1 /* Copyright (C) 1992-2021 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 #ifndef _SYS_CDEFS_H 19 #define _SYS_CDEFS_H 1 20 21 /* We are almost always included from features.h. */ 22 #ifndef _FEATURES_H 23 # include <features.h> 24 #endif 25 26 /* The GNU libc does not support any K&R compilers or the traditional mode 27 of ISO C compilers anymore. Check for some of the combinations not 28 anymore supported. */ 29 #if defined __GNUC__ && !defined __STDC__ 30 # error "You need a ISO C conforming compiler to use the glibc headers" 31 #endif 32 33 /* Some user header file might have defined this before. */ 34 #undef __P 35 #undef __PMT 36 37 /* Compilers that are not clang may object to 38 #if defined __clang__ && __has_attribute(...) 39 even though they do not need to evaluate the right-hand side of the &&. */ 40 #if defined __clang__ && defined __has_attribute 41 # define __glibc_clang_has_attribute(name) __has_attribute (name) 42 #else 43 # define __glibc_clang_has_attribute(name) 0 44 #endif 45 46 /* Compilers that are not clang may object to 47 #if defined __clang__ && __has_builtin(...) 48 even though they do not need to evaluate the right-hand side of the &&. */ 49 #if defined __clang__ && defined __has_builtin 50 # define __glibc_clang_has_builtin(name) __has_builtin (name) 51 #else 52 # define __glibc_clang_has_builtin(name) 0 53 #endif 54 55 /* Compilers that are not clang may object to 56 #if defined __clang__ && __has_extension(...) 57 even though they do not need to evaluate the right-hand side of the &&. */ 58 #if defined __clang__ && defined __has_extension 59 # define __glibc_clang_has_extension(ext) __has_extension (ext) 60 #else 61 # define __glibc_clang_has_extension(ext) 0 62 #endif 63 64 #if defined __GNUC__ || defined __clang__ 65 66 /* All functions, except those with callbacks or those that 67 synchronize memory, are leaf functions. */ 68 # if __GNUC_PREREQ (4, 6) && !defined _LIBC 69 # define __LEAF , __leaf__ 70 # define __LEAF_ATTR __attribute__ ((__leaf__)) 71 # else 72 # define __LEAF 73 # define __LEAF_ATTR 74 # endif 75 76 /* GCC can always grok prototypes. For C++ programs we add throw() 77 to help it optimize the function calls. But this works only with 78 gcc 2.8.x and egcs. For gcc 3.4 and up we even mark C functions 79 as non-throwing using a function attribute since programs can use 80 the -fexceptions options for C code as well. */ 81 # if !defined __cplusplus \ 82 && (__GNUC_PREREQ (3, 4) || __glibc_clang_has_attribute (__nothrow__)) 83 # define __THROW __attribute__ ((__nothrow__ __LEAF)) 84 # define __THROWNL __attribute__ ((__nothrow__)) 85 # define __NTH(fct) __attribute__ ((__nothrow__ __LEAF)) fct 86 # define __NTHNL(fct) __attribute__ ((__nothrow__)) fct 87 # else 88 # if defined __cplusplus && (__GNUC_PREREQ (2,8) || __clang_major >= 4) 89 # define __THROW throw () 90 # define __THROWNL throw () 91 # define __NTH(fct) __LEAF_ATTR fct throw () 92 # define __NTHNL(fct) fct throw () 93 # else 94 # define __THROW 95 # define __THROWNL 96 # define __NTH(fct) fct 97 # define __NTHNL(fct) fct 98 # endif 99 # endif 100 101 #else /* Not GCC or clang. */ 102 103 # if (defined __cplusplus \ 104 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)) 105 # define __inline inline 106 # else 107 # define __inline /* No inline functions. */ 108 # endif 109 110 # define __THROW 111 # define __THROWNL 112 # define __NTH(fct) fct 113 114 #endif /* GCC || clang. */ 115 116 /* These two macros are not used in glibc anymore. They are kept here 117 only because some other projects expect the macros to be defined. */ 118 #define __P(args) args 119 #define __PMT(args) args 120 121 /* For these things, GCC behaves the ANSI way normally, 122 and the non-ANSI way under -traditional. */ 123 124 #define __CONCAT(x,y) x ## y 125 #define __STRING(x) #x 126 127 /* This is not a typedef so `const __ptr_t' does the right thing. */ 128 #define __ptr_t void * 129 130 131 /* C++ needs to know that types and declarations are C, not C++. */ 132 #ifdef __cplusplus 133 # define __BEGIN_DECLS extern "C" { 134 # define __END_DECLS } 135 #else 136 # define __BEGIN_DECLS 137 # define __END_DECLS 138 #endif 139 140 141 /* Fortify support. */ 142 #define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1) 143 #define __bos0(ptr) __builtin_object_size (ptr, 0) 144 145 #if __GNUC_PREREQ (4,3) 146 # define __warndecl(name, msg) \ 147 extern void name (void) __attribute__((__warning__ (msg))) 148 # define __warnattr(msg) __attribute__((__warning__ (msg))) 149 # define __errordecl(name, msg) \ 150 extern void name (void) __attribute__((__error__ (msg))) 151 #elif __glibc_clang_has_attribute (__diagnose_if__) && 0 152 /* These definitions are not enabled, because they produce bogus warnings 153 in the glibc Fortify functions. These functions are written in a style 154 that works with GCC. In order to work with clang, these functions would 155 need to be modified. */ 156 # define __warndecl(name, msg) \ 157 extern void name (void) __attribute__((__diagnose_if__ (1, msg, "warning"))) 158 # define __warnattr(msg) __attribute__((__diagnose_if__ (1, msg, "warning"))) 159 # define __errordecl(name, msg) \ 160 extern void name (void) __attribute__((__diagnose_if__ (1, msg, "error"))) 161 #else 162 # define __warndecl(name, msg) extern void name (void) 163 # define __warnattr(msg) 164 # define __errordecl(name, msg) extern void name (void) 165 #endif 166 167 /* Support for flexible arrays. 168 Headers that should use flexible arrays only if they're "real" 169 (e.g. only if they won't affect sizeof()) should test 170 #if __glibc_c99_flexarr_available. */ 171 #if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L && !defined __HP_cc 172 # define __flexarr [] 173 # define __glibc_c99_flexarr_available 1 174 #elif __GNUC_PREREQ (2,97) || defined __clang__ 175 /* GCC 2.97 and clang support C99 flexible array members as an extension, 176 even when in C89 mode or compiling C++ (any version). */ 177 # define __flexarr [] 178 # define __glibc_c99_flexarr_available 1 179 #elif defined __GNUC__ 180 /* Pre-2.97 GCC did not support C99 flexible arrays but did have 181 an equivalent extension with slightly different notation. */ 182 # define __flexarr [0] 183 # define __glibc_c99_flexarr_available 1 184 #else 185 /* Some other non-C99 compiler. Approximate with [1]. */ 186 # define __flexarr [1] 187 # define __glibc_c99_flexarr_available 0 188 #endif 189 190 191 /* __asm__ ("xyz") is used throughout the headers to rename functions 192 at the assembly language level. This is wrapped by the __REDIRECT 193 macro, in order to support compilers that can do this some other 194 way. When compilers don't support asm-names at all, we have to do 195 preprocessor tricks instead (which don't have exactly the right 196 semantics, but it's the best we can do). 197 198 Example: 199 int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */ 200 201 #if (defined __GNUC__ && __GNUC__ >= 2) || (__clang_major__ >= 4) 202 203 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias)) 204 # ifdef __cplusplus 205 # define __REDIRECT_NTH(name, proto, alias) \ 206 name proto __THROW __asm__ (__ASMNAME (#alias)) 207 # define __REDIRECT_NTHNL(name, proto, alias) \ 208 name proto __THROWNL __asm__ (__ASMNAME (#alias)) 209 # else 210 # define __REDIRECT_NTH(name, proto, alias) \ 211 name proto __asm__ (__ASMNAME (#alias)) __THROW 212 # define __REDIRECT_NTHNL(name, proto, alias) \ 213 name proto __asm__ (__ASMNAME (#alias)) __THROWNL 214 # endif 215 # define __ASMNAME(cname) __ASMNAME2 (__USER_LABEL_PREFIX__, cname) 216 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname 217 218 /* 219 #elif __SOME_OTHER_COMPILER__ 220 221 # define __REDIRECT(name, proto, alias) name proto; \ 222 _Pragma("let " #name " = " #alias) 223 */ 224 #endif 225 226 /* GCC and clang have various useful declarations that can be made with 227 the '__attribute__' syntax. All of the ways we use this do fine if 228 they are omitted for compilers that don't understand it. */ 229 #if !(defined __GNUC__ || defined __clang__) 230 # define __attribute__(xyz) /* Ignore */ 231 #endif 232 233 /* At some point during the gcc 2.96 development the `malloc' attribute 234 for functions was introduced. We don't want to use it unconditionally 235 (although this would be possible) since it generates warnings. */ 236 #if __GNUC_PREREQ (2,96) || __glibc_clang_has_attribute (__malloc__) 237 # define __attribute_malloc__ __attribute__ ((__malloc__)) 238 #else 239 # define __attribute_malloc__ /* Ignore */ 240 #endif 241 242 /* Tell the compiler which arguments to an allocation function 243 indicate the size of the allocation. */ 244 #if __GNUC_PREREQ (4, 3) 245 # define __attribute_alloc_size__(params) \ 246 __attribute__ ((__alloc_size__ params)) 247 #else 248 # define __attribute_alloc_size__(params) /* Ignore. */ 249 #endif 250 251 /* At some point during the gcc 2.96 development the `pure' attribute 252 for functions was introduced. We don't want to use it unconditionally 253 (although this would be possible) since it generates warnings. */ 254 #if __GNUC_PREREQ (2,96) || __glibc_clang_has_attribute (__pure__) 255 # define __attribute_pure__ __attribute__ ((__pure__)) 256 #else 257 # define __attribute_pure__ /* Ignore */ 258 #endif 259 260 /* This declaration tells the compiler that the value is constant. */ 261 #if __GNUC_PREREQ (2,5) || __glibc_clang_has_attribute (__const__) 262 # define __attribute_const__ __attribute__ ((__const__)) 263 #else 264 # define __attribute_const__ /* Ignore */ 265 #endif 266 267 /* At some point during the gcc 3.1 development the `used' attribute 268 for functions was introduced. We don't want to use it unconditionally 269 (although this would be possible) since it generates warnings. */ 270 #if __GNUC_PREREQ (3,1) || __glibc_clang_has_attribute (__used__) 271 # define __attribute_used__ __attribute__ ((__used__)) 272 # define __attribute_noinline__ __attribute__ ((__noinline__)) 273 #else 274 # define __attribute_used__ __attribute__ ((__unused__)) 275 # define __attribute_noinline__ /* Ignore */ 276 #endif 277 278 /* Since version 3.2, gcc allows marking deprecated functions. */ 279 #if __GNUC_PREREQ (3,2) || __glibc_clang_has_attribute (__deprecated__) 280 # define __attribute_deprecated__ __attribute__ ((__deprecated__)) 281 #else 282 # define __attribute_deprecated__ /* Ignore */ 283 #endif 284 285 /* Since version 4.5, gcc also allows one to specify the message printed 286 when a deprecated function is used. clang claims to be gcc 4.2, but 287 may also support this feature. */ 288 #if __GNUC_PREREQ (4,5) || \ 289 __glibc_clang_has_extension (__attribute_deprecated_with_message__) 290 # define __attribute_deprecated_msg__(msg) \ 291 __attribute__ ((__deprecated__ (msg))) 292 #else 293 # define __attribute_deprecated_msg__(msg) __attribute_deprecated__ 294 #endif 295 296 /* At some point during the gcc 2.8 development the `format_arg' attribute 297 for functions was introduced. We don't want to use it unconditionally 298 (although this would be possible) since it generates warnings. 299 If several `format_arg' attributes are given for the same function, in 300 gcc-3.0 and older, all but the last one are ignored. In newer gccs, 301 all designated arguments are considered. */ 302 #if __GNUC_PREREQ (2,8) || __glibc_clang_has_attribute (__format_arg__) 303 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x))) 304 #else 305 # define __attribute_format_arg__(x) /* Ignore */ 306 #endif 307 308 /* At some point during the gcc 2.97 development the `strfmon' format 309 attribute for functions was introduced. We don't want to use it 310 unconditionally (although this would be possible) since it 311 generates warnings. */ 312 #if __GNUC_PREREQ (2,97) || __glibc_clang_has_attribute (__format__) 313 # define __attribute_format_strfmon__(a,b) \ 314 __attribute__ ((__format__ (__strfmon__, a, b))) 315 #else 316 # define __attribute_format_strfmon__(a,b) /* Ignore */ 317 #endif 318 319 /* The nonnull function attribute marks pointer parameters that 320 must not be NULL. Do not define __nonnull if it is already defined, 321 for portability when this file is used in Gnulib. */ 322 #ifndef __nonnull 323 # if __GNUC_PREREQ (3,3) || __glibc_clang_has_attribute (__nonnull__) 324 # define __nonnull(params) __attribute__ ((__nonnull__ params)) 325 # else 326 # define __nonnull(params) 327 # endif 328 #endif 329 330 /* If fortification mode, we warn about unused results of certain 331 function calls which can lead to problems. */ 332 #if __GNUC_PREREQ (3,4) || __glibc_clang_has_attribute (__warn_unused_result__) 333 # define __attribute_warn_unused_result__ \ 334 __attribute__ ((__warn_unused_result__)) 335 # if defined __USE_FORTIFY_LEVEL && __USE_FORTIFY_LEVEL > 0 336 # define __wur __attribute_warn_unused_result__ 337 # endif 338 #else 339 # define __attribute_warn_unused_result__ /* empty */ 340 #endif 341 #ifndef __wur 342 # define __wur /* Ignore */ 343 #endif 344 345 /* Forces a function to be always inlined. */ 346 #if __GNUC_PREREQ (3,2) || __glibc_clang_has_attribute (__always_inline__) 347 /* The Linux kernel defines __always_inline in stddef.h (283d7573), and 348 it conflicts with this definition. Therefore undefine it first to 349 allow either header to be included first. */ 350 # undef __always_inline 351 # define __always_inline __inline __attribute__ ((__always_inline__)) 352 #else 353 # undef __always_inline 354 # define __always_inline __inline 355 #endif 356 357 /* Associate error messages with the source location of the call site rather 358 than with the source location inside the function. */ 359 #if __GNUC_PREREQ (4,3) || __glibc_clang_has_attribute (__artificial__) 360 # define __attribute_artificial__ __attribute__ ((__artificial__)) 361 #else 362 # define __attribute_artificial__ /* Ignore */ 363 #endif 364 365 /* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99 366 inline semantics, unless -fgnu89-inline is used. Using __GNUC_STDC_INLINE__ 367 or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions 368 older than 4.3 may define these macros and still not guarantee GNU inlining 369 semantics. 370 371 clang++ identifies itself as gcc-4.2, but has support for GNU inlining 372 semantics, that can be checked for by using the __GNUC_STDC_INLINE_ and 373 __GNUC_GNU_INLINE__ macro definitions. */ 374 #if (!defined __cplusplus || __GNUC_PREREQ (4,3) \ 375 || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \ 376 || defined __GNUC_GNU_INLINE__))) 377 # if defined __GNUC_STDC_INLINE__ || defined __cplusplus 378 # define __extern_inline extern __inline __attribute__ ((__gnu_inline__)) 379 # define __extern_always_inline \ 380 extern __always_inline __attribute__ ((__gnu_inline__)) 381 # else 382 # define __extern_inline extern __inline 383 # define __extern_always_inline extern __always_inline 384 # endif 385 #endif 386 387 #ifdef __extern_always_inline 388 # define __fortify_function __extern_always_inline __attribute_artificial__ 389 #endif 390 391 /* GCC 4.3 and above allow passing all anonymous arguments of an 392 __extern_always_inline function to some other vararg function. */ 393 #if __GNUC_PREREQ (4,3) 394 # define __va_arg_pack() __builtin_va_arg_pack () 395 # define __va_arg_pack_len() __builtin_va_arg_pack_len () 396 #endif 397 398 /* It is possible to compile containing GCC extensions even if GCC is 399 run in pedantic mode if the uses are carefully marked using the 400 `__extension__' keyword. But this is not generally available before 401 version 2.8. */ 402 #if !(__GNUC_PREREQ (2,8) || defined __clang__) 403 # define __extension__ /* Ignore */ 404 #endif 405 406 /* __restrict is known in EGCS 1.2 and above, and in clang. 407 It works also in C++ mode (outside of arrays), but only when spelled 408 as '__restrict', not 'restrict'. */ 409 #if !(__GNUC_PREREQ (2,92) || __clang_major__ >= 3) 410 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L 411 # define __restrict restrict 412 # else 413 # define __restrict /* Ignore */ 414 # endif 415 #endif 416 417 /* ISO C99 also allows to declare arrays as non-overlapping. The syntax is 418 array_name[restrict] 419 GCC 3.1 and clang support this. 420 This syntax is not usable in C++ mode. */ 421 #if (__GNUC_PREREQ (3,1) || __clang_major__ >= 3) && !defined __cplusplus 422 # define __restrict_arr __restrict 423 #else 424 # ifdef __GNUC__ 425 # define __restrict_arr /* Not supported in old GCC. */ 426 # else 427 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L 428 # define __restrict_arr restrict 429 # else 430 /* Some other non-C99 compiler. */ 431 # define __restrict_arr /* Not supported. */ 432 # endif 433 # endif 434 #endif 435 436 #if (__GNUC__ >= 3) || __glibc_clang_has_builtin (__builtin_expect) 437 # define __glibc_unlikely(cond) __builtin_expect ((cond), 0) 438 # define __glibc_likely(cond) __builtin_expect ((cond), 1) 439 #else 440 # define __glibc_unlikely(cond) (cond) 441 # define __glibc_likely(cond) (cond) 442 #endif 443 444 #ifdef __has_attribute 445 # define __glibc_has_attribute(attr) __has_attribute (attr) 446 #else 447 # define __glibc_has_attribute(attr) 0 448 #endif 449 450 #if (!defined _Noreturn \ 451 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \ 452 && !(__GNUC_PREREQ (4,7) \ 453 || (3 < __clang_major__ + (5 <= __clang_minor__)))) 454 # if __GNUC_PREREQ (2,8) 455 # define _Noreturn __attribute__ ((__noreturn__)) 456 # else 457 # define _Noreturn 458 # endif 459 #endif 460 461 #if __GNUC_PREREQ (8, 0) 462 /* Describes a char array whose address can safely be passed as the first 463 argument to strncpy and strncat, as the char array is not necessarily 464 a NUL-terminated string. */ 465 # define __attribute_nonstring__ __attribute__ ((__nonstring__)) 466 #else 467 # define __attribute_nonstring__ 468 #endif 469 470 #if (!defined _Static_assert && !defined __cplusplus \ 471 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \ 472 && (!(__GNUC_PREREQ (4, 6) || __clang_major__ >= 4) \ 473 || defined __STRICT_ANSI__)) 474 # define _Static_assert(expr, diagnostic) \ 475 extern int (*__Static_assert_function (void)) \ 476 [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })] 477 #endif 478 479 /* The #ifndef lets Gnulib avoid including these on non-glibc 480 platforms, where the includes typically do not exist. */ 481 #ifndef __WORDSIZE 482 # include <bits/wordsize.h> 483 # include <bits/long-double.h> 484 #endif 485 486 #if defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH 487 # define __LDBL_COMPAT 1 488 # ifdef __REDIRECT 489 # define __LDBL_REDIR1(name, proto, alias) __REDIRECT (name, proto, alias) 490 # define __LDBL_REDIR(name, proto) \ 491 __LDBL_REDIR1 (name, proto, __nldbl_##name) 492 # define __LDBL_REDIR1_NTH(name, proto, alias) __REDIRECT_NTH (name, proto, alias) 493 # define __LDBL_REDIR_NTH(name, proto) \ 494 __LDBL_REDIR1_NTH (name, proto, __nldbl_##name) 495 # define __LDBL_REDIR1_DECL(name, alias) \ 496 extern __typeof (name) name __asm (__ASMNAME (#alias)); 497 # define __LDBL_REDIR_DECL(name) \ 498 extern __typeof (name) name __asm (__ASMNAME ("__nldbl_" #name)); 499 # define __REDIRECT_LDBL(name, proto, alias) \ 500 __LDBL_REDIR1 (name, proto, __nldbl_##alias) 501 # define __REDIRECT_NTH_LDBL(name, proto, alias) \ 502 __LDBL_REDIR1_NTH (name, proto, __nldbl_##alias) 503 # endif 504 #endif 505 #if !defined __LDBL_COMPAT || !defined __REDIRECT 506 # define __LDBL_REDIR1(name, proto, alias) name proto 507 # define __LDBL_REDIR(name, proto) name proto 508 # define __LDBL_REDIR1_NTH(name, proto, alias) name proto __THROW 509 # define __LDBL_REDIR_NTH(name, proto) name proto __THROW 510 # define __LDBL_REDIR_DECL(name) 511 # ifdef __REDIRECT 512 # define __REDIRECT_LDBL(name, proto, alias) __REDIRECT (name, proto, alias) 513 # define __REDIRECT_NTH_LDBL(name, proto, alias) \ 514 __REDIRECT_NTH (name, proto, alias) 515 # endif 516 #endif 517 518 /* __glibc_macro_warning (MESSAGE) issues warning MESSAGE. This is 519 intended for use in preprocessor macros. 520 521 Note: MESSAGE must be a _single_ string; concatenation of string 522 literals is not supported. */ 523 #if __GNUC_PREREQ (4,8) || __glibc_clang_prereq (3,5) 524 # define __glibc_macro_warning1(message) _Pragma (#message) 525 # define __glibc_macro_warning(message) \ 526 __glibc_macro_warning1 (GCC warning message) 527 #else 528 # define __glibc_macro_warning(msg) 529 #endif 530 531 /* Generic selection (ISO C11) is a C-only feature, available in GCC 532 since version 4.9. Previous versions do not provide generic 533 selection, even though they might set __STDC_VERSION__ to 201112L, 534 when in -std=c11 mode. Thus, we must check for !defined __GNUC__ 535 when testing __STDC_VERSION__ for generic selection support. 536 On the other hand, Clang also defines __GNUC__, so a clang-specific 537 check is required to enable the use of generic selection. */ 538 #if !defined __cplusplus \ 539 && (__GNUC_PREREQ (4, 9) \ 540 || __glibc_clang_has_extension (c_generic_selections) \ 541 || (!defined __GNUC__ && defined __STDC_VERSION__ \ 542 && __STDC_VERSION__ >= 201112L)) 543 # define __HAVE_GENERIC_SELECTION 1 544 #else 545 # define __HAVE_GENERIC_SELECTION 0 546 #endif 547 548 #endif /* sys/cdefs.h */ 549