 The return type is 'INTEGER', of the same kind as the arguments. 13454 (If the argument kinds differ, it is of the same kind as the larger 13455 argument.) 13456 13457_Specific names_: 13458 Name Argument Return type Standard 13459 'IEOR(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 13460 later 13461 'BIEOR(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 13462 A' 13463 'IIEOR(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 13464 A' 13465 'JIEOR(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 13466 A' 13467 'KIEOR(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 13468 A' 13469 13470_See also_: 13471 *note IOR::, *note IAND::, *note IBITS::, *note IBSET::, *note 13472 IBCLR::, *note NOT:: 13473 13474 13475File: gfortran.info, Node: IERRNO, Next: IMAGE_INDEX, Prev: IEOR, Up: Intrinsic Procedures 13476 134779.145 'IERRNO' -- Get the last system error number 13478================================================== 13479 13480_Description_: 13481 Returns the last system error number, as given by the C 'errno' 13482 variable. 13483 13484_Standard_: 13485 GNU extension 13486 13487_Class_: 13488 Function 13489 13490_Syntax_: 13491 'RESULT = IERRNO()' 13492 13493_Arguments_: 13494 None. 13495 13496_Return value_: 13497 The return value is of type 'INTEGER' and of the default integer 13498 kind. 13499 13500_See also_: 13501 *note PERROR:: 13502 13503 13504File: gfortran.info, Node: IMAGE_INDEX, Next: INDEX intrinsic, Prev: IERRNO, Up: Intrinsic Procedures 13505 135069.146 'IMAGE_INDEX' -- Function that converts a cosubscript to an image index 13507============================================================================= 13508 13509_Description_: 13510 Returns the image index belonging to a cosubscript. 13511 13512_Standard_: 13513 Fortran 2008 and later 13514 13515_Class_: 13516 Inquiry function. 13517 13518_Syntax_: 13519 'RESULT = IMAGE_INDEX(COARRAY, SUB)' 13520 13521_Arguments_: None. 13522 COARRAY Coarray of any type. 13523 SUB default integer rank-1 array of a size equal to 13524 the corank of COARRAY. 13525 13526_Return value_: 13527 Scalar default integer with the value of the image index which 13528 corresponds to the cosubscripts. For invalid cosubscripts the 13529 result is zero. 13530 13531_Example_: 13532 INTEGER :: array[2,-1:4,8,*] 13533 ! Writes 28 (or 0 if there are fewer than 28 images) 13534 WRITE (*,*) IMAGE_INDEX (array, [2,0,3,1]) 13535 13536_See also_: 13537 *note THIS_IMAGE::, *note NUM_IMAGES:: 13538 13539 13540File: gfortran.info, Node: INDEX intrinsic, Next: INT, Prev: IMAGE_INDEX, Up: Intrinsic Procedures 13541 135429.147 'INDEX' -- Position of a substring within a string 13543======================================================== 13544 13545_Description_: 13546 Returns the position of the start of the first occurrence of string 13547 SUBSTRING as a substring in STRING, counting from one. If 13548 SUBSTRING is not present in STRING, zero is returned. If the BACK 13549 argument is present and true, the return value is the start of the 13550 last occurrence rather than the first. 13551 13552_Standard_: 13553 Fortran 77 and later, with KIND argument Fortran 2003 and later 13554 13555_Class_: 13556 Elemental function 13557 13558_Syntax_: 13559 'RESULT = INDEX(STRING, SUBSTRING [, BACK [, KIND]])' 13560 13561_Arguments_: 13562 STRING Shall be a scalar 'CHARACTER', with 'INTENT(IN)' 13563 SUBSTRING Shall be a scalar 'CHARACTER', with 'INTENT(IN)' 13564 BACK (Optional) Shall be a scalar 'LOGICAL', with 13565 'INTENT(IN)' 13566 KIND (Optional) An 'INTEGER' initialization 13567 expression indicating the kind parameter of the 13568 result. 13569 13570_Return value_: 13571 The return value is of type 'INTEGER' and of kind KIND. If KIND is 13572 absent, the return value is of default integer kind. 13573 13574_Specific names_: 13575 Name Argument Return type Standard 13576 'INDEX(STRING, 'CHARACTER' 'INTEGER(4)' Fortran 77 and 13577 SUBSTRING)' later 13578 13579_See also_: 13580 *note SCAN::, *note VERIFY:: 13581 13582 13583File: gfortran.info, Node: INT, Next: INT2, Prev: INDEX intrinsic, Up: Intrinsic Procedures 13584 135859.148 'INT' -- Convert to integer type 13586====================================== 13587 13588_Description_: 13589 Convert to integer type 13590 13591_Standard_: 13592 Fortran 77 and later 13593 13594_Class_: 13595 Elemental function 13596 13597_Syntax_: 13598 'RESULT = INT(A [, KIND))' 13599 13600_Arguments_: 13601 A Shall be of type 'INTEGER', 'REAL', or 13602 'COMPLEX'. 13603 KIND (Optional) An 'INTEGER' initialization 13604 expression indicating the kind parameter of the 13605 result. 13606 13607_Return value_: 13608 These functions return a 'INTEGER' variable or array under the 13609 following rules: 13610 13611 (A) 13612 If A is of type 'INTEGER', 'INT(A) = A' 13613 (B) 13614 If A is of type 'REAL' and |A| < 1, 'INT(A)' equals '0'. If 13615 |A| \geq 1, then 'INT(A)' is the integer whose magnitude is 13616 the largest integer that does not exceed the magnitude of A 13617 and whose sign is the same as the sign of A. 13618 (C) 13619 If A is of type 'COMPLEX', rule B is applied to the real part 13620 of A. 13621 13622_Example_: 13623 program test_int 13624 integer :: i = 42 13625 complex :: z = (-3.7, 1.0) 13626 print *, int(i) 13627 print *, int(z), int(z,8) 13628 end program 13629 13630_Specific names_: 13631 Name Argument Return type Standard 13632 'INT(A)' 'REAL(4) A' 'INTEGER' Fortran 77 and 13633 later 13634 'IFIX(A)' 'REAL(4) A' 'INTEGER' Fortran 77 and 13635 later 13636 'IDINT(A)' 'REAL(8) A' 'INTEGER' Fortran 77 and 13637 later 13638 13639 13640File: gfortran.info, Node: INT2, Next: INT8, Prev: INT, Up: Intrinsic Procedures 13641 136429.149 'INT2' -- Convert to 16-bit integer type 13643============================================== 13644 13645_Description_: 13646 Convert to a 'KIND=2' integer type. This is equivalent to the 13647 standard 'INT' intrinsic with an optional argument of 'KIND=2', and 13648 is only included for backwards compatibility. 13649 13650 The 'SHORT' intrinsic is equivalent to 'INT2'. 13651 13652_Standard_: 13653 GNU extension 13654 13655_Class_: 13656 Elemental function 13657 13658_Syntax_: 13659 'RESULT = INT2(A)' 13660 13661_Arguments_: 13662 A Shall be of type 'INTEGER', 'REAL', or 13663 'COMPLEX'. 13664 13665_Return value_: 13666 The return value is a 'INTEGER(2)' variable. 13667 13668_See also_: 13669 *note INT::, *note INT8::, *note LONG:: 13670 13671 13672File: gfortran.info, Node: INT8, Next: IOR, Prev: INT2, Up: Intrinsic Procedures 13673 136749.150 'INT8' -- Convert to 64-bit integer type 13675============================================== 13676 13677_Description_: 13678 Convert to a 'KIND=8' integer type. This is equivalent to the 13679 standard 'INT' intrinsic with an optional argument of 'KIND=8', and 13680 is only included for backwards compatibility. 13681 13682_Standard_: 13683 GNU extension 13684 13685_Class_: 13686 Elemental function 13687 13688_Syntax_: 13689 'RESULT = INT8(A)' 13690 13691_Arguments_: 13692 A Shall be of type 'INTEGER', 'REAL', or 13693 'COMPLEX'. 13694 13695_Return value_: 13696 The return value is a 'INTEGER(8)' variable. 13697 13698_See also_: 13699 *note INT::, *note INT2::, *note LONG:: 13700 13701 13702File: gfortran.info, Node: IOR, Next: IPARITY, Prev: INT8, Up: Intrinsic Procedures 13703 137049.151 'IOR' -- Bitwise logical or 13705================================= 13706 13707_Description_: 13708 'IOR' returns the bitwise Boolean inclusive-OR of I and J. 13709 13710_Standard_: 13711 Fortran 95 and later, has overloads that are GNU extensions 13712 13713_Class_: 13714 Elemental function 13715 13716_Syntax_: 13717 'RESULT = IOR(I, J)' 13718 13719_Arguments_: 13720 I The type shall be 'INTEGER'. 13721 J The type shall be 'INTEGER', of the same kind as 13722 I. (As a GNU extension, different kinds are 13723 also permitted.) 13724 13725_Return value_: 13726 The return type is 'INTEGER', of the same kind as the arguments. 13727 (If the argument kinds differ, it is of the same kind as the larger 13728 argument.) 13729 13730_Specific names_: 13731 Name Argument Return type Standard 13732 'IOR(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 13733 later 13734 'BIOR(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 13735 A' 13736 'IIOR(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 13737 A' 13738 'JIOR(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 13739 A' 13740 'KIOR(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 13741 A' 13742 13743_See also_: 13744 *note IEOR::, *note IAND::, *note IBITS::, *note IBSET::, *note 13745 IBCLR::, *note NOT:: 13746 13747 13748File: gfortran.info, Node: IPARITY, Next: IRAND, Prev: IOR, Up: Intrinsic Procedures 13749 137509.152 'IPARITY' -- Bitwise XOR of array elements 13751================================================ 13752 13753_Description_: 13754 Reduces with bitwise XOR (exclusive or) the elements of ARRAY along 13755 dimension DIM if the corresponding element in MASK is 'TRUE'. 13756 13757_Standard_: 13758 Fortran 2008 and later 13759 13760_Class_: 13761 Transformational function 13762 13763_Syntax_: 13764 'RESULT = IPARITY(ARRAY[, MASK])' 13765 'RESULT = IPARITY(ARRAY, DIM[, MASK])' 13766 13767_Arguments_: 13768 ARRAY Shall be an array of type 'INTEGER' 13769 DIM (Optional) shall be a scalar of type 'INTEGER' 13770 with a value in the range from 1 to n, where n 13771 equals the rank of ARRAY. 13772 MASK (Optional) shall be of type 'LOGICAL' and either 13773 be a scalar or an array of the same shape as 13774 ARRAY. 13775 13776_Return value_: 13777 The result is of the same type as ARRAY. 13778 13779 If DIM is absent, a scalar with the bitwise XOR of all elements in 13780 ARRAY is returned. Otherwise, an array of rank n-1, where n equals 13781 the rank of ARRAY, and a shape similar to that of ARRAY with 13782 dimension DIM dropped is returned. 13783 13784_Example_: 13785 PROGRAM test_iparity 13786 INTEGER(1) :: a(2) 13787 13788 a(1) = b'00100100' 13789 a(2) = b'01101010' 13790 13791 ! prints 01001110 13792 PRINT '(b8.8)', IPARITY(a) 13793 END PROGRAM 13794 13795_See also_: 13796 *note IANY::, *note IALL::, *note IEOR::, *note PARITY:: 13797 13798 13799File: gfortran.info, Node: IRAND, Next: IS_IOSTAT_END, Prev: IPARITY, Up: Intrinsic Procedures 13800 138019.153 'IRAND' -- Integer pseudo-random number 13802============================================= 13803 13804_Description_: 13805 'IRAND(FLAG)' returns a pseudo-random number from a uniform 13806 distribution between 0 and a system-dependent limit (which is in 13807 most cases 2147483647). If FLAG is 0, the next number in the 13808 current sequence is returned; if FLAG is 1, the generator is 13809 restarted by 'CALL SRAND(0)'; if FLAG has any other value, it is 13810 used as a new seed with 'SRAND'. 13811 13812 This intrinsic routine is provided for backwards compatibility with 13813 GNU Fortran 77. It implements a simple modulo generator as 13814 provided by 'g77'. For new code, one should consider the use of 13815 *note RANDOM_NUMBER:: as it implements a superior algorithm. 13816 13817_Standard_: 13818 GNU extension 13819 13820_Class_: 13821 Function 13822 13823_Syntax_: 13824 'RESULT = IRAND(I)' 13825 13826_Arguments_: 13827 I Shall be a scalar 'INTEGER' of kind 4. 13828 13829_Return value_: 13830 The return value is of 'INTEGER(kind=4)' type. 13831 13832_Example_: 13833 program test_irand 13834 integer,parameter :: seed = 86456 13835 13836 call srand(seed) 13837 print *, irand(), irand(), irand(), irand() 13838 print *, irand(seed), irand(), irand(), irand() 13839 end program test_irand 13840 13841 13842File: gfortran.info, Node: IS_IOSTAT_END, Next: IS_IOSTAT_EOR, Prev: IRAND, Up: Intrinsic Procedures 13843 138449.154 'IS_IOSTAT_END' -- Test for end-of-file value 13845=================================================== 13846 13847_Description_: 13848 'IS_IOSTAT_END' tests whether an variable has the value of the I/O 13849 status "end of file". The function is equivalent to comparing the 13850 variable with the 'IOSTAT_END' parameter of the intrinsic module 13851 'ISO_FORTRAN_ENV'. 13852 13853_Standard_: 13854 Fortran 2003 and later 13855 13856_Class_: 13857 Elemental function 13858 13859_Syntax_: 13860 'RESULT = IS_IOSTAT_END(I)' 13861 13862_Arguments_: 13863 I Shall be of the type 'INTEGER'. 13864 13865_Return value_: 13866 Returns a 'LOGICAL' of the default kind, which '.TRUE.' if I has 13867 the value which indicates an end of file condition for 'IOSTAT=' 13868 specifiers, and is '.FALSE.' otherwise. 13869 13870_Example_: 13871 PROGRAM iostat 13872 IMPLICIT NONE 13873 INTEGER :: stat, i 13874 OPEN(88, FILE='test.dat') 13875 READ(88, *, IOSTAT=stat) i 13876 IF(IS_IOSTAT_END(stat)) STOP 'END OF FILE' 13877 END PROGRAM 13878 13879 13880File: gfortran.info, Node: IS_IOSTAT_EOR, Next: ISATTY, Prev: IS_IOSTAT_END, Up: Intrinsic Procedures 13881 138829.155 'IS_IOSTAT_EOR' -- Test for end-of-record value 13883===================================================== 13884 13885_Description_: 13886 'IS_IOSTAT_EOR' tests whether an variable has the value of the I/O 13887 status "end of record". The function is equivalent to comparing 13888 the variable with the 'IOSTAT_EOR' parameter of the intrinsic 13889 module 'ISO_FORTRAN_ENV'. 13890 13891_Standard_: 13892 Fortran 2003 and later 13893 13894_Class_: 13895 Elemental function 13896 13897_Syntax_: 13898 'RESULT = IS_IOSTAT_EOR(I)' 13899 13900_Arguments_: 13901 I Shall be of the type 'INTEGER'. 13902 13903_Return value_: 13904 Returns a 'LOGICAL' of the default kind, which '.TRUE.' if I has 13905 the value which indicates an end of file condition for 'IOSTAT=' 13906 specifiers, and is '.FALSE.' otherwise. 13907 13908_Example_: 13909 PROGRAM iostat 13910 IMPLICIT NONE 13911 INTEGER :: stat, i(50) 13912 OPEN(88, FILE='test.dat', FORM='UNFORMATTED') 13913 READ(88, IOSTAT=stat) i 13914 IF(IS_IOSTAT_EOR(stat)) STOP 'END OF RECORD' 13915 END PROGRAM 13916 13917 13918File: gfortran.info, Node: ISATTY, Next: ISHFT, Prev: IS_IOSTAT_EOR, Up: Intrinsic Procedures 13919 139209.156 'ISATTY' -- Whether a unit is a terminal device. 13921====================================================== 13922 13923_Description_: 13924 Determine whether a unit is connected to a terminal device. 13925 13926_Standard_: 13927 GNU extension 13928 13929_Class_: 13930 Function 13931 13932_Syntax_: 13933 'RESULT = ISATTY(UNIT)' 13934 13935_Arguments_: 13936 UNIT Shall be a scalar 'INTEGER'. 13937 13938_Return value_: 13939 Returns '.TRUE.' if the UNIT is connected to a terminal device, 13940 '.FALSE.' otherwise. 13941 13942_Example_: 13943 PROGRAM test_isatty 13944 INTEGER(kind=1) :: unit 13945 DO unit = 1, 10 13946 write(*,*) isatty(unit=unit) 13947 END DO 13948 END PROGRAM 13949_See also_: 13950 *note TTYNAM:: 13951 13952 13953File: gfortran.info, Node: ISHFT, Next: ISHFTC, Prev: ISATTY, Up: Intrinsic Procedures 13954 139559.157 'ISHFT' -- Shift bits 13956=========================== 13957 13958_Description_: 13959 'ISHFT' returns a value corresponding to I with all of the bits 13960 shifted SHIFT places. A value of SHIFT greater than zero 13961 corresponds to a left shift, a value of zero corresponds to no 13962 shift, and a value less than zero corresponds to a right shift. If 13963 the absolute value of SHIFT is greater than 'BIT_SIZE(I)', the 13964 value is undefined. Bits shifted out from the left end or right 13965 end are lost; zeros are shifted in from the opposite end. 13966 13967_Standard_: 13968 Fortran 95 and later, has overloads that are GNU extensions 13969 13970_Class_: 13971 Elemental function 13972 13973_Syntax_: 13974 'RESULT = ISHFT(I, SHIFT)' 13975 13976_Arguments_: 13977 I The type shall be 'INTEGER'. 13978 SHIFT The type shall be 'INTEGER'. 13979 13980_Return value_: 13981 The return value is of type 'INTEGER' and of the same kind as I. 13982 13983_Specific names_: 13984 Name Argument Return type Standard 13985 'ISHFT(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 13986 later 13987 'BSHFT(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 13988 A' 13989 'IISHFT(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 13990 A' 13991 'JISHFT(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 13992 A' 13993 'KISHFT(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 13994 A' 13995 13996_See also_: 13997 *note ISHFTC:: 13998 13999 14000File: gfortran.info, Node: ISHFTC, Next: ISNAN, Prev: ISHFT, Up: Intrinsic Procedures 14001 140029.158 'ISHFTC' -- Shift bits circularly 14003======================================= 14004 14005_Description_: 14006 'ISHFTC' returns a value corresponding to I with the rightmost SIZE 14007 bits shifted circularly SHIFT places; that is, bits shifted out one 14008 end are shifted into the opposite end. A value of SHIFT greater 14009 than zero corresponds to a left shift, a value of zero corresponds 14010 to no shift, and a value less than zero corresponds to a right 14011 shift. The absolute value of SHIFT must be less than SIZE. If the 14012 SIZE argument is omitted, it is taken to be equivalent to 14013 'BIT_SIZE(I)'. 14014 14015_Standard_: 14016 Fortran 95 and later, has overloads that are GNU extensions 14017 14018_Class_: 14019 Elemental function 14020 14021_Syntax_: 14022 'RESULT = ISHFTC(I, SHIFT [, SIZE])' 14023 14024_Arguments_: 14025 I The type shall be 'INTEGER'. 14026 SHIFT The type shall be 'INTEGER'. 14027 SIZE (Optional) The type shall be 'INTEGER'; the 14028 value must be greater than zero and less than or 14029 equal to 'BIT_SIZE(I)'. 14030 14031_Return value_: 14032 The return value is of type 'INTEGER' and of the same kind as I. 14033 14034_Specific names_: 14035 Name Argument Return type Standard 14036 'ISHFTC(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 14037 later 14038 'BSHFTC(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 14039 A' 14040 'IISHFTC(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 14041 A' 14042 'JISHFTC(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 14043 A' 14044 'KISHFTC(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 14045 A' 14046 14047_See also_: 14048 *note ISHFT:: 14049 14050 14051File: gfortran.info, Node: ISNAN, Next: ITIME, Prev: ISHFTC, Up: Intrinsic Procedures 14052 140539.159 'ISNAN' -- Test for a NaN 14054=============================== 14055 14056_Description_: 14057 'ISNAN' tests whether a floating-point value is an IEEE 14058 Not-a-Number (NaN). 14059_Standard_: 14060 GNU extension 14061 14062_Class_: 14063 Elemental function 14064 14065_Syntax_: 14066 'ISNAN(X)' 14067 14068_Arguments_: 14069 X Variable of the type 'REAL'. 14070 14071 14072_Return value_: 14073 Returns a default-kind 'LOGICAL'. The returned value is 'TRUE' if 14074 X is a NaN and 'FALSE' otherwise. 14075 14076_Example_: 14077 program test_nan 14078 implicit none 14079 real :: x 14080 x = -1.0 14081 x = sqrt(x) 14082 if (isnan(x)) stop '"x" is a NaN' 14083 end program test_nan 14084 14085 14086File: gfortran.info, Node: ITIME, Next: KILL, Prev: ISNAN, Up: Intrinsic Procedures 14087 140889.160 'ITIME' -- Get current local time subroutine (hour/minutes/seconds) 14089========================================================================= 14090 14091_Description_: 14092 'ITIME(VALUES)' Fills VALUES with the numerical values at the 14093 current local time. The hour (in the range 1-24), minute (in the 14094 range 1-60), and seconds (in the range 1-60) appear in elements 1, 14095 2, and 3 of VALUES, respectively. 14096 14097 This intrinsic routine is provided for backwards compatibility with 14098 GNU Fortran 77. In new code, programmers should consider the use 14099 of the *note DATE_AND_TIME:: intrinsic defined by the Fortran 95 14100 standard. 14101 14102_Standard_: 14103 GNU extension 14104 14105_Class_: 14106 Subroutine 14107 14108_Syntax_: 14109 'CALL ITIME(VALUES)' 14110 14111_Arguments_: 14112 VALUES The type shall be 'INTEGER, DIMENSION(3)' and 14113 the kind shall be the default integer kind. 14114 14115_Return value_: 14116 Does not return anything. 14117 14118_Example_: 14119 program test_itime 14120 integer, dimension(3) :: tarray 14121 call itime(tarray) 14122 print *, tarray(1) 14123 print *, tarray(2) 14124 print *, tarray(3) 14125 end program test_itime 14126 14127_See also_: 14128 *note DATE_AND_TIME:: 14129 14130 14131File: gfortran.info, Node: KILL, Next: KIND, Prev: ITIME, Up: Intrinsic Procedures 14132 141339.161 'KILL' -- Send a signal to a process 14134========================================== 14135 14136_Description_: 14137_Standard_: 14138 Sends the signal specified by SIG to the process PID. See 14139 'kill(2)'. 14140 14141 This intrinsic is provided in both subroutine and function forms; 14142 however, only one form can be used in any given program unit. 14143 14144_Class_: 14145 Subroutine, function 14146 14147_Syntax_: 14148 'CALL KILL(PID, SIG [, STATUS])' 14149 'STATUS = KILL(PID, SIG)' 14150 14151_Arguments_: 14152 PID Shall be a scalar 'INTEGER' with 'INTENT(IN)'. 14153 SIG Shall be a scalar 'INTEGER' with 'INTENT(IN)'. 14154 STATUS [Subroutine](Optional) Shall be a scalar 14155 'INTEGER'. Returns 0 on success; otherwise a 14156 system-specific error code is returned. 14157 STATUS [Function] The kind type parameter is that of 14158 'pid'. Returns 0 on success; otherwise a 14159 system-specific error code is returned. 14160 14161_See also_: 14162 *note ABORT::, *note EXIT:: 14163 14164 14165File: gfortran.info, Node: KIND, Next: LBOUND, Prev: KILL, Up: Intrinsic Procedures 14166 141679.162 'KIND' -- Kind of an entity 14168================================= 14169 14170_Description_: 14171 'KIND(X)' returns the kind value of the entity X. 14172 14173_Standard_: 14174 Fortran 95 and later 14175 14176_Class_: 14177 Inquiry function 14178 14179_Syntax_: 14180 'K = KIND(X)' 14181 14182_Arguments_: 14183 X Shall be of type 'LOGICAL', 'INTEGER', 'REAL', 14184 'COMPLEX' or 'CHARACTER'. 14185 14186_Return value_: 14187 The return value is a scalar of type 'INTEGER' and of the default 14188 integer kind. 14189 14190_Example_: 14191 program test_kind 14192 integer,parameter :: kc = kind(' ') 14193 integer,parameter :: kl = kind(.true.) 14194 14195 print *, "The default character kind is ", kc 14196 print *, "The default logical kind is ", kl 14197 end program test_kind 14198 14199 14200File: gfortran.info, Node: LBOUND, Next: LCOBOUND, Prev: KIND, Up: Intrinsic Procedures 14201 142029.163 'LBOUND' -- Lower dimension bounds of an array 14203==================================================== 14204 14205_Description_: 14206 Returns the lower bounds of an array, or a single lower bound along 14207 the DIM dimension. 14208_Standard_: 14209 Fortran 95 and later, with KIND argument Fortran 2003 and later 14210 14211_Class_: 14212 Inquiry function 14213 14214_Syntax_: 14215 'RESULT = LBOUND(ARRAY [, DIM [, KIND]])' 14216 14217_Arguments_: 14218 ARRAY Shall be an array, of any type. 14219 DIM (Optional) Shall be a scalar 'INTEGER'. 14220 KIND (Optional) An 'INTEGER' initialization 14221 expression indicating the kind parameter of the 14222 result. 14223 14224_Return value_: 14225 The return value is of type 'INTEGER' and of kind KIND. If KIND is 14226 absent, the return value is of default integer kind. If DIM is 14227 absent, the result is an array of the lower bounds of ARRAY. If 14228 DIM is present, the result is a scalar corresponding to the lower 14229 bound of the array along that dimension. If ARRAY is an expression 14230 rather than a whole array or array structure component, or if it 14231 has a zero extent along the relevant dimension, the lower bound is 14232 taken to be 1. 14233 14234_See also_: 14235 *note UBOUND::, *note LCOBOUND:: 14236 14237 14238File: gfortran.info, Node: LCOBOUND, Next: LEADZ, Prev: LBOUND, Up: Intrinsic Procedures 14239 142409.164 'LCOBOUND' -- Lower codimension bounds of an array 14241======================================================== 14242 14243_Description_: 14244 Returns the lower bounds of a coarray, or a single lower cobound 14245 along the DIM codimension. 14246_Standard_: 14247 Fortran 2008 and later 14248 14249_Class_: 14250 Inquiry function 14251 14252_Syntax_: 14253 'RESULT = LCOBOUND(COARRAY [, DIM [, KIND]])' 14254 14255_Arguments_: 14256 ARRAY Shall be an coarray, of any type. 14257 DIM (Optional) Shall be a scalar 'INTEGER'. 14258 KIND (Optional) An 'INTEGER' initialization 14259 expression indicating the kind parameter of the 14260 result. 14261 14262_Return value_: 14263 The return value is of type 'INTEGER' and of kind KIND. If KIND is 14264 absent, the return value is of default integer kind. If DIM is 14265 absent, the result is an array of the lower cobounds of COARRAY. 14266 If DIM is present, the result is a scalar corresponding to the 14267 lower cobound of the array along that codimension. 14268 14269_See also_: 14270 *note UCOBOUND::, *note LBOUND:: 14271 14272 14273File: gfortran.info, Node: LEADZ, Next: LEN, Prev: LCOBOUND, Up: Intrinsic Procedures 14274 142759.165 'LEADZ' -- Number of leading zero bits of an integer 14276========================================================== 14277 14278_Description_: 14279 'LEADZ' returns the number of leading zero bits of an integer. 14280 14281_Standard_: 14282 Fortran 2008 and later 14283 14284_Class_: 14285 Elemental function 14286 14287_Syntax_: 14288 'RESULT = LEADZ(I)' 14289 14290_Arguments_: 14291 I Shall be of type 'INTEGER'. 14292 14293_Return value_: 14294 The type of the return value is the default 'INTEGER'. If all the 14295 bits of 'I' are zero, the result value is 'BIT_SIZE(I)'. 14296 14297_Example_: 14298 PROGRAM test_leadz 14299 WRITE (*,*) BIT_SIZE(1) ! prints 32 14300 WRITE (*,*) LEADZ(1) ! prints 31 14301 END PROGRAM 14302 14303_See also_: 14304 *note BIT_SIZE::, *note TRAILZ::, *note POPCNT::, *note POPPAR:: 14305 14306 14307File: gfortran.info, Node: LEN, Next: LEN_TRIM, Prev: LEADZ, Up: Intrinsic Procedures 14308 143099.166 'LEN' -- Length of a character entity 14310=========================================== 14311 14312_Description_: 14313 Returns the length of a character string. If STRING is an array, 14314 the length of an element of STRING is returned. Note that STRING 14315 need not be defined when this intrinsic is invoked, since only the 14316 length, not the content, of STRING is needed. 14317 14318_Standard_: 14319 Fortran 77 and later, with KIND argument Fortran 2003 and later 14320 14321_Class_: 14322 Inquiry function 14323 14324_Syntax_: 14325 'L = LEN(STRING [, KIND])' 14326 14327_Arguments_: 14328 STRING Shall be a scalar or array of type 'CHARACTER', 14329 with 'INTENT(IN)' 14330 KIND (Optional) An 'INTEGER' initialization 14331 expression indicating the kind parameter of the 14332 result. 14333 14334_Return value_: 14335 The return value is of type 'INTEGER' and of kind KIND. If KIND is 14336 absent, the return value is of default integer kind. 14337 14338_Specific names_: 14339 Name Argument Return type Standard 14340 'LEN(STRING)' 'CHARACTER' 'INTEGER' Fortran 77 and 14341 later 14342 14343_See also_: 14344 *note LEN_TRIM::, *note ADJUSTL::, *note ADJUSTR:: 14345 14346 14347File: gfortran.info, Node: LEN_TRIM, Next: LGE, Prev: LEN, Up: Intrinsic Procedures 14348 143499.167 'LEN_TRIM' -- Length of a character entity without trailing blank characters 14350================================================================================== 14351 14352_Description_: 14353 Returns the length of a character string, ignoring any trailing 14354 blanks. 14355 14356_Standard_: 14357 Fortran 95 and later, with KIND argument Fortran 2003 and later 14358 14359_Class_: 14360 Elemental function 14361 14362_Syntax_: 14363 'RESULT = LEN_TRIM(STRING [, KIND])' 14364 14365_Arguments_: 14366 STRING Shall be a scalar of type 'CHARACTER', with 14367 'INTENT(IN)' 14368 KIND (Optional) An 'INTEGER' initialization 14369 expression indicating the kind parameter of the 14370 result. 14371 14372_Return value_: 14373 The return value is of type 'INTEGER' and of kind KIND. If KIND is 14374 absent, the return value is of default integer kind. 14375 14376_See also_: 14377 *note LEN::, *note ADJUSTL::, *note ADJUSTR:: 14378 14379 14380File: gfortran.info, Node: LGE, Next: LGT, Prev: LEN_TRIM, Up: Intrinsic Procedures 14381 143829.168 'LGE' -- Lexical greater than or equal 14383============================================ 14384 14385_Description_: 14386 Determines whether one string is lexically greater than or equal to 14387 another string, where the two strings are interpreted as containing 14388 ASCII character codes. If the String A and String B are not the 14389 same length, the shorter is compared as if spaces were appended to 14390 it to form a value that has the same length as the longer. 14391 14392 In general, the lexical comparison intrinsics 'LGE', 'LGT', 'LLE', 14393 and 'LLT' differ from the corresponding intrinsic operators '.GE.', 14394 '.GT.', '.LE.', and '.LT.', in that the latter use the processor's 14395 character ordering (which is not ASCII on some targets), whereas 14396 the former always use the ASCII ordering. 14397 14398_Standard_: 14399 Fortran 77 and later 14400 14401_Class_: 14402 Elemental function 14403 14404_Syntax_: 14405 'RESULT = LGE(STRING_A, STRING_B)' 14406 14407_Arguments_: 14408 STRING_A Shall be of default 'CHARACTER' type. 14409 STRING_B Shall be of default 'CHARACTER' type. 14410 14411_Return value_: 14412 Returns '.TRUE.' if 'STRING_A >= STRING_B', and '.FALSE.' 14413 otherwise, based on the ASCII ordering. 14414 14415_Specific names_: 14416 Name Argument Return type Standard 14417 'LGE(STRING_A, 'CHARACTER' 'LOGICAL' Fortran 77 and 14418 STRING_B)' later 14419 14420_See also_: 14421 *note LGT::, *note LLE::, *note LLT:: 14422 14423 14424File: gfortran.info, Node: LGT, Next: LINK, Prev: LGE, Up: Intrinsic Procedures 14425 144269.169 'LGT' -- Lexical greater than 14427=================================== 14428 14429_Description_: 14430 Determines whether one string is lexically greater than another 14431 string, where the two strings are interpreted as containing ASCII 14432 character codes. If the String A and String B are not the same 14433 length, the shorter is compared as if spaces were appended to it to 14434 form a value that has the same length as the longer. 14435 14436 In general, the lexical comparison intrinsics 'LGE', 'LGT', 'LLE', 14437 and 'LLT' differ from the corresponding intrinsic operators '.GE.', 14438 '.GT.', '.LE.', and '.LT.', in that the latter use the processor's 14439 character ordering (which is not ASCII on some targets), whereas 14440 the former always use the ASCII ordering. 14441 14442_Standard_: 14443 Fortran 77 and later 14444 14445_Class_: 14446 Elemental function 14447 14448_Syntax_: 14449 'RESULT = LGT(STRING_A, STRING_B)' 14450 14451_Arguments_: 14452 STRING_A Shall be of default 'CHARACTER' type. 14453 STRING_B Shall be of default 'CHARACTER' type. 14454 14455_Return value_: 14456 Returns '.TRUE.' if 'STRING_A > STRING_B', and '.FALSE.' otherwise, 14457 based on the ASCII ordering. 14458 14459_Specific names_: 14460 Name Argument Return type Standard 14461 'LGT(STRING_A, 'CHARACTER' 'LOGICAL' Fortran 77 and 14462 STRING_B)' later 14463 14464_See also_: 14465 *note LGE::, *note LLE::, *note LLT:: 14466 14467 14468File: gfortran.info, Node: LINK, Next: LLE, Prev: LGT, Up: Intrinsic Procedures 14469 144709.170 'LINK' -- Create a hard link 14471================================== 14472 14473_Description_: 14474 Makes a (hard) link from file PATH1 to PATH2. A null character 14475 ('CHAR(0)') can be used to mark the end of the names in PATH1 and 14476 PATH2; otherwise, trailing blanks in the file names are ignored. 14477 If the STATUS argument is supplied, it contains 0 on success or a 14478 nonzero error code upon return; see 'link(2)'. 14479 14480 This intrinsic is provided in both subroutine and function forms; 14481 however, only one form can be used in any given program unit. 14482 14483_Standard_: 14484 GNU extension 14485 14486_Class_: 14487 Subroutine, function 14488 14489_Syntax_: 14490 'CALL LINK(PATH1, PATH2 [, STATUS])' 14491 'STATUS = LINK(PATH1, PATH2)' 14492 14493_Arguments_: 14494 PATH1 Shall be of default 'CHARACTER' type. 14495 PATH2 Shall be of default 'CHARACTER' type. 14496 STATUS (Optional) Shall be of default 'INTEGER' type. 14497 14498_See also_: 14499 *note SYMLNK::, *note UNLINK:: 14500 14501 14502File: gfortran.info, Node: LLE, Next: LLT, Prev: LINK, Up: Intrinsic Procedures 14503 145049.171 'LLE' -- Lexical less than or equal 14505========================================= 14506 14507_Description_: 14508 Determines whether one string is lexically less than or equal to 14509 another string, where the two strings are interpreted as containing 14510 ASCII character codes. If the String A and String B are not the 14511 same length, the shorter is compared as if spaces were appended to 14512 it to form a value that has the same length as the longer. 14513 14514 In general, the lexical comparison intrinsics 'LGE', 'LGT', 'LLE', 14515 and 'LLT' differ from the corresponding intrinsic operators '.GE.', 14516 '.GT.', '.LE.', and '.LT.', in that the latter use the processor's 14517 character ordering (which is not ASCII on some targets), whereas 14518 the former always use the ASCII ordering. 14519 14520_Standard_: 14521 Fortran 77 and later 14522 14523_Class_: 14524 Elemental function 14525 14526_Syntax_: 14527 'RESULT = LLE(STRING_A, STRING_B)' 14528 14529_Arguments_: 14530 STRING_A Shall be of default 'CHARACTER' type. 14531 STRING_B Shall be of default 'CHARACTER' type. 14532 14533_Return value_: 14534 Returns '.TRUE.' if 'STRING_A <= STRING_B', and '.FALSE.' 14535 otherwise, based on the ASCII ordering. 14536 14537_Specific names_: 14538 Name Argument Return type Standard 14539 'LLE(STRING_A, 'CHARACTER' 'LOGICAL' Fortran 77 and 14540 STRING_B)' later 14541 14542_See also_: 14543 *note LGE::, *note LGT::, *note LLT:: 14544 14545 14546File: gfortran.info, Node: LLT, Next: LNBLNK, Prev: LLE, Up: Intrinsic Procedures 14547 145489.172 'LLT' -- Lexical less than 14549================================ 14550 14551_Description_: 14552 Determines whether one string is lexically less than another 14553 string, where the two strings are interpreted as containing ASCII 14554 character codes. If the String A and String B are not the same 14555 length, the shorter is compared as if spaces were appended to it to 14556 form a value that has the same length as the longer. 14557 14558 In general, the lexical comparison intrinsics 'LGE', 'LGT', 'LLE', 14559 and 'LLT' differ from the corresponding intrinsic operators '.GE.', 14560 '.GT.', '.LE.', and '.LT.', in that the latter use the processor's 14561 character ordering (which is not ASCII on some targets), whereas 14562 the former always use the ASCII ordering. 14563 14564_Standard_: 14565 Fortran 77 and later 14566 14567_Class_: 14568 Elemental function 14569 14570_Syntax_: 14571 'RESULT = LLT(STRING_A, STRING_B)' 14572 14573_Arguments_: 14574 STRING_A Shall be of default 'CHARACTER' type. 14575 STRING_B Shall be of default 'CHARACTER' type. 14576 14577_Return value_: 14578 Returns '.TRUE.' if 'STRING_A < STRING_B', and '.FALSE.' otherwise, 14579 based on the ASCII ordering. 14580 14581_Specific names_: 14582 Name Argument Return type Standard 14583 'LLT(STRING_A, 'CHARACTER' 'LOGICAL' Fortran 77 and 14584 STRING_B)' later 14585 14586_See also_: 14587 *note LGE::, *note LGT::, *note LLE:: 14588 14589 14590File: gfortran.info, Node: LNBLNK, Next: LOC, Prev: LLT, Up: Intrinsic Procedures 14591 145929.173 'LNBLNK' -- Index of the last non-blank character in a string 14593=================================================================== 14594 14595_Description_: 14596 Returns the length of a character string, ignoring any trailing 14597 blanks. This is identical to the standard 'LEN_TRIM' intrinsic, 14598 and is only included for backwards compatibility. 14599 14600_Standard_: 14601 GNU extension 14602 14603_Class_: 14604 Elemental function 14605 14606_Syntax_: 14607 'RESULT = LNBLNK(STRING)' 14608 14609_Arguments_: 14610 STRING Shall be a scalar of type 'CHARACTER', with 14611 'INTENT(IN)' 14612 14613_Return value_: 14614 The return value is of 'INTEGER(kind=4)' type. 14615 14616_See also_: 14617 *note INDEX intrinsic::, *note LEN_TRIM:: 14618 14619 14620File: gfortran.info, Node: LOC, Next: LOG, Prev: LNBLNK, Up: Intrinsic Procedures 14621 146229.174 'LOC' -- Returns the address of a variable 14623================================================ 14624 14625_Description_: 14626 'LOC(X)' returns the address of X as an integer. 14627 14628_Standard_: 14629 GNU extension 14630 14631_Class_: 14632 Inquiry function 14633 14634_Syntax_: 14635 'RESULT = LOC(X)' 14636 14637_Arguments_: 14638 X Variable of any type. 14639 14640_Return value_: 14641 The return value is of type 'INTEGER', with a 'KIND' corresponding 14642 to the size (in bytes) of a memory address on the target machine. 14643 14644_Example_: 14645 program test_loc 14646 integer :: i 14647 real :: r 14648 i = loc(r) 14649 print *, i 14650 end program test_loc 14651 14652 14653File: gfortran.info, Node: LOG, Next: LOG10, Prev: LOC, Up: Intrinsic Procedures 14654 146559.175 'LOG' -- Natural logarithm function 14656========================================= 14657 14658_Description_: 14659 'LOG(X)' computes the natural logarithm of X, i.e. the logarithm 14660 to the base e. 14661 14662_Standard_: 14663 Fortran 77 and later 14664 14665_Class_: 14666 Elemental function 14667 14668_Syntax_: 14669 'RESULT = LOG(X)' 14670 14671_Arguments_: 14672 X The type shall be 'REAL' or 'COMPLEX'. 14673 14674_Return value_: 14675 The return value is of type 'REAL' or 'COMPLEX'. The kind type 14676 parameter is the same as X. If X is 'COMPLEX', the imaginary part 14677 \omega is in the range -\pi < \omega \leq \pi. 14678 14679_Example_: 14680 program test_log 14681 real(8) :: x = 2.7182818284590451_8 14682 complex :: z = (1.0, 2.0) 14683 x = log(x) ! will yield (approximately) 1 14684 z = log(z) 14685 end program test_log 14686 14687_Specific names_: 14688 Name Argument Return type Standard 14689 'ALOG(X)' 'REAL(4) X' 'REAL(4)' f95, gnu 14690 'DLOG(X)' 'REAL(8) X' 'REAL(8)' f95, gnu 14691 'CLOG(X)' 'COMPLEX(4) 'COMPLEX(4)' f95, gnu 14692 X' 14693 'ZLOG(X)' 'COMPLEX(8) 'COMPLEX(8)' f95, gnu 14694 X' 14695 'CDLOG(X)' 'COMPLEX(8) 'COMPLEX(8)' f95, gnu 14696 X' 14697 14698 14699File: gfortran.info, Node: LOG10, Next: LOG_GAMMA, Prev: LOG, Up: Intrinsic Procedures 14700 147019.176 'LOG10' -- Base 10 logarithm function 14702=========================================== 14703 14704_Description_: 14705 'LOG10(X)' computes the base 10 logarithm of X. 14706 14707_Standard_: 14708 Fortran 77 and later 14709 14710_Class_: 14711 Elemental function 14712 14713_Syntax_: 14714 'RESULT = LOG10(X)' 14715 14716_Arguments_: 14717 X The type shall be 'REAL'. 14718 14719_Return value_: 14720 The return value is of type 'REAL' or 'COMPLEX'. The kind type 14721 parameter is the same as X. 14722 14723_Example_: 14724 program test_log10 14725 real(8) :: x = 10.0_8 14726 x = log10(x) 14727 end program test_log10 14728 14729_Specific names_: 14730 Name Argument Return type Standard 14731 'ALOG10(X)' 'REAL(4) X' 'REAL(4)' Fortran 95 and 14732 later 14733 'DLOG10(X)' 'REAL(8) X' 'REAL(8)' Fortran 95 and 14734 later 14735 14736 14737File: gfortran.info, Node: LOG_GAMMA, Next: LOGICAL, Prev: LOG10, Up: Intrinsic Procedures 14738 147399.177 'LOG_GAMMA' -- Logarithm of the Gamma function 14740==================================================== 14741 14742_Description_: 14743 'LOG_GAMMA(X)' computes the natural logarithm of the absolute value 14744 of the Gamma (\Gamma) function. 14745 14746_Standard_: 14747 Fortran 2008 and later 14748 14749_Class_: 14750 Elemental function 14751 14752_Syntax_: 14753 'X = LOG_GAMMA(X)' 14754 14755_Arguments_: 14756 X Shall be of type 'REAL' and neither zero nor a 14757 negative integer. 14758 14759_Return value_: 14760 The return value is of type 'REAL' of the same kind as X. 14761 14762_Example_: 14763 program test_log_gamma 14764 real :: x = 1.0 14765 x = lgamma(x) ! returns 0.0 14766 end program test_log_gamma 14767 14768_Specific names_: 14769 Name Argument Return type Standard 14770 'LGAMMA(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 14771 'ALGAMA(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 14772 'DLGAMA(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 14773 14774_See also_: 14775 Gamma function: *note GAMMA:: 14776 14777 14778File: gfortran.info, Node: LOGICAL, Next: LONG, Prev: LOG_GAMMA, Up: Intrinsic Procedures 14779 147809.178 'LOGICAL' -- Convert to logical type 14781========================================== 14782 14783_Description_: 14784 Converts one kind of 'LOGICAL' variable to another. 14785 14786_Standard_: 14787 Fortran 95 and later 14788 14789_Class_: 14790 Elemental function 14791 14792_Syntax_: 14793 'RESULT = LOGICAL(L [, KIND])' 14794 14795_Arguments_: 14796 L The type shall be 'LOGICAL'. 14797 KIND (Optional) An 'INTEGER' initialization 14798 expression indicating the kind parameter of the 14799 result. 14800 14801_Return value_: 14802 The return value is a 'LOGICAL' value equal to L, with a kind 14803 corresponding to KIND, or of the default logical kind if KIND is 14804 not given. 14805 14806_See also_: 14807 *note INT::, *note REAL::, *note CMPLX:: 14808 14809 14810File: gfortran.info, Node: LONG, Next: LSHIFT, Prev: LOGICAL, Up: Intrinsic Procedures 14811 148129.179 'LONG' -- Convert to integer type 14813======================================= 14814 14815_Description_: 14816 Convert to a 'KIND=4' integer type, which is the same size as a C 14817 'long' integer. This is equivalent to the standard 'INT' intrinsic 14818 with an optional argument of 'KIND=4', and is only included for 14819 backwards compatibility. 14820 14821_Standard_: 14822 GNU extension 14823 14824_Class_: 14825 Elemental function 14826 14827_Syntax_: 14828 'RESULT = LONG(A)' 14829 14830_Arguments_: 14831 A Shall be of type 'INTEGER', 'REAL', or 14832 'COMPLEX'. 14833 14834_Return value_: 14835 The return value is a 'INTEGER(4)' variable. 14836 14837_See also_: 14838 *note INT::, *note INT2::, *note INT8:: 14839 14840 14841File: gfortran.info, Node: LSHIFT, Next: LSTAT, Prev: LONG, Up: Intrinsic Procedures 14842 148439.180 'LSHIFT' -- Left shift bits 14844================================= 14845 14846_Description_: 14847 'LSHIFT' returns a value corresponding to I with all of the bits 14848 shifted left by SHIFT places. If the absolute value of SHIFT is 14849 greater than 'BIT_SIZE(I)', the value is undefined. Bits shifted 14850 out from the left end are lost; zeros are shifted in from the 14851 opposite end. 14852 14853 This function has been superseded by the 'ISHFT' intrinsic, which 14854 is standard in Fortran 95 and later, and the 'SHIFTL' intrinsic, 14855 which is standard in Fortran 2008 and later. 14856 14857_Standard_: 14858 GNU extension 14859 14860_Class_: 14861 Elemental function 14862 14863_Syntax_: 14864 'RESULT = LSHIFT(I, SHIFT)' 14865 14866_Arguments_: 14867 I The type shall be 'INTEGER'. 14868 SHIFT The type shall be 'INTEGER'. 14869 14870_Return value_: 14871 The return value is of type 'INTEGER' and of the same kind as I. 14872 14873_See also_: 14874 *note ISHFT::, *note ISHFTC::, *note RSHIFT::, *note SHIFTA::, 14875 *note SHIFTL::, *note SHIFTR:: 14876 14877 14878File: gfortran.info, Node: LSTAT, Next: LTIME, Prev: LSHIFT, Up: Intrinsic Procedures 14879 148809.181 'LSTAT' -- Get file status 14881================================ 14882 14883_Description_: 14884 'LSTAT' is identical to *note STAT::, except that if path is a 14885 symbolic link, then the link itself is statted, not the file that 14886 it refers to. 14887 14888 The elements in 'VALUES' are the same as described by *note STAT::. 14889 14890 This intrinsic is provided in both subroutine and function forms; 14891 however, only one form can be used in any given program unit. 14892 14893_Standard_: 14894 GNU extension 14895 14896_Class_: 14897 Subroutine, function 14898 14899_Syntax_: 14900 'CALL LSTAT(NAME, VALUES [, STATUS])' 14901 'STATUS = LSTAT(NAME, VALUES)' 14902 14903_Arguments_: 14904 NAME The type shall be 'CHARACTER' of the default 14905 kind, a valid path within the file system. 14906 VALUES The type shall be 'INTEGER(4), DIMENSION(13)'. 14907 STATUS (Optional) status flag of type 'INTEGER(4)'. 14908 Returns 0 on success and a system specific error 14909 code otherwise. 14910 14911_Example_: 14912 See *note STAT:: for an example. 14913 14914_See also_: 14915 To stat an open file: *note FSTAT::, to stat a file: *note STAT:: 14916 14917 14918File: gfortran.info, Node: LTIME, Next: MALLOC, Prev: LSTAT, Up: Intrinsic Procedures 14919 149209.182 'LTIME' -- Convert time to local time info 14921================================================ 14922 14923_Description_: 14924 Given a system time value TIME (as provided by the *note TIME:: 14925 intrinsic), fills VALUES with values extracted from it appropriate 14926 to the local time zone using 'localtime(3)'. 14927 14928 This intrinsic routine is provided for backwards compatibility with 14929 GNU Fortran 77. In new code, programmers should consider the use 14930 of the *note DATE_AND_TIME:: intrinsic defined by the Fortran 95 14931 standard. 14932 14933_Standard_: 14934 GNU extension 14935 14936_Class_: 14937 Subroutine 14938 14939_Syntax_: 14940 'CALL LTIME(TIME, VALUES)' 14941 14942_Arguments_: 14943 TIME An 'INTEGER' scalar expression corresponding to 14944 a system time, with 'INTENT(IN)'. 14945 VALUES A default 'INTEGER' array with 9 elements, with 14946 'INTENT(OUT)'. 14947 14948_Return value_: 14949 The elements of VALUES are assigned as follows: 14950 1. Seconds after the minute, range 0-59 or 0-61 to allow for leap 14951 seconds 14952 2. Minutes after the hour, range 0-59 14953 3. Hours past midnight, range 0-23 14954 4. Day of month, range 1-31 14955 5. Number of months since January, range 0-11 14956 6. Years since 1900 14957 7. Number of days since Sunday, range 0-6 14958 8. Days since January 1, range 0-365 14959 9. Daylight savings indicator: positive if daylight savings is in 14960 effect, zero if not, and negative if the information is not 14961 available. 14962 14963_See also_: 14964 *note DATE_AND_TIME::, *note CTIME::, *note GMTIME::, *note TIME::, 14965 *note TIME8:: 14966 14967 14968File: gfortran.info, Node: MALLOC, Next: MASKL, Prev: LTIME, Up: Intrinsic Procedures 14969 149709.183 'MALLOC' -- Allocate dynamic memory 14971========================================= 14972 14973_Description_: 14974 'MALLOC(SIZE)' allocates SIZE bytes of dynamic memory and returns 14975 the address of the allocated memory. The 'MALLOC' intrinsic is an 14976 extension intended to be used with Cray pointers, and is provided 14977 in GNU Fortran to allow the user to compile legacy code. For new 14978 code using Fortran 95 pointers, the memory allocation intrinsic is 14979 'ALLOCATE'. 14980 14981_Standard_: 14982 GNU extension 14983 14984_Class_: 14985 Function 14986 14987_Syntax_: 14988 'PTR = MALLOC(SIZE)' 14989 14990_Arguments_: 14991 SIZE The type shall be 'INTEGER'. 14992 14993_Return value_: 14994 The return value is of type 'INTEGER(K)', with K such that 14995 variables of type 'INTEGER(K)' have the same size as C pointers 14996 ('sizeof(void *)'). 14997 14998_Example_: 14999 The following example demonstrates the use of 'MALLOC' and 'FREE' 15000 with Cray pointers. 15001 15002 program test_malloc 15003 implicit none 15004 integer i 15005 real*8 x(*), z 15006 pointer(ptr_x,x) 15007 15008 ptr_x = malloc(20*8) 15009 do i = 1, 20 15010 x(i) = sqrt(1.0d0 / i) 15011 end do 15012 z = 0 15013 do i = 1, 20 15014 z = z + x(i) 15015 print *, z 15016 end do 15017 call free(ptr_x) 15018 end program test_malloc 15019 15020_See also_: 15021 *note FREE:: 15022 15023 15024File: gfortran.info, Node: MASKL, Next: MASKR, Prev: MALLOC, Up: Intrinsic Procedures 15025 150269.184 'MASKL' -- Left justified mask 15027==================================== 15028 15029_Description_: 15030 'MASKL(I[, KIND])' has its leftmost I bits set to 1, and the 15031 remaining bits set to 0. 15032 15033_Standard_: 15034 Fortran 2008 and later 15035 15036_Class_: 15037 Elemental function 15038 15039_Syntax_: 15040 'RESULT = MASKL(I[, KIND])' 15041 15042_Arguments_: 15043 I Shall be of type 'INTEGER'. 15044 KIND Shall be a scalar constant expression of type 15045 'INTEGER'. 15046 15047_Return value_: 15048 The return value is of type 'INTEGER'. If KIND is present, it 15049 specifies the kind value of the return type; otherwise, it is of 15050 the default integer kind. 15051 15052_See also_: 15053 *note MASKR:: 15054 15055 15056File: gfortran.info, Node: MASKR, Next: MATMUL, Prev: MASKL, Up: Intrinsic Procedures 15057 150589.185 'MASKR' -- Right justified mask 15059===================================== 15060 15061_Description_: 15062 'MASKL(I[, KIND])' has its rightmost I bits set to 1, and the 15063 remaining bits set to 0. 15064 15065_Standard_: 15066 Fortran 2008 and later 15067 15068_Class_: 15069 Elemental function 15070 15071_Syntax_: 15072 'RESULT = MASKR(I[, KIND])' 15073 15074_Arguments_: 15075 I Shall be of type 'INTEGER'. 15076 KIND Shall be a scalar constant expression of type 15077 'INTEGER'. 15078 15079_Return value_: 15080 The return value is of type 'INTEGER'. If KIND is present, it 15081 specifies the kind value of the return type; otherwise, it is of 15082 the default integer kind. 15083 15084_See also_: 15085 *note MASKL:: 15086 15087 15088File: gfortran.info, Node: MATMUL, Next: MAX, Prev: MASKR, Up: Intrinsic Procedures 15089 150909.186 'MATMUL' -- matrix multiplication 15091======================================= 15092 15093_Description_: 15094 Performs a matrix multiplication on numeric or logical arguments. 15095 15096_Standard_: 15097 Fortran 95 and later 15098 15099_Class_: 15100 Transformational function 15101 15102_Syntax_: 15103 'RESULT = MATMUL(MATRIX_A, MATRIX_B)' 15104 15105_Arguments_: 15106 MATRIX_A An array of 'INTEGER', 'REAL', 'COMPLEX', or 15107 'LOGICAL' type, with a rank of one or two. 15108 MATRIX_B An array of 'INTEGER', 'REAL', or 'COMPLEX' type 15109 if MATRIX_A is of a numeric type; otherwise, an 15110 array of 'LOGICAL' type. The rank shall be one 15111 or two, and the first (or only) dimension of 15112 MATRIX_B shall be equal to the last (or only) 15113 dimension of MATRIX_A. MATRIX_A and MATRIX_B 15114 shall not both be rank one arrays. 15115 15116_Return value_: 15117 The matrix product of MATRIX_A and MATRIX_B. The type and kind of 15118 the result follow the usual type and kind promotion rules, as for 15119 the '*' or '.AND.' operators. 15120 15121_See also_: 15122 15123 15124File: gfortran.info, Node: MAX, Next: MAXEXPONENT, Prev: MATMUL, Up: Intrinsic Procedures 15125 151269.187 'MAX' -- Maximum value of an argument list 15127================================================ 15128 15129_Description_: 15130 Returns the argument with the largest (most positive) value. 15131 15132_Standard_: 15133 Fortran 77 and later 15134 15135_Class_: 15136 Elemental function 15137 15138_Syntax_: 15139 'RESULT = MAX(A1, A2 [, A3 [, ...]])' 15140 15141_Arguments_: 15142 A1 The type shall be 'INTEGER' or 'REAL'. 15143 A2, A3, An expression of the same type and kind as A1. 15144 ... (As a GNU extension, arguments of different 15145 kinds are permitted.) 15146 15147_Return value_: 15148 The return value corresponds to the maximum value among the 15149 arguments, and has the same type and kind as the first argument. 15150 15151_Specific names_: 15152 Name Argument Return type Standard 15153 'MAX0(A1)' 'INTEGER(4) 'INTEGER(4)' Fortran 77 and 15154 A1' later 15155 'AMAX0(A1)' 'INTEGER(4) 'REAL(MAX(X))' Fortran 77 and 15156 A1' later 15157 'MAX1(A1)' 'REAL A1' 'INT(MAX(X))' Fortran 77 and 15158 later 15159 'AMAX1(A1)' 'REAL(4) A1' 'REAL(4)' Fortran 77 and 15160 later 15161 'DMAX1(A1)' 'REAL(8) A1' 'REAL(8)' Fortran 77 and 15162 later 15163 15164_See also_: 15165 *note MAXLOC:: *note MAXVAL::, *note MIN:: 15166 15167 15168File: gfortran.info, Node: MAXEXPONENT, Next: MAXLOC, Prev: MAX, Up: Intrinsic Procedures 15169 151709.188 'MAXEXPONENT' -- Maximum exponent of a real kind 15171====================================================== 15172 15173_Description_: 15174 'MAXEXPONENT(X)' returns the maximum exponent in the model of the 15175 type of 'X'. 15176 15177_Standard_: 15178 Fortran 95 and later 15179 15180_Class_: 15181 Inquiry function 15182 15183_Syntax_: 15184 'RESULT = MAXEXPONENT(X)' 15185 15186_Arguments_: 15187 X Shall be of type 'REAL'. 15188 15189_Return value_: 15190 The return value is of type 'INTEGER' and of the default integer 15191 kind. 15192 15193_Example_: 15194 program exponents 15195 real(kind=4) :: x 15196 real(kind=8) :: y 15197 15198 print *, minexponent(x), maxexponent(x) 15199 print *, minexponent(y), maxexponent(y) 15200 end program exponents 15201 15202 15203File: gfortran.info, Node: MAXLOC, Next: MAXVAL, Prev: MAXEXPONENT, Up: Intrinsic Procedures 15204 152059.189 'MAXLOC' -- Location of the maximum value within an array 15206=============================================================== 15207 15208_Description_: 15209 Determines the location of the element in the array with the 15210 maximum value, or, if the DIM argument is supplied, determines the 15211 locations of the maximum element along each row of the array in the 15212 DIM direction. If MASK is present, only the elements for which 15213 MASK is '.TRUE.' are considered. If more than one element in the 15214 array has the maximum value, the location returned is that of the 15215 first such element in array element order. If the array has zero 15216 size, or all of the elements of MASK are '.FALSE.', then the result 15217 is an array of zeroes. Similarly, if DIM is supplied and all of 15218 the elements of MASK along a given row are zero, the result value 15219 for that row is zero. 15220 15221_Standard_: 15222 Fortran 95 and later; ARRAY of 'CHARACTER' and the KIND argument 15223 are available in Fortran 2003 and later. 15224 15225_Class_: 15226 Transformational function 15227 15228_Syntax_: 15229 'RESULT = MAXLOC(ARRAY, DIM [, MASK] [,KIND])' 15230 'RESULT = MAXLOC(ARRAY [, MASK] [,KIND])' 15231 15232_Arguments_: 15233 ARRAY Shall be an array of type 'INTEGER' or 'REAL'. 15234 DIM (Optional) Shall be a scalar of type 'INTEGER', 15235 with a value between one and the rank of ARRAY, 15236 inclusive. It may not be an optional dummy 15237 argument. 15238 MASK Shall be an array of type 'LOGICAL', and 15239 conformable with ARRAY. 15240 KIND (Optional) An 'INTEGER' initialization 15241 expression indicating the kind parameter of the 15242 result. 15243 15244_Return value_: 15245 If DIM is absent, the result is a rank-one array with a length 15246 equal to the rank of ARRAY. If DIM is present, the result is an 15247 array with a rank one less than the rank of ARRAY, and a size 15248 corresponding to the size of ARRAY with the DIM dimension removed. 15249 If DIM is present and ARRAY has a rank of one, the result is a 15250 scalar. If the optional argument KIND is present, the result is an 15251 integer of kind KIND, otherwise it is of default kind. 15252 15253_See also_: 15254 *note MAX::, *note MAXVAL:: 15255 15256 15257File: gfortran.info, Node: MAXVAL, Next: MCLOCK, Prev: MAXLOC, Up: Intrinsic Procedures 15258 152599.190 'MAXVAL' -- Maximum value of an array 15260=========================================== 15261 15262_Description_: 15263 Determines the maximum value of the elements in an array value, or, 15264 if the DIM argument is supplied, determines the maximum value along 15265 each row of the array in the DIM direction. If MASK is present, 15266 only the elements for which MASK is '.TRUE.' are considered. If 15267 the array has zero size, or all of the elements of MASK are 15268 '.FALSE.', then the result is '-HUGE(ARRAY)' if ARRAY is numeric, 15269 or a string of nulls if ARRAY is of character type. 15270 15271_Standard_: 15272 Fortran 95 and later 15273 15274_Class_: 15275 Transformational function 15276 15277_Syntax_: 15278 'RESULT = MAXVAL(ARRAY, DIM [, MASK])' 15279 'RESULT = MAXVAL(ARRAY [, MASK])' 15280 15281_Arguments_: 15282 ARRAY Shall be an array of type 'INTEGER' or 'REAL'. 15283 DIM (Optional) Shall be a scalar of type 'INTEGER', 15284 with a value between one and the rank of ARRAY, 15285 inclusive. It may not be an optional dummy 15286 argument. 15287 MASK Shall be an array of type 'LOGICAL', and 15288 conformable with ARRAY. 15289 15290_Return value_: 15291 If DIM is absent, or if ARRAY has a rank of one, the result is a 15292 scalar. If DIM is present, the result is an array with a rank one 15293 less than the rank of ARRAY, and a size corresponding to the size 15294 of ARRAY with the DIM dimension removed. In all cases, the result 15295 is of the same type and kind as ARRAY. 15296 15297_See also_: 15298 *note MAX::, *note MAXLOC:: 15299 15300 15301File: gfortran.info, Node: MCLOCK, Next: MCLOCK8, Prev: MAXVAL, Up: Intrinsic Procedures 15302 153039.191 'MCLOCK' -- Time function 15304=============================== 15305 15306_Description_: 15307 Returns the number of clock ticks since the start of the process, 15308 based on the function 'clock(3)' in the C standard library. 15309 15310 This intrinsic is not fully portable, such as to systems with 15311 32-bit 'INTEGER' types but supporting times wider than 32 bits. 15312 Therefore, the values returned by this intrinsic might be, or 15313 become, negative, or numerically less than previous values, during 15314 a single run of the compiled program. 15315 15316_Standard_: 15317 GNU extension 15318 15319_Class_: 15320 Function 15321 15322_Syntax_: 15323 'RESULT = MCLOCK()' 15324 15325_Return value_: 15326 The return value is a scalar of type 'INTEGER(4)', equal to the 15327 number of clock ticks since the start of the process, or '-1' if 15328 the system does not support 'clock(3)'. 15329 15330_See also_: 15331 *note CTIME::, *note GMTIME::, *note LTIME::, *note MCLOCK::, *note 15332 TIME:: 15333 15334 15335File: gfortran.info, Node: MCLOCK8, Next: MERGE, Prev: MCLOCK, Up: Intrinsic Procedures 15336 153379.192 'MCLOCK8' -- Time function (64-bit) 15338========================================= 15339 15340_Description_: 15341 Returns the number of clock ticks since the start of the process, 15342 based on the function 'clock(3)' in the C standard library. 15343 15344 _Warning:_ this intrinsic does not increase the range of the timing 15345 values over that returned by 'clock(3)'. On a system with a 32-bit 15346 'clock(3)', 'MCLOCK8' will return a 32-bit value, even though it is 15347 converted to a 64-bit 'INTEGER(8)' value. That means overflows of 15348 the 32-bit value can still occur. Therefore, the values returned 15349 by this intrinsic might be or become negative or numerically less 15350 than previous values during a single run of the compiled program. 15351 15352_Standard_: 15353 GNU extension 15354 15355_Class_: 15356 Function 15357 15358_Syntax_: 15359 'RESULT = MCLOCK8()' 15360 15361_Return value_: 15362 The return value is a scalar of type 'INTEGER(8)', equal to the 15363 number of clock ticks since the start of the process, or '-1' if 15364 the system does not support 'clock(3)'. 15365 15366_See also_: 15367 *note CTIME::, *note GMTIME::, *note LTIME::, *note MCLOCK::, *note 15368 TIME8:: 15369 15370 15371File: gfortran.info, Node: MERGE, Next: MERGE_BITS, Prev: MCLOCK8, Up: Intrinsic Procedures 15372 153739.193 'MERGE' -- Merge variables 15374================================ 15375 15376_Description_: 15377 Select values from two arrays according to a logical mask. The 15378 result is equal to TSOURCE if MASK is '.TRUE.', or equal to FSOURCE 15379 if it is '.FALSE.'. 15380 15381_Standard_: 15382 Fortran 95 and later 15383 15384_Class_: 15385 Elemental function 15386 15387_Syntax_: 15388 'RESULT = MERGE(TSOURCE, FSOURCE, MASK)' 15389 15390_Arguments_: 15391 TSOURCE May be of any type. 15392 FSOURCE Shall be of the same type and type parameters as 15393 TSOURCE. 15394 MASK Shall be of type 'LOGICAL'. 15395 15396_Return value_: 15397 The result is of the same type and type parameters as TSOURCE. 15398 15399 15400File: gfortran.info, Node: MERGE_BITS, Next: MIN, Prev: MERGE, Up: Intrinsic Procedures 15401 154029.194 'MERGE_BITS' -- Merge of bits under mask 15403============================================== 15404 15405_Description_: 15406 'MERGE_BITS(I, J, MASK)' merges the bits of I and J as determined 15407 by the mask. The i-th bit of the result is equal to the i-th bit 15408 of I if the i-th bit of MASK is 1; it is equal to the i-th bit of J 15409 otherwise. 15410 15411_Standard_: 15412 Fortran 2008 and later 15413 15414_Class_: 15415 Elemental function 15416 15417_Syntax_: 15418 'RESULT = MERGE_BITS(I, J, MASK)' 15419 15420_Arguments_: 15421 I Shall be of type 'INTEGER'. 15422 J Shall be of type 'INTEGER' and of the same kind 15423 as I. 15424 MASK Shall be of type 'INTEGER' and of the same kind 15425 as I. 15426 15427_Return value_: 15428 The result is of the same type and kind as I. 15429 15430 15431File: gfortran.info, Node: MIN, Next: MINEXPONENT, Prev: MERGE_BITS, Up: Intrinsic Procedures 15432 154339.195 'MIN' -- Minimum value of an argument list 15434================================================ 15435 15436_Description_: 15437 Returns the argument with the smallest (most negative) value. 15438 15439_Standard_: 15440 Fortran 77 and later 15441 15442_Class_: 15443 Elemental function 15444 15445_Syntax_: 15446 'RESULT = MIN(A1, A2 [, A3, ...])' 15447 15448_Arguments_: 15449 A1 The type shall be 'INTEGER' or 'REAL'. 15450 A2, A3, An expression of the same type and kind as A1. 15451 ... (As a GNU extension, arguments of different 15452 kinds are permitted.) 15453 15454_Return value_: 15455 The return value corresponds to the maximum value among the 15456 arguments, and has the same type and kind as the first argument. 15457 15458_Specific names_: 15459 Name Argument Return type Standard 15460 'MIN0(A1)' 'INTEGER(4) 'INTEGER(4)' Fortran 77 and 15461 A1' later 15462 'AMIN0(A1)' 'INTEGER(4) 'REAL(4)' Fortran 77 and 15463 A1' later 15464 'MIN1(A1)' 'REAL A1' 'INTEGER(4)' Fortran 77 and 15465 later 15466 'AMIN1(A1)' 'REAL(4) A1' 'REAL(4)' Fortran 77 and 15467 later 15468 'DMIN1(A1)' 'REAL(8) A1' 'REAL(8)' Fortran 77 and 15469 later 15470 15471_See also_: 15472 *note MAX::, *note MINLOC::, *note MINVAL:: 15473 15474 15475File: gfortran.info, Node: MINEXPONENT, Next: MINLOC, Prev: MIN, Up: Intrinsic Procedures 15476 154779.196 'MINEXPONENT' -- Minimum exponent of a real kind 15478====================================================== 15479 15480_Description_: 15481 'MINEXPONENT(X)' returns the minimum exponent in the model of the 15482 type of 'X'. 15483 15484_Standard_: 15485 Fortran 95 and later 15486 15487_Class_: 15488 Inquiry function 15489 15490_Syntax_: 15491 'RESULT = MINEXPONENT(X)' 15492 15493_Arguments_: 15494 X Shall be of type 'REAL'. 15495 15496_Return value_: 15497 The return value is of type 'INTEGER' and of the default integer 15498 kind. 15499 15500_Example_: 15501 See 'MAXEXPONENT' for an example. 15502 15503 15504File: gfortran.info, Node: MINLOC, Next: MINVAL, Prev: MINEXPONENT, Up: Intrinsic Procedures 15505 155069.197 'MINLOC' -- Location of the minimum value within an array 15507=============================================================== 15508 15509_Description_: 15510 Determines the location of the element in the array with the 15511 minimum value, or, if the DIM argument is supplied, determines the 15512 locations of the minimum element along each row of the array in the 15513 DIM direction. If MASK is present, only the elements for which 15514 MASK is '.TRUE.' are considered. If more than one element in the 15515 array has the minimum value, the location returned is that of the 15516 first such element in array element order. If the array has zero 15517 size, or all of the elements of MASK are '.FALSE.', then the result 15518 is an array of zeroes. Similarly, if DIM is supplied and all of 15519 the elements of MASK along a given row are zero, the result value 15520 for that row is zero. 15521 15522_Standard_: 15523 Fortran 95 and later; ARRAY of 'CHARACTER' and the KIND argument 15524 are available in Fortran 2003 and later. 15525 15526_Class_: 15527 Transformational function 15528 15529_Syntax_: 15530 'RESULT = MINLOC(ARRAY, DIM [, MASK] [,KIND])' 15531 'RESULT = MINLOC(ARRAY [, MASK], [,KIND])' 15532 15533_Arguments_: 15534 ARRAY Shall be an array of type 'INTEGER', 'REAL' or 15535 'CHARACTER'. 15536 DIM (Optional) Shall be a scalar of type 'INTEGER', 15537 with a value between one and the rank of ARRAY, 15538 inclusive. It may not be an optional dummy 15539 argument. 15540 MASK Shall be an array of type 'LOGICAL', and 15541 conformable with ARRAY. 15542 KIND (Optional) An 'INTEGER' initialization 15543 expression indicating the kind parameter of the 15544 result. 15545 15546_Return value_: 15547 If DIM is absent, the result is a rank-one array with a length 15548 equal to the rank of ARRAY. If DIM is present, the result is an 15549 array with a rank one less than the rank of ARRAY, and a size 15550 corresponding to the size of ARRAY with the DIM dimension removed. 15551 If DIM is present and ARRAY has a rank of one, the result is a 15552 scalar. If the optional argument KIND is present, the result is an 15553 integer of kind KIND, otherwise it is of default kind. 15554 15555_See also_: 15556 *note MIN::, *note MINVAL:: 15557 15558 15559File: gfortran.info, Node: MINVAL, Next: MOD, Prev: MINLOC, Up: Intrinsic Procedures 15560 155619.198 'MINVAL' -- Minimum value of an array 15562=========================================== 15563 15564_Description_: 15565 Determines the minimum value of the elements in an array value, or, 15566 if the DIM argument is supplied, determines the minimum value along 15567 each row of the array in the DIM direction. If MASK is present, 15568 only the elements for which MASK is '.TRUE.' are considered. If 15569 the array has zero size, or all of the elements of MASK are 15570 '.FALSE.', then the result is 'HUGE(ARRAY)' if ARRAY is numeric, or 15571 a string of 'CHAR(255)' characters if ARRAY is of character type. 15572 15573_Standard_: 15574 Fortran 95 and later 15575 15576_Class_: 15577 Transformational function 15578 15579_Syntax_: 15580 'RESULT = MINVAL(ARRAY, DIM [, MASK])' 15581 'RESULT = MINVAL(ARRAY [, MASK])' 15582 15583_Arguments_: 15584 ARRAY Shall be an array of type 'INTEGER' or 'REAL'. 15585 DIM (Optional) Shall be a scalar of type 'INTEGER', 15586 with a value between one and the rank of ARRAY, 15587 inclusive. It may not be an optional dummy 15588 argument. 15589 MASK Shall be an array of type 'LOGICAL', and 15590 conformable with ARRAY. 15591 15592_Return value_: 15593 If DIM is absent, or if ARRAY has a rank of one, the result is a 15594 scalar. If DIM is present, the result is an array with a rank one 15595 less than the rank of ARRAY, and a size corresponding to the size 15596 of ARRAY with the DIM dimension removed. In all cases, the result 15597 is of the same type and kind as ARRAY. 15598 15599_See also_: 15600 *note MIN::, *note MINLOC:: 15601 15602 15603File: gfortran.info, Node: MOD, Next: MODULO, Prev: MINVAL, Up: Intrinsic Procedures 15604 156059.199 'MOD' -- Remainder function 15606================================= 15607 15608_Description_: 15609 'MOD(A,P)' computes the remainder of the division of A by P. 15610 15611_Standard_: 15612 Fortran 77 and later, has overloads that are GNU extensions 15613 15614_Class_: 15615 Elemental function 15616 15617_Syntax_: 15618 'RESULT = MOD(A, P)' 15619 15620_Arguments_: 15621 A Shall be a scalar of type 'INTEGER' or 'REAL'. 15622 P Shall be a scalar of the same type and kind as A 15623 and not equal to zero. 15624 15625_Return value_: 15626 The return value is the result of 'A - (INT(A/P) * P)'. The type 15627 and kind of the return value is the same as that of the arguments. 15628 The returned value has the same sign as A and a magnitude less than 15629 the magnitude of P. 15630 15631_Example_: 15632 program test_mod 15633 print *, mod(17,3) 15634 print *, mod(17.5,5.5) 15635 print *, mod(17.5d0,5.5) 15636 print *, mod(17.5,5.5d0) 15637 15638 print *, mod(-17,3) 15639 print *, mod(-17.5,5.5) 15640 print *, mod(-17.5d0,5.5) 15641 print *, mod(-17.5,5.5d0) 15642 15643 print *, mod(17,-3) 15644 print *, mod(17.5,-5.5) 15645 print *, mod(17.5d0,-5.5) 15646 print *, mod(17.5,-5.5d0) 15647 end program test_mod 15648 15649_Specific names_: 15650 Name Arguments Return type Standard 15651 'MOD(A,P)' 'INTEGER 'INTEGER' Fortran 95 and 15652 A,P' later 15653 'AMOD(A,P)' 'REAL(4) 'REAL(4)' Fortran 95 and 15654 A,P' later 15655 'DMOD(A,P)' 'REAL(8) 'REAL(8)' Fortran 95 and 15656 A,P' later 15657 'BMOD(A,P)' 'INTEGER(1) 'INTEGER(1)' GNU extension 15658 A,P' 15659 'IMOD(A,P)' 'INTEGER(2) 'INTEGER(2)' GNU extension 15660 A,P' 15661 'JMOD(A,P)' 'INTEGER(4) 'INTEGER(4)' GNU extension 15662 A,P' 15663 'KMOD(A,P)' 'INTEGER(8) 'INTEGER(8)' GNU extension 15664 A,P' 15665 15666_See also_: 15667 *note MODULO:: 15668 15669 15670File: gfortran.info, Node: MODULO, Next: MOVE_ALLOC, Prev: MOD, Up: Intrinsic Procedures 15671 156729.200 'MODULO' -- Modulo function 15673================================= 15674 15675_Description_: 15676 'MODULO(A,P)' computes the A modulo P. 15677 15678_Standard_: 15679 Fortran 95 and later 15680 15681_Class_: 15682 Elemental function 15683 15684_Syntax_: 15685 'RESULT = MODULO(A, P)' 15686 15687_Arguments_: 15688 A Shall be a scalar of type 'INTEGER' or 'REAL'. 15689 P Shall be a scalar of the same type and kind as 15690 A. It shall not be zero. 15691 15692_Return value_: 15693 The type and kind of the result are those of the arguments. 15694 If A and P are of type 'INTEGER': 15695 'MODULO(A,P)' has the value R such that 'A=Q*P+R', where Q is 15696 an integer and R is between 0 (inclusive) and P (exclusive). 15697 If A and P are of type 'REAL': 15698 'MODULO(A,P)' has the value of 'A - FLOOR (A / P) * P'. 15699 The returned value has the same sign as P and a magnitude less than 15700 the magnitude of P. 15701 15702_Example_: 15703 program test_modulo 15704 print *, modulo(17,3) 15705 print *, modulo(17.5,5.5) 15706 15707 print *, modulo(-17,3) 15708 print *, modulo(-17.5,5.5) 15709 15710 print *, modulo(17,-3) 15711 print *, modulo(17.5,-5.5) 15712 end program 15713 15714_See also_: 15715 *note MOD:: 15716 15717 15718File: gfortran.info, Node: MOVE_ALLOC, Next: MVBITS, Prev: MODULO, Up: Intrinsic Procedures 15719 157209.201 'MOVE_ALLOC' -- Move allocation from one object to another 15721================================================================ 15722 15723_Description_: 15724 'MOVE_ALLOC(FROM, TO)' moves the allocation from FROM to TO. FROM 15725 will become deallocated in the process. 15726 15727_Standard_: 15728 Fortran 2003 and later 15729 15730_Class_: 15731 Pure subroutine 15732 15733_Syntax_: 15734 'CALL MOVE_ALLOC(FROM, TO)' 15735 15736_Arguments_: 15737 FROM 'ALLOCATABLE', 'INTENT(INOUT)', may be of any 15738 type and kind. 15739 TO 'ALLOCATABLE', 'INTENT(OUT)', shall be of the 15740 same type, kind and rank as FROM. 15741 15742_Return value_: 15743 None 15744 15745_Example_: 15746 program test_move_alloc 15747 integer, allocatable :: a(:), b(:) 15748 15749 allocate(a(3)) 15750 a = [ 1, 2, 3 ] 15751 call move_alloc(a, b) 15752 print *, allocated(a), allocated(b) 15753 print *, b 15754 end program test_move_alloc 15755 15756 15757File: gfortran.info, Node: MVBITS, Next: NEAREST, Prev: MOVE_ALLOC, Up: Intrinsic Procedures 15758 157599.202 'MVBITS' -- Move bits from one integer to another 15760======================================================= 15761 15762_Description_: 15763 Moves LEN bits from positions FROMPOS through 'FROMPOS+LEN-1' of 15764 FROM to positions TOPOS through 'TOPOS+LEN-1' of TO. The portion 15765 of argument TO not affected by the movement of bits is unchanged. 15766 The values of 'FROMPOS+LEN-1' and 'TOPOS+LEN-1' must be less than 15767 'BIT_SIZE(FROM)'. 15768 15769_Standard_: 15770 Fortran 95 and later, has overloads that are GNU extensions 15771 15772_Class_: 15773 Elemental subroutine 15774 15775_Syntax_: 15776 'CALL MVBITS(FROM, FROMPOS, LEN, TO, TOPOS)' 15777 15778_Arguments_: 15779 FROM The type shall be 'INTEGER'. 15780 FROMPOS The type shall be 'INTEGER'. 15781 LEN The type shall be 'INTEGER'. 15782 TO The type shall be 'INTEGER', of the same kind as 15783 FROM. 15784 TOPOS The type shall be 'INTEGER'. 15785 15786_Specific names_: 15787 Name Argument Return type Standard 15788 'MVBITS(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 15789 later 15790 'BMVBITS(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 15791 A' 15792 'IMVBITS(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 15793 A' 15794 'JMVBITS(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 15795 A' 15796 'KMVBITS(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 15797 A' 15798 15799_See also_: 15800 *note IBCLR::, *note IBSET::, *note IBITS::, *note IAND::, *note 15801 IOR::, *note IEOR:: 15802 15803 15804File: gfortran.info, Node: NEAREST, Next: NEW_LINE, Prev: MVBITS, Up: Intrinsic Procedures 15805 158069.203 'NEAREST' -- Nearest representable number 15807=============================================== 15808 15809_Description_: 15810 'NEAREST(X, S)' returns the processor-representable number nearest 15811 to 'X' in the direction indicated by the sign of 'S'. 15812 15813_Standard_: 15814 Fortran 95 and later 15815 15816_Class_: 15817 Elemental function 15818 15819_Syntax_: 15820 'RESULT = NEAREST(X, S)' 15821 15822_Arguments_: 15823 X Shall be of type 'REAL'. 15824 S Shall be of type 'REAL' and not equal to zero. 15825 15826_Return value_: 15827 The return value is of the same type as 'X'. If 'S' is positive, 15828 'NEAREST' returns the processor-representable number greater than 15829 'X' and nearest to it. If 'S' is negative, 'NEAREST' returns the 15830 processor-representable number smaller than 'X' and nearest to it. 15831 15832_Example_: 15833 program test_nearest 15834 real :: x, y 15835 x = nearest(42.0, 1.0) 15836 y = nearest(42.0, -1.0) 15837 write (*,"(3(G20.15))") x, y, x - y 15838 end program test_nearest 15839 15840 15841File: gfortran.info, Node: NEW_LINE, Next: NINT, Prev: NEAREST, Up: Intrinsic Procedures 15842 158439.204 'NEW_LINE' -- New line character 15844====================================== 15845 15846_Description_: 15847 'NEW_LINE(C)' returns the new-line character. 15848 15849_Standard_: 15850 Fortran 2003 and later 15851 15852_Class_: 15853 Inquiry function 15854 15855_Syntax_: 15856 'RESULT = NEW_LINE(C)' 15857 15858_Arguments_: 15859 C The argument shall be a scalar or array of the 15860 type 'CHARACTER'. 15861 15862_Return value_: 15863 Returns a CHARACTER scalar of length one with the new-line 15864 character of the same kind as parameter C. 15865 15866_Example_: 15867 program newline 15868 implicit none 15869 write(*,'(A)') 'This is record 1.'//NEW_LINE('A')//'This is record 2.' 15870 end program newline 15871 15872 15873File: gfortran.info, Node: NINT, Next: NORM2, Prev: NEW_LINE, Up: Intrinsic Procedures 15874 158759.205 'NINT' -- Nearest whole number 15876==================================== 15877 15878_Description_: 15879 'NINT(A)' rounds its argument to the nearest whole number. 15880 15881_Standard_: 15882 Fortran 77 and later, with KIND argument Fortran 90 and later 15883 15884_Class_: 15885 Elemental function 15886 15887_Syntax_: 15888 'RESULT = NINT(A [, KIND])' 15889 15890_Arguments_: 15891 A The type of the argument shall be 'REAL'. 15892 KIND (Optional) An 'INTEGER' initialization 15893 expression indicating the kind parameter of the 15894 result. 15895 15896_Return value_: 15897 Returns A with the fractional portion of its magnitude eliminated 15898 by rounding to the nearest whole number and with its sign 15899 preserved, converted to an 'INTEGER' of the default kind. 15900 15901_Example_: 15902 program test_nint 15903 real(4) x4 15904 real(8) x8 15905 x4 = 1.234E0_4 15906 x8 = 4.321_8 15907 print *, nint(x4), idnint(x8) 15908 end program test_nint 15909 15910_Specific names_: 15911 Name Argument Return Type Standard 15912 'NINT(A)' 'REAL(4) A' 'INTEGER' Fortran 95 and 15913 later 15914 'IDNINT(A)' 'REAL(8) A' 'INTEGER' Fortran 95 and 15915 later 15916 15917_See also_: 15918 *note CEILING::, *note FLOOR:: 15919 15920 15921File: gfortran.info, Node: NORM2, Next: NOT, Prev: NINT, Up: Intrinsic Procedures 15922 159239.206 'NORM2' -- Euclidean vector norms 15924======================================= 15925 15926_Description_: 15927 Calculates the Euclidean vector norm (L_2 norm) of of ARRAY along 15928 dimension DIM. 15929 15930_Standard_: 15931 Fortran 2008 and later 15932 15933_Class_: 15934 Transformational function 15935 15936_Syntax_: 15937 'RESULT = NORM2(ARRAY[, DIM])' 15938 15939_Arguments_: 15940 ARRAY Shall be an array of type 'REAL' 15941 DIM (Optional) shall be a scalar of type 'INTEGER' 15942 with a value in the range from 1 to n, where n 15943 equals the rank of ARRAY. 15944 15945_Return value_: 15946 The result is of the same type as ARRAY. 15947 15948 If DIM is absent, a scalar with the square root of the sum of all 15949 elements in ARRAY squared is returned. Otherwise, an array of rank 15950 n-1, where n equals the rank of ARRAY, and a shape similar to that 15951 of ARRAY with dimension DIM dropped is returned. 15952 15953_Example_: 15954 PROGRAM test_sum 15955 REAL :: x(5) = [ real :: 1, 2, 3, 4, 5 ] 15956 print *, NORM2(x) ! = sqrt(55.) ~ 7.416 15957 END PROGRAM 15958 15959 15960File: gfortran.info, Node: NOT, Next: NULL, Prev: NORM2, Up: Intrinsic Procedures 15961 159629.207 'NOT' -- Logical negation 15963=============================== 15964 15965_Description_: 15966 'NOT' returns the bitwise Boolean inverse of I. 15967 15968_Standard_: 15969 Fortran 95 and later, has overloads that are GNU extensions 15970 15971_Class_: 15972 Elemental function 15973 15974_Syntax_: 15975 'RESULT = NOT(I)' 15976 15977_Arguments_: 15978 I The type shall be 'INTEGER'. 15979 15980_Return value_: 15981 The return type is 'INTEGER', of the same kind as the argument. 15982 15983_Specific names_: 15984 Name Argument Return type Standard 15985 'NOT(A)' 'INTEGER A' 'INTEGER' Fortran 95 and 15986 later 15987 'BNOT(A)' 'INTEGER(1) 'INTEGER(1)' GNU extension 15988 A' 15989 'INOT(A)' 'INTEGER(2) 'INTEGER(2)' GNU extension 15990 A' 15991 'JNOT(A)' 'INTEGER(4) 'INTEGER(4)' GNU extension 15992 A' 15993 'KNOT(A)' 'INTEGER(8) 'INTEGER(8)' GNU extension 15994 A' 15995 15996_See also_: 15997 *note IAND::, *note IEOR::, *note IOR::, *note IBITS::, *note 15998 IBSET::, *note IBCLR:: 15999 16000 16001File: gfortran.info, Node: NULL, Next: NUM_IMAGES, Prev: NOT, Up: Intrinsic Procedures 16002 160039.208 'NULL' -- Function that returns an disassociated pointer 16004============================================================== 16005 16006_Description_: 16007 Returns a disassociated pointer. 16008 16009 If MOLD is present, a disassociated pointer of the same type is 16010 returned, otherwise the type is determined by context. 16011 16012 In Fortran 95, MOLD is optional. Please note that Fortran 2003 16013 includes cases where it is required. 16014 16015_Standard_: 16016 Fortran 95 and later 16017 16018_Class_: 16019 Transformational function 16020 16021_Syntax_: 16022 'PTR => NULL([MOLD])' 16023 16024_Arguments_: 16025 MOLD (Optional) shall be a pointer of any association 16026 status and of any type. 16027 16028_Return value_: 16029 A disassociated pointer. 16030 16031_Example_: 16032 REAL, POINTER, DIMENSION(:) :: VEC => NULL () 16033 16034_See also_: 16035 *note ASSOCIATED:: 16036 16037 16038File: gfortran.info, Node: NUM_IMAGES, Next: OR, Prev: NULL, Up: Intrinsic Procedures 16039 160409.209 'NUM_IMAGES' -- Function that returns the number of images 16041================================================================ 16042 16043_Description_: 16044 Returns the number of images. 16045 16046_Standard_: 16047 Fortran 2008 and later. With DISTANCE or FAILED argument, 16048 Technical Specification (TS) 18508 or later 16049 16050_Class_: 16051 Transformational function 16052 16053_Syntax_: 16054 'RESULT = NUM_IMAGES(DISTANCE, FAILED)' 16055 16056_Arguments_: 16057 DISTANCE (optional, intent(in)) Nonnegative scalar 16058 integer 16059 FAILED (optional, intent(in)) Scalar logical expression 16060 16061_Return value_: 16062 Scalar default-kind integer. If DISTANCE is not present or has 16063 value 0, the number of images in the current team is returned. For 16064 values smaller or equal distance to the initial team, it returns 16065 the number of images index on the ancestor team which has a 16066 distance of DISTANCE from the invoking team. If DISTANCE is larger 16067 than the distance to the initial team, the number of images of the 16068 initial team is returned. If FAILED is not present the total 16069 number of images is returned; if it has the value '.TRUE.', the 16070 number of failed images is returned, otherwise, the number of 16071 images which do have not the failed status. 16072 16073_Example_: 16074 INTEGER :: value[*] 16075 INTEGER :: i 16076 value = THIS_IMAGE() 16077 SYNC ALL 16078 IF (THIS_IMAGE() == 1) THEN 16079 DO i = 1, NUM_IMAGES() 16080 WRITE(*,'(2(a,i0))') 'value[', i, '] is ', value[i] 16081 END DO 16082 END IF 16083 16084_See also_: 16085 *note THIS_IMAGE::, *note IMAGE_INDEX:: 16086 16087 16088File: gfortran.info, Node: OR, Next: PACK, Prev: NUM_IMAGES, Up: Intrinsic Procedures 16089 160909.210 'OR' -- Bitwise logical OR 16091================================ 16092 16093_Description_: 16094 Bitwise logical 'OR'. 16095 16096 This intrinsic routine is provided for backwards compatibility with 16097 GNU Fortran 77. For integer arguments, programmers should consider 16098 the use of the *note IOR:: intrinsic defined by the Fortran 16099 standard. 16100 16101_Standard_: 16102 GNU extension 16103 16104_Class_: 16105 Function 16106 16107_Syntax_: 16108 'RESULT = OR(I, J)' 16109 16110_Arguments_: 16111 I The type shall be either a scalar 'INTEGER' type 16112 or a scalar 'LOGICAL' type. 16113 J The type shall be the same as the type of J. 16114 16115_Return value_: 16116 The return type is either a scalar 'INTEGER' or a scalar 'LOGICAL'. 16117 If the kind type parameters differ, then the smaller kind type is 16118 implicitly converted to larger kind, and the return has the larger 16119 kind. 16120 16121_Example_: 16122 PROGRAM test_or 16123 LOGICAL :: T = .TRUE., F = .FALSE. 16124 INTEGER :: a, b 16125 DATA a / Z'F' /, b / Z'3' / 16126 16127 WRITE (*,*) OR(T, T), OR(T, F), OR(F, T), OR(F, F) 16128 WRITE (*,*) OR(a, b) 16129 END PROGRAM 16130 16131_See also_: 16132 Fortran 95 elemental function: *note IOR:: 16133 16134 16135File: gfortran.info, Node: PACK, Next: PARITY, Prev: OR, Up: Intrinsic Procedures 16136 161379.211 'PACK' -- Pack an array into an array of rank one 16138======================================================= 16139 16140_Description_: 16141 Stores the elements of ARRAY in an array of rank one. 16142 16143 The beginning of the resulting array is made up of elements whose 16144 MASK equals 'TRUE'. Afterwards, positions are filled with elements 16145 taken from VECTOR. 16146 16147_Standard_: 16148 Fortran 95 and later 16149 16150_Class_: 16151 Transformational function 16152 16153_Syntax_: 16154 'RESULT = PACK(ARRAY, MASK[,VECTOR])' 16155 16156_Arguments_: 16157 ARRAY Shall be an array of any type. 16158 MASK Shall be an array of type 'LOGICAL' and of the 16159 same size as ARRAY. Alternatively, it may be a 16160 'LOGICAL' scalar. 16161 VECTOR (Optional) shall be an array of the same type as 16162 ARRAY and of rank one. If present, the number 16163 of elements in VECTOR shall be equal to or 16164 greater than the number of true elements in 16165 MASK. If MASK is scalar, the number of elements 16166 in VECTOR shall be equal to or greater than the 16167 number of elements in ARRAY. 16168 16169_Return value_: 16170 The result is an array of rank one and the same type as that of 16171 ARRAY. If VECTOR is present, the result size is that of VECTOR, 16172 the number of 'TRUE' values in MASK otherwise. 16173 16174_Example_: 16175 Gathering nonzero elements from an array: 16176 PROGRAM test_pack_1 16177 INTEGER :: m(6) 16178 m = (/ 1, 0, 0, 0, 5, 0 /) 16179 WRITE(*, FMT="(6(I0, ' '))") pack(m, m /= 0) ! "1 5" 16180 END PROGRAM 16181 16182 Gathering nonzero elements from an array and appending elements 16183 from VECTOR: 16184 PROGRAM test_pack_2 16185 INTEGER :: m(4) 16186 m = (/ 1, 0, 0, 2 /) 16187 WRITE(*, FMT="(4(I0, ' '))") pack(m, m /= 0, (/ 0, 0, 3, 4 /)) ! "1 2 3 4" 16188 END PROGRAM 16189 16190_See also_: 16191 *note UNPACK:: 16192 16193 16194File: gfortran.info, Node: PARITY, Next: PERROR, Prev: PACK, Up: Intrinsic Procedures 16195 161969.212 'PARITY' -- Reduction with exclusive OR 16197============================================= 16198 16199_Description_: 16200 Calculates the parity, i.e. the reduction using '.XOR.', of MASK 16201 along dimension DIM. 16202 16203_Standard_: 16204 Fortran 2008 and later 16205 16206_Class_: 16207 Transformational function 16208 16209_Syntax_: 16210 'RESULT = PARITY(MASK[, DIM])' 16211 16212_Arguments_: 16213 LOGICAL Shall be an array of type 'LOGICAL' 16214 DIM (Optional) shall be a scalar of type 'INTEGER' 16215 with a value in the range from 1 to n, where n 16216 equals the rank of MASK. 16217 16218_Return value_: 16219 The result is of the same type as MASK. 16220 16221 If DIM is absent, a scalar with the parity of all elements in MASK 16222 is returned, i.e. true if an odd number of elements is '.true.' 16223 and false otherwise. If DIM is present, an array of rank n-1, 16224 where n equals the rank of ARRAY, and a shape similar to that of 16225 MASK with dimension DIM dropped is returned. 16226 16227_Example_: 16228 PROGRAM test_sum 16229 LOGICAL :: x(2) = [ .true., .false. ] 16230 print *, PARITY(x) ! prints "T" (true). 16231 END PROGRAM 16232 16233 16234File: gfortran.info, Node: PERROR, Next: POPCNT, Prev: PARITY, Up: Intrinsic Procedures 16235 162369.213 'PERROR' -- Print system error message 16237============================================ 16238 16239_Description_: 16240 Prints (on the C 'stderr' stream) a newline-terminated error 16241 message corresponding to the last system error. This is prefixed 16242 by STRING, a colon and a space. See 'perror(3)'. 16243 16244_Standard_: 16245 GNU extension 16246 16247_Class_: 16248 Subroutine 16249 16250_Syntax_: 16251 'CALL PERROR(STRING)' 16252 16253_Arguments_: 16254 STRING A scalar of type 'CHARACTER' and of the default 16255 kind. 16256 16257_See also_: 16258 *note IERRNO:: 16259 16260 16261File: gfortran.info, Node: POPCNT, Next: POPPAR, Prev: PERROR, Up: Intrinsic Procedures 16262 162639.214 'POPCNT' -- Number of bits set 16264==================================== 16265 16266_Description_: 16267 'POPCNT(I)' returns the number of bits set ('1' bits) in the binary 16268 representation of 'I'. 16269 16270_Standard_: 16271 Fortran 2008 and later 16272 16273_Class_: 16274 Elemental function 16275 16276_Syntax_: 16277 'RESULT = POPCNT(I)' 16278 16279_Arguments_: 16280 I Shall be of type 'INTEGER'. 16281 16282_Return value_: 16283 The return value is of type 'INTEGER' and of the default integer 16284 kind. 16285 16286_See also_: 16287 *note POPPAR::, *note LEADZ::, *note TRAILZ:: 16288 16289_Example_: 16290 program test_population 16291 print *, popcnt(127), poppar(127) 16292 print *, popcnt(huge(0_4)), poppar(huge(0_4)) 16293 print *, popcnt(huge(0_8)), poppar(huge(0_8)) 16294 end program test_population 16295 16296 16297File: gfortran.info, Node: POPPAR, Next: PRECISION, Prev: POPCNT, Up: Intrinsic Procedures 16298 162999.215 'POPPAR' -- Parity of the number of bits set 16300================================================== 16301 16302_Description_: 16303 'POPPAR(I)' returns parity of the integer 'I', i.e. the parity of 16304 the number of bits set ('1' bits) in the binary representation of 16305 'I'. It is equal to 0 if 'I' has an even number of bits set, and 1 16306 for an odd number of '1' bits. 16307 16308_Standard_: 16309 Fortran 2008 and later 16310 16311_Class_: 16312 Elemental function 16313 16314_Syntax_: 16315 'RESULT = POPPAR(I)' 16316 16317_Arguments_: 16318 I Shall be of type 'INTEGER'. 16319 16320_Return value_: 16321 The return value is of type 'INTEGER' and of the default integer 16322 kind. 16323 16324_See also_: 16325 *note POPCNT::, *note LEADZ::, *note TRAILZ:: 16326 16327_Example_: 16328 program test_population 16329 print *, popcnt(127), poppar(127) 16330 print *, popcnt(huge(0_4)), poppar(huge(0_4)) 16331 print *, popcnt(huge(0_8)), poppar(huge(0_8)) 16332 end program test_population 16333 16334 16335File: gfortran.info, Node: PRECISION, Next: PRESENT, Prev: POPPAR, Up: Intrinsic Procedures 16336 163379.216 'PRECISION' -- Decimal precision of a real kind 16338===================================================== 16339 16340_Description_: 16341 'PRECISION(X)' returns the decimal precision in the model of the 16342 type of 'X'. 16343 16344_Standard_: 16345 Fortran 95 and later 16346 16347_Class_: 16348 Inquiry function 16349 16350_Syntax_: 16351 'RESULT = PRECISION(X)' 16352 16353_Arguments_: 16354 X Shall be of type 'REAL' or 'COMPLEX'. 16355 16356_Return value_: 16357 The return value is of type 'INTEGER' and of the default integer 16358 kind. 16359 16360_See also_: 16361 *note SELECTED_REAL_KIND::, *note RANGE:: 16362 16363_Example_: 16364 program prec_and_range 16365 real(kind=4) :: x(2) 16366 complex(kind=8) :: y 16367 16368 print *, precision(x), range(x) 16369 print *, precision(y), range(y) 16370 end program prec_and_range 16371 16372 16373File: gfortran.info, Node: PRESENT, Next: PRODUCT, Prev: PRECISION, Up: Intrinsic Procedures 16374 163759.217 'PRESENT' -- Determine whether an optional dummy argument is specified 16376============================================================================ 16377 16378_Description_: 16379 Determines whether an optional dummy argument is present. 16380 16381_Standard_: 16382 Fortran 95 and later 16383 16384_Class_: 16385 Inquiry function 16386 16387_Syntax_: 16388 'RESULT = PRESENT(A)' 16389 16390_Arguments_: 16391 A May be of any type and may be a pointer, scalar 16392 or array value, or a dummy procedure. It shall 16393 be the name of an optional dummy argument 16394 accessible within the current subroutine or 16395 function. 16396 16397_Return value_: 16398 Returns either 'TRUE' if the optional argument A is present, or 16399 'FALSE' otherwise. 16400 16401_Example_: 16402 PROGRAM test_present 16403 WRITE(*,*) f(), f(42) ! "F T" 16404 CONTAINS 16405 LOGICAL FUNCTION f(x) 16406 INTEGER, INTENT(IN), OPTIONAL :: x 16407 f = PRESENT(x) 16408 END FUNCTION 16409 END PROGRAM 16410 16411 16412File: gfortran.info, Node: PRODUCT, Next: RADIX, Prev: PRESENT, Up: Intrinsic Procedures 16413 164149.218 'PRODUCT' -- Product of array elements 16415============================================ 16416 16417_Description_: 16418 Multiplies the elements of ARRAY along dimension DIM if the 16419 corresponding element in MASK is 'TRUE'. 16420 16421_Standard_: 16422 Fortran 95 and later 16423 16424_Class_: 16425 Transformational function 16426 16427_Syntax_: 16428 'RESULT = PRODUCT(ARRAY[, MASK])' 16429 'RESULT = PRODUCT(ARRAY, DIM[, MASK])' 16430 16431_Arguments_: 16432 ARRAY Shall be an array of type 'INTEGER', 'REAL' or 16433 'COMPLEX'. 16434 DIM (Optional) shall be a scalar of type 'INTEGER' 16435 with a value in the range from 1 to n, where n 16436 equals the rank of ARRAY. 16437 MASK (Optional) shall be of type 'LOGICAL' and either 16438 be a scalar or an array of the same shape as 16439 ARRAY. 16440 16441_Return value_: 16442 The result is of the same type as ARRAY. 16443 16444 If DIM is absent, a scalar with the product of all elements in 16445 ARRAY is returned. Otherwise, an array of rank n-1, where n equals 16446 the rank of ARRAY, and a shape similar to that of ARRAY with 16447 dimension DIM dropped is returned. 16448 16449_Example_: 16450 PROGRAM test_product 16451 INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /) 16452 print *, PRODUCT(x) ! all elements, product = 120 16453 print *, PRODUCT(x, MASK=MOD(x, 2)==1) ! odd elements, product = 15 16454 END PROGRAM 16455 16456_See also_: 16457 *note SUM:: 16458 16459 16460File: gfortran.info, Node: RADIX, Next: RAN, Prev: PRODUCT, Up: Intrinsic Procedures 16461 164629.219 'RADIX' -- Base of a model number 16463======================================= 16464 16465_Description_: 16466 'RADIX(X)' returns the base of the model representing the entity X. 16467 16468_Standard_: 16469 Fortran 95 and later 16470 16471_Class_: 16472 Inquiry function 16473 16474_Syntax_: 16475 'RESULT = RADIX(X)' 16476 16477_Arguments_: 16478 X Shall be of type 'INTEGER' or 'REAL' 16479 16480_Return value_: 16481 The return value is a scalar of type 'INTEGER' and of the default 16482 integer kind. 16483 16484_See also_: 16485 *note SELECTED_REAL_KIND:: 16486 16487_Example_: 16488 program test_radix 16489 print *, "The radix for the default integer kind is", radix(0) 16490 print *, "The radix for the default real kind is", radix(0.0) 16491 end program test_radix 16492 16493 16494File: gfortran.info, Node: RAN, Next: RAND, Prev: RADIX, Up: Intrinsic Procedures 16495 164969.220 'RAN' -- Real pseudo-random number 16497======================================== 16498 16499_Description_: 16500 For compatibility with HP FORTRAN 77/iX, the 'RAN' intrinsic is 16501 provided as an alias for 'RAND'. See *note RAND:: for complete 16502 documentation. 16503 16504_Standard_: 16505 GNU extension 16506 16507_Class_: 16508 Function 16509 16510_See also_: 16511 *note RAND::, *note RANDOM_NUMBER:: 16512 16513 16514File: gfortran.info, Node: RAND, Next: RANDOM_NUMBER, Prev: RAN, Up: Intrinsic Procedures 16515 165169.221 'RAND' -- Real pseudo-random number 16517========================================= 16518 16519_Description_: 16520 'RAND(FLAG)' returns a pseudo-random number from a uniform 16521 distribution between 0 and 1. If FLAG is 0, the next number in the 16522 current sequence is returned; if FLAG is 1, the generator is 16523 restarted by 'CALL SRAND(0)'; if FLAG has any other value, it is 16524 used as a new seed with 'SRAND'. 16525 16526 This intrinsic routine is provided for backwards compatibility with 16527 GNU Fortran 77. It implements a simple modulo generator as 16528 provided by 'g77'. For new code, one should consider the use of 16529 *note RANDOM_NUMBER:: as it implements a superior algorithm. 16530 16531_Standard_: 16532 GNU extension 16533 16534_Class_: 16535 Function 16536 16537_Syntax_: 16538 'RESULT = RAND(I)' 16539 16540_Arguments_: 16541 I Shall be a scalar 'INTEGER' of kind 4. 16542 16543_Return value_: 16544 The return value is of 'REAL' type and the default kind. 16545 16546_Example_: 16547 program test_rand 16548 integer,parameter :: seed = 86456 16549 16550 call srand(seed) 16551 print *, rand(), rand(), rand(), rand() 16552 print *, rand(seed), rand(), rand(), rand() 16553 end program test_rand 16554 16555_See also_: 16556 *note SRAND::, *note RANDOM_NUMBER:: 16557 16558 16559File: gfortran.info, Node: RANDOM_NUMBER, Next: RANDOM_SEED, Prev: RAND, Up: Intrinsic Procedures 16560 165619.222 'RANDOM_NUMBER' -- Pseudo-random number 16562============================================= 16563 16564_Description_: 16565 Returns a single pseudorandom number or an array of pseudorandom 16566 numbers from the uniform distribution over the range 0 \leq x < 1. 16567 16568 The runtime-library implements the xorshift1024* random number 16569 generator (RNG). This generator has a period of 2^{1024} - 1, and 16570 when using multiple threads up to 2^{512} threads can each generate 16571 2^{512} random numbers before any aliasing occurs. 16572 16573 Note that in a multi-threaded program (e.g. using OpenMP 16574 directives), each thread will have its own random number state. 16575 For details of the seeding procedure, see the documentation for the 16576 'RANDOM_SEED' intrinsic. 16577 16578_Standard_: 16579 Fortran 95 and later 16580 16581_Class_: 16582 Subroutine 16583 16584_Syntax_: 16585 'RANDOM_NUMBER(HARVEST)' 16586 16587_Arguments_: 16588 HARVEST Shall be a scalar or an array of type 'REAL'. 16589 16590_Example_: 16591 program test_random_number 16592 REAL :: r(5,5) 16593 CALL RANDOM_NUMBER(r) 16594 end program 16595 16596_See also_: 16597 *note RANDOM_SEED:: 16598 16599 16600File: gfortran.info, Node: RANDOM_SEED, Next: RANGE, Prev: RANDOM_NUMBER, Up: Intrinsic Procedures 16601 166029.223 'RANDOM_SEED' -- Initialize a pseudo-random number sequence 16603================================================================= 16604 16605_Description_: 16606 Restarts or queries the state of the pseudorandom number generator 16607 used by 'RANDOM_NUMBER'. 16608 16609 If 'RANDOM_SEED' is called without arguments, it is seeded with 16610 random data retrieved from the operating system. 16611 16612 As an extension to the Fortran standard, the GFortran 16613 'RANDOM_NUMBER' supports multiple threads. Each thread in a 16614 multi-threaded program has its own seed. When 'RANDOM_SEED' is 16615 called either without arguments or with the PUT argument, the given 16616 seed is copied into a master seed as well as the seed of the 16617 current thread. When a new thread uses 'RANDOM_NUMBER' for the 16618 first time, the seed is copied from the master seed, and forwarded 16619 N * 2^{512} steps to guarantee that the random stream does not 16620 alias any other stream in the system, where N is the number of 16621 threads that have used 'RANDOM_NUMBER' so far during the program 16622 execution. 16623 16624_Standard_: 16625 Fortran 95 and later 16626 16627_Class_: 16628 Subroutine 16629 16630_Syntax_: 16631 'CALL RANDOM_SEED([SIZE, PUT, GET])' 16632 16633_Arguments_: 16634 SIZE (Optional) Shall be a scalar and of type default 16635 'INTEGER', with 'INTENT(OUT)'. It specifies the 16636 minimum size of the arrays used with the PUT and 16637 GET arguments. 16638 PUT (Optional) Shall be an array of type default 16639 'INTEGER' and rank one. It is 'INTENT(IN)' and 16640 the size of the array must be larger than or 16641 equal to the number returned by the SIZE 16642 argument. 16643 GET (Optional) Shall be an array of type default 16644 'INTEGER' and rank one. It is 'INTENT(OUT)' and 16645 the size of the array must be larger than or 16646 equal to the number returned by the SIZE 16647 argument. 16648 16649_Example_: 16650 program test_random_seed 16651 implicit none 16652 integer, allocatable :: seed(:) 16653 integer :: n 16654 16655 call random_seed(size = n) 16656 allocate(seed(n)) 16657 call random_seed(get=seed) 16658 write (*, *) seed 16659 end program test_random_seed 16660 16661_See also_: 16662 *note RANDOM_NUMBER:: 16663 16664 16665File: gfortran.info, Node: RANGE, Next: RANK, Prev: RANDOM_SEED, Up: Intrinsic Procedures 16666 166679.224 'RANGE' -- Decimal exponent range 16668======================================= 16669 16670_Description_: 16671 'RANGE(X)' returns the decimal exponent range in the model of the 16672 type of 'X'. 16673 16674_Standard_: 16675 Fortran 95 and later 16676 16677_Class_: 16678 Inquiry function 16679 16680_Syntax_: 16681 'RESULT = RANGE(X)' 16682 16683_Arguments_: 16684 X Shall be of type 'INTEGER', 'REAL' or 'COMPLEX'. 16685 16686_Return value_: 16687 The return value is of type 'INTEGER' and of the default integer 16688 kind. 16689 16690_See also_: 16691 *note SELECTED_REAL_KIND::, *note PRECISION:: 16692 16693_Example_: 16694 See 'PRECISION' for an example. 16695 16696 16697File: gfortran.info, Node: RANK, Next: REAL, Prev: RANGE, Up: Intrinsic Procedures 16698 166999.225 'RANK' -- Rank of a data object 16700===================================== 16701 16702_Description_: 16703 'RANK(A)' returns the rank of a scalar or array data object. 16704 16705_Standard_: 16706 Technical Specification (TS) 29113 16707 16708_Class_: 16709 Inquiry function 16710 16711_Syntax_: 16712 'RESULT = RANK(A)' 16713 16714_Arguments_: 16715 A can be of any type 16716 16717_Return value_: 16718 The return value is of type 'INTEGER' and of the default integer 16719 kind. For arrays, their rank is returned; for scalars zero is 16720 returned. 16721 16722_Example_: 16723 program test_rank 16724 integer :: a 16725 real, allocatable :: b(:,:) 16726 16727 print *, rank(a), rank(b) ! Prints: 0 2 16728 end program test_rank 16729 16730 16731File: gfortran.info, Node: REAL, Next: RENAME, Prev: RANK, Up: Intrinsic Procedures 16732 167339.226 'REAL' -- Convert to real type 16734==================================== 16735 16736_Description_: 16737 'REAL(A [, KIND])' converts its argument A to a real type. The 16738 'REALPART' function is provided for compatibility with 'g77', and 16739 its use is strongly discouraged. 16740 16741_Standard_: 16742 Fortran 77 and later 16743 16744_Class_: 16745 Elemental function 16746 16747_Syntax_: 16748 'RESULT = REAL(A [, KIND])' 16749 'RESULT = REALPART(Z)' 16750 16751_Arguments_: 16752 A Shall be 'INTEGER', 'REAL', or 'COMPLEX'. 16753 KIND (Optional) An 'INTEGER' initialization 16754 expression indicating the kind parameter of the 16755 result. 16756 16757_Return value_: 16758 These functions return a 'REAL' variable or array under the 16759 following rules: 16760 16761 (A) 16762 'REAL(A)' is converted to a default real type if A is an 16763 integer or real variable. 16764 (B) 16765 'REAL(A)' is converted to a real type with the kind type 16766 parameter of A if A is a complex variable. 16767 (C) 16768 'REAL(A, KIND)' is converted to a real type with kind type 16769 parameter KIND if A is a complex, integer, or real variable. 16770 16771_Example_: 16772 program test_real 16773 complex :: x = (1.0, 2.0) 16774 print *, real(x), real(x,8), realpart(x) 16775 end program test_real 16776 16777_Specific names_: 16778 Name Argument Return type Standard 16779 'FLOAT(A)' 'INTEGER(4)' 'REAL(4)' Fortran 77 and 16780 later 16781 'DFLOAT(A)' 'INTEGER(4)' 'REAL(8)' GNU extension 16782 'FLOATI(A)' 'INTEGER(2)' 'REAL(4)' GNU extension 16783 'FLOATJ(A)' 'INTEGER(4)' 'REAL(4)' GNU extension 16784 'FLOATK(A)' 'INTEGER(8)' 'REAL(4)' GNU extension 16785 'SNGL(A)' 'INTEGER(8)' 'REAL(4)' Fortran 77 and 16786 later 16787 16788_See also_: 16789 *note DBLE:: 16790 16791 16792File: gfortran.info, Node: RENAME, Next: REPEAT, Prev: REAL, Up: Intrinsic Procedures 16793 167949.227 'RENAME' -- Rename a file 16795=============================== 16796 16797_Description_: 16798 Renames a file from file PATH1 to PATH2. A null character 16799 ('CHAR(0)') can be used to mark the end of the names in PATH1 and 16800 PATH2; otherwise, trailing blanks in the file names are ignored. 16801 If the STATUS argument is supplied, it contains 0 on success or a 16802 nonzero error code upon return; see 'rename(2)'. 16803 16804 This intrinsic is provided in both subroutine and function forms; 16805 however, only one form can be used in any given program unit. 16806 16807_Standard_: 16808 GNU extension 16809 16810_Class_: 16811 Subroutine, function 16812 16813_Syntax_: 16814 'CALL RENAME(PATH1, PATH2 [, STATUS])' 16815 'STATUS = RENAME(PATH1, PATH2)' 16816 16817_Arguments_: 16818 PATH1 Shall be of default 'CHARACTER' type. 16819 PATH2 Shall be of default 'CHARACTER' type. 16820 STATUS (Optional) Shall be of default 'INTEGER' type. 16821 16822_See also_: 16823 *note LINK:: 16824 16825 16826File: gfortran.info, Node: REPEAT, Next: RESHAPE, Prev: RENAME, Up: Intrinsic Procedures 16827 168289.228 'REPEAT' -- Repeated string concatenation 16829=============================================== 16830 16831_Description_: 16832 Concatenates NCOPIES copies of a string. 16833 16834_Standard_: 16835 Fortran 95 and later 16836 16837_Class_: 16838 Transformational function 16839 16840_Syntax_: 16841 'RESULT = REPEAT(STRING, NCOPIES)' 16842 16843_Arguments_: 16844 STRING Shall be scalar and of type 'CHARACTER'. 16845 NCOPIES Shall be scalar and of type 'INTEGER'. 16846 16847_Return value_: 16848 A new scalar of type 'CHARACTER' built up from NCOPIES copies of 16849 STRING. 16850 16851_Example_: 16852 program test_repeat 16853 write(*,*) repeat("x", 5) ! "xxxxx" 16854 end program 16855 16856 16857File: gfortran.info, Node: RESHAPE, Next: RRSPACING, Prev: REPEAT, Up: Intrinsic Procedures 16858 168599.229 'RESHAPE' -- Function to reshape an array 16860=============================================== 16861 16862_Description_: 16863 Reshapes SOURCE to correspond to SHAPE. If necessary, the new 16864 array may be padded with elements from PAD or permuted as defined 16865 by ORDER. 16866 16867_Standard_: 16868 Fortran 95 and later 16869 16870_Class_: 16871 Transformational function 16872 16873_Syntax_: 16874 'RESULT = RESHAPE(SOURCE, SHAPE[, PAD, ORDER])' 16875 16876_Arguments_: 16877 SOURCE Shall be an array of any type. 16878 SHAPE Shall be of type 'INTEGER' and an array of rank 16879 one. Its values must be positive or zero. 16880 PAD (Optional) shall be an array of the same type as 16881 SOURCE. 16882 ORDER (Optional) shall be of type 'INTEGER' and an 16883 array of the same shape as SHAPE. Its values 16884 shall be a permutation of the numbers from 1 to 16885 n, where n is the size of SHAPE. If ORDER is 16886 absent, the natural ordering shall be assumed. 16887 16888_Return value_: 16889 The result is an array of shape SHAPE with the same type as SOURCE. 16890 16891_Example_: 16892 PROGRAM test_reshape 16893 INTEGER, DIMENSION(4) :: x 16894 WRITE(*,*) SHAPE(x) ! prints "4" 16895 WRITE(*,*) SHAPE(RESHAPE(x, (/2, 2/))) ! prints "2 2" 16896 END PROGRAM 16897 16898_See also_: 16899 *note SHAPE:: 16900 16901 16902File: gfortran.info, Node: RRSPACING, Next: RSHIFT, Prev: RESHAPE, Up: Intrinsic Procedures 16903 169049.230 'RRSPACING' -- Reciprocal of the relative spacing 16905======================================================= 16906 16907_Description_: 16908 'RRSPACING(X)' returns the reciprocal of the relative spacing of 16909 model numbers near X. 16910 16911_Standard_: 16912 Fortran 95 and later 16913 16914_Class_: 16915 Elemental function 16916 16917_Syntax_: 16918 'RESULT = RRSPACING(X)' 16919 16920_Arguments_: 16921 X Shall be of type 'REAL'. 16922 16923_Return value_: 16924 The return value is of the same type and kind as X. The value 16925 returned is equal to 'ABS(FRACTION(X)) * 16926 FLOAT(RADIX(X))**DIGITS(X)'. 16927 16928_See also_: 16929 *note SPACING:: 16930 16931 16932File: gfortran.info, Node: RSHIFT, Next: SAME_TYPE_AS, Prev: RRSPACING, Up: Intrinsic Procedures 16933 169349.231 'RSHIFT' -- Right shift bits 16935================================== 16936 16937_Description_: 16938 'RSHIFT' returns a value corresponding to I with all of the bits 16939 shifted right by SHIFT places. If the absolute value of SHIFT is 16940 greater than 'BIT_SIZE(I)', the value is undefined. Bits shifted 16941 out from the right end are lost. The fill is arithmetic: the bits 16942 shifted in from the left end are equal to the leftmost bit, which 16943 in two's complement representation is the sign bit. 16944 16945 This function has been superseded by the 'SHIFTA' intrinsic, which 16946 is standard in Fortran 2008 and later. 16947 16948_Standard_: 16949 GNU extension 16950 16951_Class_: 16952 Elemental function 16953 16954_Syntax_: 16955 'RESULT = RSHIFT(I, SHIFT)' 16956 16957_Arguments_: 16958 I The type shall be 'INTEGER'. 16959 SHIFT The type shall be 'INTEGER'. 16960 16961_Return value_: 16962 The return value is of type 'INTEGER' and of the same kind as I. 16963 16964_See also_: 16965 *note ISHFT::, *note ISHFTC::, *note LSHIFT::, *note SHIFTA::, 16966 *note SHIFTR::, *note SHIFTL:: 16967 16968 16969File: gfortran.info, Node: SAME_TYPE_AS, Next: SCALE, Prev: RSHIFT, Up: Intrinsic Procedures 16970 169719.232 'SAME_TYPE_AS' -- Query dynamic types for equality 16972======================================================== 16973 16974_Description_: 16975 Query dynamic types for equality. 16976 16977_Standard_: 16978 Fortran 2003 and later 16979 16980_Class_: 16981 Inquiry function 16982 16983_Syntax_: 16984 'RESULT = SAME_TYPE_AS(A, B)' 16985 16986_Arguments_: 16987 A Shall be an object of extensible declared type 16988 or unlimited polymorphic. 16989 B Shall be an object of extensible declared type 16990 or unlimited polymorphic. 16991 16992_Return value_: 16993 The return value is a scalar of type default logical. It is true 16994 if and only if the dynamic type of A is the same as the dynamic 16995 type of B. 16996 16997_See also_: 16998 *note EXTENDS_TYPE_OF:: 16999 17000 17001File: gfortran.info, Node: SCALE, Next: SCAN, Prev: SAME_TYPE_AS, Up: Intrinsic Procedures 17002 170039.233 'SCALE' -- Scale a real value 17004=================================== 17005 17006_Description_: 17007 'SCALE(X,I)' returns 'X * RADIX(X)**I'. 17008 17009_Standard_: 17010 Fortran 95 and later 17011 17012_Class_: 17013 Elemental function 17014 17015_Syntax_: 17016 'RESULT = SCALE(X, I)' 17017 17018_Arguments_: 17019 X The type of the argument shall be a 'REAL'. 17020 I The type of the argument shall be a 'INTEGER'. 17021 17022_Return value_: 17023 The return value is of the same type and kind as X. Its value is 17024 'X * RADIX(X)**I'. 17025 17026_Example_: 17027 program test_scale 17028 real :: x = 178.1387e-4 17029 integer :: i = 5 17030 print *, scale(x,i), x*radix(x)**i 17031 end program test_scale 17032 17033 17034File: gfortran.info, Node: SCAN, Next: SECNDS, Prev: SCALE, Up: Intrinsic Procedures 17035 170369.234 'SCAN' -- Scan a string for the presence of a set of characters 17037===================================================================== 17038 17039_Description_: 17040 Scans a STRING for any of the characters in a SET of characters. 17041 17042 If BACK is either absent or equals 'FALSE', this function returns 17043 the position of the leftmost character of STRING that is in SET. 17044 If BACK equals 'TRUE', the rightmost position is returned. If no 17045 character of SET is found in STRING, the result is zero. 17046 17047_Standard_: 17048 Fortran 95 and later, with KIND argument Fortran 2003 and later 17049 17050_Class_: 17051 Elemental function 17052 17053_Syntax_: 17054 'RESULT = SCAN(STRING, SET[, BACK [, KIND]])' 17055 17056_Arguments_: 17057 STRING Shall be of type 'CHARACTER'. 17058 SET Shall be of type 'CHARACTER'. 17059 BACK (Optional) shall be of type 'LOGICAL'. 17060 KIND (Optional) An 'INTEGER' initialization 17061 expression indicating the kind parameter of the 17062 result. 17063 17064_Return value_: 17065 The return value is of type 'INTEGER' and of kind KIND. If KIND is 17066 absent, the return value is of default integer kind. 17067 17068_Example_: 17069 PROGRAM test_scan 17070 WRITE(*,*) SCAN("FORTRAN", "AO") ! 2, found 'O' 17071 WRITE(*,*) SCAN("FORTRAN", "AO", .TRUE.) ! 6, found 'A' 17072 WRITE(*,*) SCAN("FORTRAN", "C++") ! 0, found none 17073 END PROGRAM 17074 17075_See also_: 17076 *note INDEX intrinsic::, *note VERIFY:: 17077 17078 17079File: gfortran.info, Node: SECNDS, Next: SECOND, Prev: SCAN, Up: Intrinsic Procedures 17080 170819.235 'SECNDS' -- Time function 17082=============================== 17083 17084_Description_: 17085 'SECNDS(X)' gets the time in seconds from the real-time system 17086 clock. X is a reference time, also in seconds. If this is zero, 17087 the time in seconds from midnight is returned. This function is 17088 non-standard and its use is discouraged. 17089 17090_Standard_: 17091 GNU extension 17092 17093_Class_: 17094 Function 17095 17096_Syntax_: 17097 'RESULT = SECNDS (X)' 17098 17099_Arguments_: 17100 T Shall be of type 'REAL(4)'. 17101 X Shall be of type 'REAL(4)'. 17102 17103_Return value_: 17104 None 17105 17106_Example_: 17107 program test_secnds 17108 integer :: i 17109 real(4) :: t1, t2 17110 print *, secnds (0.0) ! seconds since midnight 17111 t1 = secnds (0.0) ! reference time 17112 do i = 1, 10000000 ! do something 17113 end do 17114 t2 = secnds (t1) ! elapsed time 17115 print *, "Something took ", t2, " seconds." 17116 end program test_secnds 17117 17118 17119File: gfortran.info, Node: SECOND, Next: SELECTED_CHAR_KIND, Prev: SECNDS, Up: Intrinsic Procedures 17120 171219.236 'SECOND' -- CPU time function 17122=================================== 17123 17124_Description_: 17125 Returns a 'REAL(4)' value representing the elapsed CPU time in 17126 seconds. This provides the same functionality as the standard 17127 'CPU_TIME' intrinsic, and is only included for backwards 17128 compatibility. 17129 17130 This intrinsic is provided in both subroutine and function forms; 17131 however, only one form can be used in any given program unit. 17132 17133_Standard_: 17134 GNU extension 17135 17136_Class_: 17137 Subroutine, function 17138 17139_Syntax_: 17140 'CALL SECOND(TIME)' 17141 'TIME = SECOND()' 17142 17143_Arguments_: 17144 TIME Shall be of type 'REAL(4)'. 17145 17146_Return value_: 17147 In either syntax, TIME is set to the process's current runtime in 17148 seconds. 17149 17150_See also_: 17151 *note CPU_TIME:: 17152 17153 17154File: gfortran.info, Node: SELECTED_CHAR_KIND, Next: SELECTED_INT_KIND, Prev: SECOND, Up: Intrinsic Procedures 17155 171569.237 'SELECTED_CHAR_KIND' -- Choose character kind 17157=================================================== 17158 17159_Description_: 17160 17161 'SELECTED_CHAR_KIND(NAME)' returns the kind value for the character 17162 set named NAME, if a character set with such a name is supported, 17163 or -1 otherwise. Currently, supported character sets include 17164 "ASCII" and "DEFAULT", which are equivalent, and "ISO_10646" 17165 (Universal Character Set, UCS-4) which is commonly known as 17166 Unicode. 17167 17168_Standard_: 17169 Fortran 2003 and later 17170 17171_Class_: 17172 Transformational function 17173 17174_Syntax_: 17175 'RESULT = SELECTED_CHAR_KIND(NAME)' 17176 17177_Arguments_: 17178 NAME Shall be a scalar and of the default character 17179 type. 17180 17181_Example_: 17182 program character_kind 17183 use iso_fortran_env 17184 implicit none 17185 integer, parameter :: ascii = selected_char_kind ("ascii") 17186 integer, parameter :: ucs4 = selected_char_kind ('ISO_10646') 17187 17188 character(kind=ascii, len=26) :: alphabet 17189 character(kind=ucs4, len=30) :: hello_world 17190 17191 alphabet = ascii_"abcdefghijklmnopqrstuvwxyz" 17192 hello_world = ucs4_'Hello World and Ni Hao -- ' & 17193 // char (int (z'4F60'), ucs4) & 17194 // char (int (z'597D'), ucs4) 17195 17196 write (*,*) alphabet 17197 17198 open (output_unit, encoding='UTF-8') 17199 write (*,*) trim (hello_world) 17200 end program character_kind 17201 17202 17203File: gfortran.info, Node: SELECTED_INT_KIND, Next: SELECTED_REAL_KIND, Prev: SELECTED_CHAR_KIND, Up: Intrinsic Procedures 17204 172059.238 'SELECTED_INT_KIND' -- Choose integer kind 17206================================================ 17207 17208_Description_: 17209 'SELECTED_INT_KIND(R)' return the kind value of the smallest 17210 integer type that can represent all values ranging from -10^R 17211 (exclusive) to 10^R (exclusive). If there is no integer kind that 17212 accommodates this range, 'SELECTED_INT_KIND' returns -1. 17213 17214_Standard_: 17215 Fortran 95 and later 17216 17217_Class_: 17218 Transformational function 17219 17220_Syntax_: 17221 'RESULT = SELECTED_INT_KIND(R)' 17222 17223_Arguments_: 17224 R Shall be a scalar and of type 'INTEGER'. 17225 17226_Example_: 17227 program large_integers 17228 integer,parameter :: k5 = selected_int_kind(5) 17229 integer,parameter :: k15 = selected_int_kind(15) 17230 integer(kind=k5) :: i5 17231 integer(kind=k15) :: i15 17232 17233 print *, huge(i5), huge(i15) 17234 17235 ! The following inequalities are always true 17236 print *, huge(i5) >= 10_k5**5-1 17237 print *, huge(i15) >= 10_k15**15-1 17238 end program large_integers 17239 17240 17241File: gfortran.info, Node: SELECTED_REAL_KIND, Next: SET_EXPONENT, Prev: SELECTED_INT_KIND, Up: Intrinsic Procedures 17242 172439.239 'SELECTED_REAL_KIND' -- Choose real kind 17244============================================== 17245 17246_Description_: 17247 'SELECTED_REAL_KIND(P,R)' returns the kind value of a real data 17248 type with decimal precision of at least 'P' digits, exponent range 17249 of at least 'R', and with a radix of 'RADIX'. 17250 17251_Standard_: 17252 Fortran 95 and later, with 'RADIX' Fortran 2008 or later 17253 17254_Class_: 17255 Transformational function 17256 17257_Syntax_: 17258 'RESULT = SELECTED_REAL_KIND([P, R, RADIX])' 17259 17260_Arguments_: 17261 P (Optional) shall be a scalar and of type 17262 'INTEGER'. 17263 R (Optional) shall be a scalar and of type 17264 'INTEGER'. 17265 RADIX (Optional) shall be a scalar and of type 17266 'INTEGER'. 17267 Before Fortran 2008, at least one of the arguments R or P shall be 17268 present; since Fortran 2008, they are assumed to be zero if absent. 17269 17270_Return value_: 17271 17272 'SELECTED_REAL_KIND' returns the value of the kind type parameter 17273 of a real data type with decimal precision of at least 'P' digits, 17274 a decimal exponent range of at least 'R', and with the requested 17275 'RADIX'. If the 'RADIX' parameter is absent, real kinds with any 17276 radix can be returned. If more than one real data type meet the 17277 criteria, the kind of the data type with the smallest decimal 17278 precision is returned. If no real data type matches the criteria, 17279 the result is 17280 -1 if the processor does not support a real data type with a 17281 precision greater than or equal to 'P', but the 'R' and 17282 'RADIX' requirements can be fulfilled 17283 -2 if the processor does not support a real type with an exponent 17284 range greater than or equal to 'R', but 'P' and 'RADIX' are 17285 fulfillable 17286 -3 if 'RADIX' but not 'P' and 'R' requirements 17287 are fulfillable 17288 -4 if 'RADIX' and either 'P' or 'R' requirements 17289 are fulfillable 17290 -5 if there is no real type with the given 'RADIX' 17291 17292_See also_: 17293 *note PRECISION::, *note RANGE::, *note RADIX:: 17294 17295_Example_: 17296 program real_kinds 17297 integer,parameter :: p6 = selected_real_kind(6) 17298 integer,parameter :: p10r100 = selected_real_kind(10,100) 17299 integer,parameter :: r400 = selected_real_kind(r=400) 17300 real(kind=p6) :: x 17301 real(kind=p10r100) :: y 17302 real(kind=r400) :: z 17303 17304 print *, precision(x), range(x) 17305 print *, precision(y), range(y) 17306 print *, precision(z), range(z) 17307 end program real_kinds 17308 17309 17310File: gfortran.info, Node: SET_EXPONENT, Next: SHAPE, Prev: SELECTED_REAL_KIND, Up: Intrinsic Procedures 17311 173129.240 'SET_EXPONENT' -- Set the exponent of the model 17313===================================================== 17314 17315_Description_: 17316 'SET_EXPONENT(X, I)' returns the real number whose fractional part 17317 is that that of X and whose exponent part is I. 17318 17319_Standard_: 17320 Fortran 95 and later 17321 17322_Class_: 17323 Elemental function 17324 17325_Syntax_: 17326 'RESULT = SET_EXPONENT(X, I)' 17327 17328_Arguments_: 17329 X Shall be of type 'REAL'. 17330 I Shall be of type 'INTEGER'. 17331 17332_Return value_: 17333 The return value is of the same type and kind as X. The real 17334 number whose fractional part is that that of X and whose exponent 17335 part if I is returned; it is 'FRACTION(X) * RADIX(X)**I'. 17336 17337_Example_: 17338 PROGRAM test_setexp 17339 REAL :: x = 178.1387e-4 17340 INTEGER :: i = 17 17341 PRINT *, SET_EXPONENT(x, i), FRACTION(x) * RADIX(x)**i 17342 END PROGRAM 17343 17344 17345File: gfortran.info, Node: SHAPE, Next: SHIFTA, Prev: SET_EXPONENT, Up: Intrinsic Procedures 17346 173479.241 'SHAPE' -- Determine the shape of an array 17348================================================ 17349 17350_Description_: 17351 Determines the shape of an array. 17352 17353_Standard_: 17354 Fortran 95 and later, with KIND argument Fortran 2003 and later 17355 17356_Class_: 17357 Inquiry function 17358 17359_Syntax_: 17360 'RESULT = SHAPE(SOURCE [, KIND])' 17361 17362_Arguments_: 17363 SOURCE Shall be an array or scalar of any type. If 17364 SOURCE is a pointer it must be associated and 17365 allocatable arrays must be allocated. 17366 KIND (Optional) An 'INTEGER' initialization 17367 expression indicating the kind parameter of the 17368 result. 17369 17370_Return value_: 17371 An 'INTEGER' array of rank one with as many elements as SOURCE has 17372 dimensions. The elements of the resulting array correspond to the 17373 extend of SOURCE along the respective dimensions. If SOURCE is a 17374 scalar, the result is the rank one array of size zero. If KIND is 17375 absent, the return value has the default integer kind otherwise the 17376 specified kind. 17377 17378_Example_: 17379 PROGRAM test_shape 17380 INTEGER, DIMENSION(-1:1, -1:2) :: A 17381 WRITE(*,*) SHAPE(A) ! (/ 3, 4 /) 17382 WRITE(*,*) SIZE(SHAPE(42)) ! (/ /) 17383 END PROGRAM 17384 17385_See also_: 17386 *note RESHAPE::, *note SIZE:: 17387 17388 17389File: gfortran.info, Node: SHIFTA, Next: SHIFTL, Prev: SHAPE, Up: Intrinsic Procedures 17390 173919.242 'SHIFTA' -- Right shift with fill 17392======================================= 17393 17394_Description_: 17395 'SHIFTA' returns a value corresponding to I with all of the bits 17396 shifted right by SHIFT places. If the absolute value of SHIFT is 17397 greater than 'BIT_SIZE(I)', the value is undefined. Bits shifted 17398 out from the right end are lost. The fill is arithmetic: the bits 17399 shifted in from the left end are equal to the leftmost bit, which 17400 in two's complement representation is the sign bit. 17401 17402_Standard_: 17403 Fortran 2008 and later 17404 17405_Class_: 17406 Elemental function 17407 17408_Syntax_: 17409 'RESULT = SHIFTA(I, SHIFT)' 17410 17411_Arguments_: 17412 I The type shall be 'INTEGER'. 17413 SHIFT The type shall be 'INTEGER'. 17414 17415_Return value_: 17416 The return value is of type 'INTEGER' and of the same kind as I. 17417 17418_See also_: 17419 *note SHIFTL::, *note SHIFTR:: 17420 17421 17422File: gfortran.info, Node: SHIFTL, Next: SHIFTR, Prev: SHIFTA, Up: Intrinsic Procedures 17423 174249.243 'SHIFTL' -- Left shift 17425============================ 17426 17427_Description_: 17428 'SHIFTL' returns a value corresponding to I with all of the bits 17429 shifted left by SHIFT places. If the absolute value of SHIFT is 17430 greater than 'BIT_SIZE(I)', the value is undefined. Bits shifted 17431 out from the left end are lost, and bits shifted in from the right 17432 end are set to 0. 17433 17434_Standard_: 17435 Fortran 2008 and later 17436 17437_Class_: 17438 Elemental function 17439 17440_Syntax_: 17441 'RESULT = SHIFTL(I, SHIFT)' 17442 17443_Arguments_: 17444 I The type shall be 'INTEGER'. 17445 SHIFT The type shall be 'INTEGER'. 17446 17447_Return value_: 17448 The return value is of type 'INTEGER' and of the same kind as I. 17449 17450_See also_: 17451 *note SHIFTA::, *note SHIFTR:: 17452 17453 17454File: gfortran.info, Node: SHIFTR, Next: SIGN, Prev: SHIFTL, Up: Intrinsic Procedures 17455 174569.244 'SHIFTR' -- Right shift 17457============================= 17458 17459_Description_: 17460 'SHIFTR' returns a value corresponding to I with all of the bits 17461 shifted right by SHIFT places. If the absolute value of SHIFT is 17462 greater than 'BIT_SIZE(I)', the value is undefined. Bits shifted 17463 out from the right end are lost, and bits shifted in from the left 17464 end are set to 0. 17465 17466_Standard_: 17467 Fortran 2008 and later 17468 17469_Class_: 17470 Elemental function 17471 17472_Syntax_: 17473 'RESULT = SHIFTR(I, SHIFT)' 17474 17475_Arguments_: 17476 I The type shall be 'INTEGER'. 17477 SHIFT The type shall be 'INTEGER'. 17478 17479_Return value_: 17480 The return value is of type 'INTEGER' and of the same kind as I. 17481 17482_See also_: 17483 *note SHIFTA::, *note SHIFTL:: 17484 17485 17486File: gfortran.info, Node: SIGN, Next: SIGNAL, Prev: SHIFTR, Up: Intrinsic Procedures 17487 174889.245 'SIGN' -- Sign copying function 17489===================================== 17490 17491_Description_: 17492 'SIGN(A,B)' returns the value of A with the sign of B. 17493 17494_Standard_: 17495 Fortran 77 and later 17496 17497_Class_: 17498 Elemental function 17499 17500_Syntax_: 17501 'RESULT = SIGN(A, B)' 17502 17503_Arguments_: 17504 A Shall be of type 'INTEGER' or 'REAL' 17505 B Shall be of the same type and kind as A 17506 17507_Return value_: 17508 The kind of the return value is that of A and B. If B\ge 0 then 17509 the result is 'ABS(A)', else it is '-ABS(A)'. 17510 17511_Example_: 17512 program test_sign 17513 print *, sign(-12,1) 17514 print *, sign(-12,0) 17515 print *, sign(-12,-1) 17516 17517 print *, sign(-12.,1.) 17518 print *, sign(-12.,0.) 17519 print *, sign(-12.,-1.) 17520 end program test_sign 17521 17522_Specific names_: 17523 Name Arguments Return type Standard 17524 'SIGN(A,B)' 'REAL(4) A, 'REAL(4)' f77, gnu 17525 B' 17526 'ISIGN(A,B)' 'INTEGER(4) 'INTEGER(4)' f77, gnu 17527 A, B' 17528 'DSIGN(A,B)' 'REAL(8) A, 'REAL(8)' f77, gnu 17529 B' 17530 17531 17532File: gfortran.info, Node: SIGNAL, Next: SIN, Prev: SIGN, Up: Intrinsic Procedures 17533 175349.246 'SIGNAL' -- Signal handling subroutine (or function) 17535========================================================== 17536 17537_Description_: 17538 'SIGNAL(NUMBER, HANDLER [, STATUS])' causes external subroutine 17539 HANDLER to be executed with a single integer argument when signal 17540 NUMBER occurs. If HANDLER is an integer, it can be used to turn 17541 off handling of signal NUMBER or revert to its default action. See 17542 'signal(2)'. 17543 17544 If 'SIGNAL' is called as a subroutine and the STATUS argument is 17545 supplied, it is set to the value returned by 'signal(2)'. 17546 17547_Standard_: 17548 GNU extension 17549 17550_Class_: 17551 Subroutine, function 17552 17553_Syntax_: 17554 'CALL SIGNAL(NUMBER, HANDLER [, STATUS])' 17555 'STATUS = SIGNAL(NUMBER, HANDLER)' 17556 17557_Arguments_: 17558 NUMBER Shall be a scalar integer, with 'INTENT(IN)' 17559 HANDLER Signal handler ('INTEGER FUNCTION' or 17560 'SUBROUTINE') or dummy/global 'INTEGER' scalar. 17561 'INTEGER'. It is 'INTENT(IN)'. 17562 STATUS (Optional) STATUS shall be a scalar integer. It 17563 has 'INTENT(OUT)'. 17564 17565_Return value_: 17566 The 'SIGNAL' function returns the value returned by 'signal(2)'. 17567 17568_Example_: 17569 program test_signal 17570 intrinsic signal 17571 external handler_print 17572 17573 call signal (12, handler_print) 17574 call signal (10, 1) 17575 17576 call sleep (30) 17577 end program test_signal 17578 17579 17580File: gfortran.info, Node: SIN, Next: SIND, Prev: SIGNAL, Up: Intrinsic Procedures 17581 175829.247 'SIN' -- Sine function 17583============================ 17584 17585_Description_: 17586 'SIN(X)' computes the sine of X. 17587 17588_Standard_: 17589 Fortran 77 and later 17590 17591_Class_: 17592 Elemental function 17593 17594_Syntax_: 17595 'RESULT = SIN(X)' 17596 17597_Arguments_: 17598 X The type shall be 'REAL' or 'COMPLEX'. 17599 17600_Return value_: 17601 The return value has same type and kind as X. 17602 17603_Example_: 17604 program test_sin 17605 real :: x = 0.0 17606 x = sin(x) 17607 end program test_sin 17608 17609_Specific names_: 17610 Name Argument Return type Standard 17611 'SIN(X)' 'REAL(4) X' 'REAL(4)' f77, gnu 17612 'DSIN(X)' 'REAL(8) X' 'REAL(8)' f95, gnu 17613 'CSIN(X)' 'COMPLEX(4) 'COMPLEX(4)' f95, gnu 17614 X' 17615 'ZSIN(X)' 'COMPLEX(8) 'COMPLEX(8)' f95, gnu 17616 X' 17617 'CDSIN(X)' 'COMPLEX(8) 'COMPLEX(8)' f95, gnu 17618 X' 17619 17620_See also_: 17621 Inverse function: *note ASIN:: Degrees function: *note SIND:: 17622 17623 17624File: gfortran.info, Node: SIND, Next: SINH, Prev: SIN, Up: Intrinsic Procedures 17625 176269.248 'SIND' -- Sine function, degrees 17627====================================== 17628 17629_Description_: 17630 'SIND(X)' computes the sine of X in degrees. 17631 17632 This function is for compatibility only and should be avoided in 17633 favor of standard constructs wherever possible. 17634 17635_Standard_: 17636 GNU Extension, enabled with '-fdec-math'. 17637 17638_Class_: 17639 Elemental function 17640 17641_Syntax_: 17642 'RESULT = SIND(X)' 17643 17644_Arguments_: 17645 X The type shall be 'REAL' or 'COMPLEX'. 17646 17647_Return value_: 17648 The return value has same type and kind as X, and its value is in 17649 degrees. 17650 17651_Example_: 17652 program test_sind 17653 real :: x = 0.0 17654 x = sind(x) 17655 end program test_sind 17656 17657_Specific names_: 17658 Name Argument Return type Standard 17659 'SIND(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 17660 'DSIND(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 17661 'CSIND(X)' 'COMPLEX(4) 'COMPLEX(4)' GNU Extension 17662 X' 17663 'ZSIND(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU Extension 17664 X' 17665 'CDSIND(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU Extension 17666 X' 17667 17668_See also_: 17669 Inverse function: *note ASIND:: Radians function: *note SIN:: 17670 17671 17672File: gfortran.info, Node: SINH, Next: SIZE, Prev: SIND, Up: Intrinsic Procedures 17673 176749.249 'SINH' -- Hyperbolic sine function 17675======================================== 17676 17677_Description_: 17678 'SINH(X)' computes the hyperbolic sine of X. 17679 17680_Standard_: 17681 Fortran 95 and later, for a complex argument Fortran 2008 or later 17682 17683_Class_: 17684 Elemental function 17685 17686_Syntax_: 17687 'RESULT = SINH(X)' 17688 17689_Arguments_: 17690 X The type shall be 'REAL' or 'COMPLEX'. 17691 17692_Return value_: 17693 The return value has same type and kind as X. 17694 17695_Example_: 17696 program test_sinh 17697 real(8) :: x = - 1.0_8 17698 x = sinh(x) 17699 end program test_sinh 17700 17701_Specific names_: 17702 Name Argument Return type Standard 17703 'SINH(X)' 'REAL(4) X' 'REAL(4)' Fortran 95 and 17704 later 17705 'DSINH(X)' 'REAL(8) X' 'REAL(8)' Fortran 95 and 17706 later 17707 17708_See also_: 17709 *note ASINH:: 17710 17711 17712File: gfortran.info, Node: SIZE, Next: SIZEOF, Prev: SINH, Up: Intrinsic Procedures 17713 177149.250 'SIZE' -- Determine the size of an array 17715============================================== 17716 17717_Description_: 17718 Determine the extent of ARRAY along a specified dimension DIM, or 17719 the total number of elements in ARRAY if DIM is absent. 17720 17721_Standard_: 17722 Fortran 95 and later, with KIND argument Fortran 2003 and later 17723 17724_Class_: 17725 Inquiry function 17726 17727_Syntax_: 17728 'RESULT = SIZE(ARRAY[, DIM [, KIND]])' 17729 17730_Arguments_: 17731 ARRAY Shall be an array of any type. If ARRAY is a 17732 pointer it must be associated and allocatable 17733 arrays must be allocated. 17734 DIM (Optional) shall be a scalar of type 'INTEGER' 17735 and its value shall be in the range from 1 to n, 17736 where n equals the rank of ARRAY. 17737 KIND (Optional) An 'INTEGER' initialization 17738 expression indicating the kind parameter of the 17739 result. 17740 17741_Return value_: 17742 The return value is of type 'INTEGER' and of kind KIND. If KIND is 17743 absent, the return value is of default integer kind. 17744 17745_Example_: 17746 PROGRAM test_size 17747 WRITE(*,*) SIZE((/ 1, 2 /)) ! 2 17748 END PROGRAM 17749 17750_See also_: 17751 *note SHAPE::, *note RESHAPE:: 17752 17753 17754File: gfortran.info, Node: SIZEOF, Next: SLEEP, Prev: SIZE, Up: Intrinsic Procedures 17755 177569.251 'SIZEOF' -- Size in bytes of an expression 17757================================================ 17758 17759_Description_: 17760 'SIZEOF(X)' calculates the number of bytes of storage the 17761 expression 'X' occupies. 17762 17763_Standard_: 17764 GNU extension 17765 17766_Class_: 17767 Inquiry function 17768 17769_Syntax_: 17770 'N = SIZEOF(X)' 17771 17772_Arguments_: 17773 X The argument shall be of any type, rank or 17774 shape. 17775 17776_Return value_: 17777 The return value is of type integer and of the system-dependent 17778 kind C_SIZE_T (from the ISO_C_BINDING module). Its value is the 17779 number of bytes occupied by the argument. If the argument has the 17780 'POINTER' attribute, the number of bytes of the storage area 17781 pointed to is returned. If the argument is of a derived type with 17782 'POINTER' or 'ALLOCATABLE' components, the return value does not 17783 account for the sizes of the data pointed to by these components. 17784 If the argument is polymorphic, the size according to the dynamic 17785 type is returned. The argument may not be a procedure or procedure 17786 pointer. Note that the code assumes for arrays that those are 17787 contiguous; for contiguous arrays, it returns the storage or an 17788 array element multiplied by the size of the array. 17789 17790_Example_: 17791 integer :: i 17792 real :: r, s(5) 17793 print *, (sizeof(s)/sizeof(r) == 5) 17794 end 17795 The example will print '.TRUE.' unless you are using a platform 17796 where default 'REAL' variables are unusually padded. 17797 17798_See also_: 17799 *note C_SIZEOF::, *note STORAGE_SIZE:: 17800 17801 17802File: gfortran.info, Node: SLEEP, Next: SPACING, Prev: SIZEOF, Up: Intrinsic Procedures 17803 178049.252 'SLEEP' -- Sleep for the specified number of seconds 17805========================================================== 17806 17807_Description_: 17808 Calling this subroutine causes the process to pause for SECONDS 17809 seconds. 17810 17811_Standard_: 17812 GNU extension 17813 17814_Class_: 17815 Subroutine 17816 17817_Syntax_: 17818 'CALL SLEEP(SECONDS)' 17819 17820_Arguments_: 17821 SECONDS The type shall be of default 'INTEGER'. 17822 17823_Example_: 17824 program test_sleep 17825 call sleep(5) 17826 end 17827 17828 17829File: gfortran.info, Node: SPACING, Next: SPREAD, Prev: SLEEP, Up: Intrinsic Procedures 17830 178319.253 'SPACING' -- Smallest distance between two numbers of a given type 17832======================================================================== 17833 17834_Description_: 17835 Determines the distance between the argument X and the nearest 17836 adjacent number of the same type. 17837 17838_Standard_: 17839 Fortran 95 and later 17840 17841_Class_: 17842 Elemental function 17843 17844_Syntax_: 17845 'RESULT = SPACING(X)' 17846 17847_Arguments_: 17848 X Shall be of type 'REAL'. 17849 17850_Return value_: 17851 The result is of the same type as the input argument X. 17852 17853_Example_: 17854 PROGRAM test_spacing 17855 INTEGER, PARAMETER :: SGL = SELECTED_REAL_KIND(p=6, r=37) 17856 INTEGER, PARAMETER :: DBL = SELECTED_REAL_KIND(p=13, r=200) 17857 17858 WRITE(*,*) spacing(1.0_SGL) ! "1.1920929E-07" on i686 17859 WRITE(*,*) spacing(1.0_DBL) ! "2.220446049250313E-016" on i686 17860 END PROGRAM 17861 17862_See also_: 17863 *note RRSPACING:: 17864 17865 17866File: gfortran.info, Node: SPREAD, Next: SQRT, Prev: SPACING, Up: Intrinsic Procedures 17867 178689.254 'SPREAD' -- Add a dimension to an array 17869============================================= 17870 17871_Description_: 17872 Replicates a SOURCE array NCOPIES times along a specified dimension 17873 DIM. 17874 17875_Standard_: 17876 Fortran 95 and later 17877 17878_Class_: 17879 Transformational function 17880 17881_Syntax_: 17882 'RESULT = SPREAD(SOURCE, DIM, NCOPIES)' 17883 17884_Arguments_: 17885 SOURCE Shall be a scalar or an array of any type and a 17886 rank less than seven. 17887 DIM Shall be a scalar of type 'INTEGER' with a value 17888 in the range from 1 to n+1, where n equals the 17889 rank of SOURCE. 17890 NCOPIES Shall be a scalar of type 'INTEGER'. 17891 17892_Return value_: 17893 The result is an array of the same type as SOURCE and has rank n+1 17894 where n equals the rank of SOURCE. 17895 17896_Example_: 17897 PROGRAM test_spread 17898 INTEGER :: a = 1, b(2) = (/ 1, 2 /) 17899 WRITE(*,*) SPREAD(A, 1, 2) ! "1 1" 17900 WRITE(*,*) SPREAD(B, 1, 2) ! "1 1 2 2" 17901 END PROGRAM 17902 17903_See also_: 17904 *note UNPACK:: 17905 17906 17907File: gfortran.info, Node: SQRT, Next: SRAND, Prev: SPREAD, Up: Intrinsic Procedures 17908 179099.255 'SQRT' -- Square-root function 17910==================================== 17911 17912_Description_: 17913 'SQRT(X)' computes the square root of X. 17914 17915_Standard_: 17916 Fortran 77 and later 17917 17918_Class_: 17919 Elemental function 17920 17921_Syntax_: 17922 'RESULT = SQRT(X)' 17923 17924_Arguments_: 17925 X The type shall be 'REAL' or 'COMPLEX'. 17926 17927_Return value_: 17928 The return value is of type 'REAL' or 'COMPLEX'. The kind type 17929 parameter is the same as X. 17930 17931_Example_: 17932 program test_sqrt 17933 real(8) :: x = 2.0_8 17934 complex :: z = (1.0, 2.0) 17935 x = sqrt(x) 17936 z = sqrt(z) 17937 end program test_sqrt 17938 17939_Specific names_: 17940 Name Argument Return type Standard 17941 'SQRT(X)' 'REAL(4) X' 'REAL(4)' Fortran 95 and 17942 later 17943 'DSQRT(X)' 'REAL(8) X' 'REAL(8)' Fortran 95 and 17944 later 17945 'CSQRT(X)' 'COMPLEX(4) 'COMPLEX(4)' Fortran 95 and 17946 X' later 17947 'ZSQRT(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 17948 X' 17949 'CDSQRT(X)' 'COMPLEX(8) 'COMPLEX(8)' GNU extension 17950 X' 17951 17952 17953File: gfortran.info, Node: SRAND, Next: STAT, Prev: SQRT, Up: Intrinsic Procedures 17954 179559.256 'SRAND' -- Reinitialize the random number generator 17956========================================================= 17957 17958_Description_: 17959 'SRAND' reinitializes the pseudo-random number generator called by 17960 'RAND' and 'IRAND'. The new seed used by the generator is 17961 specified by the required argument SEED. 17962 17963_Standard_: 17964 GNU extension 17965 17966_Class_: 17967 Subroutine 17968 17969_Syntax_: 17970 'CALL SRAND(SEED)' 17971 17972_Arguments_: 17973 SEED Shall be a scalar 'INTEGER(kind=4)'. 17974 17975_Return value_: 17976 Does not return anything. 17977 17978_Example_: 17979 See 'RAND' and 'IRAND' for examples. 17980 17981_Notes_: 17982 The Fortran standard specifies the intrinsic subroutines 17983 'RANDOM_SEED' to initialize the pseudo-random number generator and 17984 'RANDOM_NUMBER' to generate pseudo-random numbers. These 17985 subroutines should be used in new codes. 17986 17987 Please note that in GNU Fortran, these two sets of intrinsics 17988 ('RAND', 'IRAND' and 'SRAND' on the one hand, 'RANDOM_NUMBER' and 17989 'RANDOM_SEED' on the other hand) access two independent 17990 pseudo-random number generators. 17991 17992_See also_: 17993 *note RAND::, *note RANDOM_SEED::, *note RANDOM_NUMBER:: 17994 17995 17996File: gfortran.info, Node: STAT, Next: STORAGE_SIZE, Prev: SRAND, Up: Intrinsic Procedures 17997 179989.257 'STAT' -- Get file status 17999=============================== 18000 18001_Description_: 18002 This function returns information about a file. No permissions are 18003 required on the file itself, but execute (search) permission is 18004 required on all of the directories in path that lead to the file. 18005 18006 The elements that are obtained and stored in the array 'VALUES': 18007 'VALUES(1)' Device ID 18008 'VALUES(2)' Inode number 18009 'VALUES(3)' File mode 18010 'VALUES(4)' Number of links 18011 'VALUES(5)' Owner's uid 18012 'VALUES(6)' Owner's gid 18013 'VALUES(7)' ID of device containing directory entry for file 18014 (0 if not available) 18015 'VALUES(8)' File size (bytes) 18016 'VALUES(9)' Last access time 18017 'VALUES(10)'Last modification time 18018 'VALUES(11)'Last file status change time 18019 'VALUES(12)'Preferred I/O block size (-1 if not available) 18020 'VALUES(13)'Number of blocks allocated (-1 if not available) 18021 18022 Not all these elements are relevant on all systems. If an element 18023 is not relevant, it is returned as 0. 18024 18025 This intrinsic is provided in both subroutine and function forms; 18026 however, only one form can be used in any given program unit. 18027 18028_Standard_: 18029 GNU extension 18030 18031_Class_: 18032 Subroutine, function 18033 18034_Syntax_: 18035 'CALL STAT(NAME, VALUES [, STATUS])' 18036 'STATUS = STAT(NAME, VALUES)' 18037 18038_Arguments_: 18039 NAME The type shall be 'CHARACTER', of the default 18040 kind and a valid path within the file system. 18041 VALUES The type shall be 'INTEGER(4), DIMENSION(13)'. 18042 STATUS (Optional) status flag of type 'INTEGER(4)'. 18043 Returns 0 on success and a system specific error 18044 code otherwise. 18045 18046_Example_: 18047 PROGRAM test_stat 18048 INTEGER, DIMENSION(13) :: buff 18049 INTEGER :: status 18050 18051 CALL STAT("/etc/passwd", buff, status) 18052 18053 IF (status == 0) THEN 18054 WRITE (*, FMT="('Device ID:', T30, I19)") buff(1) 18055 WRITE (*, FMT="('Inode number:', T30, I19)") buff(2) 18056 WRITE (*, FMT="('File mode (octal):', T30, O19)") buff(3) 18057 WRITE (*, FMT="('Number of links:', T30, I19)") buff(4) 18058 WRITE (*, FMT="('Owner''s uid:', T30, I19)") buff(5) 18059 WRITE (*, FMT="('Owner''s gid:', T30, I19)") buff(6) 18060 WRITE (*, FMT="('Device where located:', T30, I19)") buff(7) 18061 WRITE (*, FMT="('File size:', T30, I19)") buff(8) 18062 WRITE (*, FMT="('Last access time:', T30, A19)") CTIME(buff(9)) 18063 WRITE (*, FMT="('Last modification time', T30, A19)") CTIME(buff(10)) 18064 WRITE (*, FMT="('Last status change time:', T30, A19)") CTIME(buff(11)) 18065 WRITE (*, FMT="('Preferred block size:', T30, I19)") buff(12) 18066 WRITE (*, FMT="('No. of blocks allocated:', T30, I19)") buff(13) 18067 END IF 18068 END PROGRAM 18069 18070_See also_: 18071 To stat an open file: *note FSTAT::, to stat a link: *note LSTAT:: 18072 18073 18074File: gfortran.info, Node: STORAGE_SIZE, Next: SUM, Prev: STAT, Up: Intrinsic Procedures 18075 180769.258 'STORAGE_SIZE' -- Storage size in bits 18077============================================ 18078 18079_Description_: 18080 Returns the storage size of argument A in bits. 18081_Standard_: 18082 Fortran 2008 and later 18083_Class_: 18084 Inquiry function 18085_Syntax_: 18086 'RESULT = STORAGE_SIZE(A [, KIND])' 18087 18088_Arguments_: 18089 A Shall be a scalar or array of any type. 18090 KIND (Optional) shall be a scalar integer constant 18091 expression. 18092 18093_Return Value_: 18094 The result is a scalar integer with the kind type parameter 18095 specified by KIND (or default integer type if KIND is missing). 18096 The result value is the size expressed in bits for an element of an 18097 array that has the dynamic type and type parameters of A. 18098 18099_See also_: 18100 *note C_SIZEOF::, *note SIZEOF:: 18101 18102 18103File: gfortran.info, Node: SUM, Next: SYMLNK, Prev: STORAGE_SIZE, Up: Intrinsic Procedures 18104 181059.259 'SUM' -- Sum of array elements 18106==================================== 18107 18108_Description_: 18109 Adds the elements of ARRAY along dimension DIM if the corresponding 18110 element in MASK is 'TRUE'. 18111 18112_Standard_: 18113 Fortran 95 and later 18114 18115_Class_: 18116 Transformational function 18117 18118_Syntax_: 18119 'RESULT = SUM(ARRAY[, MASK])' 18120 'RESULT = SUM(ARRAY, DIM[, MASK])' 18121 18122_Arguments_: 18123 ARRAY Shall be an array of type 'INTEGER', 'REAL' or 18124 'COMPLEX'. 18125 DIM (Optional) shall be a scalar of type 'INTEGER' 18126 with a value in the range from 1 to n, where n 18127 equals the rank of ARRAY. 18128 MASK (Optional) shall be of type 'LOGICAL' and either 18129 be a scalar or an array of the same shape as 18130 ARRAY. 18131 18132_Return value_: 18133 The result is of the same type as ARRAY. 18134 18135 If DIM is absent, a scalar with the sum of all elements in ARRAY is 18136 returned. Otherwise, an array of rank n-1, where n equals the rank 18137 of ARRAY, and a shape similar to that of ARRAY with dimension DIM 18138 dropped is returned. 18139 18140_Example_: 18141 PROGRAM test_sum 18142 INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /) 18143 print *, SUM(x) ! all elements, sum = 15 18144 print *, SUM(x, MASK=MOD(x, 2)==1) ! odd elements, sum = 9 18145 END PROGRAM 18146 18147_See also_: 18148 *note PRODUCT:: 18149 18150 18151File: gfortran.info, Node: SYMLNK, Next: SYSTEM, Prev: SUM, Up: Intrinsic Procedures 18152 181539.260 'SYMLNK' -- Create a symbolic link 18154======================================== 18155 18156_Description_: 18157 Makes a symbolic link from file PATH1 to PATH2. A null character 18158 ('CHAR(0)') can be used to mark the end of the names in PATH1 and 18159 PATH2; otherwise, trailing blanks in the file names are ignored. 18160 If the STATUS argument is supplied, it contains 0 on success or a 18161 nonzero error code upon return; see 'symlink(2)'. If the system 18162 does not supply 'symlink(2)', 'ENOSYS' is returned. 18163 18164 This intrinsic is provided in both subroutine and function forms; 18165 however, only one form can be used in any given program unit. 18166 18167_Standard_: 18168 GNU extension 18169 18170_Class_: 18171 Subroutine, function 18172 18173_Syntax_: 18174 'CALL SYMLNK(PATH1, PATH2 [, STATUS])' 18175 'STATUS = SYMLNK(PATH1, PATH2)' 18176 18177_Arguments_: 18178 PATH1 Shall be of default 'CHARACTER' type. 18179 PATH2 Shall be of default 'CHARACTER' type. 18180 STATUS (Optional) Shall be of default 'INTEGER' type. 18181 18182_See also_: 18183 *note LINK::, *note UNLINK:: 18184 18185 18186File: gfortran.info, Node: SYSTEM, Next: SYSTEM_CLOCK, Prev: SYMLNK, Up: Intrinsic Procedures 18187 181889.261 'SYSTEM' -- Execute a shell command 18189========================================= 18190 18191_Description_: 18192 Passes the command COMMAND to a shell (see 'system(3)'). If 18193 argument STATUS is present, it contains the value returned by 18194 'system(3)', which is presumably 0 if the shell command succeeded. 18195 Note that which shell is used to invoke the command is 18196 system-dependent and environment-dependent. 18197 18198 This intrinsic is provided in both subroutine and function forms; 18199 however, only one form can be used in any given program unit. 18200 18201 Note that the 'system' function need not be thread-safe. It is the 18202 responsibility of the user to ensure that 'system' is not called 18203 concurrently. 18204 18205_Standard_: 18206 GNU extension 18207 18208_Class_: 18209 Subroutine, function 18210 18211_Syntax_: 18212 'CALL SYSTEM(COMMAND [, STATUS])' 18213 'STATUS = SYSTEM(COMMAND)' 18214 18215_Arguments_: 18216 COMMAND Shall be of default 'CHARACTER' type. 18217 STATUS (Optional) Shall be of default 'INTEGER' type. 18218 18219_See also_: 18220 *note EXECUTE_COMMAND_LINE::, which is part of the Fortran 2008 18221 standard and should considered in new code for future portability. 18222 18223 18224File: gfortran.info, Node: SYSTEM_CLOCK, Next: TAN, Prev: SYSTEM, Up: Intrinsic Procedures 18225 182269.262 'SYSTEM_CLOCK' -- Time function 18227===================================== 18228 18229_Description_: 18230 Determines the COUNT of a processor clock since an unspecified time 18231 in the past modulo COUNT_MAX, COUNT_RATE determines the number of 18232 clock ticks per second. If the platform supports a monotonic 18233 clock, that clock is used and can, depending on the platform clock 18234 implementation, provide up to nanosecond resolution. If a 18235 monotonic clock is not available, the implementation falls back to 18236 a realtime clock. 18237 18238 COUNT_RATE is system dependent and can vary depending on the kind 18239 of the arguments. For KIND=4 arguments (and smaller integer 18240 kinds), COUNT represents milliseconds, while for KIND=8 arguments 18241 (and larger integer kinds), COUNT typically represents micro- or 18242 nanoseconds depending on resolution of the underlying platform 18243 clock. COUNT_MAX usually equals 'HUGE(COUNT_MAX)'. Note that the 18244 millisecond resolution of the KIND=4 version implies that the COUNT 18245 will wrap around in roughly 25 days. In order to avoid issues with 18246 the wrap around and for more precise timing, please use the KIND=8 18247 version. 18248 18249 If there is no clock, or querying the clock fails, COUNT is set to 18250 '-HUGE(COUNT)', and COUNT_RATE and COUNT_MAX are set to zero. 18251 18252 When running on a platform using the GNU C library (glibc) version 18253 2.16 or older, or a derivative thereof, the high resolution 18254 monotonic clock is available only when linking with the RT library. 18255 This can be done explicitly by adding the '-lrt' flag when linking 18256 the application, but is also done implicitly when using OpenMP. 18257 18258 On the Windows platform, the version with KIND=4 arguments uses the 18259 'GetTickCount' function, whereas the KIND=8 version uses 18260 'QueryPerformanceCounter' and 'QueryPerformanceCounterFrequency'. 18261 For more information, and potential caveats, please see the 18262 platform documentation. 18263 18264_Standard_: 18265 Fortran 95 and later 18266 18267_Class_: 18268 Subroutine 18269 18270_Syntax_: 18271 'CALL SYSTEM_CLOCK([COUNT, COUNT_RATE, COUNT_MAX])' 18272 18273_Arguments_: 18274 COUNT (Optional) shall be a scalar of type 'INTEGER' 18275 with 'INTENT(OUT)'. 18276 COUNT_RATE (Optional) shall be a scalar of type 'INTEGER' 18277 or 'REAL', with 'INTENT(OUT)'. 18278 COUNT_MAX (Optional) shall be a scalar of type 'INTEGER' 18279 with 'INTENT(OUT)'. 18280 18281_Example_: 18282 PROGRAM test_system_clock 18283 INTEGER :: count, count_rate, count_max 18284 CALL SYSTEM_CLOCK(count, count_rate, count_max) 18285 WRITE(*,*) count, count_rate, count_max 18286 END PROGRAM 18287 18288_See also_: 18289 *note DATE_AND_TIME::, *note CPU_TIME:: 18290 18291 18292File: gfortran.info, Node: TAN, Next: TAND, Prev: SYSTEM_CLOCK, Up: Intrinsic Procedures 18293 182949.263 'TAN' -- Tangent function 18295=============================== 18296 18297_Description_: 18298 'TAN(X)' computes the tangent of X. 18299 18300_Standard_: 18301 Fortran 77 and later, for a complex argument Fortran 2008 or later 18302 18303_Class_: 18304 Elemental function 18305 18306_Syntax_: 18307 'RESULT = TAN(X)' 18308 18309_Arguments_: 18310 X The type shall be 'REAL' or 'COMPLEX'. 18311 18312_Return value_: 18313 The return value has same type and kind as X, and its value is in 18314 radians. 18315 18316_Example_: 18317 program test_tan 18318 real(8) :: x = 0.165_8 18319 x = tan(x) 18320 end program test_tan 18321 18322_Specific names_: 18323 Name Argument Return type Standard 18324 'TAN(X)' 'REAL(4) X' 'REAL(4)' Fortran 95 and 18325 later 18326 'DTAN(X)' 'REAL(8) X' 'REAL(8)' Fortran 95 and 18327 later 18328 18329_See also_: 18330 Inverse function: *note ATAN:: Degrees function: *note TAND:: 18331 18332 18333File: gfortran.info, Node: TAND, Next: TANH, Prev: TAN, Up: Intrinsic Procedures 18334 183359.264 'TAND' -- Tangent function, degrees 18336========================================= 18337 18338_Description_: 18339 'TAND(X)' computes the tangent of X in degrees. 18340 18341 This function is for compatibility only and should be avoided in 18342 favor of standard constructs wherever possible. 18343 18344_Standard_: 18345 GNU Extension, enabled with '-fdec-math'. 18346 18347_Class_: 18348 Elemental function 18349 18350_Syntax_: 18351 'RESULT = TAND(X)' 18352 18353_Arguments_: 18354 X The type shall be 'REAL' or 'COMPLEX'. 18355 18356_Return value_: 18357 The return value has same type and kind as X, and its value is in 18358 degrees. 18359 18360_Example_: 18361 program test_tand 18362 real(8) :: x = 0.165_8 18363 x = tand(x) 18364 end program test_tand 18365 18366_Specific names_: 18367 Name Argument Return type Standard 18368 'TAND(X)' 'REAL(4) X' 'REAL(4)' GNU Extension 18369 'DTAND(X)' 'REAL(8) X' 'REAL(8)' GNU Extension 18370 18371_See also_: 18372 Inverse function: *note ATAND:: Radians function: *note TAN:: 18373 18374 18375File: gfortran.info, Node: TANH, Next: THIS_IMAGE, Prev: TAND, Up: Intrinsic Procedures 18376 183779.265 'TANH' -- Hyperbolic tangent function 18378=========================================== 18379 18380_Description_: 18381 'TANH(X)' computes the hyperbolic tangent of X. 18382 18383_Standard_: 18384 Fortran 77 and later, for a complex argument Fortran 2008 or later 18385 18386_Class_: 18387 Elemental function 18388 18389_Syntax_: 18390 'X = TANH(X)' 18391 18392_Arguments_: 18393 X The type shall be 'REAL' or 'COMPLEX'. 18394 18395_Return value_: 18396 The return value has same type and kind as X. If X is complex, the 18397 imaginary part of the result is in radians. If X is 'REAL', the 18398 return value lies in the range - 1 \leq tanh(x) \leq 1 . 18399 18400_Example_: 18401 program test_tanh 18402 real(8) :: x = 2.1_8 18403 x = tanh(x) 18404 end program test_tanh 18405 18406_Specific names_: 18407 Name Argument Return type Standard 18408 'TANH(X)' 'REAL(4) X' 'REAL(4)' Fortran 95 and 18409 later 18410 'DTANH(X)' 'REAL(8) X' 'REAL(8)' Fortran 95 and 18411 later 18412 18413_See also_: 18414 *note ATANH:: 18415 18416 18417File: gfortran.info, Node: THIS_IMAGE, Next: TIME, Prev: TANH, Up: Intrinsic Procedures 18418 184199.266 'THIS_IMAGE' -- Function that returns the cosubscript index of this image 18420=============================================================================== 18421 18422_Description_: 18423 Returns the cosubscript for this image. 18424 18425_Standard_: 18426 Fortran 2008 and later. With DISTANCE argument, Technical 18427 Specification (TS) 18508 or later 18428 18429_Class_: 18430 Transformational function 18431 18432_Syntax_: 18433 'RESULT = THIS_IMAGE()' 18434 'RESULT = THIS_IMAGE(DISTANCE)' 18435 'RESULT = THIS_IMAGE(COARRAY [, DIM])' 18436 18437_Arguments_: 18438 DISTANCE (optional, intent(in)) Nonnegative scalar 18439 integer (not permitted together with COARRAY). 18440 COARRAY Coarray of any type (optional; if DIM present, 18441 required). 18442 DIM default integer scalar (optional). If present, 18443 DIM shall be between one and the corank of 18444 COARRAY. 18445 18446_Return value_: 18447 Default integer. If COARRAY is not present, it is scalar; if 18448 DISTANCE is not present or has value 0, its value is the image 18449 index on the invoking image for the current team, for values 18450 smaller or equal distance to the initial team, it returns the image 18451 index on the ancestor team which has a distance of DISTANCE from 18452 the invoking team. If DISTANCE is larger than the distance to the 18453 initial team, the image index of the initial team is returned. 18454 Otherwise when the COARRAY is present, if DIM is not present, a 18455 rank-1 array with corank elements is returned, containing the 18456 cosubscripts for COARRAY specifying the invoking image. If DIM is 18457 present, a scalar is returned, with the value of the DIM element of 18458 'THIS_IMAGE(COARRAY)'. 18459 18460_Example_: 18461 INTEGER :: value[*] 18462 INTEGER :: i 18463 value = THIS_IMAGE() 18464 SYNC ALL 18465 IF (THIS_IMAGE() == 1) THEN 18466 DO i = 1, NUM_IMAGES() 18467 WRITE(*,'(2(a,i0))') 'value[', i, '] is ', value[i] 18468 END DO 18469 END IF 18470 18471 ! Check whether the current image is the initial image 18472 IF (THIS_IMAGE(HUGE(1)) /= THIS_IMAGE()) 18473 error stop "something is rotten here" 18474 18475_See also_: 18476 *note NUM_IMAGES::, *note IMAGE_INDEX:: 18477 18478 18479File: gfortran.info, Node: TIME, Next: TIME8, Prev: THIS_IMAGE, Up: Intrinsic Procedures 18480 184819.267 'TIME' -- Time function 18482============================= 18483 18484_Description_: 18485 Returns the current time encoded as an integer (in the manner of 18486 the function 'time(3)' in the C standard library). This value is 18487 suitable for passing to *note CTIME::, *note GMTIME::, and *note 18488 LTIME::. 18489 18490 This intrinsic is not fully portable, such as to systems with 18491 32-bit 'INTEGER' types but supporting times wider than 32 bits. 18492 Therefore, the values returned by this intrinsic might be, or 18493 become, negative, or numerically less than previous values, during 18494 a single run of the compiled program. 18495 18496 See *note TIME8::, for information on a similar intrinsic that 18497 might be portable to more GNU Fortran implementations, though to 18498 fewer Fortran compilers. 18499 18500_Standard_: 18501 GNU extension 18502 18503_Class_: 18504 Function 18505 18506_Syntax_: 18507 'RESULT = TIME()' 18508 18509_Return value_: 18510 The return value is a scalar of type 'INTEGER(4)'. 18511 18512_See also_: 18513 *note DATE_AND_TIME::, *note CTIME::, *note GMTIME::, *note 18514 LTIME::, *note MCLOCK::, *note TIME8:: 18515 18516 18517File: gfortran.info, Node: TIME8, Next: TINY, Prev: TIME, Up: Intrinsic Procedures 18518 185199.268 'TIME8' -- Time function (64-bit) 18520======================================= 18521 18522_Description_: 18523 Returns the current time encoded as an integer (in the manner of 18524 the function 'time(3)' in the C standard library). This value is 18525 suitable for passing to *note CTIME::, *note GMTIME::, and *note 18526 LTIME::. 18527 18528 _Warning:_ this intrinsic does not increase the range of the timing 18529 values over that returned by 'time(3)'. On a system with a 32-bit 18530 'time(3)', 'TIME8' will return a 32-bit value, even though it is 18531 converted to a 64-bit 'INTEGER(8)' value. That means overflows of 18532 the 32-bit value can still occur. Therefore, the values returned 18533 by this intrinsic might be or become negative or numerically less 18534 than previous values during a single run of the compiled program. 18535 18536_Standard_: 18537 GNU extension 18538 18539_Class_: 18540 Function 18541 18542_Syntax_: 18543 'RESULT = TIME8()' 18544 18545_Return value_: 18546 The return value is a scalar of type 'INTEGER(8)'. 18547 18548_See also_: 18549 *note DATE_AND_TIME::, *note CTIME::, *note GMTIME::, *note 18550 LTIME::, *note MCLOCK8::, *note TIME:: 18551 18552 18553File: gfortran.info, Node: TINY, Next: TRAILZ, Prev: TIME8, Up: Intrinsic Procedures 18554 185559.269 'TINY' -- Smallest positive number of a real kind 18556======================================================= 18557 18558_Description_: 18559 'TINY(X)' returns the smallest positive (non zero) number in the 18560 model of the type of 'X'. 18561 18562_Standard_: 18563 Fortran 95 and later 18564 18565_Class_: 18566 Inquiry function 18567 18568_Syntax_: 18569 'RESULT = TINY(X)' 18570 18571_Arguments_: 18572 X Shall be of type 'REAL'. 18573 18574_Return value_: 18575 The return value is of the same type and kind as X 18576 18577_Example_: 18578 See 'HUGE' for an example. 18579 18580 18581File: gfortran.info, Node: TRAILZ, Next: TRANSFER, Prev: TINY, Up: Intrinsic Procedures 18582 185839.270 'TRAILZ' -- Number of trailing zero bits of an integer 18584============================================================ 18585 18586_Description_: 18587 'TRAILZ' returns the number of trailing zero bits of an integer. 18588 18589_Standard_: 18590 Fortran 2008 and later 18591 18592_Class_: 18593 Elemental function 18594 18595_Syntax_: 18596 'RESULT = TRAILZ(I)' 18597 18598_Arguments_: 18599 I Shall be of type 'INTEGER'. 18600 18601_Return value_: 18602 The type of the return value is the default 'INTEGER'. If all the 18603 bits of 'I' are zero, the result value is 'BIT_SIZE(I)'. 18604 18605_Example_: 18606 PROGRAM test_trailz 18607 WRITE (*,*) TRAILZ(8) ! prints 3 18608 END PROGRAM 18609 18610_See also_: 18611 *note BIT_SIZE::, *note LEADZ::, *note POPPAR::, *note POPCNT:: 18612 18613 18614File: gfortran.info, Node: TRANSFER, Next: TRANSPOSE, Prev: TRAILZ, Up: Intrinsic Procedures 18615 186169.271 'TRANSFER' -- Transfer bit patterns 18617========================================= 18618 18619_Description_: 18620 Interprets the bitwise representation of SOURCE in memory as if it 18621 is the representation of a variable or array of the same type and 18622 type parameters as MOLD. 18623 18624 This is approximately equivalent to the C concept of _casting_ one 18625 type to another. 18626 18627_Standard_: 18628 Fortran 95 and later 18629 18630_Class_: 18631 Transformational function 18632 18633_Syntax_: 18634 'RESULT = TRANSFER(SOURCE, MOLD[, SIZE])' 18635 18636_Arguments_: 18637 SOURCE Shall be a scalar or an array of any type. 18638 MOLD Shall be a scalar or an array of any type. 18639 SIZE (Optional) shall be a scalar of type 'INTEGER'. 18640 18641_Return value_: 18642 The result has the same type as MOLD, with the bit level 18643 representation of SOURCE. If SIZE is present, the result is a 18644 one-dimensional array of length SIZE. If SIZE is absent but MOLD 18645 is an array (of any size or shape), the result is a one- 18646 dimensional array of the minimum length needed to contain the 18647 entirety of the bitwise representation of SOURCE. If SIZE is 18648 absent and MOLD is a scalar, the result is a scalar. 18649 18650 If the bitwise representation of the result is longer than that of 18651 SOURCE, then the leading bits of the result correspond to those of 18652 SOURCE and any trailing bits are filled arbitrarily. 18653 18654 When the resulting bit representation does not correspond to a 18655 valid representation of a variable of the same type as MOLD, the 18656 results are undefined, and subsequent operations on the result 18657 cannot be guaranteed to produce sensible behavior. For example, it 18658 is possible to create 'LOGICAL' variables for which 'VAR' and 18659 '.NOT.VAR' both appear to be true. 18660 18661_Example_: 18662 PROGRAM test_transfer 18663 integer :: x = 2143289344 18664 print *, transfer(x, 1.0) ! prints "NaN" on i686 18665 END PROGRAM 18666 18667 18668File: gfortran.info, Node: TRANSPOSE, Next: TRIM, Prev: TRANSFER, Up: Intrinsic Procedures 18669 186709.272 'TRANSPOSE' -- Transpose an array of rank two 18671=================================================== 18672 18673_Description_: 18674 Transpose an array of rank two. Element (i, j) of the result has 18675 the value 'MATRIX(j, i)', for all i, j. 18676 18677_Standard_: 18678 Fortran 95 and later 18679 18680_Class_: 18681 Transformational function 18682 18683_Syntax_: 18684 'RESULT = TRANSPOSE(MATRIX)' 18685 18686_Arguments_: 18687 MATRIX Shall be an array of any type and have a rank of 18688 two. 18689 18690_Return value_: 18691 The result has the same type as MATRIX, and has shape '(/ m, n /)' 18692 if MATRIX has shape '(/ n, m /)'. 18693 18694 18695File: gfortran.info, Node: TRIM, Next: TTYNAM, Prev: TRANSPOSE, Up: Intrinsic Procedures 18696 186979.273 'TRIM' -- Remove trailing blank characters of a string 18698============================================================ 18699 18700_Description_: 18701 Removes trailing blank characters of a string. 18702 18703_Standard_: 18704 Fortran 95 and later 18705 18706_Class_: 18707 Transformational function 18708 18709_Syntax_: 18710 'RESULT = TRIM(STRING)' 18711 18712_Arguments_: 18713 STRING Shall be a scalar of type 'CHARACTER'. 18714 18715_Return value_: 18716 A scalar of type 'CHARACTER' which length is that of STRING less 18717 the number of trailing blanks. 18718 18719_Example_: 18720 PROGRAM test_trim 18721 CHARACTER(len=10), PARAMETER :: s = "GFORTRAN " 18722 WRITE(*,*) LEN(s), LEN(TRIM(s)) ! "10 8", with/without trailing blanks 18723 END PROGRAM 18724 18725_See also_: 18726 *note ADJUSTL::, *note ADJUSTR:: 18727 18728 18729File: gfortran.info, Node: TTYNAM, Next: UBOUND, Prev: TRIM, Up: Intrinsic Procedures 18730 187319.274 'TTYNAM' -- Get the name of a terminal device. 18732==================================================== 18733 18734_Description_: 18735 Get the name of a terminal device. For more information, see 18736 'ttyname(3)'. 18737 18738 This intrinsic is provided in both subroutine and function forms; 18739 however, only one form can be used in any given program unit. 18740 18741_Standard_: 18742 GNU extension 18743 18744_Class_: 18745 Subroutine, function 18746 18747_Syntax_: 18748 'CALL TTYNAM(UNIT, NAME)' 18749 'NAME = TTYNAM(UNIT)' 18750 18751_Arguments_: 18752 UNIT Shall be a scalar 'INTEGER'. 18753 NAME Shall be of type 'CHARACTER'. 18754 18755_Example_: 18756 PROGRAM test_ttynam 18757 INTEGER :: unit 18758 DO unit = 1, 10 18759 IF (isatty(unit=unit)) write(*,*) ttynam(unit) 18760 END DO 18761 END PROGRAM 18762 18763_See also_: 18764 *note ISATTY:: 18765 18766 18767File: gfortran.info, Node: UBOUND, Next: UCOBOUND, Prev: TTYNAM, Up: Intrinsic Procedures 18768 187699.275 'UBOUND' -- Upper dimension bounds of an array 18770==================================================== 18771 18772_Description_: 18773 Returns the upper bounds of an array, or a single upper bound along 18774 the DIM dimension. 18775_Standard_: 18776 Fortran 95 and later, with KIND argument Fortran 2003 and later 18777 18778_Class_: 18779 Inquiry function 18780 18781_Syntax_: 18782 'RESULT = UBOUND(ARRAY [, DIM [, KIND]])' 18783 18784_Arguments_: 18785 ARRAY Shall be an array, of any type. 18786 DIM (Optional) Shall be a scalar 'INTEGER'. 18787 KIND (Optional) An 'INTEGER' initialization 18788 expression indicating the kind parameter of the 18789 result. 18790 18791_Return value_: 18792 The return value is of type 'INTEGER' and of kind KIND. If KIND is 18793 absent, the return value is of default integer kind. If DIM is 18794 absent, the result is an array of the upper bounds of ARRAY. If 18795 DIM is present, the result is a scalar corresponding to the upper 18796 bound of the array along that dimension. If ARRAY is an expression 18797 rather than a whole array or array structure component, or if it 18798 has a zero extent along the relevant dimension, the upper bound is 18799 taken to be the number of elements along the relevant dimension. 18800 18801_See also_: 18802 *note LBOUND::, *note LCOBOUND:: 18803 18804 18805File: gfortran.info, Node: UCOBOUND, Next: UMASK, Prev: UBOUND, Up: Intrinsic Procedures 18806 188079.276 'UCOBOUND' -- Upper codimension bounds of an array 18808======================================================== 18809 18810_Description_: 18811 Returns the upper cobounds of a coarray, or a single upper cobound 18812 along the DIM codimension. 18813_Standard_: 18814 Fortran 2008 and later 18815 18816_Class_: 18817 Inquiry function 18818 18819_Syntax_: 18820 'RESULT = UCOBOUND(COARRAY [, DIM [, KIND]])' 18821 18822_Arguments_: 18823 ARRAY Shall be an coarray, of any type. 18824 DIM (Optional) Shall be a scalar 'INTEGER'. 18825 KIND (Optional) An 'INTEGER' initialization 18826 expression indicating the kind parameter of the 18827 result. 18828 18829_Return value_: 18830 The return value is of type 'INTEGER' and of kind KIND. If KIND is 18831 absent, the return value is of default integer kind. If DIM is 18832 absent, the result is an array of the lower cobounds of COARRAY. 18833 If DIM is present, the result is a scalar corresponding to the 18834 lower cobound of the array along that codimension. 18835 18836_See also_: 18837 *note LCOBOUND::, *note LBOUND:: 18838 18839 18840File: gfortran.info, Node: UMASK, Next: UNLINK, Prev: UCOBOUND, Up: Intrinsic Procedures 18841 188429.277 'UMASK' -- Set the file creation mask 18843=========================================== 18844 18845_Description_: 18846 Sets the file creation mask to MASK. If called as a function, it 18847 returns the old value. If called as a subroutine and argument OLD 18848 if it is supplied, it is set to the old value. See 'umask(2)'. 18849 18850_Standard_: 18851 GNU extension 18852 18853_Class_: 18854 Subroutine, function 18855 18856_Syntax_: 18857 'CALL UMASK(MASK [, OLD])' 18858 'OLD = UMASK(MASK)' 18859 18860_Arguments_: 18861 MASK Shall be a scalar of type 'INTEGER'. 18862 OLD (Optional) Shall be a scalar of type 'INTEGER'. 18863 18864 18865File: gfortran.info, Node: UNLINK, Next: UNPACK, Prev: UMASK, Up: Intrinsic Procedures 18866 188679.278 'UNLINK' -- Remove a file from the file system 18868==================================================== 18869 18870_Description_: 18871 Unlinks the file PATH. A null character ('CHAR(0)') can be used to 18872 mark the end of the name in PATH; otherwise, trailing blanks in the 18873 file name are ignored. If the STATUS argument is supplied, it 18874 contains 0 on success or a nonzero error code upon return; see 18875 'unlink(2)'. 18876 18877 This intrinsic is provided in both subroutine and function forms; 18878 however, only one form can be used in any given program unit. 18879 18880_Standard_: 18881 GNU extension 18882 18883_Class_: 18884 Subroutine, function 18885 18886_Syntax_: 18887 'CALL UNLINK(PATH [, STATUS])' 18888 'STATUS = UNLINK(PATH)' 18889 18890_Arguments_: 18891 PATH Shall be of default 'CHARACTER' type. 18892 STATUS (Optional) Shall be of default 'INTEGER' type. 18893 18894_See also_: 18895 *note LINK::, *note SYMLNK:: 18896 18897 18898File: gfortran.info, Node: UNPACK, Next: VERIFY, Prev: UNLINK, Up: Intrinsic Procedures 18899 189009.279 'UNPACK' -- Unpack an array of rank one into an array 18901=========================================================== 18902 18903_Description_: 18904 Store the elements of VECTOR in an array of higher rank. 18905 18906_Standard_: 18907 Fortran 95 and later 18908 18909_Class_: 18910 Transformational function 18911 18912_Syntax_: 18913 'RESULT = UNPACK(VECTOR, MASK, FIELD)' 18914 18915_Arguments_: 18916 VECTOR Shall be an array of any type and rank one. It 18917 shall have at least as many elements as MASK has 18918 'TRUE' values. 18919 MASK Shall be an array of type 'LOGICAL'. 18920 FIELD Shall be of the same type as VECTOR and have the 18921 same shape as MASK. 18922 18923_Return value_: 18924 The resulting array corresponds to FIELD with 'TRUE' elements of 18925 MASK replaced by values from VECTOR in array element order. 18926 18927_Example_: 18928 PROGRAM test_unpack 18929 integer :: vector(2) = (/1,1/) 18930 logical :: mask(4) = (/ .TRUE., .FALSE., .FALSE., .TRUE. /) 18931 integer :: field(2,2) = 0, unity(2,2) 18932 18933 ! result: unity matrix 18934 unity = unpack(vector, reshape(mask, (/2,2/)), field) 18935 END PROGRAM 18936 18937_See also_: 18938 *note PACK::, *note SPREAD:: 18939 18940 18941File: gfortran.info, Node: VERIFY, Next: XOR, Prev: UNPACK, Up: Intrinsic Procedures 18942 189439.280 'VERIFY' -- Scan a string for characters not a given set 18944============================================================== 18945 18946_Description_: 18947 Verifies that all the characters in STRING belong to the set of 18948 characters in SET. 18949 18950 If BACK is either absent or equals 'FALSE', this function returns 18951 the position of the leftmost character of STRING that is not in 18952 SET. If BACK equals 'TRUE', the rightmost position is returned. 18953 If all characters of STRING are found in SET, the result is zero. 18954 18955_Standard_: 18956 Fortran 95 and later, with KIND argument Fortran 2003 and later 18957 18958_Class_: 18959 Elemental function 18960 18961_Syntax_: 18962 'RESULT = VERIFY(STRING, SET[, BACK [, KIND]])' 18963 18964_Arguments_: 18965 STRING Shall be of type 'CHARACTER'. 18966 SET Shall be of type 'CHARACTER'. 18967 BACK (Optional) shall be of type 'LOGICAL'. 18968 KIND (Optional) An 'INTEGER' initialization 18969 expression indicating the kind parameter of the 18970 result. 18971 18972_Return value_: 18973 The return value is of type 'INTEGER' and of kind KIND. If KIND is 18974 absent, the return value is of default integer kind. 18975 18976_Example_: 18977 PROGRAM test_verify 18978 WRITE(*,*) VERIFY("FORTRAN", "AO") ! 1, found 'F' 18979 WRITE(*,*) VERIFY("FORTRAN", "FOO") ! 3, found 'R' 18980 WRITE(*,*) VERIFY("FORTRAN", "C++") ! 1, found 'F' 18981 WRITE(*,*) VERIFY("FORTRAN", "C++", .TRUE.) ! 7, found 'N' 18982 WRITE(*,*) VERIFY("FORTRAN", "FORTRAN") ! 0' found none 18983 END PROGRAM 18984 18985_See also_: 18986 *note SCAN::, *note INDEX intrinsic:: 18987 18988 18989File: gfortran.info, Node: XOR, Prev: VERIFY, Up: Intrinsic Procedures 18990 189919.281 'XOR' -- Bitwise logical exclusive OR 18992=========================================== 18993 18994_Description_: 18995 Bitwise logical exclusive or. 18996 18997 This intrinsic routine is provided for backwards compatibility with 18998 GNU Fortran 77. For integer arguments, programmers should consider 18999 the use of the *note IEOR:: intrinsic and for logical arguments the 19000 '.NEQV.' operator, which are both defined by the Fortran standard. 19001 19002_Standard_: 19003 GNU extension 19004 19005_Class_: 19006 Function 19007 19008_Syntax_: 19009 'RESULT = XOR(I, J)' 19010 19011_Arguments_: 19012 I The type shall be either a scalar 'INTEGER' type 19013 or a scalar 'LOGICAL' type. 19014 J The type shall be the same as the type of I. 19015 19016_Return value_: 19017 The return type is either a scalar 'INTEGER' or a scalar 'LOGICAL'. 19018 If the kind type parameters differ, then the smaller kind type is 19019 implicitly converted to larger kind, and the return has the larger 19020 kind. 19021 19022_Example_: 19023 PROGRAM test_xor 19024 LOGICAL :: T = .TRUE., F = .FALSE. 19025 INTEGER :: a, b 19026 DATA a / Z'F' /, b / Z'3' / 19027 19028 WRITE (*,*) XOR(T, T), XOR(T, F), XOR(F, T), XOR(F, F) 19029 WRITE (*,*) XOR(a, b) 19030 END PROGRAM 19031 19032_See also_: 19033 Fortran 95 elemental function: *note IEOR:: 19034 19035 19036File: gfortran.info, Node: Intrinsic Modules, Next: Contributing, Prev: Intrinsic Procedures, Up: Top 19037 1903810 Intrinsic Modules 19039******************** 19040 19041* Menu: 19042 19043* ISO_FORTRAN_ENV:: 19044* ISO_C_BINDING:: 19045* IEEE modules:: 19046* OpenMP Modules OMP_LIB and OMP_LIB_KINDS:: 19047* OpenACC Module OPENACC:: 19048 19049 19050File: gfortran.info, Node: ISO_FORTRAN_ENV, Next: ISO_C_BINDING, Up: Intrinsic Modules 19051 1905210.1 'ISO_FORTRAN_ENV' 19053====================== 19054 19055_Standard_: 19056 Fortran 2003 and later, except when otherwise noted 19057 19058 The 'ISO_FORTRAN_ENV' module provides the following scalar 19059default-integer named constants: 19060 19061'ATOMIC_INT_KIND': 19062 Default-kind integer constant to be used as kind parameter when 19063 defining integer variables used in atomic operations. (Fortran 19064 2008 or later.) 19065 19066'ATOMIC_LOGICAL_KIND': 19067 Default-kind integer constant to be used as kind parameter when 19068 defining logical variables used in atomic operations. (Fortran 19069 2008 or later.) 19070 19071'CHARACTER_KINDS': 19072 Default-kind integer constant array of rank one containing the 19073 supported kind parameters of the 'CHARACTER' type. (Fortran 2008 19074 or later.) 19075 19076'CHARACTER_STORAGE_SIZE': 19077 Size in bits of the character storage unit. 19078 19079'ERROR_UNIT': 19080 Identifies the preconnected unit used for error reporting. 19081 19082'FILE_STORAGE_SIZE': 19083 Size in bits of the file-storage unit. 19084 19085'INPUT_UNIT': 19086 Identifies the preconnected unit identified by the asterisk ('*') 19087 in 'READ' statement. 19088 19089'INT8', 'INT16', 'INT32', 'INT64': 19090 Kind type parameters to specify an INTEGER type with a storage size 19091 of 16, 32, and 64 bits. It is negative if a target platform does 19092 not support the particular kind. (Fortran 2008 or later.) 19093 19094'INTEGER_KINDS': 19095 Default-kind integer constant array of rank one containing the 19096 supported kind parameters of the 'INTEGER' type. (Fortran 2008 or 19097 later.) 19098 19099'IOSTAT_END': 19100 The value assigned to the variable passed to the 'IOSTAT=' 19101 specifier of an input/output statement if an end-of-file condition 19102 occurred. 19103 19104'IOSTAT_EOR': 19105 The value assigned to the variable passed to the 'IOSTAT=' 19106 specifier of an input/output statement if an end-of-record 19107 condition occurred. 19108 19109'IOSTAT_INQUIRE_INTERNAL_UNIT': 19110 Scalar default-integer constant, used by 'INQUIRE' for the 19111 'IOSTAT=' specifier to denote an that a unit number identifies an 19112 internal unit. (Fortran 2008 or later.) 19113 19114'NUMERIC_STORAGE_SIZE': 19115 The size in bits of the numeric storage unit. 19116 19117'LOGICAL_KINDS': 19118 Default-kind integer constant array of rank one containing the 19119 supported kind parameters of the 'LOGICAL' type. (Fortran 2008 or 19120 later.) 19121 19122'OUTPUT_UNIT': 19123 Identifies the preconnected unit identified by the asterisk ('*') 19124 in 'WRITE' statement. 19125 19126'REAL32', 'REAL64', 'REAL128': 19127 Kind type parameters to specify a REAL type with a storage size of 19128 32, 64, and 128 bits. It is negative if a target platform does not 19129 support the particular kind. (Fortran 2008 or later.) 19130 19131'REAL_KINDS': 19132 Default-kind integer constant array of rank one containing the 19133 supported kind parameters of the 'REAL' type. (Fortran 2008 or 19134 later.) 19135 19136'STAT_LOCKED': 19137 Scalar default-integer constant used as STAT= return value by 19138 'LOCK' to denote that the lock variable is locked by the executing 19139 image. (Fortran 2008 or later.) 19140 19141'STAT_LOCKED_OTHER_IMAGE': 19142 Scalar default-integer constant used as STAT= return value by 19143 'UNLOCK' to denote that the lock variable is locked by another 19144 image. (Fortran 2008 or later.) 19145 19146'STAT_STOPPED_IMAGE': 19147 Positive, scalar default-integer constant used as STAT= return 19148 value if the argument in the statement requires synchronisation 19149 with an image, which has initiated the termination of the 19150 execution. (Fortran 2008 or later.) 19151 19152'STAT_FAILED_IMAGE': 19153 Positive, scalar default-integer constant used as STAT= return 19154 value if the argument in the statement requires communication with 19155 an image, which has is in the failed state. (TS 18508 or later.) 19156 19157'STAT_UNLOCKED': 19158 Scalar default-integer constant used as STAT= return value by 19159 'UNLOCK' to denote that the lock variable is unlocked. (Fortran 19160 2008 or later.) 19161 19162 The module provides the following derived type: 19163 19164'LOCK_TYPE': 19165 Derived type with private components to be use with the 'LOCK' and 19166 'UNLOCK' statement. A variable of its type has to be always 19167 declared as coarray and may not appear in a variable-definition 19168 context. (Fortran 2008 or later.) 19169 19170 The module also provides the following intrinsic procedures: *note 19171COMPILER_OPTIONS:: and *note COMPILER_VERSION::. 19172 19173 19174File: gfortran.info, Node: ISO_C_BINDING, Next: IEEE modules, Prev: ISO_FORTRAN_ENV, Up: Intrinsic Modules 19175 1917610.2 'ISO_C_BINDING' 19177==================== 19178 19179_Standard_: 19180 Fortran 2003 and later, GNU extensions 19181 19182 The following intrinsic procedures are provided by the module; their 19183definition can be found in the section Intrinsic Procedures of this 19184manual. 19185 19186'C_ASSOCIATED' 19187'C_F_POINTER' 19188'C_F_PROCPOINTER' 19189'C_FUNLOC' 19190'C_LOC' 19191'C_SIZEOF' 19192 19193 The 'ISO_C_BINDING' module provides the following named constants of 19194type default integer, which can be used as KIND type parameters. 19195 19196 In addition to the integer named constants required by the Fortran 191972003 standard and 'C_PTRDIFF_T' of TS 29113, GNU Fortran provides as an 19198extension named constants for the 128-bit integer types supported by the 19199C compiler: 'C_INT128_T, C_INT_LEAST128_T, C_INT_FAST128_T'. 19200Furthermore, if '__float128' is supported in C, the named constants 19201'C_FLOAT128, C_FLOAT128_COMPLEX' are defined. 19202 19203Fortran Named constant C type Extension 19204Type 19205'INTEGER' 'C_INT' 'int' 19206'INTEGER' 'C_SHORT' 'short int' 19207'INTEGER' 'C_LONG' 'long int' 19208'INTEGER' 'C_LONG_LONG' 'long long int' 19209'INTEGER' 'C_SIGNED_CHAR' 'signed char'/'unsigned 19210 char' 19211'INTEGER' 'C_SIZE_T' 'size_t' 19212'INTEGER' 'C_INT8_T' 'int8_t' 19213'INTEGER' 'C_INT16_T' 'int16_t' 19214'INTEGER' 'C_INT32_T' 'int32_t' 19215'INTEGER' 'C_INT64_T' 'int64_t' 19216'INTEGER' 'C_INT128_T' 'int128_t' Ext. 19217'INTEGER' 'C_INT_LEAST8_T' 'int_least8_t' 19218'INTEGER' 'C_INT_LEAST16_T' 'int_least16_t' 19219'INTEGER' 'C_INT_LEAST32_T' 'int_least32_t' 19220'INTEGER' 'C_INT_LEAST64_T' 'int_least64_t' 19221'INTEGER' 'C_INT_LEAST128_T' 'int_least128_t' Ext. 19222'INTEGER' 'C_INT_FAST8_T' 'int_fast8_t' 19223'INTEGER' 'C_INT_FAST16_T' 'int_fast16_t' 19224'INTEGER' 'C_INT_FAST32_T' 'int_fast32_t' 19225'INTEGER' 'C_INT_FAST64_T' 'int_fast64_t' 19226'INTEGER' 'C_INT_FAST128_T' 'int_fast128_t' Ext. 19227'INTEGER' 'C_INTMAX_T' 'intmax_t' 19228'INTEGER' 'C_INTPTR_T' 'intptr_t' 19229'INTEGER' 'C_PTRDIFF_T' 'ptrdiff_t' TS 29113 19230'REAL' 'C_FLOAT' 'float' 19231'REAL' 'C_DOUBLE' 'double' 19232'REAL' 'C_LONG_DOUBLE' 'long double' 19233'REAL' 'C_FLOAT128' '__float128' Ext. 19234'COMPLEX' 'C_FLOAT_COMPLEX' 'float _Complex' 19235'COMPLEX' 'C_DOUBLE_COMPLEX' 'double _Complex' 19236'COMPLEX' 'C_LONG_DOUBLE_COMPLEX' 'long double _Complex' 19237'REAL' 'C_FLOAT128_COMPLEX' '__float128 _Complex' Ext. 19238'LOGICAL' 'C_BOOL' '_Bool' 19239'CHARACTER' 'C_CHAR' 'char' 19240 19241 Additionally, the following parameters of type 19242'CHARACTER(KIND=C_CHAR)' are defined. 19243 19244Name C definition Value 19245'C_NULL_CHAR' null character ''\0'' 19246'C_ALERT' alert ''\a'' 19247'C_BACKSPACE' backspace ''\b'' 19248'C_FORM_FEED' form feed ''\f'' 19249'C_NEW_LINE' new line ''\n'' 19250'C_CARRIAGE_RETURN'carriage return ''\r'' 19251'C_HORIZONTAL_TAB'horizontal tab ''\t'' 19252'C_VERTICAL_TAB'vertical tab ''\v'' 19253 19254 Moreover, the following two named constants are defined: 19255 19256Name Type 19257'C_NULL_PTR' 'C_PTR' 19258'C_NULL_FUNPTR''C_FUNPTR' 19259 19260 Both are equivalent to the value 'NULL' in C. 19261 19262 19263File: gfortran.info, Node: IEEE modules, Next: OpenMP Modules OMP_LIB and OMP_LIB_KINDS, Prev: ISO_C_BINDING, Up: Intrinsic Modules 19264 1926510.3 IEEE modules: 'IEEE_EXCEPTIONS', 'IEEE_ARITHMETIC', and 'IEEE_FEATURES' 19266============================================================================ 19267 19268_Standard_: 19269 Fortran 2003 and later 19270 19271 The 'IEEE_EXCEPTIONS', 'IEEE_ARITHMETIC', and 'IEEE_FEATURES' 19272intrinsic modules provide support for exceptions and IEEE arithmetic, as 19273defined in Fortran 2003 and later standards, and the IEC 60559:1989 19274standard (_Binary floating-point arithmetic for microprocessor 19275systems_). These modules are only provided on the following supported 19276platforms: 19277 19278 * i386 and x86_64 processors 19279 * platforms which use the GNU C Library (glibc) 19280 * platforms with support for SysV/386 routines for floating point 19281 interface (including Solaris and BSDs) 19282 * platforms with the AIX OS 19283 19284 For full compliance with the Fortran standards, code using the 19285'IEEE_EXCEPTIONS' or 'IEEE_ARITHMETIC' modules should be compiled with 19286the following options: '-fno-unsafe-math-optimizations -frounding-math 19287-fsignaling-nans'. 19288 19289 19290File: gfortran.info, Node: OpenMP Modules OMP_LIB and OMP_LIB_KINDS, Next: OpenACC Module OPENACC, Prev: IEEE modules, Up: Intrinsic Modules 19291 1929210.4 OpenMP Modules 'OMP_LIB' and 'OMP_LIB_KINDS' 19293================================================= 19294 19295_Standard_: 19296 OpenMP Application Program Interface v4.5 19297 19298 The OpenMP Fortran runtime library routines are provided both in a 19299form of two Fortran 90 modules, named 'OMP_LIB' and 'OMP_LIB_KINDS', and 19300in a form of a Fortran 'include' file named 'omp_lib.h'. The procedures 19301provided by 'OMP_LIB' can be found in the *note Introduction: 19302(libgomp)Top. manual, the named constants defined in the modules are 19303listed below. 19304 19305 For details refer to the actual OpenMP Application Program Interface 19306v4.5 (http://www.openmp.org/wp-content/uploads/openmp-4.5.pdf). 19307 19308 'OMP_LIB_KINDS' provides the following scalar default-integer named 19309constants: 19310 19311'omp_lock_kind' 19312'omp_lock_hint_kind' 19313'omp_nest_lock_kind' 19314'omp_proc_bind_kind' 19315'omp_sched_kind' 19316 19317 'OMP_LIB' provides the scalar default-integer named constant 19318'openmp_version' with a value of the form YYYYMM, where 'yyyy' is the 19319year and MM the month of the OpenMP version; for OpenMP v4.5 the value 19320is '201511'. 19321 19322 The following scalar integer named constants of the kind 19323'omp_sched_kind': 19324 19325'omp_sched_static' 19326'omp_sched_dynamic' 19327'omp_sched_guided' 19328'omp_sched_auto' 19329 19330 And the following scalar integer named constants of the kind 19331'omp_proc_bind_kind': 19332 19333'omp_proc_bind_false' 19334'omp_proc_bind_true' 19335'omp_proc_bind_master' 19336'omp_proc_bind_close' 19337'omp_proc_bind_spread' 19338 19339 The following scalar integer named constants are of the kind 19340'omp_lock_hint_kind': 19341 19342'omp_lock_hint_none' 19343'omp_lock_hint_uncontended' 19344'omp_lock_hint_contended' 19345'omp_lock_hint_nonspeculative' 19346'omp_lock_hint_speculative' 19347 19348 19349File: gfortran.info, Node: OpenACC Module OPENACC, Prev: OpenMP Modules OMP_LIB and OMP_LIB_KINDS, Up: Intrinsic Modules 19350 1935110.5 OpenACC Module 'OPENACC' 19352============================= 19353 19354_Standard_: 19355 OpenACC Application Programming Interface v2.0 19356 19357 The OpenACC Fortran runtime library routines are provided both in a 19358form of a Fortran 90 module, named 'OPENACC', and in form of a Fortran 19359'include' file named 'openacc_lib.h'. The procedures provided by 19360'OPENACC' can be found in the *note Introduction: (libgomp)Top. manual, 19361the named constants defined in the modules are listed below. 19362 19363 For details refer to the actual OpenACC Application Programming 19364Interface v2.0 (http://www.openacc.org/). 19365 19366 'OPENACC' provides the scalar default-integer named constant 19367'openacc_version' with a value of the form YYYYMM, where 'yyyy' is the 19368year and MM the month of the OpenACC version; for OpenACC v2.0 the value 19369is '201306'. 19370 19371 19372File: gfortran.info, Node: Contributing, Next: Copying, Prev: Intrinsic Modules, Up: Top 19373 19374Contributing 19375************ 19376 19377Free software is only possible if people contribute to efforts to create 19378it. We're always in need of more people helping out with ideas and 19379comments, writing documentation and contributing code. 19380 19381 If you want to contribute to GNU Fortran, have a look at the long 19382lists of projects you can take on. Some of these projects are small, 19383some of them are large; some are completely orthogonal to the rest of 19384what is happening on GNU Fortran, but others are "mainstream" projects 19385in need of enthusiastic hackers. All of these projects are important! 19386We will eventually get around to the things here, but they are also 19387things doable by someone who is willing and able. 19388 19389* Menu: 19390 19391* Contributors:: 19392* Projects:: 19393* Proposed Extensions:: 19394 19395 19396File: gfortran.info, Node: Contributors, Next: Projects, Up: Contributing 19397 19398Contributors to GNU Fortran 19399=========================== 19400 19401Most of the parser was hand-crafted by _Andy Vaught_, who is also the 19402initiator of the whole project. Thanks Andy! Most of the interface 19403with GCC was written by _Paul Brook_. 19404 19405 The following individuals have contributed code and/or ideas and 19406significant help to the GNU Fortran project (in alphabetical order): 19407 19408 - Janne Blomqvist 19409 - Steven Bosscher 19410 - Paul Brook 19411 - Tobias Burnus 19412 - Franc,ois-Xavier Coudert 19413 - Bud Davis 19414 - Jerry DeLisle 19415 - Erik Edelmann 19416 - Bernhard Fischer 19417 - Daniel Franke 19418 - Richard Guenther 19419 - Richard Henderson 19420 - Katherine Holcomb 19421 - Jakub Jelinek 19422 - Niels Kristian Bech Jensen 19423 - Steven Johnson 19424 - Steven G. Kargl 19425 - Thomas Koenig 19426 - Asher Langton 19427 - H. J. Lu 19428 - Toon Moene 19429 - Brooks Moses 19430 - Andrew Pinski 19431 - Tim Prince 19432 - Christopher D. Rickett 19433 - Richard Sandiford 19434 - Tobias Schlu"ter 19435 - Roger Sayle 19436 - Paul Thomas 19437 - Andy Vaught 19438 - Feng Wang 19439 - Janus Weil 19440 - Daniel Kraft 19441 19442 The following people have contributed bug reports, smaller or larger 19443patches, and much needed feedback and encouragement for the GNU Fortran 19444project: 19445 19446 - Bill Clodius 19447 - Dominique d'Humie`res 19448 - Kate Hedstrom 19449 - Erik Schnetter 19450 - Joost VandeVondele 19451 19452 Many other individuals have helped debug, test and improve the GNU 19453Fortran compiler over the past few years, and we welcome you to do the 19454same! If you already have done so, and you would like to see your name 19455listed in the list above, please contact us. 19456 19457 19458File: gfortran.info, Node: Projects, Next: Proposed Extensions, Prev: Contributors, Up: Contributing 19459 19460Projects 19461======== 19462 19463_Help build the test suite_ 19464 Solicit more code for donation to the test suite: the more 19465 extensive the testsuite, the smaller the risk of breaking things in 19466 the future! We can keep code private on request. 19467 19468_Bug hunting/squishing_ 19469 Find bugs and write more test cases! Test cases are especially 19470 very welcome, because it allows us to concentrate on fixing bugs 19471 instead of isolating them. Going through the bugzilla database at 19472 <https://gcc.gnu.org/bugzilla/> to reduce testcases posted there 19473 and add more information (for example, for which version does the 19474 testcase work, for which versions does it fail?) is also very 19475 helpful. 19476 19477 19478File: gfortran.info, Node: Proposed Extensions, Prev: Projects, Up: Contributing 19479 19480Proposed Extensions 19481=================== 19482 19483Here's a list of proposed extensions for the GNU Fortran compiler, in no 19484particular order. Most of these are necessary to be fully compatible 19485with existing Fortran compilers, but they are not part of the official 19486J3 Fortran 95 standard. 19487 19488Compiler extensions: 19489-------------------- 19490 19491 * User-specified alignment rules for structures. 19492 19493 * Automatically extend single precision constants to double. 19494 19495 * Compile code that conserves memory by dynamically allocating common 19496 and module storage either on stack or heap. 19497 19498 * Compile flag to generate code for array conformance checking 19499 (suggest -CC). 19500 19501 * User control of symbol names (underscores, etc). 19502 19503 * Compile setting for maximum size of stack frame size before 19504 spilling parts to static or heap. 19505 19506 * Flag to force local variables into static space. 19507 19508 * Flag to force local variables onto stack. 19509 19510Environment Options 19511------------------- 19512 19513 * Pluggable library modules for random numbers, linear algebra. LA 19514 should use BLAS calling conventions. 19515 19516 * Environment variables controlling actions on arithmetic exceptions 19517 like overflow, underflow, precision loss--Generate NaN, abort, 19518 default. action. 19519 19520 * Set precision for fp units that support it (i387). 19521 19522 * Variable for setting fp rounding mode. 19523 19524 * Variable to fill uninitialized variables with a user-defined bit 19525 pattern. 19526 19527 * Environment variable controlling filename that is opened for that 19528 unit number. 19529 19530 * Environment variable to clear/trash memory being freed. 19531 19532 * Environment variable to control tracing of allocations and frees. 19533 19534 * Environment variable to display allocated memory at normal program 19535 end. 19536 19537 * Environment variable for filename for * IO-unit. 19538 19539 * Environment variable for temporary file directory. 19540 19541 * Environment variable forcing standard output to be line buffered 19542 (Unix). 19543 19544 19545File: gfortran.info, Node: Copying, Next: GNU Free Documentation License, Prev: Contributing, Up: Top 19546 19547GNU General Public License 19548************************** 19549 19550 Version 3, 29 June 2007 19551 19552 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/> 19553 19554 Everyone is permitted to copy and distribute verbatim copies of this 19555 license document, but changing it is not allowed. 19556 19557Preamble 19558======== 19559 19560The GNU General Public License is a free, copyleft license for software 19561and other kinds of works. 19562 19563 The licenses for most software and other practical works are designed 19564to take away your freedom to share and change the works. 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The work must carry prominent notices stating that you 19776 modified it, and giving a relevant date. 19777 19778 b. The work must carry prominent notices stating that it is 19779 released under this License and any conditions added under 19780 section 7. This requirement modifies the requirement in 19781 section 4 to "keep intact all notices". 19782 19783 c. You must license the entire work, as a whole, under this 19784 License to anyone who comes into possession of a copy. This 19785 License will therefore apply, along with any applicable 19786 section 7 additional terms, to the whole of the work, and all 19787 its parts, regardless of how they are packaged. This License 19788 gives no permission to license the work in any other way, but 19789 it does not invalidate such permission if you have separately 19790 received it. 19791 19792 d. If the work has interactive user interfaces, each must display 19793 Appropriate Legal Notices; however, if the Program has 19794 interactive interfaces that do not display Appropriate Legal 19795 Notices, your work need not make them do so. 19796 19797 A compilation of a covered work with other separate and independent 19798 works, which are not by their nature extensions of the covered 19799 work, and which are not combined with it such as to form a larger 19800 program, in or on a volume of a storage or distribution medium, is 19801 called an "aggregate" if the compilation and its resulting 19802 copyright are not used to limit the access or legal rights of the 19803 compilation's users beyond what the individual works permit. 19804 Inclusion of a covered work in an aggregate does not cause this 19805 License to apply to the other parts of the aggregate. 19806 19807 6. Conveying Non-Source Forms. 19808 19809 You may convey a covered work in object code form under the terms 19810 of sections 4 and 5, provided that you also convey the 19811 machine-readable Corresponding Source under the terms of this 19812 License, in one of these ways: 19813 19814 a. Convey the object code in, or embodied in, a physical product 19815 (including a physical distribution medium), accompanied by the 19816 Corresponding Source fixed on a durable physical medium 19817 customarily used for software interchange. 19818 19819 b. Convey the object code in, or embodied in, a physical product 19820 (including a physical distribution medium), accompanied by a 19821 written offer, valid for at least three years and valid for as 19822 long as you offer spare parts or customer support for that 19823 product model, to give anyone who possesses the object code 19824 either (1) a copy of the Corresponding Source for all the 19825 software in the product that is covered by this License, on a 19826 durable physical medium customarily used for software 19827 interchange, for a price no more than your reasonable cost of 19828 physically performing this conveying of source, or (2) access 19829 to copy the Corresponding Source from a network server at no 19830 charge. 19831 19832 c. Convey individual copies of the object code with a copy of the 19833 written offer to provide the Corresponding Source. This 19834 alternative is allowed only occasionally and noncommercially, 19835 and only if you received the object code with such an offer, 19836 in accord with subsection 6b. 19837 19838 d. Convey the object code by offering access from a designated 19839 place (gratis or for a charge), and offer equivalent access to 19840 the Corresponding Source in the same way through the same 19841 place at no further charge. You need not require recipients 19842 to copy the Corresponding Source along with the object code. 19843 If the place to copy the object code is a network server, the 19844 Corresponding Source may be on a different server (operated by 19845 you or a third party) that supports equivalent copying 19846 facilities, provided you maintain clear directions next to the 19847 object code saying where to find the Corresponding Source. 19848 Regardless of what server hosts the Corresponding Source, you 19849 remain obligated to ensure that it is available for as long as 19850 needed to satisfy these requirements. 19851 19852 e. Convey the object code using peer-to-peer transmission, 19853 provided you inform other peers where the object code and 19854 Corresponding Source of the work are being offered to the 19855 general public at no charge under subsection 6d. 19856 19857 A separable portion of the object code, whose source code is 19858 excluded from the Corresponding Source as a System Library, need 19859 not be included in conveying the object code work. 19860 19861 A "User Product" is either (1) a "consumer product", which means 19862 any tangible personal property which is normally used for personal, 19863 family, or household purposes, or (2) anything designed or sold for 19864 incorporation into a dwelling. In determining whether a product is 19865 a consumer product, doubtful cases shall be resolved in favor of 19866 coverage. 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But 19890 this requirement does not apply if neither you nor any third party 19891 retains the ability to install modified object code on the User 19892 Product (for example, the work has been installed in ROM). 19893 19894 The requirement to provide Installation Information does not 19895 include a requirement to continue to provide support service, 19896 warranty, or updates for a work that has been modified or installed 19897 by the recipient, or for the User Product in which it has been 19898 modified or installed. Access to a network may be denied when the 19899 modification itself materially and adversely affects the operation 19900 of the network or violates the rules and protocols for 19901 communication across the network. 19902 19903 Corresponding Source conveyed, and Installation Information 19904 provided, in accord with this section must be in a format that is 19905 publicly documented (and with an implementation available to the 19906 public in source code form), and must require no special password 19907 or key for unpacking, reading or copying. 19908 19909 7. Additional Terms. 19910 19911 "Additional permissions" are terms that supplement the terms of 19912 this License by making exceptions from one or more of its 19913 conditions. Additional permissions that are applicable to the 19914 entire Program shall be treated as though they were included in 19915 this License, to the extent that they are valid under applicable 19916 law. If additional permissions apply only to part of the Program, 19917 that part may be used separately under those permissions, but the 19918 entire Program remains governed by this License without regard to 19919 the additional permissions. 19920 19921 When you convey a copy of a covered work, you may at your option 19922 remove any additional permissions from that copy, or from any part 19923 of it. (Additional permissions may be written to require their own 19924 removal in certain cases when you modify the work.) You may place 19925 additional permissions on material, added by you to a covered work, 19926 for which you have or can give appropriate copyright permission. 19927 19928 Notwithstanding any other provision of this License, for material 19929 you add to a covered work, you may (if authorized by the copyright 19930 holders of that material) supplement the terms of this License with 19931 terms: 19932 19933 a. Disclaiming warranty or limiting liability differently from 19934 the terms of sections 15 and 16 of this License; or 19935 19936 b. Requiring preservation of specified reasonable legal notices 19937 or author attributions in that material or in the Appropriate 19938 Legal Notices displayed by works containing it; or 19939 19940 c. Prohibiting misrepresentation of the origin of that material, 19941 or requiring that modified versions of such material be marked 19942 in reasonable ways as different from the original version; or 19943 19944 d. Limiting the use for publicity purposes of names of licensors 19945 or authors of the material; or 19946 19947 e. Declining to grant rights under trademark law for use of some 19948 trade names, trademarks, or service marks; or 19949 19950 f. Requiring indemnification of licensors and authors of that 19951 material by anyone who conveys the material (or modified 19952 versions of it) with contractual assumptions of liability to 19953 the recipient, for any liability that these contractual 19954 assumptions directly impose on those licensors and authors. 19955 19956 All other non-permissive additional terms are considered "further 19957 restrictions" within the meaning of section 10. If the Program as 19958 you received it, or any part of it, contains a notice stating that 19959 it is governed by this License along with a term that is a further 19960 restriction, you may remove that term. If a license document 19961 contains a further restriction but permits relicensing or conveying 19962 under this License, you may add to a covered work material governed 19963 by the terms of that license document, provided that the further 19964 restriction does not survive such relicensing or conveying. 19965 19966 If you add terms to a covered work in accord with this section, you 19967 must place, in the relevant source files, a statement of the 19968 additional terms that apply to those files, or a notice indicating 19969 where to find the applicable terms. 19970 19971 Additional terms, permissive or non-permissive, may be stated in 19972 the form of a separately written license, or stated as exceptions; 19973 the above requirements apply either way. 19974 19975 8. Termination. 19976 19977 You may not propagate or modify a covered work except as expressly 19978 provided under this License. Any attempt otherwise to propagate or 19979 modify it is void, and will automatically terminate your rights 19980 under this License (including any patent licenses granted under the 19981 third paragraph of section 11). 19982 19983 However, if you cease all violation of this License, then your 19984 license from a particular copyright holder is reinstated (a) 19985 provisionally, unless and until the copyright holder explicitly and 19986 finally terminates your license, and (b) permanently, if the 19987 copyright holder fails to notify you of the violation by some 19988 reasonable means prior to 60 days after the cessation. 19989 19990 Moreover, your license from a particular copyright holder is 19991 reinstated permanently if the copyright holder notifies you of the 19992 violation by some reasonable means, this is the first time you have 19993 received notice of violation of this License (for any work) from 19994 that copyright holder, and you cure the violation prior to 30 days 19995 after your receipt of the notice. 19996 19997 Termination of your rights under this section does not terminate 19998 the licenses of parties who have received copies or rights from you 19999 under this License. If your rights have been terminated and not 20000 permanently reinstated, you do not qualify to receive new licenses 20001 for the same material under section 10. 20002 20003 9. Acceptance Not Required for Having Copies. 20004 20005 You are not required to accept this License in order to receive or 20006 run a copy of the Program. Ancillary propagation of a covered work 20007 occurring solely as a consequence of using peer-to-peer 20008 transmission to receive a copy likewise does not require 20009 acceptance. However, nothing other than this License grants you 20010 permission to propagate or modify any covered work. These actions 20011 infringe copyright if you do not accept this License. Therefore, 20012 by modifying or propagating a covered work, you indicate your 20013 acceptance of this License to do so. 20014 20015 10. Automatic Licensing of Downstream Recipients. 20016 20017 Each time you convey a covered work, the recipient automatically 20018 receives a license from the original licensors, to run, modify and 20019 propagate that work, subject to this License. You are not 20020 responsible for enforcing compliance by third parties with this 20021 License. 20022 20023 An "entity transaction" is a transaction transferring control of an 20024 organization, or substantially all assets of one, or subdividing an 20025 organization, or merging organizations. If propagation of a 20026 covered work results from an entity transaction, each party to that 20027 transaction who receives a copy of the work also receives whatever 20028 licenses to the work the party's predecessor in interest had or 20029 could give under the previous paragraph, plus a right to possession 20030 of the Corresponding Source of the work from the predecessor in 20031 interest, if the predecessor has it or can get it with reasonable 20032 efforts. 20033 20034 You may not impose any further restrictions on the exercise of the 20035 rights granted or affirmed under this License. For example, you 20036 may not impose a license fee, royalty, or other charge for exercise 20037 of rights granted under this License, and you may not initiate 20038 litigation (including a cross-claim or counterclaim in a lawsuit) 20039 alleging that any patent claim is infringed by making, using, 20040 selling, offering for sale, or importing the Program or any portion 20041 of it. 20042 20043 11. Patents. 20044 20045 A "contributor" is a copyright holder who authorizes use under this 20046 License of the Program or a work on which the Program is based. 20047 The work thus licensed is called the contributor's "contributor 20048 version". 20049 20050 A contributor's "essential patent claims" are all patent claims 20051 owned or controlled by the contributor, whether already acquired or 20052 hereafter acquired, that would be infringed by some manner, 20053 permitted by this License, of making, using, or selling its 20054 contributor version, but do not include claims that would be 20055 infringed only as a consequence of further modification of the 20056 contributor version. For purposes of this definition, "control" 20057 includes the right to grant patent sublicenses in a manner 20058 consistent with the requirements of this License. 20059 20060 Each contributor grants you a non-exclusive, worldwide, 20061 royalty-free patent license under the contributor's essential 20062 patent claims, to make, use, sell, offer for sale, import and 20063 otherwise run, modify and propagate the contents of its contributor 20064 version. 20065 20066 In the following three paragraphs, a "patent license" is any 20067 express agreement or commitment, however denominated, not to 20068 enforce a patent (such as an express permission to practice a 20069 patent or covenant not to sue for patent infringement). To "grant" 20070 such a patent license to a party means to make such an agreement or 20071 commitment not to enforce a patent against the party. 20072 20073 If you convey a covered work, knowingly relying on a patent 20074 license, and the Corresponding Source of the work is not available 20075 for anyone to copy, free of charge and under the terms of this 20076 License, through a publicly available network server or other 20077 readily accessible means, then you must either (1) cause the 20078 Corresponding Source to be so available, or (2) arrange to deprive 20079 yourself of the benefit of the patent license for this particular 20080 work, or (3) arrange, in a manner consistent with the requirements 20081 of this License, to extend the patent license to downstream 20082 recipients. "Knowingly relying" means you have actual knowledge 20083 that, but for the patent license, your conveying the covered work 20084 in a country, or your recipient's use of the covered work in a 20085 country, would infringe one or more identifiable patents in that 20086 country that you have reason to believe are valid. 20087 20088 If, pursuant to or in connection with a single transaction or 20089 arrangement, you convey, or propagate by procuring conveyance of, a 20090 covered work, and grant a patent license to some of the parties 20091 receiving the covered work authorizing them to use, propagate, 20092 modify or convey a specific copy of the covered work, then the 20093 patent license you grant is automatically extended to all 20094 recipients of the covered work and works based on it. 20095 20096 A patent license is "discriminatory" if it does not include within 20097 the scope of its coverage, prohibits the exercise of, or is 20098 conditioned on the non-exercise of one or more of the rights that 20099 are specifically granted under this License. You may not convey a 20100 covered work if you are a party to an arrangement with a third 20101 party that is in the business of distributing software, under which 20102 you make payment to the third party based on the extent of your 20103 activity of conveying the work, and under which the third party 20104 grants, to any of the parties who would receive the covered work 20105 from you, a discriminatory patent license (a) in connection with 20106 copies of the covered work conveyed by you (or copies made from 20107 those copies), or (b) primarily for and in connection with specific 20108 products or compilations that contain the covered work, unless you 20109 entered into that arrangement, or that patent license was granted, 20110 prior to 28 March 2007. 20111 20112 Nothing in this License shall be construed as excluding or limiting 20113 any implied license or other defenses to infringement that may 20114 otherwise be available to you under applicable patent law. 20115 20116 12. No Surrender of Others' Freedom. 20117 20118 If conditions are imposed on you (whether by court order, agreement 20119 or otherwise) that contradict the conditions of this License, they 20120 do not excuse you from the conditions of this License. If you 20121 cannot convey a covered work so as to satisfy simultaneously your 20122 obligations under this License and any other pertinent obligations, 20123 then as a consequence you may not convey it at all. For example, 20124 if you agree to terms that obligate you to collect a royalty for 20125 further conveying from those to whom you convey the Program, the 20126 only way you could satisfy both those terms and this License would 20127 be to refrain entirely from conveying the Program. 20128 20129 13. Use with the GNU Affero General Public License. 20130 20131 Notwithstanding any other provision of this License, you have 20132 permission to link or combine any covered work with a work licensed 20133 under version 3 of the GNU Affero General Public License into a 20134 single combined work, and to convey the resulting work. The terms 20135 of this License will continue to apply to the part which is the 20136 covered work, but the special requirements of the GNU Affero 20137 General Public License, section 13, concerning interaction through 20138 a network will apply to the combination as such. 20139 20140 14. Revised Versions of this License. 20141 20142 The Free Software Foundation may publish revised and/or new 20143 versions of the GNU General Public License from time to time. Such 20144 new versions will be similar in spirit to the present version, but 20145 may differ in detail to address new problems or concerns. 20146 20147 Each version is given a distinguishing version number. If the 20148 Program specifies that a certain numbered version of the GNU 20149 General Public License "or any later version" applies to it, you 20150 have the option of following the terms and conditions either of 20151 that numbered version or of any later version published by the Free 20152 Software Foundation. If the Program does not specify a version 20153 number of the GNU General Public License, you may choose any 20154 version ever published by the Free Software Foundation. 20155 20156 If the Program specifies that a proxy can decide which future 20157 versions of the GNU General Public License can be used, that 20158 proxy's public statement of acceptance of a version permanently 20159 authorizes you to choose that version for the Program. 20160 20161 Later license versions may give you additional or different 20162 permissions. However, no additional obligations are imposed on any 20163 author or copyright holder as a result of your choosing to follow a 20164 later version. 20165 20166 15. Disclaimer of Warranty. 20167 20168 THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 20169 APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE 20170 COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" 20171 WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, 20172 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 20173 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE 20174 RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. 20175 SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL 20176 NECESSARY SERVICING, REPAIR OR CORRECTION. 20177 20178 16. Limitation of Liability. 20179 20180 IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN 20181 WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES 20182 AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR 20183 DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR 20184 CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE 20185 THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA 20186 BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 20187 PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER 20188 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF 20189 THE POSSIBILITY OF SUCH DAMAGES. 20190 20191 17. Interpretation of Sections 15 and 16. 20192 20193 If the disclaimer of warranty and limitation of liability provided 20194 above cannot be given local legal effect according to their terms, 20195 reviewing courts shall apply local law that most closely 20196 approximates an absolute waiver of all civil liability in 20197 connection with the Program, unless a warranty or assumption of 20198 liability accompanies a copy of the Program in return for a fee. 20199 20200END OF TERMS AND CONDITIONS 20201=========================== 20202 20203How to Apply These Terms to Your New Programs 20204============================================= 20205 20206If you develop a new program, and you want it to be of the greatest 20207possible use to the public, the best way to achieve this is to make it 20208free software which everyone can redistribute and change under these 20209terms. 20210 20211 To do so, attach the following notices to the program. It is safest 20212to attach them to the start of each source file to most effectively 20213state the exclusion of warranty; and each file should have at least the 20214"copyright" line and a pointer to where the full notice is found. 20215 20216 ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES. 20217 Copyright (C) YEAR NAME OF AUTHOR 20218 20219 This program is free software: you can redistribute it and/or modify 20220 it under the terms of the GNU General Public License as published by 20221 the Free Software Foundation, either version 3 of the License, or (at 20222 your option) any later version. 20223 20224 This program is distributed in the hope that it will be useful, but 20225 WITHOUT ANY WARRANTY; without even the implied warranty of 20226 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20227 General Public License for more details. 20228 20229 You should have received a copy of the GNU General Public License 20230 along with this program. If not, see <http://www.gnu.org/licenses/>. 20231 20232 Also add information on how to contact you by electronic and paper 20233mail. 20234 20235 If the program does terminal interaction, make it output a short 20236notice like this when it starts in an interactive mode: 20237 20238 PROGRAM Copyright (C) YEAR NAME OF AUTHOR 20239 This program comes with ABSOLUTELY NO WARRANTY; for details type 'show w'. 20240 This is free software, and you are welcome to redistribute it 20241 under certain conditions; type 'show c' for details. 20242 20243 The hypothetical commands 'show w' and 'show c' should show the 20244appropriate parts of the General Public License. Of course, your 20245program's commands might be different; for a GUI interface, you would 20246use an "about box". 20247 20248 You should also get your employer (if you work as a programmer) or 20249school, if any, to sign a "copyright disclaimer" for the program, if 20250necessary. For more information on this, and how to apply and follow 20251the GNU GPL, see <http://www.gnu.org/licenses/>. 20252 20253 The GNU General Public License does not permit incorporating your 20254program into proprietary programs. If your program is a subroutine 20255library, you may consider it more useful to permit linking proprietary 20256applications with the library. If this is what you want to do, use the 20257GNU Lesser General Public License instead of this License. But first, 20258please read <http://www.gnu.org/philosophy/why-not-lgpl.html>. 20259 20260 20261File: gfortran.info, Node: GNU Free Documentation License, Next: Funding, Prev: Copying, Up: Top 20262 20263GNU Free Documentation License 20264****************************** 20265 20266 Version 1.3, 3 November 2008 20267 20268 Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. 20269 <http://fsf.org/> 20270 20271 Everyone is permitted to copy and distribute verbatim copies 20272 of this license document, but changing it is not allowed. 20273 20274 0. PREAMBLE 20275 20276 The purpose of this License is to make a manual, textbook, or other 20277 functional and useful document "free" in the sense of freedom: to 20278 assure everyone the effective freedom to copy and redistribute it, 20279 with or without modifying it, either commercially or 20280 noncommercially. Secondarily, this License preserves for the 20281 author and publisher a way to get credit for their work, while not 20282 being considered responsible for modifications made by others. 20283 20284 This License is a kind of "copyleft", which means that derivative 20285 works of the document must themselves be free in the same sense. 20286 It complements the GNU General Public License, which is a copyleft 20287 license designed for free software. 20288 20289 We have designed this License in order to use it for manuals for 20290 free software, because free software needs free documentation: a 20291 free program should come with manuals providing the same freedoms 20292 that the software does. But this License is not limited to 20293 software manuals; it can be used for any textual work, regardless 20294 of subject matter or whether it is published as a printed book. We 20295 recommend this License principally for works whose purpose is 20296 instruction or reference. 20297 20298 1. APPLICABILITY AND DEFINITIONS 20299 20300 This License applies to any manual or other work, in any medium, 20301 that contains a notice placed by the copyright holder saying it can 20302 be distributed under the terms of this License. Such a notice 20303 grants a world-wide, royalty-free license, unlimited in duration, 20304 to use that work under the conditions stated herein. The 20305 "Document", below, refers to any such manual or work. Any member 20306 of the public is a licensee, and is addressed as "you". You accept 20307 the license if you copy, modify or distribute the work in a way 20308 requiring permission under copyright law. 20309 20310 A "Modified Version" of the Document means any work containing the 20311 Document or a portion of it, either copied verbatim, or with 20312 modifications and/or translated into another language. 20313 20314 A "Secondary Section" is a named appendix or a front-matter section 20315 of the Document that deals exclusively with the relationship of the 20316 publishers or authors of the Document to the Document's overall 20317 subject (or to related matters) and contains nothing that could 20318 fall directly within that overall subject. (Thus, if the Document 20319 is in part a textbook of mathematics, a Secondary Section may not 20320 explain any mathematics.) The relationship could be a matter of 20321 historical connection with the subject or with related matters, or 20322 of legal, commercial, philosophical, ethical or political position 20323 regarding them. 20324 20325 The "Invariant Sections" are certain Secondary Sections whose 20326 titles are designated, as being those of Invariant Sections, in the 20327 notice that says that the Document is released under this License. 20328 If a section does not fit the above definition of Secondary then it 20329 is not allowed to be designated as Invariant. The Document may 20330 contain zero Invariant Sections. If the Document does not identify 20331 any Invariant Sections then there are none. 20332 20333 The "Cover Texts" are certain short passages of text that are 20334 listed, as Front-Cover Texts or Back-Cover Texts, in the notice 20335 that says that the Document is released under this License. A 20336 Front-Cover Text may be at most 5 words, and a Back-Cover Text may 20337 be at most 25 words. 20338 20339 A "Transparent" copy of the Document means a machine-readable copy, 20340 represented in a format whose specification is available to the 20341 general public, that is suitable for revising the document 20342 straightforwardly with generic text editors or (for images composed 20343 of pixels) generic paint programs or (for drawings) some widely 20344 available drawing editor, and that is suitable for input to text 20345 formatters or for automatic translation to a variety of formats 20346 suitable for input to text formatters. A copy made in an otherwise 20347 Transparent file format whose markup, or absence of markup, has 20348 been arranged to thwart or discourage subsequent modification by 20349 readers is not Transparent. An image format is not Transparent if 20350 used for any substantial amount of text. A copy that is not 20351 "Transparent" is called "Opaque". 20352 20353 Examples of suitable formats for Transparent copies include plain 20354 ASCII without markup, Texinfo input format, LaTeX input format, 20355 SGML or XML using a publicly available DTD, and standard-conforming 20356 simple HTML, PostScript or PDF designed for human modification. 20357 Examples of transparent image formats include PNG, XCF and JPG. 20358 Opaque formats include proprietary formats that can be read and 20359 edited only by proprietary word processors, SGML or XML for which 20360 the DTD and/or processing tools are not generally available, and 20361 the machine-generated HTML, PostScript or PDF produced by some word 20362 processors for output purposes only. 20363 20364 The "Title Page" means, for a printed book, the title page itself, 20365 plus such following pages as are needed to hold, legibly, the 20366 material this License requires to appear in the title page. For 20367 works in formats which do not have any title page as such, "Title 20368 Page" means the text near the most prominent appearance of the 20369 work's title, preceding the beginning of the body of the text. 20370 20371 The "publisher" means any person or entity that distributes copies 20372 of the Document to the public. 20373 20374 A section "Entitled XYZ" means a named subunit of the Document 20375 whose title either is precisely XYZ or contains XYZ in parentheses 20376 following text that translates XYZ in another language. (Here XYZ 20377 stands for a specific section name mentioned below, such as 20378 "Acknowledgements", "Dedications", "Endorsements", or "History".) 20379 To "Preserve the Title" of such a section when you modify the 20380 Document means that it remains a section "Entitled XYZ" according 20381 to this definition. 20382 20383 The Document may include Warranty Disclaimers next to the notice 20384 which states that this License applies to the Document. These 20385 Warranty Disclaimers are considered to be included by reference in 20386 this License, but only as regards disclaiming warranties: any other 20387 implication that these Warranty Disclaimers may have is void and 20388 has no effect on the meaning of this License. 20389 20390 2. VERBATIM COPYING 20391 20392 You may copy and distribute the Document in any medium, either 20393 commercially or noncommercially, provided that this License, the 20394 copyright notices, and the license notice saying this License 20395 applies to the Document are reproduced in all copies, and that you 20396 add no other conditions whatsoever to those of this License. You 20397 may not use technical measures to obstruct or control the reading 20398 or further copying of the copies you make or distribute. However, 20399 you may accept compensation in exchange for copies. If you 20400 distribute a large enough number of copies you must also follow the 20401 conditions in section 3. 20402 20403 You may also lend copies, under the same conditions stated above, 20404 and you may publicly display copies. 20405 20406 3. COPYING IN QUANTITY 20407 20408 If you publish printed copies (or copies in media that commonly 20409 have printed covers) of the Document, numbering more than 100, and 20410 the Document's license notice requires Cover Texts, you must 20411 enclose the copies in covers that carry, clearly and legibly, all 20412 these Cover Texts: Front-Cover Texts on the front cover, and 20413 Back-Cover Texts on the back cover. Both covers must also clearly 20414 and legibly identify you as the publisher of these copies. The 20415 front cover must present the full title with all words of the title 20416 equally prominent and visible. You may add other material on the 20417 covers in addition. Copying with changes limited to the covers, as 20418 long as they preserve the title of the Document and satisfy these 20419 conditions, can be treated as verbatim copying in other respects. 20420 20421 If the required texts for either cover are too voluminous to fit 20422 legibly, you should put the first ones listed (as many as fit 20423 reasonably) on the actual cover, and continue the rest onto 20424 adjacent pages. 20425 20426 If you publish or distribute Opaque copies of the Document 20427 numbering more than 100, you must either include a machine-readable 20428 Transparent copy along with each Opaque copy, or state in or with 20429 each Opaque copy a computer-network location from which the general 20430 network-using public has access to download using public-standard 20431 network protocols a complete Transparent copy of the Document, free 20432 of added material. If you use the latter option, you must take 20433 reasonably prudent steps, when you begin distribution of Opaque 20434 copies in quantity, to ensure that this Transparent copy will 20435 remain thus accessible at the stated location until at least one 20436 year after the last time you distribute an Opaque copy (directly or 20437 through your agents or retailers) of that edition to the public. 20438 20439 It is requested, but not required, that you contact the authors of 20440 the Document well before redistributing any large number of copies, 20441 to give them a chance to provide you with an updated version of the 20442 Document. 20443 20444 4. MODIFICATIONS 20445 20446 You may copy and distribute a Modified Version of the Document 20447 under the conditions of sections 2 and 3 above, provided that you 20448 release the Modified Version under precisely this License, with the 20449 Modified Version filling the role of the Document, thus licensing 20450 distribution and modification of the Modified Version to whoever 20451 possesses a copy of it. In addition, you must do these things in 20452 the Modified Version: 20453 20454 A. Use in the Title Page (and on the covers, if any) a title 20455 distinct from that of the Document, and from those of previous 20456 versions (which should, if there were any, be listed in the 20457 History section of the Document). You may use the same title 20458 as a previous version if the original publisher of that 20459 version gives permission. 20460 20461 B. List on the Title Page, as authors, one or more persons or 20462 entities responsible for authorship of the modifications in 20463 the Modified Version, together with at least five of the 20464 principal authors of the Document (all of its principal 20465 authors, if it has fewer than five), unless they release you 20466 from this requirement. 20467 20468 C. State on the Title page the name of the publisher of the 20469 Modified Version, as the publisher. 20470 20471 D. Preserve all the copyright notices of the Document. 20472 20473 E. Add an appropriate copyright notice for your modifications 20474 adjacent to the other copyright notices. 20475 20476 F. Include, immediately after the copyright notices, a license 20477 notice giving the public permission to use the Modified 20478 Version under the terms of this License, in the form shown in 20479 the Addendum below. 20480 20481 G. Preserve in that license notice the full lists of Invariant 20482 Sections and required Cover Texts given in the Document's 20483 license notice. 20484 20485 H. Include an unaltered copy of this License. 20486 20487 I. Preserve the section Entitled "History", Preserve its Title, 20488 and add to it an item stating at least the title, year, new 20489 authors, and publisher of the Modified Version as given on the 20490 Title Page. If there is no section Entitled "History" in the 20491 Document, create one stating the title, year, authors, and 20492 publisher of the Document as given on its Title Page, then add 20493 an item describing the Modified Version as stated in the 20494 previous sentence. 20495 20496 J. Preserve the network location, if any, given in the Document 20497 for public access to a Transparent copy of the Document, and 20498 likewise the network locations given in the Document for 20499 previous versions it was based on. These may be placed in the 20500 "History" section. You may omit a network location for a work 20501 that was published at least four years before the Document 20502 itself, or if the original publisher of the version it refers 20503 to gives permission. 20504 20505 K. For any section Entitled "Acknowledgements" or "Dedications", 20506 Preserve the Title of the section, and preserve in the section 20507 all the substance and tone of each of the contributor 20508 acknowledgements and/or dedications given therein. 20509 20510 L. Preserve all the Invariant Sections of the Document, unaltered 20511 in their text and in their titles. Section numbers or the 20512 equivalent are not considered part of the section titles. 20513 20514 M. Delete any section Entitled "Endorsements". Such a section 20515 may not be included in the Modified Version. 20516 20517 N. Do not retitle any existing section to be Entitled 20518 "Endorsements" or to conflict in title with any Invariant 20519 Section. 20520 20521 O. Preserve any Warranty Disclaimers. 20522 20523 If the Modified Version includes new front-matter sections or 20524 appendices that qualify as Secondary Sections and contain no 20525 material copied from the Document, you may at your option designate 20526 some or all of these sections as invariant. To do this, add their 20527 titles to the list of Invariant Sections in the Modified Version's 20528 license notice. These titles must be distinct from any other 20529 section titles. 20530 20531 You may add a section Entitled "Endorsements", provided it contains 20532 nothing but endorsements of your Modified Version by various 20533 parties--for example, statements of peer review or that the text 20534 has been approved by an organization as the authoritative 20535 definition of a standard. 20536 20537 You may add a passage of up to five words as a Front-Cover Text, 20538 and a passage of up to 25 words as a Back-Cover Text, to the end of 20539 the list of Cover Texts in the Modified Version. Only one passage 20540 of Front-Cover Text and one of Back-Cover Text may be added by (or 20541 through arrangements made by) any one entity. If the Document 20542 already includes a cover text for the same cover, previously added 20543 by you or by arrangement made by the same entity you are acting on 20544 behalf of, you may not add another; but you may replace the old 20545 one, on explicit permission from the previous publisher that added 20546 the old one. 20547 20548 The author(s) and publisher(s) of the Document do not by this 20549 License give permission to use their names for publicity for or to 20550 assert or imply endorsement of any Modified Version. 20551 20552 5. COMBINING DOCUMENTS 20553 20554 You may combine the Document with other documents released under 20555 this License, under the terms defined in section 4 above for 20556 modified versions, provided that you include in the combination all 20557 of the Invariant Sections of all of the original documents, 20558 unmodified, and list them all as Invariant Sections of your 20559 combined work in its license notice, and that you preserve all 20560 their Warranty Disclaimers. 20561 20562 The combined work need only contain one copy of this License, and 20563 multiple identical Invariant Sections may be replaced with a single 20564 copy. If there are multiple Invariant Sections with the same name 20565 but different contents, make the title of each such section unique 20566 by adding at the end of it, in parentheses, the name of the 20567 original author or publisher of that section if known, or else a 20568 unique number. Make the same adjustment to the section titles in 20569 the list of Invariant Sections in the license notice of the 20570 combined work. 20571 20572 In the combination, you must combine any sections Entitled 20573 "History" in the various original documents, forming one section 20574 Entitled "History"; likewise combine any sections Entitled 20575 "Acknowledgements", and any sections Entitled "Dedications". You 20576 must delete all sections Entitled "Endorsements." 20577 20578 6. COLLECTIONS OF DOCUMENTS 20579 20580 You may make a collection consisting of the Document and other 20581 documents released under this License, and replace the individual 20582 copies of this License in the various documents with a single copy 20583 that is included in the collection, provided that you follow the 20584 rules of this License for verbatim copying of each of the documents 20585 in all other respects. 20586 20587 You may extract a single document from such a collection, and 20588 distribute it individually under this License, provided you insert 20589 a copy of this License into the extracted document, and follow this 20590 License in all other respects regarding verbatim copying of that 20591 document. 20592 20593 7. AGGREGATION WITH INDEPENDENT WORKS 20594 20595 A compilation of the Document or its derivatives with other 20596 separate and independent documents or works, in or on a volume of a 20597 storage or distribution medium, is called an "aggregate" if the 20598 copyright resulting from the compilation is not used to limit the 20599 legal rights of the compilation's users beyond what the individual 20600 works permit. When the Document is included in an aggregate, this 20601 License does not apply to the other works in the aggregate which 20602 are not themselves derivative works of the Document. 20603 20604 If the Cover Text requirement of section 3 is applicable to these 20605 copies of the Document, then if the Document is less than one half 20606 of the entire aggregate, the Document's Cover Texts may be placed 20607 on covers that bracket the Document within the aggregate, or the 20608 electronic equivalent of covers if the Document is in electronic 20609 form. Otherwise they must appear on printed covers that bracket 20610 the whole aggregate. 20611 20612 8. TRANSLATION 20613 20614 Translation is considered a kind of modification, so you may 20615 distribute translations of the Document under the terms of section 20616 4. Replacing Invariant Sections with translations requires special 20617 permission from their copyright holders, but you may include 20618 translations of some or all Invariant Sections in addition to the 20619 original versions of these Invariant Sections. You may include a 20620 translation of this License, and all the license notices in the 20621 Document, and any Warranty Disclaimers, provided that you also 20622 include the original English version of this License and the 20623 original versions of those notices and disclaimers. In case of a 20624 disagreement between the translation and the original version of 20625 this License or a notice or disclaimer, the original version will 20626 prevail. 20627 20628 If a section in the Document is Entitled "Acknowledgements", 20629 "Dedications", or "History", the requirement (section 4) to 20630 Preserve its Title (section 1) will typically require changing the 20631 actual title. 20632 20633 9. TERMINATION 20634 20635 You may not copy, modify, sublicense, or distribute the Document 20636 except as expressly provided under this License. Any attempt 20637 otherwise to copy, modify, sublicense, or distribute it is void, 20638 and will automatically terminate your rights under this License. 20639 20640 However, if you cease all violation of this License, then your 20641 license from a particular copyright holder is reinstated (a) 20642 provisionally, unless and until the copyright holder explicitly and 20643 finally terminates your license, and (b) permanently, if the 20644 copyright holder fails to notify you of the violation by some 20645 reasonable means prior to 60 days after the cessation. 20646 20647 Moreover, your license from a particular copyright holder is 20648 reinstated permanently if the copyright holder notifies you of the 20649 violation by some reasonable means, this is the first time you have 20650 received notice of violation of this License (for any work) from 20651 that copyright holder, and you cure the violation prior to 30 days 20652 after your receipt of the notice. 20653 20654 Termination of your rights under this section does not terminate 20655 the licenses of parties who have received copies or rights from you 20656 under this License. If your rights have been terminated and not 20657 permanently reinstated, receipt of a copy of some or all of the 20658 same material does not give you any rights to use it. 20659 20660 10. FUTURE REVISIONS OF THIS LICENSE 20661 20662 The Free Software Foundation may publish new, revised versions of 20663 the GNU Free Documentation License from time to time. Such new 20664 versions will be similar in spirit to the present version, but may 20665 differ in detail to address new problems or concerns. See 20666 <http://www.gnu.org/copyleft/>. 20667 20668 Each version of the License is given a distinguishing version 20669 number. If the Document specifies that a particular numbered 20670 version of this License "or any later version" applies to it, you 20671 have the option of following the terms and conditions either of 20672 that specified version or of any later version that has been 20673 published (not as a draft) by the Free Software Foundation. If the 20674 Document does not specify a version number of this License, you may 20675 choose any version ever published (not as a draft) by the Free 20676 Software Foundation. If the Document specifies that a proxy can 20677 decide which future versions of this License can be used, that 20678 proxy's public statement of acceptance of a version permanently 20679 authorizes you to choose that version for the Document. 20680 20681 11. RELICENSING 20682 20683 "Massive Multiauthor Collaboration Site" (or "MMC Site") means any 20684 World Wide Web server that publishes copyrightable works and also 20685 provides prominent facilities for anybody to edit those works. A 20686 public wiki that anybody can edit is an example of such a server. 20687 A "Massive Multiauthor Collaboration" (or "MMC") contained in the 20688 site means any set of copyrightable works thus published on the MMC 20689 site. 20690 20691 "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0 20692 license published by Creative Commons Corporation, a not-for-profit 20693 corporation with a principal place of business in San Francisco, 20694 California, as well as future copyleft versions of that license 20695 published by that same organization. 20696 20697 "Incorporate" means to publish or republish a Document, in whole or 20698 in part, as part of another Document. 20699 20700 An MMC is "eligible for relicensing" if it is licensed under this 20701 License, and if all works that were first published under this 20702 License somewhere other than this MMC, and subsequently 20703 incorporated in whole or in part into the MMC, (1) had no cover 20704 texts or invariant sections, and (2) were thus incorporated prior 20705 to November 1, 2008. 20706 20707 The operator of an MMC Site may republish an MMC contained in the 20708 site under CC-BY-SA on the same site at any time before August 1, 20709 2009, provided the MMC is eligible for relicensing. 20710 20711ADDENDUM: How to use this License for your documents 20712==================================================== 20713 20714To use this License in a document you have written, include a copy of 20715the License in the document and put the following copyright and license 20716notices just after the title page: 20717 20718 Copyright (C) YEAR YOUR NAME. 20719 Permission is granted to copy, distribute and/or modify this document 20720 under the terms of the GNU Free Documentation License, Version 1.3 20721 or any later version published by the Free Software Foundation; 20722 with no Invariant Sections, no Front-Cover Texts, and no Back-Cover 20723 Texts. A copy of the license is included in the section entitled ``GNU 20724 Free Documentation License''. 20725 20726 If you have Invariant Sections, Front-Cover Texts and Back-Cover 20727Texts, replace the "with...Texts." line with this: 20728 20729 with the Invariant Sections being LIST THEIR TITLES, with 20730 the Front-Cover Texts being LIST, and with the Back-Cover Texts 20731 being LIST. 20732 20733 If you have Invariant Sections without Cover Texts, or some other 20734combination of the three, merge those two alternatives to suit the 20735situation. 20736 20737 If your document contains nontrivial examples of program code, we 20738recommend releasing these examples in parallel under your choice of free 20739software license, such as the GNU General Public License, to permit 20740their use in free software. 20741 20742 20743File: gfortran.info, Node: Funding, Next: Option Index, Prev: GNU Free Documentation License, Up: Top 20744 20745Funding Free Software 20746********************* 20747 20748If you want to have more free software a few years from now, it makes 20749sense for you to help encourage people to contribute funds for its 20750development. The most effective approach known is to encourage 20751commercial redistributors to donate. 20752 20753 Users of free software systems can boost the pace of development by 20754encouraging for-a-fee distributors to donate part of their selling price 20755to free software developers--the Free Software Foundation, and others. 20756 20757 The way to convince distributors to do this is to demand it and 20758expect it from them. So when you compare distributors, judge them 20759partly by how much they give to free software development. Show 20760distributors they must compete to be the one who gives the most. 20761 20762 To make this approach work, you must insist on numbers that you can 20763compare, such as, "We will donate ten dollars to the Frobnitz project 20764for each disk sold." Don't be satisfied with a vague promise, such as 20765"A portion of the profits are donated," since it doesn't give a basis 20766for comparison. 20767 20768 Even a precise fraction "of the profits from this disk" is not very 20769meaningful, since creative accounting and unrelated business decisions 20770can greatly alter what fraction of the sales price counts as profit. If 20771the price you pay is $50, ten percent of the profit is probably less 20772than a dollar; it might be a few cents, or nothing at all. 20773 20774 Some redistributors do development work themselves. This is useful 20775too; but to keep everyone honest, you need to inquire how much they do, 20776and what kind. Some kinds of development make much more long-term 20777difference than others. For example, maintaining a separate version of 20778a program contributes very little; maintaining the standard version of a 20779program for the whole community contributes much. Easy new ports 20780contribute little, since someone else would surely do them; difficult 20781ports such as adding a new CPU to the GNU Compiler Collection contribute 20782more; major new features or packages contribute the most. 20783 20784 By establishing the idea that supporting further development is "the 20785proper thing to do" when distributing free software for a fee, we can 20786assure a steady flow of resources into making more free software. 20787 20788 Copyright (C) 1994 Free Software Foundation, Inc. 20789 Verbatim copying and redistribution of this section is permitted 20790 without royalty; alteration is not permitted. 20791 20792 20793File: gfortran.info, Node: Option Index, Next: Keyword Index, Prev: Funding, Up: Top 20794 20795Option Index 20796************ 20797 20798'gfortran''s command line options are indexed here without any initial 20799'-' or '--'. Where an option has both positive and negative forms (such 20800as -foption and -fno-option), relevant entries in the manual are indexed 20801under the most appropriate form; it may sometimes be useful to look up 20802both forms. 20803 20804�[index�] 20805* Menu: 20806 20807* A-PREDICATE=ANSWER: Preprocessing Options. 20808 (line 119) 20809* APREDICATE=ANSWER: Preprocessing Options. 20810 (line 113) 20811* backslash: Fortran Dialect Options. 20812 (line 74) 20813* C: Preprocessing Options. 20814 (line 122) 20815* c-prototypes: Interoperability Options. 20816 (line 7) 20817* CC: Preprocessing Options. 20818 (line 137) 20819* cpp: Preprocessing Options. 20820 (line 12) 20821* dD: Preprocessing Options. 20822 (line 35) 20823* dI: Preprocessing Options. 20824 (line 51) 20825* dM: Preprocessing Options. 20826 (line 26) 20827* dN: Preprocessing Options. 20828 (line 41) 20829* DNAME: Preprocessing Options. 20830 (line 151) 20831* DNAME=DEFINITION: Preprocessing Options. 20832 (line 154) 20833* dU: Preprocessing Options. 20834 (line 44) 20835* faggressive-function-elimination: Code Gen Options. (line 398) 20836* falign-commons: Code Gen Options. (line 371) 20837* fall-intrinsics: Fortran Dialect Options. 20838 (line 17) 20839* fblas-matmul-limit: Code Gen Options. (line 305) 20840* fbounds-check: Code Gen Options. (line 198) 20841* fcheck: Code Gen Options. (line 141) 20842* fcheck-array-temporaries: Code Gen Options. (line 232) 20843* fcoarray: Code Gen Options. (line 127) 20844* fconvert=CONVERSION: Runtime Options. (line 10) 20845* fcray-pointer: Fortran Dialect Options. 20846 (line 120) 20847* fd-lines-as-code: Fortran Dialect Options. 20848 (line 27) 20849* fd-lines-as-comments: Fortran Dialect Options. 20850 (line 27) 20851* fdec: Fortran Dialect Options. 20852 (line 34) 20853* fdec-intrinsic-ints: Fortran Dialect Options. 20854 (line 54) 20855* fdec-math: Fortran Dialect Options. 20856 (line 59) 20857* fdec-static: Fortran Dialect Options. 20858 (line 64) 20859* fdec-structure: Fortran Dialect Options. 20860 (line 48) 20861* fdefault-double-8: Fortran Dialect Options. 20862 (line 185) 20863* fdefault-integer-8: Fortran Dialect Options. 20864 (line 155) 20865* fdefault-real-10: Fortran Dialect Options. 20866 (line 169) 20867* fdefault-real-16: Fortran Dialect Options. 20868 (line 177) 20869* fdefault-real-8: Fortran Dialect Options. 20870 (line 161) 20871* fdollar-ok: Fortran Dialect Options. 20872 (line 68) 20873* fdump-fortran-optimized: Debugging Options. (line 18) 20874* fdump-fortran-original: Debugging Options. (line 10) 20875* fdump-parse-tree: Debugging Options. (line 25) 20876* fexternal-blas: Code Gen Options. (line 297) 20877* ff2c: Code Gen Options. (line 25) 20878* ffixed-form: Fortran Dialect Options. 20879 (line 11) 20880* ffixed-line-length-N: Fortran Dialect Options. 20881 (line 91) 20882* ffpe-summary=LIST: Debugging Options. (line 59) 20883* ffpe-trap=LIST: Debugging Options. (line 33) 20884* ffree-form: Fortran Dialect Options. 20885 (line 11) 20886* ffree-line-length-N: Fortran Dialect Options. 20887 (line 104) 20888* fimplicit-none: Fortran Dialect Options. 20889 (line 115) 20890* finit-character: Code Gen Options. (line 340) 20891* finit-derived: Code Gen Options. (line 340) 20892* finit-integer: Code Gen Options. (line 340) 20893* finit-local-zero: Code Gen Options. (line 340) 20894* finit-logical: Code Gen Options. (line 340) 20895* finit-real: Code Gen Options. (line 340) 20896* finline-matmul-limit: Code Gen Options. (line 316) 20897* finteger-4-integer-8: Fortran Dialect Options. 20898 (line 194) 20899* fintrinsic-modules-path DIR: Directory Options. (line 36) 20900* fmax-array-constructor: Code Gen Options. (line 235) 20901* fmax-errors=N: Error and Warning Options. 20902 (line 27) 20903* fmax-identifier-length=N: Fortran Dialect Options. 20904 (line 111) 20905* fmax-stack-var-size: Code Gen Options. (line 253) 20906* fmax-subrecord-length=LENGTH: Runtime Options. (line 29) 20907* fmodule-private: Fortran Dialect Options. 20908 (line 86) 20909* fno-automatic: Code Gen Options. (line 15) 20910* fno-backtrace: Debugging Options. (line 69) 20911* fno-protect-parens: Code Gen Options. (line 383) 20912* fno-underscoring: Code Gen Options. (line 54) 20913* fopenacc: Fortran Dialect Options. 20914 (line 124) 20915* fopenmp: Fortran Dialect Options. 20916 (line 135) 20917* fpack-derived: Code Gen Options. (line 275) 20918* fpp: Preprocessing Options. 20919 (line 12) 20920* frange-check: Fortran Dialect Options. 20921 (line 143) 20922* freal-4-real-10: Fortran Dialect Options. 20923 (line 209) 20924* freal-4-real-16: Fortran Dialect Options. 20925 (line 209) 20926* freal-4-real-8: Fortran Dialect Options. 20927 (line 209) 20928* freal-8-real-10: Fortran Dialect Options. 20929 (line 209) 20930* freal-8-real-16: Fortran Dialect Options. 20931 (line 209) 20932* freal-8-real-4: Fortran Dialect Options. 20933 (line 209) 20934* frealloc-lhs: Code Gen Options. (line 392) 20935* frecord-marker=LENGTH: Runtime Options. (line 21) 20936* frecursive: Code Gen Options. (line 330) 20937* frepack-arrays: Code Gen Options. (line 281) 20938* frontend-loop-interchange: Code Gen Options. (line 415) 20939* frontend-optimize: Code Gen Options. (line 406) 20940* fsecond-underscore: Code Gen Options. (line 110) 20941* fshort-enums: Code Gen Options. (line 291) 20942* fshort-enums <1>: Fortran 2003 status. (line 93) 20943* fsign-zero: Runtime Options. (line 34) 20944* fstack-arrays: Code Gen Options. (line 267) 20945* fsyntax-only: Error and Warning Options. 20946 (line 33) 20947* ftest-forall-temp: Fortran Dialect Options. 20948 (line 239) 20949* fworking-directory: Preprocessing Options. 20950 (line 55) 20951* H: Preprocessing Options. 20952 (line 174) 20953* IDIR: Directory Options. (line 14) 20954* idirafter DIR: Preprocessing Options. 20955 (line 69) 20956* imultilib DIR: Preprocessing Options. 20957 (line 76) 20958* iprefix PREFIX: Preprocessing Options. 20959 (line 80) 20960* iquote DIR: Preprocessing Options. 20961 (line 89) 20962* isysroot DIR: Preprocessing Options. 20963 (line 85) 20964* isystem DIR: Preprocessing Options. 20965 (line 96) 20966* JDIR: Directory Options. (line 29) 20967* MDIR: Directory Options. (line 29) 20968* nostdinc: Preprocessing Options. 20969 (line 104) 20970* P: Preprocessing Options. 20971 (line 179) 20972* pedantic: Error and Warning Options. 20973 (line 39) 20974* pedantic-errors: Error and Warning Options. 20975 (line 58) 20976* static-libgfortran: Link Options. (line 11) 20977* std=STD option: Fortran Dialect Options. 20978 (line 220) 20979* tail-call-workaround: Code Gen Options. (line 202) 20980* UNAME: Preprocessing Options. 20981 (line 185) 20982* undef: Preprocessing Options. 20983 (line 109) 20984* Waliasing: Error and Warning Options. 20985 (line 71) 20986* Walign-commons: Error and Warning Options. 20987 (line 226) 20988* Wall: Error and Warning Options. 20989 (line 62) 20990* Wampersand: Error and Warning Options. 20991 (line 88) 20992* Wargument-mismatch: Error and Warning Options. 20993 (line 96) 20994* Warray-temporaries: Error and Warning Options. 20995 (line 101) 20996* Wc-binding-type: Error and Warning Options. 20997 (line 106) 20998* Wcharacter-truncation: Error and Warning Options. 20999 (line 113) 21000* Wcompare-reals: Error and Warning Options. 21001 (line 253) 21002* Wconversion: Error and Warning Options. 21003 (line 122) 21004* Wconversion-extra: Error and Warning Options. 21005 (line 126) 21006* Wdo-subscript: Error and Warning Options. 21007 (line 265) 21008* Werror: Error and Warning Options. 21009 (line 277) 21010* Wextra: Error and Warning Options. 21011 (line 130) 21012* Wfrontend-loop-interchange: Error and Warning Options. 21013 (line 135) 21014* Wfunction-elimination: Error and Warning Options. 21015 (line 232) 21016* Wimplicit-interface: Error and Warning Options. 21017 (line 139) 21018* Wimplicit-procedure: Error and Warning Options. 21019 (line 145) 21020* Winteger-division: Error and Warning Options. 21021 (line 149) 21022* Wintrinsic-shadow: Error and Warning Options. 21023 (line 204) 21024* Wintrinsics-std: Error and Warning Options. 21025 (line 153) 21026* Wline-truncation: Error and Warning Options. 21027 (line 116) 21028* Wpedantic: Error and Warning Options. 21029 (line 39) 21030* Wreal-q-constant: Error and Warning Options. 21031 (line 160) 21032* Wrealloc-lhs: Error and Warning Options. 21033 (line 236) 21034* Wrealloc-lhs-all: Error and Warning Options. 21035 (line 248) 21036* Wsurprising: Error and Warning Options. 21037 (line 164) 21038* Wtabs: Error and Warning Options. 21039 (line 186) 21040* Wtargt-lifetime: Error and Warning Options. 21041 (line 257) 21042* Wundefined-do-loop: Error and Warning Options. 21043 (line 194) 21044* Wunderflow: Error and Warning Options. 21045 (line 199) 21046* Wunused-dummy-argument: Error and Warning Options. 21047 (line 215) 21048* Wunused-parameter: Error and Warning Options. 21049 (line 219) 21050* Wuse-without-only: Error and Warning Options. 21051 (line 211) 21052* Wzerotrip: Error and Warning Options. 21053 (line 261) 21054 21055 21056File: gfortran.info, Node: Keyword Index, Prev: Option Index, Up: Top 21057 21058Keyword Index 21059************* 21060 21061�[index�] 21062* Menu: 21063 21064* $: Fortran Dialect Options. 21065 (line 68) 21066* %LOC: Argument list functions. 21067 (line 6) 21068* %REF: Argument list functions. 21069 (line 6) 21070* %VAL: Argument list functions. 21071 (line 6) 21072* &: Error and Warning Options. 21073 (line 88) 21074* [...]: Fortran 2003 status. (line 78) 21075* _gfortran_set_args: _gfortran_set_args. (line 6) 21076* _gfortran_set_convert: _gfortran_set_convert. 21077 (line 6) 21078* _gfortran_set_fpe: _gfortran_set_fpe. (line 6) 21079* _gfortran_set_max_subrecord_length: _gfortran_set_max_subrecord_length. 21080 (line 6) 21081* _gfortran_set_options: _gfortran_set_options. 21082 (line 6) 21083* _gfortran_set_record_marker: _gfortran_set_record_marker. 21084 (line 6) 21085* ABORT: ABORT. (line 6) 21086* ABS: ABS. (line 6) 21087* absolute value: ABS. (line 6) 21088* ACCESS: ACCESS. (line 6) 21089* ACCESS='STREAM' I/O: Fortran 2003 status. (line 103) 21090* ACHAR: ACHAR. (line 6) 21091* ACOS: ACOS. (line 6) 21092* ACOSD: ACOSD. (line 6) 21093* ACOSH: ACOSH. (line 6) 21094* adjust string: ADJUSTL. (line 6) 21095* adjust string <1>: ADJUSTR. (line 6) 21096* ADJUSTL: ADJUSTL. (line 6) 21097* ADJUSTR: ADJUSTR. (line 6) 21098* AIMAG: AIMAG. (line 6) 21099* AINT: AINT. (line 6) 21100* ALARM: ALARM. (line 6) 21101* ALGAMA: LOG_GAMMA. (line 6) 21102* aliasing: Error and Warning Options. 21103 (line 71) 21104* alignment of COMMON blocks: Error and Warning Options. 21105 (line 226) 21106* alignment of COMMON blocks <1>: Code Gen Options. (line 371) 21107* ALL: ALL. (line 6) 21108* all warnings: Error and Warning Options. 21109 (line 62) 21110* ALLOCATABLE components of derived types: Fortran 2003 status. 21111 (line 101) 21112* ALLOCATABLE dummy arguments: Fortran 2003 status. (line 99) 21113* ALLOCATABLE function results: Fortran 2003 status. (line 100) 21114* ALLOCATED: ALLOCATED. (line 6) 21115* allocation, moving: MOVE_ALLOC. (line 6) 21116* allocation, status: ALLOCATED. (line 6) 21117* ALOG: LOG. (line 6) 21118* ALOG10: LOG10. (line 6) 21119* AMAX0: MAX. (line 6) 21120* AMAX1: MAX. (line 6) 21121* AMIN0: MIN. (line 6) 21122* AMIN1: MIN. (line 6) 21123* AMOD: MOD. (line 6) 21124* AND: AND. (line 6) 21125* ANINT: ANINT. (line 6) 21126* ANY: ANY. (line 6) 21127* area hyperbolic cosine: ACOSH. (line 6) 21128* area hyperbolic sine: ASINH. (line 6) 21129* area hyperbolic tangent: ATANH. (line 6) 21130* argument list functions: Argument list functions. 21131 (line 6) 21132* arguments, to program: COMMAND_ARGUMENT_COUNT. 21133 (line 6) 21134* arguments, to program <1>: GETARG. (line 6) 21135* arguments, to program <2>: GET_COMMAND. (line 6) 21136* arguments, to program <3>: GET_COMMAND_ARGUMENT. 21137 (line 6) 21138* arguments, to program <4>: IARGC. (line 6) 21139* array, add elements: SUM. (line 6) 21140* array, AND: IALL. (line 6) 21141* array, apply condition: ALL. (line 6) 21142* array, apply condition <1>: ANY. (line 6) 21143* array, bounds checking: Code Gen Options. (line 141) 21144* array, change dimensions: RESHAPE. (line 6) 21145* array, combine arrays: MERGE. (line 6) 21146* array, condition testing: ALL. (line 6) 21147* array, condition testing <1>: ANY. (line 6) 21148* array, conditionally add elements: SUM. (line 6) 21149* array, conditionally count elements: COUNT. (line 6) 21150* array, conditionally multiply elements: PRODUCT. (line 6) 21151* array, constructors: Fortran 2003 status. (line 78) 21152* array, count elements: SIZE. (line 6) 21153* array, duplicate dimensions: SPREAD. (line 6) 21154* array, duplicate elements: SPREAD. (line 6) 21155* array, element counting: COUNT. (line 6) 21156* array, gather elements: PACK. (line 6) 21157* array, increase dimension: SPREAD. (line 6) 21158* array, increase dimension <1>: UNPACK. (line 6) 21159* array, indices of type real: Real array indices. (line 6) 21160* array, location of maximum element: MAXLOC. (line 6) 21161* array, location of minimum element: MINLOC. (line 6) 21162* array, lower bound: LBOUND. (line 6) 21163* array, maximum value: MAXVAL. (line 6) 21164* array, merge arrays: MERGE. (line 6) 21165* array, minimum value: MINVAL. (line 6) 21166* array, multiply elements: PRODUCT. (line 6) 21167* array, number of elements: COUNT. (line 6) 21168* array, number of elements <1>: SIZE. (line 6) 21169* array, OR: IANY. (line 6) 21170* array, packing: PACK. (line 6) 21171* array, parity: IPARITY. (line 6) 21172* array, permutation: CSHIFT. (line 6) 21173* array, product: PRODUCT. (line 6) 21174* array, reduce dimension: PACK. (line 6) 21175* array, rotate: CSHIFT. (line 6) 21176* array, scatter elements: UNPACK. (line 6) 21177* array, shape: SHAPE. (line 6) 21178* array, shift: EOSHIFT. (line 6) 21179* array, shift circularly: CSHIFT. (line 6) 21180* array, size: SIZE. (line 6) 21181* array, sum: SUM. (line 6) 21182* array, transmogrify: RESHAPE. (line 6) 21183* array, transpose: TRANSPOSE. (line 6) 21184* array, unpacking: UNPACK. (line 6) 21185* array, upper bound: UBOUND. (line 6) 21186* array, XOR: IPARITY. (line 6) 21187* ASCII collating sequence: ACHAR. (line 6) 21188* ASCII collating sequence <1>: IACHAR. (line 6) 21189* ASIN: ASIN. (line 6) 21190* ASIND: ASIND. (line 6) 21191* ASINH: ASINH. (line 6) 21192* ASSOCIATED: ASSOCIATED. (line 6) 21193* association status: ASSOCIATED. (line 6) 21194* association status, C pointer: C_ASSOCIATED. (line 6) 21195* ATAN: ATAN. (line 6) 21196* ATAN2: ATAN2. (line 6) 21197* ATAN2D: ATAN2D. (line 6) 21198* ATAND: ATAND. (line 6) 21199* ATANH: ATANH. (line 6) 21200* Atomic subroutine, add: ATOMIC_ADD. (line 6) 21201* Atomic subroutine, ADD with fetch: ATOMIC_FETCH_ADD. (line 6) 21202* Atomic subroutine, AND: ATOMIC_AND. (line 6) 21203* Atomic subroutine, AND with fetch: ATOMIC_FETCH_AND. (line 6) 21204* Atomic subroutine, compare and swap: ATOMIC_CAS. (line 6) 21205* Atomic subroutine, define: ATOMIC_DEFINE. (line 6) 21206* Atomic subroutine, OR: ATOMIC_OR. (line 6) 21207* Atomic subroutine, OR with fetch: ATOMIC_FETCH_OR. (line 6) 21208* Atomic subroutine, reference: ATOMIC_REF. (line 6) 21209* Atomic subroutine, XOR: ATOMIC_XOR. (line 6) 21210* Atomic subroutine, XOR with fetch: ATOMIC_FETCH_XOR. (line 6) 21211* ATOMIC_ADD: ATOMIC_ADD. (line 6) 21212* ATOMIC_AND: ATOMIC_AND. (line 6) 21213* ATOMIC_DEFINE: ATOMIC_CAS. (line 6) 21214* ATOMIC_DEFINE <1>: ATOMIC_DEFINE. (line 6) 21215* ATOMIC_FETCH_ADD: ATOMIC_FETCH_ADD. (line 6) 21216* ATOMIC_FETCH_AND: ATOMIC_FETCH_AND. (line 6) 21217* ATOMIC_FETCH_OR: ATOMIC_FETCH_OR. (line 6) 21218* ATOMIC_FETCH_XOR: ATOMIC_FETCH_XOR. (line 6) 21219* ATOMIC_OR: ATOMIC_OR. (line 6) 21220* ATOMIC_REF: ATOMIC_REF. (line 6) 21221* ATOMIC_XOR: ATOMIC_XOR. (line 6) 21222* Authors: Contributors. (line 6) 21223* AUTOMATIC: AUTOMATIC and STATIC attributes. 21224 (line 6) 21225* BABS: ABS. (line 6) 21226* backslash: Fortran Dialect Options. 21227 (line 74) 21228* BACKSPACE: Read/Write after EOF marker. 21229 (line 6) 21230* BACKTRACE: BACKTRACE. (line 6) 21231* backtrace: Debugging Options. (line 69) 21232* backtrace <1>: BACKTRACE. (line 6) 21233* base 10 logarithm function: LOG10. (line 6) 21234* BBCLR: IBCLR. (line 6) 21235* BBITS: IBITS. (line 6) 21236* BBSET: IBSET. (line 6) 21237* BBTEST: BTEST. (line 6) 21238* BESJ0: BESSEL_J0. (line 6) 21239* BESJ1: BESSEL_J1. (line 6) 21240* BESJN: BESSEL_JN. (line 6) 21241* Bessel function, first kind: BESSEL_J0. (line 6) 21242* Bessel function, first kind <1>: BESSEL_J1. (line 6) 21243* Bessel function, first kind <2>: BESSEL_JN. (line 6) 21244* Bessel function, second kind: BESSEL_Y0. (line 6) 21245* Bessel function, second kind <1>: BESSEL_Y1. (line 6) 21246* Bessel function, second kind <2>: BESSEL_YN. (line 6) 21247* BESSEL_J0: BESSEL_J0. (line 6) 21248* BESSEL_J1: BESSEL_J1. (line 6) 21249* BESSEL_JN: BESSEL_JN. (line 6) 21250* BESSEL_Y0: BESSEL_Y0. (line 6) 21251* BESSEL_Y1: BESSEL_Y1. (line 6) 21252* BESSEL_YN: BESSEL_YN. (line 6) 21253* BESY0: BESSEL_Y0. (line 6) 21254* BESY1: BESSEL_Y1. (line 6) 21255* BESYN: BESSEL_YN. (line 6) 21256* BGE: BGE. (line 6) 21257* BGT: BGT. (line 6) 21258* BIAND: IAND. (line 6) 21259* BIEOR: IEOR. (line 6) 21260* binary representation: POPCNT. (line 6) 21261* binary representation <1>: POPPAR. (line 6) 21262* BIOR: IOR. (line 6) 21263* BITEST: BTEST. (line 6) 21264* bits set: POPCNT. (line 6) 21265* bits, AND of array elements: IALL. (line 6) 21266* bits, clear: IBCLR. (line 6) 21267* bits, extract: IBITS. (line 6) 21268* bits, get: IBITS. (line 6) 21269* bits, merge: MERGE_BITS. (line 6) 21270* bits, move: MVBITS. (line 6) 21271* bits, move <1>: TRANSFER. (line 6) 21272* bits, negate: NOT. (line 6) 21273* bits, number of: BIT_SIZE. (line 6) 21274* bits, OR of array elements: IANY. (line 6) 21275* bits, set: IBSET. (line 6) 21276* bits, shift: ISHFT. (line 6) 21277* bits, shift circular: ISHFTC. (line 6) 21278* bits, shift left: LSHIFT. (line 6) 21279* bits, shift left <1>: SHIFTL. (line 6) 21280* bits, shift right: RSHIFT. (line 6) 21281* bits, shift right <1>: SHIFTA. (line 6) 21282* bits, shift right <2>: SHIFTR. (line 6) 21283* bits, testing: BTEST. (line 6) 21284* bits, unset: IBCLR. (line 6) 21285* bits, XOR of array elements: IPARITY. (line 6) 21286* bitwise comparison: BGE. (line 6) 21287* bitwise comparison <1>: BGT. (line 6) 21288* bitwise comparison <2>: BLE. (line 6) 21289* bitwise comparison <3>: BLT. (line 6) 21290* bitwise logical and: AND. (line 6) 21291* bitwise logical and <1>: IAND. (line 6) 21292* bitwise logical exclusive or: IEOR. (line 6) 21293* bitwise logical exclusive or <1>: XOR. (line 6) 21294* bitwise logical not: NOT. (line 6) 21295* bitwise logical or: IOR. (line 6) 21296* bitwise logical or <1>: OR. (line 6) 21297* BIT_SIZE: BIT_SIZE. (line 6) 21298* BJTEST: BTEST. (line 6) 21299* BKTEST: BTEST. (line 6) 21300* BLE: BLE. (line 6) 21301* BLT: BLT. (line 6) 21302* BMOD: MOD. (line 6) 21303* BMVBITS: MVBITS. (line 6) 21304* BNOT: NOT. (line 6) 21305* bounds checking: Code Gen Options. (line 141) 21306* BOZ literal constants: BOZ literal constants. 21307 (line 6) 21308* BSHFT: ISHFT. (line 6) 21309* BSHFTC: ISHFTC. (line 6) 21310* BTEST: BTEST. (line 6) 21311* CABS: ABS. (line 6) 21312* calling convention: Code Gen Options. (line 25) 21313* CARRIAGECONTROL: Extended I/O specifiers. 21314 (line 6) 21315* CCOS: COS. (line 6) 21316* CCOSD: COSD. (line 6) 21317* CDABS: ABS. (line 6) 21318* CDCOS: COS. (line 6) 21319* CDCOSD: COSD. (line 6) 21320* CDEXP: EXP. (line 6) 21321* CDLOG: LOG. (line 6) 21322* CDSIN: SIN. (line 6) 21323* CDSIND: SIND. (line 6) 21324* CDSQRT: SQRT. (line 6) 21325* CEILING: CEILING. (line 6) 21326* ceiling: ANINT. (line 6) 21327* ceiling <1>: CEILING. (line 6) 21328* CEXP: EXP. (line 6) 21329* CHAR: CHAR. (line 6) 21330* character kind: SELECTED_CHAR_KIND. (line 6) 21331* character set: Fortran Dialect Options. 21332 (line 68) 21333* CHDIR: CHDIR. (line 6) 21334* checking array temporaries: Code Gen Options. (line 141) 21335* checking subscripts: Code Gen Options. (line 141) 21336* CHMOD: CHMOD. (line 6) 21337* clock ticks: MCLOCK. (line 6) 21338* clock ticks <1>: MCLOCK8. (line 6) 21339* clock ticks <2>: SYSTEM_CLOCK. (line 6) 21340* CLOG: LOG. (line 6) 21341* CMPLX: CMPLX. (line 6) 21342* coarray, IMAGE_INDEX: IMAGE_INDEX. (line 6) 21343* coarray, lower bound: LCOBOUND. (line 6) 21344* coarray, NUM_IMAGES: NUM_IMAGES. (line 6) 21345* coarray, THIS_IMAGE: THIS_IMAGE. (line 6) 21346* coarray, upper bound: UCOBOUND. (line 6) 21347* Coarray, _gfortran_caf_atomic_cas: _gfortran_caf_atomic_cas. 21348 (line 6) 21349* Coarray, _gfortran_caf_atomic_define: _gfortran_caf_atomic_define. 21350 (line 6) 21351* Coarray, _gfortran_caf_atomic_op: _gfortran_caf_atomic_op. 21352 (line 6) 21353* Coarray, _gfortran_caf_atomic_ref: _gfortran_caf_atomic_ref. 21354 (line 6) 21355* Coarray, _gfortran_caf_co_broadcast: _gfortran_caf_co_broadcast. 21356 (line 6) 21357* Coarray, _gfortran_caf_co_max: _gfortran_caf_co_max. 21358 (line 6) 21359* Coarray, _gfortran_caf_co_min: _gfortran_caf_co_min. 21360 (line 6) 21361* Coarray, _gfortran_caf_co_reduce: _gfortran_caf_co_reduce. 21362 (line 6) 21363* Coarray, _gfortran_caf_co_sum: _gfortran_caf_co_sum. 21364 (line 6) 21365* Coarray, _gfortran_caf_deregister: _gfortran_caf_deregister. 21366 (line 6) 21367* Coarray, _gfortran_caf_error_stop: _gfortran_caf_error_stop. 21368 (line 6) 21369* Coarray, _gfortran_caf_error_stop_str: _gfortran_caf_error_stop_str. 21370 (line 6) 21371* Coarray, _gfortran_caf_event_post: _gfortran_caf_event_post. 21372 (line 6) 21373* Coarray, _gfortran_caf_event_query: _gfortran_caf_event_query. 21374 (line 6) 21375* Coarray, _gfortran_caf_event_wait: _gfortran_caf_event_wait. 21376 (line 6) 21377* Coarray, _gfortran_caf_failed_images: _gfortran_caf_failed_images. 21378 (line 6) 21379* Coarray, _gfortran_caf_fail_image: _gfortran_caf_fail_image. 21380 (line 6) 21381* Coarray, _gfortran_caf_finish: _gfortran_caf_finish. 21382 (line 6) 21383* Coarray, _gfortran_caf_get: _gfortran_caf_get. (line 6) 21384* Coarray, _gfortran_caf_get_by_ref: _gfortran_caf_get_by_ref. 21385 (line 6) 21386* Coarray, _gfortran_caf_image_status: _gfortran_caf_image_status. 21387 (line 6) 21388* Coarray, _gfortran_caf_init: _gfortran_caf_init. (line 6) 21389* Coarray, _gfortran_caf_is_present: _gfortran_caf_is_present. 21390 (line 6) 21391* Coarray, _gfortran_caf_lock: _gfortran_caf_lock. (line 6) 21392* Coarray, _gfortran_caf_num_images: _gfortran_caf_num_images. 21393 (line 6) 21394* Coarray, _gfortran_caf_register: _gfortran_caf_register. 21395 (line 6) 21396* Coarray, _gfortran_caf_send: _gfortran_caf_send. (line 6) 21397* Coarray, _gfortran_caf_sendget: _gfortran_caf_sendget. 21398 (line 6) 21399* Coarray, _gfortran_caf_sendget_by_ref: _gfortran_caf_sendget_by_ref. 21400 (line 6) 21401* Coarray, _gfortran_caf_send_by_ref: _gfortran_caf_send_by_ref. 21402 (line 6) 21403* Coarray, _gfortran_caf_stopped_images: _gfortran_caf_stopped_images. 21404 (line 6) 21405* Coarray, _gfortran_caf_sync_all: _gfortran_caf_sync_all. 21406 (line 6) 21407* Coarray, _gfortran_caf_sync_images: _gfortran_caf_sync_images. 21408 (line 6) 21409* Coarray, _gfortran_caf_sync_memory: _gfortran_caf_sync_memory. 21410 (line 6) 21411* Coarray, _gfortran_caf_this_image: _gfortran_caf_this_image. 21412 (line 6) 21413* Coarray, _gfortran_caf_unlock: _gfortran_caf_unlock. 21414 (line 6) 21415* coarrays: Code Gen Options. (line 127) 21416* Coarrays: Coarray Programming. (line 6) 21417* code generation, conventions: Code Gen Options. (line 6) 21418* collating sequence, ASCII: ACHAR. (line 6) 21419* collating sequence, ASCII <1>: IACHAR. (line 6) 21420* Collectives, generic reduction: CO_REDUCE. (line 6) 21421* Collectives, maximal value: CO_MAX. (line 6) 21422* Collectives, minimal value: CO_MIN. (line 6) 21423* Collectives, sum of values: CO_SUM. (line 6) 21424* Collectives, value broadcasting: CO_BROADCAST. (line 6) 21425* command line: EXECUTE_COMMAND_LINE. 21426 (line 6) 21427* command options: Invoking GNU Fortran. 21428 (line 6) 21429* command-line arguments: COMMAND_ARGUMENT_COUNT. 21430 (line 6) 21431* command-line arguments <1>: GETARG. (line 6) 21432* command-line arguments <2>: GET_COMMAND. (line 6) 21433* command-line arguments <3>: GET_COMMAND_ARGUMENT. 21434 (line 6) 21435* command-line arguments <4>: IARGC. (line 6) 21436* command-line arguments, number of: COMMAND_ARGUMENT_COUNT. 21437 (line 6) 21438* command-line arguments, number of <1>: IARGC. (line 6) 21439* COMMAND_ARGUMENT_COUNT: COMMAND_ARGUMENT_COUNT. 21440 (line 6) 21441* COMMON: Volatile COMMON blocks. 21442 (line 6) 21443* compiler flags inquiry function: COMPILER_OPTIONS. (line 6) 21444* compiler, name and version: COMPILER_VERSION. (line 6) 21445* COMPILER_OPTIONS: COMPILER_OPTIONS. (line 6) 21446* COMPILER_VERSION: COMPILER_VERSION. (line 6) 21447* COMPLEX: COMPLEX. (line 6) 21448* complex conjugate: CONJG. (line 6) 21449* Complex function: Alternate complex function syntax. 21450 (line 6) 21451* complex numbers, conversion to: CMPLX. (line 6) 21452* complex numbers, conversion to <1>: COMPLEX. (line 6) 21453* complex numbers, conversion to <2>: DCMPLX. (line 6) 21454* complex numbers, imaginary part: AIMAG. (line 6) 21455* complex numbers, real part: DREAL. (line 6) 21456* complex numbers, real part <1>: REAL. (line 6) 21457* Conditional compilation: Preprocessing and conditional compilation. 21458 (line 6) 21459* CONJG: CONJG. (line 6) 21460* consistency, durability: Data consistency and durability. 21461 (line 6) 21462* Contributing: Contributing. (line 6) 21463* Contributors: Contributors. (line 6) 21464* conversion: Error and Warning Options. 21465 (line 122) 21466* conversion <1>: Error and Warning Options. 21467 (line 126) 21468* conversion, to character: CHAR. (line 6) 21469* conversion, to complex: CMPLX. (line 6) 21470* conversion, to complex <1>: COMPLEX. (line 6) 21471* conversion, to complex <2>: DCMPLX. (line 6) 21472* conversion, to integer: Implicitly convert LOGICAL and INTEGER values. 21473 (line 6) 21474* conversion, to integer <1>: IACHAR. (line 6) 21475* conversion, to integer <2>: ICHAR. (line 6) 21476* conversion, to integer <3>: INT. (line 6) 21477* conversion, to integer <4>: INT2. (line 6) 21478* conversion, to integer <5>: INT8. (line 6) 21479* conversion, to integer <6>: LONG. (line 6) 21480* conversion, to logical: Implicitly convert LOGICAL and INTEGER values. 21481 (line 6) 21482* conversion, to logical <1>: LOGICAL. (line 6) 21483* conversion, to real: DBLE. (line 6) 21484* conversion, to real <1>: REAL. (line 6) 21485* conversion, to string: CTIME. (line 6) 21486* CONVERT specifier: CONVERT specifier. (line 6) 21487* core, dump: ABORT. (line 6) 21488* COS: COS. (line 6) 21489* COSD: COSD. (line 6) 21490* COSH: COSH. (line 6) 21491* cosine: COS. (line 6) 21492* cosine, degrees: COSD. (line 6) 21493* cosine, hyperbolic: COSH. (line 6) 21494* cosine, hyperbolic, inverse: ACOSH. (line 6) 21495* cosine, inverse: ACOS. (line 6) 21496* cosine, inverse, degrees: ACOSD. (line 6) 21497* COTAN: COTAN. (line 6) 21498* COTAND: COTAND. (line 6) 21499* cotangent: COTAN. (line 6) 21500* cotangent, degrees: COTAND. (line 6) 21501* COUNT: COUNT. (line 6) 21502* CO_BROADCAST: CO_BROADCAST. (line 6) 21503* CO_MAX: CO_MAX. (line 6) 21504* CO_MIN: CO_MIN. (line 6) 21505* CO_REDUCE: CO_REDUCE. (line 6) 21506* CO_SUM: CO_SUM. (line 6) 21507* CPP: Preprocessing and conditional compilation. 21508 (line 6) 21509* CPP <1>: Preprocessing Options. 21510 (line 6) 21511* CPU_TIME: CPU_TIME. (line 6) 21512* Credits: Contributors. (line 6) 21513* CSHIFT: CSHIFT. (line 6) 21514* CSIN: SIN. (line 6) 21515* CSIND: SIND. (line 6) 21516* CSQRT: SQRT. (line 6) 21517* CTIME: CTIME. (line 6) 21518* current date: DATE_AND_TIME. (line 6) 21519* current date <1>: FDATE. (line 6) 21520* current date <2>: IDATE. (line 6) 21521* current time: DATE_AND_TIME. (line 6) 21522* current time <1>: FDATE. (line 6) 21523* current time <2>: ITIME. (line 6) 21524* current time <3>: TIME. (line 6) 21525* current time <4>: TIME8. (line 6) 21526* C_ASSOCIATED: C_ASSOCIATED. (line 6) 21527* C_FUNLOC: C_FUNLOC. (line 6) 21528* C_F_POINTER: C_F_POINTER. (line 6) 21529* C_F_PROCPOINTER: C_F_PROCPOINTER. (line 6) 21530* C_LOC: C_LOC. (line 6) 21531* C_SIZEOF: C_SIZEOF. (line 6) 21532* DABS: ABS. (line 6) 21533* DACOS: ACOS. (line 6) 21534* DACOSD: ACOSD. (line 6) 21535* DACOSH: ACOSH. (line 6) 21536* DASIN: ASIN. (line 6) 21537* DASIND: ASIND. (line 6) 21538* DASINH: ASINH. (line 6) 21539* DATAN: ATAN. (line 6) 21540* DATAN2: ATAN2. (line 6) 21541* DATAN2D: ATAN2D. (line 6) 21542* DATAND: ATAND. (line 6) 21543* DATANH: ATANH. (line 6) 21544* date, current: DATE_AND_TIME. (line 6) 21545* date, current <1>: FDATE. (line 6) 21546* date, current <2>: IDATE. (line 6) 21547* DATE_AND_TIME: DATE_AND_TIME. (line 6) 21548* DBESJ0: BESSEL_J0. (line 6) 21549* DBESJ1: BESSEL_J1. (line 6) 21550* DBESJN: BESSEL_JN. (line 6) 21551* DBESY0: BESSEL_Y0. (line 6) 21552* DBESY1: BESSEL_Y1. (line 6) 21553* DBESYN: BESSEL_YN. (line 6) 21554* DBLE: DBLE. (line 6) 21555* DCMPLX: DCMPLX. (line 6) 21556* DCONJG: CONJG. (line 6) 21557* DCOS: COS. (line 6) 21558* DCOSD: COSD. (line 6) 21559* DCOSH: COSH. (line 6) 21560* DCOTAN: COTAN. (line 6) 21561* DCOTAND: COTAND. (line 6) 21562* DDIM: DIM. (line 6) 21563* debugging information options: Debugging Options. (line 6) 21564* debugging, preprocessor: Preprocessing Options. 21565 (line 26) 21566* debugging, preprocessor <1>: Preprocessing Options. 21567 (line 35) 21568* debugging, preprocessor <2>: Preprocessing Options. 21569 (line 41) 21570* debugging, preprocessor <3>: Preprocessing Options. 21571 (line 44) 21572* debugging, preprocessor <4>: Preprocessing Options. 21573 (line 51) 21574* DECODE: ENCODE and DECODE statements. 21575 (line 6) 21576* delayed execution: ALARM. (line 6) 21577* delayed execution <1>: SLEEP. (line 6) 21578* DEXP: EXP. (line 6) 21579* DFLOAT: REAL. (line 6) 21580* DGAMMA: GAMMA. (line 6) 21581* dialect options: Fortran Dialect Options. 21582 (line 6) 21583* DIGITS: DIGITS. (line 6) 21584* DIM: DIM. (line 6) 21585* DIMAG: AIMAG. (line 6) 21586* DINT: AINT. (line 6) 21587* directive, INCLUDE: Directory Options. (line 6) 21588* directory, options: Directory Options. (line 6) 21589* directory, search paths for inclusion: Directory Options. (line 14) 21590* division, modulo: MODULO. (line 6) 21591* division, remainder: MOD. (line 6) 21592* DLGAMA: LOG_GAMMA. (line 6) 21593* DLOG: LOG. (line 6) 21594* DLOG10: LOG10. (line 6) 21595* DMAX1: MAX. (line 6) 21596* DMIN1: MIN. (line 6) 21597* DMOD: MOD. (line 6) 21598* DNINT: ANINT. (line 6) 21599* dot product: DOT_PRODUCT. (line 6) 21600* DOT_PRODUCT: DOT_PRODUCT. (line 6) 21601* DPROD: DPROD. (line 6) 21602* DREAL: DREAL. (line 6) 21603* DSHIFTL: DSHIFTL. (line 6) 21604* DSHIFTR: DSHIFTR. (line 6) 21605* DSIGN: SIGN. (line 6) 21606* DSIN: SIN. (line 6) 21607* DSIND: SIND. (line 6) 21608* DSINH: SINH. (line 6) 21609* DSQRT: SQRT. (line 6) 21610* DTAN: TAN. (line 6) 21611* DTAND: TAND. (line 6) 21612* DTANH: TANH. (line 6) 21613* DTIME: DTIME. (line 6) 21614* dummy argument, unused: Error and Warning Options. 21615 (line 215) 21616* elapsed time: DTIME. (line 6) 21617* elapsed time <1>: SECNDS. (line 6) 21618* elapsed time <2>: SECOND. (line 6) 21619* Elimination of functions with identical argument lists: Code Gen Options. 21620 (line 398) 21621* ENCODE: ENCODE and DECODE statements. 21622 (line 6) 21623* ENUM statement: Fortran 2003 status. (line 93) 21624* ENUMERATOR statement: Fortran 2003 status. (line 93) 21625* environment variable: Environment Variables. 21626 (line 6) 21627* environment variable <1>: Runtime. (line 6) 21628* environment variable <2>: GETENV. (line 6) 21629* environment variable <3>: GET_ENVIRONMENT_VARIABLE. 21630 (line 6) 21631* EOF: Read/Write after EOF marker. 21632 (line 6) 21633* EOSHIFT: EOSHIFT. (line 6) 21634* EPSILON: EPSILON. (line 6) 21635* ERF: ERF. (line 6) 21636* ERFC: ERFC. (line 6) 21637* ERFC_SCALED: ERFC_SCALED. (line 6) 21638* error function: ERF. (line 6) 21639* error function, complementary: ERFC. (line 6) 21640* error function, complementary, exponentially-scaled: ERFC_SCALED. 21641 (line 6) 21642* errors, limiting: Error and Warning Options. 21643 (line 27) 21644* escape characters: Fortran Dialect Options. 21645 (line 74) 21646* ETIME: ETIME. (line 6) 21647* Euclidean distance: HYPOT. (line 6) 21648* Euclidean vector norm: NORM2. (line 6) 21649* Events, EVENT_QUERY: EVENT_QUERY. (line 6) 21650* EVENT_QUERY: EVENT_QUERY. (line 6) 21651* EXECUTE_COMMAND_LINE: EXECUTE_COMMAND_LINE. 21652 (line 6) 21653* EXIT: EXIT. (line 6) 21654* EXP: EXP. (line 6) 21655* EXPONENT: EXPONENT. (line 6) 21656* exponent: Default exponents. (line 6) 21657* exponential function: EXP. (line 6) 21658* exponential function, inverse: LOG. (line 6) 21659* exponential function, inverse <1>: LOG10. (line 6) 21660* expression size: C_SIZEOF. (line 6) 21661* expression size <1>: SIZEOF. (line 6) 21662* EXTENDS_TYPE_OF: EXTENDS_TYPE_OF. (line 6) 21663* extensions: Extensions. (line 6) 21664* extensions, implemented: Extensions implemented in GNU Fortran. 21665 (line 6) 21666* extensions, not implemented: Extensions not implemented in GNU Fortran. 21667 (line 6) 21668* extra warnings: Error and Warning Options. 21669 (line 130) 21670* f2c calling convention: Code Gen Options. (line 25) 21671* f2c calling convention <1>: Code Gen Options. (line 110) 21672* Factorial function: GAMMA. (line 6) 21673* FDATE: FDATE. (line 6) 21674* FDL, GNU Free Documentation License: GNU Free Documentation License. 21675 (line 6) 21676* FGET: FGET. (line 6) 21677* FGETC: FGETC. (line 6) 21678* file format, fixed: Fortran Dialect Options. 21679 (line 11) 21680* file format, fixed <1>: Fortran Dialect Options. 21681 (line 91) 21682* file format, free: Fortran Dialect Options. 21683 (line 11) 21684* file format, free <1>: Fortran Dialect Options. 21685 (line 104) 21686* file operation, file number: FNUM. (line 6) 21687* file operation, flush: FLUSH. (line 6) 21688* file operation, position: FSEEK. (line 6) 21689* file operation, position <1>: FTELL. (line 6) 21690* file operation, read character: FGET. (line 6) 21691* file operation, read character <1>: FGETC. (line 6) 21692* file operation, seek: FSEEK. (line 6) 21693* file operation, write character: FPUT. (line 6) 21694* file operation, write character <1>: FPUTC. (line 6) 21695* file system, access mode: ACCESS. (line 6) 21696* file system, change access mode: CHMOD. (line 6) 21697* file system, create link: LINK. (line 6) 21698* file system, create link <1>: SYMLNK. (line 6) 21699* file system, file creation mask: UMASK. (line 6) 21700* file system, file status: FSTAT. (line 6) 21701* file system, file status <1>: LSTAT. (line 6) 21702* file system, file status <2>: STAT. (line 6) 21703* file system, hard link: LINK. (line 6) 21704* file system, remove file: UNLINK. (line 6) 21705* file system, rename file: RENAME. (line 6) 21706* file system, soft link: SYMLNK. (line 6) 21707* file, symbolic link: File operations on symbolic links. 21708 (line 6) 21709* file, unformatted sequential: File format of unformatted sequential files. 21710 (line 6) 21711* flags inquiry function: COMPILER_OPTIONS. (line 6) 21712* FLOAT: REAL. (line 6) 21713* FLOATI: REAL. (line 6) 21714* floating point, exponent: EXPONENT. (line 6) 21715* floating point, fraction: FRACTION. (line 6) 21716* floating point, nearest different: NEAREST. (line 6) 21717* floating point, relative spacing: RRSPACING. (line 6) 21718* floating point, relative spacing <1>: SPACING. (line 6) 21719* floating point, scale: SCALE. (line 6) 21720* floating point, set exponent: SET_EXPONENT. (line 6) 21721* FLOATJ: REAL. (line 6) 21722* FLOATK: REAL. (line 6) 21723* FLOOR: FLOOR. (line 6) 21724* floor: AINT. (line 6) 21725* floor <1>: FLOOR. (line 6) 21726* FLUSH: FLUSH. (line 6) 21727* FLUSH statement: Fortran 2003 status. (line 89) 21728* FNUM: FNUM. (line 6) 21729* form feed whitespace: Form feed as whitespace. 21730 (line 6) 21731* FORMAT: Variable FORMAT expressions. 21732 (line 6) 21733* Fortran 77: GNU Fortran and G77. (line 6) 21734* FPP: Preprocessing and conditional compilation. 21735 (line 6) 21736* FPUT: FPUT. (line 6) 21737* FPUTC: FPUTC. (line 6) 21738* FRACTION: FRACTION. (line 6) 21739* FREE: FREE. (line 6) 21740* Front-end optimization: Code Gen Options. (line 406) 21741* FSEEK: FSEEK. (line 6) 21742* FSTAT: FSTAT. (line 6) 21743* FTELL: FTELL. (line 6) 21744* function elimination: Error and Warning Options. 21745 (line 232) 21746* g77: GNU Fortran and G77. (line 6) 21747* g77 calling convention: Code Gen Options. (line 25) 21748* g77 calling convention <1>: Code Gen Options. (line 110) 21749* GAMMA: GAMMA. (line 6) 21750* Gamma function: GAMMA. (line 6) 21751* Gamma function, logarithm of: LOG_GAMMA. (line 6) 21752* GCC: GNU Fortran and GCC. (line 6) 21753* Generating C prototypes from Fortran source code: Interoperability Options. 21754 (line 7) 21755* GERROR: GERROR. (line 6) 21756* GETARG: GETARG. (line 6) 21757* GETCWD: GETCWD. (line 6) 21758* GETENV: GETENV. (line 6) 21759* GETGID: GETGID. (line 6) 21760* GETLOG: GETLOG. (line 6) 21761* GETPID: GETPID. (line 6) 21762* GETUID: GETUID. (line 6) 21763* GET_COMMAND: GET_COMMAND. (line 6) 21764* GET_COMMAND_ARGUMENT: GET_COMMAND_ARGUMENT. 21765 (line 6) 21766* GET_ENVIRONMENT_VARIABLE: GET_ENVIRONMENT_VARIABLE. 21767 (line 6) 21768* GMTIME: GMTIME. (line 6) 21769* GNU Compiler Collection: GNU Fortran and GCC. (line 6) 21770* GNU Fortran command options: Invoking GNU Fortran. 21771 (line 6) 21772* Hollerith constants: Hollerith constants support. 21773 (line 6) 21774* HOSTNM: HOSTNM. (line 6) 21775* HUGE: HUGE. (line 6) 21776* hyperbolic cosine: COSH. (line 6) 21777* hyperbolic function, cosine: COSH. (line 6) 21778* hyperbolic function, cosine, inverse: ACOSH. (line 6) 21779* hyperbolic function, sine: SINH. (line 6) 21780* hyperbolic function, sine, inverse: ASINH. (line 6) 21781* hyperbolic function, tangent: TANH. (line 6) 21782* hyperbolic function, tangent, inverse: ATANH. (line 6) 21783* hyperbolic sine: SINH. (line 6) 21784* hyperbolic tangent: TANH. (line 6) 21785* HYPOT: HYPOT. (line 6) 21786* I/O item lists: I/O item lists. (line 6) 21787* I/O specifiers: Extended I/O specifiers. 21788 (line 6) 21789* IABS: ABS. (line 6) 21790* IACHAR: IACHAR. (line 6) 21791* IALL: IALL. (line 6) 21792* IAND: IAND. (line 6) 21793* IANY: IANY. (line 6) 21794* IARGC: IARGC. (line 6) 21795* IBCLR: IBCLR. (line 6) 21796* IBITS: IBITS. (line 6) 21797* IBSET: IBSET. (line 6) 21798* ICHAR: ICHAR. (line 6) 21799* IDATE: IDATE. (line 6) 21800* IDIM: DIM. (line 6) 21801* IDINT: INT. (line 6) 21802* IDNINT: NINT. (line 6) 21803* IEEE, ISNAN: ISNAN. (line 6) 21804* IEOR: IEOR. (line 6) 21805* IERRNO: IERRNO. (line 6) 21806* IFIX: INT. (line 6) 21807* IIABS: ABS. (line 6) 21808* IIAND: IAND. (line 6) 21809* IIBCLR: IBCLR. (line 6) 21810* IIBITS: IBITS. (line 6) 21811* IIBSET: IBSET. (line 6) 21812* IIEOR: IEOR. (line 6) 21813* IIOR: IOR. (line 6) 21814* IISHFT: ISHFT. (line 6) 21815* IISHFTC: ISHFTC. (line 6) 21816* IMAG: AIMAG. (line 6) 21817* images, cosubscript to image index conversion: IMAGE_INDEX. (line 6) 21818* images, index of this image: THIS_IMAGE. (line 6) 21819* images, number of: NUM_IMAGES. (line 6) 21820* IMAGE_INDEX: IMAGE_INDEX. (line 6) 21821* IMAGPART: AIMAG. (line 6) 21822* IMOD: MOD. (line 6) 21823* IMPORT statement: Fortran 2003 status. (line 120) 21824* IMVBITS: MVBITS. (line 6) 21825* INCLUDE directive: Directory Options. (line 6) 21826* inclusion, directory search paths for: Directory Options. (line 14) 21827* INDEX: INDEX intrinsic. (line 6) 21828* INOT: NOT. (line 6) 21829* INT: INT. (line 6) 21830* INT2: INT2. (line 6) 21831* INT8: INT8. (line 6) 21832* integer kind: SELECTED_INT_KIND. (line 6) 21833* Interoperability: Mixed-Language Programming. 21834 (line 6) 21835* intrinsic: Error and Warning Options. 21836 (line 204) 21837* intrinsic <1>: Error and Warning Options. 21838 (line 211) 21839* intrinsic Modules: Intrinsic Modules. (line 6) 21840* intrinsic procedures: Intrinsic Procedures. 21841 (line 6) 21842* intrinsics, integer: Type variants for integer intrinsics. 21843 (line 6) 21844* intrinsics, math: Extended math intrinsics. 21845 (line 6) 21846* intrinsics, trigonometric functions: Extended math intrinsics. 21847 (line 6) 21848* Introduction: Top. (line 6) 21849* inverse hyperbolic cosine: ACOSH. (line 6) 21850* inverse hyperbolic sine: ASINH. (line 6) 21851* inverse hyperbolic tangent: ATANH. (line 6) 21852* IOMSG= specifier: Fortran 2003 status. (line 91) 21853* IOR: IOR. (line 6) 21854* IOSTAT, end of file: IS_IOSTAT_END. (line 6) 21855* IOSTAT, end of record: IS_IOSTAT_EOR. (line 6) 21856* IPARITY: IPARITY. (line 6) 21857* IRAND: IRAND. (line 6) 21858* ISATTY: ISATTY. (line 6) 21859* ISHFT: ISHFT. (line 6) 21860* ISHFTC: ISHFTC. (line 6) 21861* ISIGN: SIGN. (line 6) 21862* ISNAN: ISNAN. (line 6) 21863* ISO_FORTRAN_ENV statement: Fortran 2003 status. (line 128) 21864* IS_IOSTAT_END: IS_IOSTAT_END. (line 6) 21865* IS_IOSTAT_EOR: IS_IOSTAT_EOR. (line 6) 21866* ITIME: ITIME. (line 6) 21867* JIABS: ABS. (line 6) 21868* JIAND: IAND. (line 6) 21869* JIBCLR: IBCLR. (line 6) 21870* JIBITS: IBITS. (line 6) 21871* JIBSET: IBSET. (line 6) 21872* JIEOR: IEOR. (line 6) 21873* JIOR: IOR. (line 6) 21874* JISHFT: ISHFT. (line 6) 21875* JISHFTC: ISHFTC. (line 6) 21876* JMOD: MOD. (line 6) 21877* JMVBITS: MVBITS. (line 6) 21878* JNOT: NOT. (line 6) 21879* KIABS: ABS. (line 6) 21880* KIAND: IAND. (line 6) 21881* KIBCLR: IBCLR. (line 6) 21882* KIBITS: IBITS. (line 6) 21883* KIBSET: IBSET. (line 6) 21884* KIEOR: IEOR. (line 6) 21885* KILL: KILL. (line 6) 21886* kind: KIND Type Parameters. 21887 (line 6) 21888* KIND: KIND. (line 6) 21889* kind <1>: KIND. (line 6) 21890* kind, character: SELECTED_CHAR_KIND. (line 6) 21891* kind, integer: SELECTED_INT_KIND. (line 6) 21892* kind, old-style: Old-style kind specifications. 21893 (line 6) 21894* kind, real: SELECTED_REAL_KIND. (line 6) 21895* KIOR: IOR. (line 6) 21896* KISHFT: ISHFT. (line 6) 21897* KISHFTC: ISHFTC. (line 6) 21898* KMOD: MOD. (line 6) 21899* KMVBITS: MVBITS. (line 6) 21900* KNOT: NOT. (line 6) 21901* L2 vector norm: NORM2. (line 6) 21902* language, dialect options: Fortran Dialect Options. 21903 (line 6) 21904* LBOUND: LBOUND. (line 6) 21905* LCOBOUND: LCOBOUND. (line 6) 21906* LEADZ: LEADZ. (line 6) 21907* left shift, combined: DSHIFTL. (line 6) 21908* LEN: LEN. (line 6) 21909* LEN_TRIM: LEN_TRIM. (line 6) 21910* lexical comparison of strings: LGE. (line 6) 21911* lexical comparison of strings <1>: LGT. (line 6) 21912* lexical comparison of strings <2>: LLE. (line 6) 21913* lexical comparison of strings <3>: LLT. (line 6) 21914* LGAMMA: LOG_GAMMA. (line 6) 21915* LGE: LGE. (line 6) 21916* LGT: LGT. (line 6) 21917* libf2c calling convention: Code Gen Options. (line 25) 21918* libf2c calling convention <1>: Code Gen Options. (line 110) 21919* libgfortran initialization, set_args: _gfortran_set_args. (line 6) 21920* libgfortran initialization, set_convert: _gfortran_set_convert. 21921 (line 6) 21922* libgfortran initialization, set_fpe: _gfortran_set_fpe. (line 6) 21923* libgfortran initialization, set_max_subrecord_length: _gfortran_set_max_subrecord_length. 21924 (line 6) 21925* libgfortran initialization, set_options: _gfortran_set_options. 21926 (line 6) 21927* libgfortran initialization, set_record_marker: _gfortran_set_record_marker. 21928 (line 6) 21929* limits, largest number: HUGE. (line 6) 21930* limits, smallest number: TINY. (line 6) 21931* LINK: LINK. (line 6) 21932* linking, static: Link Options. (line 6) 21933* LLE: LLE. (line 6) 21934* LLT: LLT. (line 6) 21935* LNBLNK: LNBLNK. (line 6) 21936* LOC: %LOC as an rvalue. (line 6) 21937* LOC <1>: LOC. (line 6) 21938* location of a variable in memory: LOC. (line 6) 21939* LOG: LOG. (line 6) 21940* LOG10: LOG10. (line 6) 21941* logarithm function: LOG. (line 6) 21942* logarithm function with base 10: LOG10. (line 6) 21943* logarithm function, inverse: EXP. (line 6) 21944* LOGICAL: LOGICAL. (line 6) 21945* logical and, bitwise: AND. (line 6) 21946* logical and, bitwise <1>: IAND. (line 6) 21947* logical exclusive or, bitwise: IEOR. (line 6) 21948* logical exclusive or, bitwise <1>: XOR. (line 6) 21949* logical not, bitwise: NOT. (line 6) 21950* logical or, bitwise: IOR. (line 6) 21951* logical or, bitwise <1>: OR. (line 6) 21952* logical, bitwise: Bitwise logical operators. 21953 (line 6) 21954* logical, variable representation: Internal representation of LOGICAL variables. 21955 (line 6) 21956* login name: GETLOG. (line 6) 21957* LOG_GAMMA: LOG_GAMMA. (line 6) 21958* LONG: LONG. (line 6) 21959* loop interchange, Fortran: Code Gen Options. (line 415) 21960* loop interchange, warning: Error and Warning Options. 21961 (line 135) 21962* LSHIFT: LSHIFT. (line 6) 21963* LSTAT: LSTAT. (line 6) 21964* LTIME: LTIME. (line 6) 21965* MALLOC: MALLOC. (line 6) 21966* MAP: UNION and MAP. (line 6) 21967* mask, left justified: MASKL. (line 6) 21968* mask, right justified: MASKR. (line 6) 21969* MASKL: MASKL. (line 6) 21970* MASKR: MASKR. (line 6) 21971* MATMUL: MATMUL. (line 6) 21972* matrix multiplication: MATMUL. (line 6) 21973* matrix, transpose: TRANSPOSE. (line 6) 21974* MAX: MAX. (line 6) 21975* MAX0: MAX. (line 6) 21976* MAX1: MAX. (line 6) 21977* MAXEXPONENT: MAXEXPONENT. (line 6) 21978* maximum value: MAX. (line 6) 21979* maximum value <1>: MAXVAL. (line 6) 21980* MAXLOC: MAXLOC. (line 6) 21981* MAXVAL: MAXVAL. (line 6) 21982* MCLOCK: MCLOCK. (line 6) 21983* MCLOCK8: MCLOCK8. (line 6) 21984* memory checking: Code Gen Options. (line 141) 21985* MERGE: MERGE. (line 6) 21986* MERGE_BITS: MERGE_BITS. (line 6) 21987* messages, error: Error and Warning Options. 21988 (line 6) 21989* messages, warning: Error and Warning Options. 21990 (line 6) 21991* MIN: MIN. (line 6) 21992* MIN0: MIN. (line 6) 21993* MIN1: MIN. (line 6) 21994* MINEXPONENT: MINEXPONENT. (line 6) 21995* minimum value: MIN. (line 6) 21996* minimum value <1>: MINVAL. (line 6) 21997* MINLOC: MINLOC. (line 6) 21998* MINVAL: MINVAL. (line 6) 21999* Mixed-language programming: Mixed-Language Programming. 22000 (line 6) 22001* MOD: MOD. (line 6) 22002* model representation, base: RADIX. (line 6) 22003* model representation, epsilon: EPSILON. (line 6) 22004* model representation, largest number: HUGE. (line 6) 22005* model representation, maximum exponent: MAXEXPONENT. (line 6) 22006* model representation, minimum exponent: MINEXPONENT. (line 6) 22007* model representation, precision: PRECISION. (line 6) 22008* model representation, radix: RADIX. (line 6) 22009* model representation, range: RANGE. (line 6) 22010* model representation, significant digits: DIGITS. (line 6) 22011* model representation, smallest number: TINY. (line 6) 22012* module entities: Fortran Dialect Options. 22013 (line 86) 22014* module search path: Directory Options. (line 14) 22015* module search path <1>: Directory Options. (line 29) 22016* module search path <2>: Directory Options. (line 36) 22017* MODULO: MODULO. (line 6) 22018* modulo: MODULO. (line 6) 22019* MOVE_ALLOC: MOVE_ALLOC. (line 6) 22020* moving allocation: MOVE_ALLOC. (line 6) 22021* multiply array elements: PRODUCT. (line 6) 22022* MVBITS: MVBITS. (line 6) 22023* NAM: OPEN( ... NAME=). (line 6) 22024* Namelist: Extensions to namelist. 22025 (line 6) 22026* natural logarithm function: LOG. (line 6) 22027* NEAREST: NEAREST. (line 6) 22028* newline: NEW_LINE. (line 6) 22029* NEW_LINE: NEW_LINE. (line 6) 22030* NINT: NINT. (line 6) 22031* norm, Euclidean: NORM2. (line 6) 22032* NORM2: NORM2. (line 6) 22033* NOSHARED: Extended I/O specifiers. 22034 (line 6) 22035* NOT: NOT. (line 6) 22036* NULL: NULL. (line 6) 22037* NUM_IMAGES: NUM_IMAGES. (line 6) 22038* open, action: Files opened without an explicit ACTION= specifier. 22039 (line 6) 22040* OpenACC: Fortran Dialect Options. 22041 (line 124) 22042* OpenACC <1>: OpenACC. (line 6) 22043* OpenMP: Fortran Dialect Options. 22044 (line 135) 22045* OpenMP <1>: OpenMP. (line 6) 22046* operators, unary: Unary operators. (line 6) 22047* operators, xor: .XOR. operator. (line 6) 22048* options inquiry function: COMPILER_OPTIONS. (line 6) 22049* options, code generation: Code Gen Options. (line 6) 22050* options, debugging: Debugging Options. (line 6) 22051* options, dialect: Fortran Dialect Options. 22052 (line 6) 22053* options, directory search: Directory Options. (line 6) 22054* options, errors: Error and Warning Options. 22055 (line 6) 22056* options, Fortran dialect: Fortran Dialect Options. 22057 (line 11) 22058* options, gfortran command: Invoking GNU Fortran. 22059 (line 6) 22060* options, linking: Link Options. (line 6) 22061* options, negative forms: Invoking GNU Fortran. 22062 (line 13) 22063* options, preprocessor: Preprocessing Options. 22064 (line 6) 22065* options, real kind type promotion: Fortran Dialect Options. 22066 (line 209) 22067* options, run-time: Code Gen Options. (line 6) 22068* options, runtime: Runtime Options. (line 6) 22069* options, warnings: Error and Warning Options. 22070 (line 6) 22071* OR: OR. (line 6) 22072* output, newline: NEW_LINE. (line 6) 22073* PACK: PACK. (line 6) 22074* PARAMETER: Legacy PARAMETER statements. 22075 (line 6) 22076* PARITY: PARITY. (line 6) 22077* Parity: PARITY. (line 6) 22078* parity: POPPAR. (line 6) 22079* paths, search: Directory Options. (line 14) 22080* paths, search <1>: Directory Options. (line 29) 22081* paths, search <2>: Directory Options. (line 36) 22082* PERROR: PERROR. (line 6) 22083* pointer checking: Code Gen Options. (line 141) 22084* pointer, C address of pointers: C_F_PROCPOINTER. (line 6) 22085* pointer, C address of procedures: C_FUNLOC. (line 6) 22086* pointer, C association status: C_ASSOCIATED. (line 6) 22087* pointer, convert C to Fortran: C_F_POINTER. (line 6) 22088* pointer, Cray: Cray pointers. (line 6) 22089* pointer, cray: FREE. (line 6) 22090* pointer, cray <1>: MALLOC. (line 6) 22091* pointer, disassociated: NULL. (line 6) 22092* pointer, status: ASSOCIATED. (line 6) 22093* pointer, status <1>: NULL. (line 6) 22094* POPCNT: POPCNT. (line 6) 22095* POPPAR: POPPAR. (line 6) 22096* positive difference: DIM. (line 6) 22097* PRECISION: PRECISION. (line 6) 22098* Preprocessing: Preprocessing and conditional compilation. 22099 (line 6) 22100* preprocessing, assertion: Preprocessing Options. 22101 (line 113) 22102* preprocessing, assertion <1>: Preprocessing Options. 22103 (line 119) 22104* preprocessing, define macros: Preprocessing Options. 22105 (line 151) 22106* preprocessing, define macros <1>: Preprocessing Options. 22107 (line 154) 22108* preprocessing, include path: Preprocessing Options. 22109 (line 69) 22110* preprocessing, include path <1>: Preprocessing Options. 22111 (line 76) 22112* preprocessing, include path <2>: Preprocessing Options. 22113 (line 80) 22114* preprocessing, include path <3>: Preprocessing Options. 22115 (line 85) 22116* preprocessing, include path <4>: Preprocessing Options. 22117 (line 89) 22118* preprocessing, include path <5>: Preprocessing Options. 22119 (line 96) 22120* preprocessing, keep comments: Preprocessing Options. 22121 (line 122) 22122* preprocessing, keep comments <1>: Preprocessing Options. 22123 (line 137) 22124* preprocessing, no linemarkers: Preprocessing Options. 22125 (line 179) 22126* preprocessing, undefine macros: Preprocessing Options. 22127 (line 185) 22128* preprocessor: Preprocessing Options. 22129 (line 6) 22130* preprocessor, debugging: Preprocessing Options. 22131 (line 26) 22132* preprocessor, debugging <1>: Preprocessing Options. 22133 (line 35) 22134* preprocessor, debugging <2>: Preprocessing Options. 22135 (line 41) 22136* preprocessor, debugging <3>: Preprocessing Options. 22137 (line 44) 22138* preprocessor, debugging <4>: Preprocessing Options. 22139 (line 51) 22140* preprocessor, disable: Preprocessing Options. 22141 (line 12) 22142* preprocessor, enable: Preprocessing Options. 22143 (line 12) 22144* preprocessor, include file handling: Preprocessing and conditional compilation. 22145 (line 6) 22146* preprocessor, working directory: Preprocessing Options. 22147 (line 55) 22148* PRESENT: PRESENT. (line 6) 22149* private: Fortran Dialect Options. 22150 (line 86) 22151* procedure pointer, convert C to Fortran: C_LOC. (line 6) 22152* process ID: GETPID. (line 6) 22153* PRODUCT: PRODUCT. (line 6) 22154* product, double-precision: DPROD. (line 6) 22155* product, matrix: MATMUL. (line 6) 22156* product, vector: DOT_PRODUCT. (line 6) 22157* program termination: EXIT. (line 6) 22158* program termination, with core dump: ABORT. (line 6) 22159* PROTECTED statement: Fortran 2003 status. (line 114) 22160* Q exponent-letter: Q exponent-letter. (line 6) 22161* RADIX: RADIX. (line 6) 22162* radix, real: SELECTED_REAL_KIND. (line 6) 22163* RAN: RAN. (line 6) 22164* RAND: RAND. (line 6) 22165* random number generation: IRAND. (line 6) 22166* random number generation <1>: RAN. (line 6) 22167* random number generation <2>: RAND. (line 6) 22168* random number generation <3>: RANDOM_NUMBER. (line 6) 22169* random number generation, seeding: RANDOM_SEED. (line 6) 22170* random number generation, seeding <1>: SRAND. (line 6) 22171* RANDOM_NUMBER: RANDOM_NUMBER. (line 6) 22172* RANDOM_SEED: RANDOM_SEED. (line 6) 22173* RANGE: RANGE. (line 6) 22174* range checking: Code Gen Options. (line 141) 22175* RANK: RANK. (line 6) 22176* rank: RANK. (line 6) 22177* re-association of parenthesized expressions: Code Gen Options. 22178 (line 383) 22179* read character, stream mode: FGET. (line 6) 22180* read character, stream mode <1>: FGETC. (line 6) 22181* READONLY: Extended I/O specifiers. 22182 (line 6) 22183* REAL: REAL. (line 6) 22184* real kind: SELECTED_REAL_KIND. (line 6) 22185* real number, exponent: EXPONENT. (line 6) 22186* real number, fraction: FRACTION. (line 6) 22187* real number, nearest different: NEAREST. (line 6) 22188* real number, relative spacing: RRSPACING. (line 6) 22189* real number, relative spacing <1>: SPACING. (line 6) 22190* real number, scale: SCALE. (line 6) 22191* real number, set exponent: SET_EXPONENT. (line 6) 22192* Reallocate the LHS in assignments: Code Gen Options. (line 392) 22193* Reallocate the LHS in assignments, notification: Error and Warning Options. 22194 (line 236) 22195* REALPART: REAL. (line 6) 22196* RECORD: STRUCTURE and RECORD. 22197 (line 6) 22198* record marker: File format of unformatted sequential files. 22199 (line 6) 22200* Reduction, XOR: PARITY. (line 6) 22201* remainder: MOD. (line 6) 22202* RENAME: RENAME. (line 6) 22203* repacking arrays: Code Gen Options. (line 281) 22204* REPEAT: REPEAT. (line 6) 22205* RESHAPE: RESHAPE. (line 6) 22206* REWIND: Read/Write after EOF marker. 22207 (line 6) 22208* right shift, combined: DSHIFTR. (line 6) 22209* root: SQRT. (line 6) 22210* rounding, ceiling: ANINT. (line 6) 22211* rounding, ceiling <1>: CEILING. (line 6) 22212* rounding, floor: AINT. (line 6) 22213* rounding, floor <1>: FLOOR. (line 6) 22214* rounding, nearest whole number: NINT. (line 6) 22215* RRSPACING: RRSPACING. (line 6) 22216* RSHIFT: RSHIFT. (line 6) 22217* run-time checking: Code Gen Options. (line 141) 22218* SAME_TYPE_AS: SAME_TYPE_AS. (line 6) 22219* SAVE statement: Code Gen Options. (line 15) 22220* SCALE: SCALE. (line 6) 22221* SCAN: SCAN. (line 6) 22222* search path: Directory Options. (line 6) 22223* search paths, for included files: Directory Options. (line 14) 22224* SECNDS: SECNDS. (line 6) 22225* SECOND: SECOND. (line 6) 22226* seeding a random number generator: RANDOM_SEED. (line 6) 22227* seeding a random number generator <1>: SRAND. (line 6) 22228* SELECTED_CHAR_KIND: SELECTED_CHAR_KIND. (line 6) 22229* SELECTED_INT_KIND: SELECTED_INT_KIND. (line 6) 22230* SELECTED_REAL_KIND: SELECTED_REAL_KIND. (line 6) 22231* sequential, unformatted: File format of unformatted sequential files. 22232 (line 6) 22233* SET_EXPONENT: SET_EXPONENT. (line 6) 22234* SHAPE: SHAPE. (line 6) 22235* SHARE: Extended I/O specifiers. 22236 (line 6) 22237* SHARED: Extended I/O specifiers. 22238 (line 6) 22239* shift, left: DSHIFTL. (line 6) 22240* shift, left <1>: SHIFTL. (line 6) 22241* shift, right: DSHIFTR. (line 6) 22242* shift, right <1>: SHIFTR. (line 6) 22243* shift, right with fill: SHIFTA. (line 6) 22244* SHIFTA: SHIFTA. (line 6) 22245* SHIFTL: SHIFTL. (line 6) 22246* SHIFTR: SHIFTR. (line 6) 22247* SHORT: INT2. (line 6) 22248* SIGN: SIGN. (line 6) 22249* sign copying: SIGN. (line 6) 22250* SIGNAL: SIGNAL. (line 6) 22251* SIN: SIN. (line 6) 22252* SIND: SIND. (line 6) 22253* sine: SIN. (line 6) 22254* sine, degrees: SIND. (line 6) 22255* sine, hyperbolic: SINH. (line 6) 22256* sine, hyperbolic, inverse: ASINH. (line 6) 22257* sine, inverse: ASIN. (line 6) 22258* sine, inverse, degrees: ASIND. (line 6) 22259* SINH: SINH. (line 6) 22260* SIZE: SIZE. (line 6) 22261* size of a variable, in bits: BIT_SIZE. (line 6) 22262* size of an expression: C_SIZEOF. (line 6) 22263* size of an expression <1>: SIZEOF. (line 6) 22264* SIZEOF: SIZEOF. (line 6) 22265* SLEEP: SLEEP. (line 6) 22266* SNGL: REAL. (line 6) 22267* SPACING: SPACING. (line 6) 22268* SPREAD: SPREAD. (line 6) 22269* SQRT: SQRT. (line 6) 22270* square-root: SQRT. (line 6) 22271* SRAND: SRAND. (line 6) 22272* Standards: Standards. (line 6) 22273* STAT: STAT. (line 6) 22274* statement, ENUM: Fortran 2003 status. (line 93) 22275* statement, ENUMERATOR: Fortran 2003 status. (line 93) 22276* statement, FLUSH: Fortran 2003 status. (line 89) 22277* statement, IMPORT: Fortran 2003 status. (line 120) 22278* statement, ISO_FORTRAN_ENV: Fortran 2003 status. (line 128) 22279* statement, PROTECTED: Fortran 2003 status. (line 114) 22280* statement, SAVE: Code Gen Options. (line 15) 22281* statement, USE, INTRINSIC: Fortran 2003 status. (line 128) 22282* statement, VALUE: Fortran 2003 status. (line 116) 22283* statement, VOLATILE: Fortran 2003 status. (line 118) 22284* STATIC: AUTOMATIC and STATIC attributes. 22285 (line 6) 22286* storage size: STORAGE_SIZE. (line 6) 22287* STORAGE_SIZE: STORAGE_SIZE. (line 6) 22288* STREAM I/O: Fortran 2003 status. (line 103) 22289* stream mode, read character: FGET. (line 6) 22290* stream mode, read character <1>: FGETC. (line 6) 22291* stream mode, write character: FPUT. (line 6) 22292* stream mode, write character <1>: FPUTC. (line 6) 22293* string, adjust left: ADJUSTL. (line 6) 22294* string, adjust right: ADJUSTR. (line 6) 22295* string, comparison: LGE. (line 6) 22296* string, comparison <1>: LGT. (line 6) 22297* string, comparison <2>: LLE. (line 6) 22298* string, comparison <3>: LLT. (line 6) 22299* string, concatenate: REPEAT. (line 6) 22300* string, find missing set: VERIFY. (line 6) 22301* string, find non-blank character: LNBLNK. (line 6) 22302* string, find subset: SCAN. (line 6) 22303* string, find substring: INDEX intrinsic. (line 6) 22304* string, length: LEN. (line 6) 22305* string, length, without trailing whitespace: LEN_TRIM. (line 6) 22306* string, remove trailing whitespace: TRIM. (line 6) 22307* string, repeat: REPEAT. (line 6) 22308* strings, varying length: Varying Length Character Strings. 22309 (line 6) 22310* STRUCTURE: STRUCTURE and RECORD. 22311 (line 6) 22312* structure packing: Code Gen Options. (line 275) 22313* subrecord: File format of unformatted sequential files. 22314 (line 6) 22315* subscript checking: Code Gen Options. (line 141) 22316* substring position: INDEX intrinsic. (line 6) 22317* SUM: SUM. (line 6) 22318* sum array elements: SUM. (line 6) 22319* suppressing warnings: Error and Warning Options. 22320 (line 6) 22321* symbol names: Fortran Dialect Options. 22322 (line 68) 22323* symbol names, transforming: Code Gen Options. (line 54) 22324* symbol names, transforming <1>: Code Gen Options. (line 110) 22325* symbol names, underscores: Code Gen Options. (line 54) 22326* symbol names, underscores <1>: Code Gen Options. (line 110) 22327* SYMLNK: SYMLNK. (line 6) 22328* syntax checking: Error and Warning Options. 22329 (line 33) 22330* SYSTEM: SYSTEM. (line 6) 22331* system, error handling: GERROR. (line 6) 22332* system, error handling <1>: IERRNO. (line 6) 22333* system, error handling <2>: PERROR. (line 6) 22334* system, group ID: GETGID. (line 6) 22335* system, host name: HOSTNM. (line 6) 22336* system, login name: GETLOG. (line 6) 22337* system, process ID: GETPID. (line 6) 22338* system, signal handling: SIGNAL. (line 6) 22339* system, system call: EXECUTE_COMMAND_LINE. 22340 (line 6) 22341* system, system call <1>: SYSTEM. (line 6) 22342* system, terminal: ISATTY. (line 6) 22343* system, terminal <1>: TTYNAM. (line 6) 22344* system, user ID: GETUID. (line 6) 22345* system, working directory: CHDIR. (line 6) 22346* system, working directory <1>: GETCWD. (line 6) 22347* SYSTEM_CLOCK: SYSTEM_CLOCK. (line 6) 22348* tabulators: Error and Warning Options. 22349 (line 186) 22350* TAN: TAN. (line 6) 22351* TAND: TAND. (line 6) 22352* tangent: TAN. (line 6) 22353* tangent, degrees: TAND. (line 6) 22354* tangent, hyperbolic: TANH. (line 6) 22355* tangent, hyperbolic, inverse: ATANH. (line 6) 22356* tangent, inverse: ATAN. (line 6) 22357* tangent, inverse <1>: ATAN2. (line 6) 22358* tangent, inverse, degrees: ATAND. (line 6) 22359* tangent, inverse, degrees <1>: ATAN2D. (line 6) 22360* TANH: TANH. (line 6) 22361* terminate program: EXIT. (line 6) 22362* terminate program, with core dump: ABORT. (line 6) 22363* THIS_IMAGE: THIS_IMAGE. (line 6) 22364* thread-safety, threads: Thread-safety of the runtime library. 22365 (line 6) 22366* TIME: TIME. (line 6) 22367* time, clock ticks: MCLOCK. (line 6) 22368* time, clock ticks <1>: MCLOCK8. (line 6) 22369* time, clock ticks <2>: SYSTEM_CLOCK. (line 6) 22370* time, conversion to GMT info: GMTIME. (line 6) 22371* time, conversion to local time info: LTIME. (line 6) 22372* time, conversion to string: CTIME. (line 6) 22373* time, current: DATE_AND_TIME. (line 6) 22374* time, current <1>: FDATE. (line 6) 22375* time, current <2>: ITIME. (line 6) 22376* time, current <3>: TIME. (line 6) 22377* time, current <4>: TIME8. (line 6) 22378* time, elapsed: CPU_TIME. (line 6) 22379* time, elapsed <1>: DTIME. (line 6) 22380* time, elapsed <2>: ETIME. (line 6) 22381* time, elapsed <3>: SECNDS. (line 6) 22382* time, elapsed <4>: SECOND. (line 6) 22383* TIME8: TIME8. (line 6) 22384* TINY: TINY. (line 6) 22385* TR 15581: Fortran 2003 status. (line 98) 22386* trace: Debugging Options. (line 69) 22387* TRAILZ: TRAILZ. (line 6) 22388* TRANSFER: TRANSFER. (line 6) 22389* transforming symbol names: Code Gen Options. (line 54) 22390* transforming symbol names <1>: Code Gen Options. (line 110) 22391* TRANSPOSE: TRANSPOSE. (line 6) 22392* transpose: TRANSPOSE. (line 6) 22393* trigonometric function, cosine: COS. (line 6) 22394* trigonometric function, cosine, degrees: COSD. (line 6) 22395* trigonometric function, cosine, inverse: ACOS. (line 6) 22396* trigonometric function, cosine, inverse, degrees: ACOSD. (line 6) 22397* trigonometric function, cotangent: COTAN. (line 6) 22398* trigonometric function, cotangent, degrees: COTAND. (line 6) 22399* trigonometric function, sine: SIN. (line 6) 22400* trigonometric function, sine, degrees: SIND. (line 6) 22401* trigonometric function, sine, inverse: ASIN. (line 6) 22402* trigonometric function, sine, inverse, degrees: ASIND. (line 6) 22403* trigonometric function, tangent: TAN. (line 6) 22404* trigonometric function, tangent, degrees: TAND. (line 6) 22405* trigonometric function, tangent, inverse: ATAN. (line 6) 22406* trigonometric function, tangent, inverse <1>: ATAN2. (line 6) 22407* trigonometric function, tangent, inverse, degrees: ATAND. (line 6) 22408* trigonometric function, tangent, inverse, degrees <1>: ATAN2D. 22409 (line 6) 22410* TRIM: TRIM. (line 6) 22411* TTYNAM: TTYNAM. (line 6) 22412* type alias print: TYPE as an alias for PRINT. 22413 (line 6) 22414* type cast: TRANSFER. (line 6) 22415* UBOUND: UBOUND. (line 6) 22416* UCOBOUND: UCOBOUND. (line 6) 22417* UMASK: UMASK. (line 6) 22418* underflow: Error and Warning Options. 22419 (line 199) 22420* underscore: Code Gen Options. (line 54) 22421* underscore <1>: Code Gen Options. (line 110) 22422* unformatted sequential: File format of unformatted sequential files. 22423 (line 6) 22424* UNION: UNION and MAP. (line 6) 22425* UNLINK: UNLINK. (line 6) 22426* UNPACK: UNPACK. (line 6) 22427* unused dummy argument: Error and Warning Options. 22428 (line 215) 22429* unused parameter: Error and Warning Options. 22430 (line 219) 22431* USE, INTRINSIC statement: Fortran 2003 status. (line 128) 22432* user id: GETUID. (line 6) 22433* VALUE statement: Fortran 2003 status. (line 116) 22434* variable attributes: AUTOMATIC and STATIC attributes. 22435 (line 6) 22436* Varying length character strings: Varying Length Character Strings. 22437 (line 6) 22438* Varying length strings: Varying Length Character Strings. 22439 (line 6) 22440* vector product: DOT_PRODUCT. (line 6) 22441* VERIFY: VERIFY. (line 6) 22442* version of the compiler: COMPILER_VERSION. (line 6) 22443* VOLATILE: Volatile COMMON blocks. 22444 (line 6) 22445* VOLATILE statement: Fortran 2003 status. (line 118) 22446* warning, C binding type: Error and Warning Options. 22447 (line 106) 22448* warnings, aliasing: Error and Warning Options. 22449 (line 71) 22450* warnings, alignment of COMMON blocks: Error and Warning Options. 22451 (line 226) 22452* warnings, all: Error and Warning Options. 22453 (line 62) 22454* warnings, ampersand: Error and Warning Options. 22455 (line 88) 22456* warnings, argument mismatch: Error and Warning Options. 22457 (line 96) 22458* warnings, array temporaries: Error and Warning Options. 22459 (line 101) 22460* warnings, character truncation: Error and Warning Options. 22461 (line 113) 22462* warnings, conversion: Error and Warning Options. 22463 (line 122) 22464* warnings, conversion <1>: Error and Warning Options. 22465 (line 126) 22466* warnings, division of integers: Error and Warning Options. 22467 (line 149) 22468* warnings, extra: Error and Warning Options. 22469 (line 130) 22470* warnings, function elimination: Error and Warning Options. 22471 (line 232) 22472* warnings, implicit interface: Error and Warning Options. 22473 (line 139) 22474* warnings, implicit procedure: Error and Warning Options. 22475 (line 145) 22476* warnings, integer division: Error and Warning Options. 22477 (line 149) 22478* warnings, interface mismatch: Error and Warning Options. 22479 (line 96) 22480* warnings, intrinsic: Error and Warning Options. 22481 (line 204) 22482* warnings, intrinsics of other standards: Error and Warning Options. 22483 (line 153) 22484* warnings, line truncation: Error and Warning Options. 22485 (line 116) 22486* warnings, loop interchange: Error and Warning Options. 22487 (line 135) 22488* warnings, non-standard intrinsics: Error and Warning Options. 22489 (line 153) 22490* warnings, parameter mismatch: Error and Warning Options. 22491 (line 96) 22492* warnings, q exponent-letter: Error and Warning Options. 22493 (line 160) 22494* warnings, suppressing: Error and Warning Options. 22495 (line 6) 22496* warnings, suspicious code: Error and Warning Options. 22497 (line 164) 22498* warnings, tabs: Error and Warning Options. 22499 (line 186) 22500* warnings, to errors: Error and Warning Options. 22501 (line 277) 22502* warnings, undefined do loop: Error and Warning Options. 22503 (line 194) 22504* warnings, underflow: Error and Warning Options. 22505 (line 199) 22506* warnings, unused dummy argument: Error and Warning Options. 22507 (line 215) 22508* warnings, unused parameter: Error and Warning Options. 22509 (line 219) 22510* warnings, use statements: Error and Warning Options. 22511 (line 211) 22512* write character, stream mode: FPUT. (line 6) 22513* write character, stream mode <1>: FPUTC. (line 6) 22514* XOR: XOR. (line 6) 22515* XOR reduction: PARITY. (line 6) 22516* ZABS: ABS. (line 6) 22517* ZCOS: COS. (line 6) 22518* ZCOSD: COSD. (line 6) 22519* zero bits: LEADZ. (line 6) 22520* zero bits <1>: TRAILZ. (line 6) 22521* ZEXP: EXP. (line 6) 22522* ZLOG: LOG. (line 6) 22523* ZSIN: SIN. (line 6) 22524* ZSIND: SIND. (line 6) 22525* ZSQRT: SQRT. (line 6) 22526 22527 22528 22529Tag Table: 22530Node: Top1950 22531Node: Introduction3367 22532Node: About GNU Fortran4116 22533Node: GNU Fortran and GCC8117 22534Node: Preprocessing and conditional compilation10231 22535Node: GNU Fortran and G7711876 22536Node: Project Status12449 22537Node: Standards15191 22538Node: Varying Length Character Strings16578 22539Node: Invoking GNU Fortran17330 22540Node: Option Summary19164 22541Node: Fortran Dialect Options23102 22542Node: Preprocessing Options34668 22543Node: Error and Warning Options42909 22544Node: Debugging Options54658 22545Node: Directory Options58687 22546Node: Link Options60122 22547Node: Runtime Options60748 22548Node: Code Gen Options62655 22549Node: Interoperability Options81967 22550Node: Environment Variables83007 22551Node: Runtime83620 22552Node: TMPDIR84654 22553Node: GFORTRAN_STDIN_UNIT85324 22554Node: GFORTRAN_STDOUT_UNIT85706 22555Node: GFORTRAN_STDERR_UNIT86107 22556Node: GFORTRAN_UNBUFFERED_ALL86509 22557Node: GFORTRAN_UNBUFFERED_PRECONNECTED87040 22558Node: GFORTRAN_SHOW_LOCUS87684 22559Node: GFORTRAN_OPTIONAL_PLUS88180 22560Node: GFORTRAN_LIST_SEPARATOR88658 22561Node: GFORTRAN_CONVERT_UNIT89266 22562Node: GFORTRAN_ERROR_BACKTRACE92121 22563Node: Fortran standards status92678 22564Node: Fortran 2003 status92970 22565Node: Fortran 2008 status98209 22566Node: TS 29113 status103583 22567Node: TS 18508 status104582 22568Node: Fortran 2018 status105397 22569Node: Compiler Characteristics106016 22570Node: KIND Type Parameters106689 22571Node: Internal representation of LOGICAL variables108117 22572Node: Thread-safety of the runtime library108977 22573Node: Data consistency and durability111380 22574Node: Files opened without an explicit ACTION= specifier114493 22575Node: File operations on symbolic links115184 22576Node: File format of unformatted sequential files116304 22577Node: Extensions118651 22578Node: Extensions implemented in GNU Fortran119256 22579Node: Old-style kind specifications121152 22580Node: Old-style variable initialization122254 22581Node: Extensions to namelist123566 22582Node: X format descriptor without count field125869 22583Node: Commas in FORMAT specifications126396 22584Node: Missing period in FORMAT specifications126913 22585Node: I/O item lists127475 22586Node: Q exponent-letter127860 22587Node: BOZ literal constants128458 22588Node: Real array indices131037 22589Node: Unary operators131336 22590Node: Implicitly convert LOGICAL and INTEGER values131750 22591Node: Hollerith constants support132709 22592Node: Cray pointers134481 22593Node: CONVERT specifier139928 22594Node: OpenMP141923 22595Node: OpenACC144181 22596Node: Argument list functions145490 22597Node: Read/Write after EOF marker147133 22598Node: STRUCTURE and RECORD147736 22599Node: UNION and MAP152823 22600Node: Type variants for integer intrinsics155791 22601Node: AUTOMATIC and STATIC attributes157686 22602Node: Extended math intrinsics159220 22603Node: Form feed as whitespace161016 22604Node: TYPE as an alias for PRINT161562 22605Node: %LOC as an rvalue162027 22606Node: .XOR. operator162674 22607Node: Bitwise logical operators163074 22608Node: Extended I/O specifiers164575 22609Node: Legacy PARAMETER statements168295 22610Node: Default exponents168900 22611Node: Extensions not implemented in GNU Fortran169252 22612Node: ENCODE and DECODE statements170197 22613Node: Variable FORMAT expressions171528 22614Node: Alternate complex function syntax172633 22615Node: Volatile COMMON blocks173183 22616Node: OPEN( ... 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22810Node: GETPID482808 22811Node: GETUID483538 22812Node: GMTIME484054 22813Node: HOSTNM485814 22814Node: HUGE486735 22815Node: HYPOT487457 22816Node: IACHAR488283 22817Node: IALL489451 22818Node: IAND490936 22819Node: IANY492509 22820Node: IARGC494003 22821Node: IBCLR495024 22822Node: IBITS496272 22823Node: IBSET497776 22824Node: ICHAR499019 22825Node: IDATE501189 22826Node: IEOR502489 22827Node: IERRNO503955 22828Node: IMAGE_INDEX504504 22829Node: INDEX intrinsic505532 22830Node: INT507058 22831Node: INT2508817 22832Node: INT8509585 22833Node: IOR510300 22834Node: IPARITY511742 22835Node: IRAND513274 22836Node: IS_IOSTAT_END514633 22837Node: IS_IOSTAT_EOR515732 22838Node: ISATTY516861 22839Node: ISHFT517644 22840Node: ISHFTC519213 22841Node: ISNAN521020 22842Node: ITIME521787 22843Node: KILL523085 22844Node: KIND524170 22845Node: LBOUND525016 22846Node: LCOBOUND526354 22847Node: LEADZ527489 22848Node: LEN528350 22849Node: LEN_TRIM529646 22850Node: LGE530634 22851Node: LGT532147 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22894Node: PARITY586350 22895Node: PERROR587571 22896Node: POPCNT588196 22897Node: POPPAR589068 22898Node: PRECISION590122 22899Node: PRESENT591009 22900Node: PRODUCT592121 22901Node: RADIX593655 22902Node: RAN594467 22903Node: RAND594923 22904Node: RANDOM_NUMBER596258 22905Node: RANDOM_SEED597472 22906Node: RANGE599921 22907Node: RANK600602 22908Node: REAL601383 22909Node: RENAME603372 22910Node: REPEAT604394 22911Node: RESHAPE605122 22912Node: RRSPACING606589 22913Node: RSHIFT607282 22914Node: SAME_TYPE_AS608422 22915Node: SCALE609254 22916Node: SCAN610035 22917Node: SECNDS611593 22918Node: SECOND612685 22919Node: SELECTED_CHAR_KIND613561 22920Node: SELECTED_INT_KIND615156 22921Node: SELECTED_REAL_KIND616333 22922Node: SET_EXPONENT619010 22923Node: SHAPE620007 22924Node: SHIFTA621431 22925Node: SHIFTL622395 22926Node: SHIFTR623232 22927Node: SIGN624070 22928Node: SIGNAL625296 22929Node: SIN626802 22930Node: SIND627893 22931Node: SINH629222 22932Node: SIZE630235 22933Node: SIZEOF631554 22934Node: SLEEP633209 22935Node: SPACING633770 22936Node: SPREAD634784 22937Node: SQRT635935 22938Node: SRAND637267 22939Node: STAT638501 22940Node: STORAGE_SIZE641669 22941Node: SUM642548 22942Node: SYMLNK644040 22943Node: SYSTEM645175 22944Node: SYSTEM_CLOCK646430 22945Node: TAN649260 22946Node: TAND650331 22947Node: TANH651415 22948Node: THIS_IMAGE652590 22949Node: TIME654890 22950Node: TIME8656061 22951Node: TINY657260 22952Node: TRAILZ657861 22953Node: TRANSFER658679 22954Node: TRANSPOSE660715 22955Node: TRIM661405 22956Node: TTYNAM662263 22957Node: UBOUND663181 22958Node: UCOBOUND664571 22959Node: UMASK665708 22960Node: UNLINK666390 22961Node: UNPACK667370 22962Node: VERIFY668665 22963Node: XOR670394 22964Node: Intrinsic Modules671767 22965Node: ISO_FORTRAN_ENV672056 22966Node: ISO_C_BINDING676459 22967Node: IEEE modules680165 22968Node: OpenMP Modules OMP_LIB and OMP_LIB_KINDS681308 22969Node: OpenACC Module OPENACC683091 22970Node: Contributing684018 22971Node: Contributors684872 22972Node: Projects686503 22973Node: Proposed Extensions687310 22974Node: Copying689320 22975Node: GNU Free Documentation License726866 22976Node: Funding751990 22977Node: Option Index754516 22978Node: Keyword Index772318 22979 22980End Tag Table 22981