1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Berkeley Software Design, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)cdefs.h 8.8 (Berkeley) 1/9/95 33 * $FreeBSD: src/sys/sys/cdefs.h,v 1.28.2.8 2002/09/18 04:05:13 mikeh Exp $ 34 */ 35 36 #ifndef _SYS_CDEFS_H_ 37 #define _SYS_CDEFS_H_ 38 39 /* 40 * Testing against Clang-specific extensions. 41 */ 42 #ifndef __has_attribute 43 #define __has_attribute(x) 0 44 #endif 45 #ifndef __has_extension 46 #define __has_extension __has_feature 47 #endif 48 #ifndef __has_feature 49 #define __has_feature(x) 0 50 #endif 51 #ifndef __has_include 52 #define __has_include(x) 0 53 #endif 54 #ifndef __has_builtin 55 #define __has_builtin(x) 0 56 #endif 57 58 /* 59 * Macro to test if we are using a specific version of gcc or later. 60 */ 61 #if defined(__GNUC__) 62 #define __GNUC_PREREQ__(ma, mi) \ 63 (__GNUC__ > (ma) || __GNUC__ == (ma) && __GNUC_MINOR__ >= (mi)) 64 #else 65 #define __GNUC_PREREQ__(ma, mi) 0 66 #endif 67 68 #if defined(__cplusplus) 69 #define __BEGIN_EXTERN_C extern "C" { 70 #define __END_EXTERN_C } 71 #else 72 #define __BEGIN_DECLS 73 #define __END_DECLS 74 #define __BEGIN_EXTERN_C 75 #define __END_EXTERN_C 76 #endif 77 78 #if __GNUC_PREREQ__(4, 0) 79 #define __dso_public __attribute__((__visibility__("default"))) 80 #define __dso_hidden __attribute__((__visibility__("hidden"))) 81 #define __BEGIN_PUBLIC_DECLS \ 82 _Pragma("GCC visibility push(default)") __BEGIN_EXTERN_C 83 #define __END_PUBLIC_DECLS \ 84 __END_EXTERN_C _Pragma("GCC visibility pop") 85 #define __BEGIN_HIDDEN_DECLS \ 86 _Pragma("GCC visibility push(hidden)") __BEGIN_EXTERN_C 87 #define __END_HIDDEN_DECLS \ 88 __END_EXTERN_C _Pragma("GCC visibility pop") 89 #else 90 #define __dso_public 91 #define __dso_hidden 92 #define __BEGIN_PUBLIC_DECLS \ 93 __BEGIN_EXTERN_C 94 #define __END_PUBLIC_DECLS \ 95 __END_EXTERN_C 96 #define __BEGIN_HIDDEN_DECLS \ 97 __BEGIN_EXTERN_C 98 #define __END_HIDDEN_DECLS \ 99 __END_EXTERN_C 100 #endif 101 102 #if defined(__cplusplus) 103 #define __BEGIN_DECLS __BEGIN_PUBLIC_DECLS 104 #define __END_DECLS __END_PUBLIC_DECLS 105 #endif 106 107 /* 108 * The __VM_CACHELINE_SIZE macro defines the common cache line alignment 109 * size that can be found across most recent and somewhat latest Intel 110 * hardware, i.e. L1 cache sizes etc. 111 * 112 * If needed, this value can be TUNED. Suitable values for this macro 113 * are 32, 64 and 128 bytes. The unit of measurement for this macro is 114 * bytes. 115 * 116 * XXX: This macro and related macros will eventually move to a MD 117 * header, but currently, we do need such a hierarchy. 118 */ 119 #define __VM_CACHELINE_SIZE 64 120 #define __VM_CACHELINE_MASK (__VM_CACHELINE_SIZE - 1) 121 #define __VM_CACHELINE_ALIGN(n) \ 122 (((n) + __VM_CACHELINE_MASK) & ~__VM_CACHELINE_MASK) 123 124 /* 125 * The __CONCAT macro is used to concatenate parts of symbol names, e.g. 126 * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo. 127 * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI 128 * mode -- there must be no spaces between its arguments, and for nested 129 * __CONCAT's, all the __CONCAT's must be at the left. __CONCAT can also 130 * concatenate double-quoted strings produced by the __STRING macro, but 131 * this only works with ANSI C. 132 * 133 * __XSTRING is like __STRING, but it expands any macros in its argument 134 * first. It is only available with ANSI C. 135 */ 136 #if defined(__STDC__) || defined(__cplusplus) 137 #define __P(protos) protos /* full-blown ANSI C */ 138 #define __CONCAT1(x,y) x ## y 139 #define __CONCAT(x,y) __CONCAT1(x,y) 140 #define __STRING(x) #x /* stringify without expanding x */ 141 #define __XSTRING(x) __STRING(x) /* expand x, then stringify */ 142 143 #define __const const /* define reserved names to standard */ 144 #define __signed signed 145 #define __volatile volatile 146 #if defined(__cplusplus) 147 #define __inline inline /* convert to C++ keyword */ 148 #else 149 #ifndef __GNUC__ 150 #define __inline /* delete GCC keyword */ 151 #endif /* !__GNUC__ */ 152 #endif /* __cplusplus */ 153 154 #else /* !(__STDC__ || __cplusplus) */ 155 #define __P(protos) () /* traditional C preprocessor */ 156 #define __CONCAT(x,y) x/**/y 157 #define __STRING(x) "x" 158 159 #ifndef __GNUC__ 160 #define __const /* delete pseudo-ANSI C keywords */ 161 #define __inline 162 #define __signed 163 #define __volatile 164 /* 165 * In non-ANSI C environments, new programs will want ANSI-only C keywords 166 * deleted from the program and old programs will want them left alone. 167 * When using a compiler other than gcc, programs using the ANSI C keywords 168 * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS. 169 * When using "gcc -traditional", we assume that this is the intent; if 170 * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone. 171 */ 172 #ifndef NO_ANSI_KEYWORDS 173 #define const /* delete ANSI C keywords */ 174 #define inline 175 #define signed 176 #define volatile 177 #endif /* !NO_ANSI_KEYWORDS */ 178 #endif /* !__GNUC__ */ 179 #endif /* __STDC__ || __cplusplus */ 180 181 /* 182 * Compiler-dependent macros to help declare dead (non-returning) and 183 * pure (no side effects) functions, and unused variables. They are 184 * null except for versions of gcc that are known to support the features 185 * properly (old versions of gcc-2 supported the dead and pure features 186 * in a different (wrong) way). 187 */ 188 #define __weak_symbol __attribute__((__weak__)) 189 #if __GNUC_PREREQ__(2, 7) 190 #define __dead2 __attribute__((__noreturn__)) 191 #define __pure2 __attribute__((__const__)) 192 #define __unused __attribute__((__unused__)) 193 #define __packed __attribute__((__packed__)) 194 #define __aligned(x) __attribute__((__aligned__(x))) 195 #define __section(x) __attribute__((__section__(x))) 196 #else 197 #define __dead2 198 #define __pure2 199 #define __unused 200 #endif 201 202 #if __GNUC_PREREQ__(2, 96) 203 #define __malloclike __attribute__((__malloc__)) 204 #define __pure __attribute__((__pure__)) 205 #else 206 #define __malloclike 207 #define __pure __pure2 208 #endif 209 210 #if __GNUC_PREREQ__(3, 1) 211 #define __always_inline __attribute__((__always_inline__)) 212 #define __noinline __attribute__((__noinline__)) 213 #else 214 #define __always_inline 215 #define __noinline 216 #endif 217 218 #if __GNUC_PREREQ__(3, 3) 219 #define __nonnull(...) __attribute__((__nonnull__(__VA_ARGS__))) 220 #define __used __attribute__((__used__)) 221 #else 222 #define __nonnull(...) 223 #define __used __unused 224 #endif 225 226 #if __GNUC_PREREQ__(3, 4) 227 #define __heedresult __attribute__((__warn_unused_result__)) 228 #else 229 #define __heedresult 230 #endif 231 232 #if __GNUC_PREREQ__(4, 1) 233 #define __returns_twice __attribute__((__returns_twice__)) 234 #else 235 #define __returns_twice 236 #endif 237 238 #if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable) 239 #define __unreachable() __builtin_unreachable() 240 #else 241 #define __unreachable() ((void)0) 242 #endif 243 244 #if __GNUC_PREREQ__(4, 3) || __has_attribute(__alloc_size__) 245 #define __alloc_size(x) __attribute__((__alloc_size__(x))) 246 #define __alloc_size2(n, x) __attribute__((__alloc_size__(n, x))) 247 #else 248 #define __alloc_size(x) 249 #define __alloc_size2(n, x) 250 #endif 251 252 #if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__) 253 #define __alloc_align(x) __attribute__((__alloc_align__(x))) 254 #else 255 #define __alloc_align(x) 256 #endif 257 258 #if !__GNUC_PREREQ__(2, 7) && __STDC_VERSION__ < 199901 259 #define __func__ NULL 260 #endif 261 262 #if (__GNUC_PREREQ__(2, 0) && !defined(__STRICT_ANSI__)) || \ 263 __STDC_VERSION__ >= 199901 264 #define __LONG_LONG_SUPPORTED 265 #endif 266 267 /* C++11 exposes a load of C99 stuff */ 268 #if defined(__cplusplus) && __cplusplus >= 201103L 269 #define __LONG_LONG_SUPPORTED 270 #ifndef __STDC_LIMIT_MACROS 271 #define __STDC_LIMIT_MACROS 272 #endif 273 #ifndef __STDC_CONSTANT_MACROS 274 #define __STDC_CONSTANT_MACROS 275 #endif 276 #endif 277 278 /* 279 * GCC 2.95 and later provides `__restrict' as an extension to C90 to support 280 * the C99-specific `restrict' type qualifier. We happen to use `__restrict' 281 * as a way to define the `restrict' type qualifier without disturbing older 282 * software that is unaware of C99 keywords. 283 */ 284 #if !__GNUC_PREREQ__(2, 95) 285 #if __STDC_VERSION__ < 199901 286 #define __restrict 287 #else 288 #define __restrict restrict 289 #endif 290 #endif 291 292 /* 293 * C99 allows to declare arrays as non-overlapping. 294 */ 295 #if __GNUC_PREREQ__(3, 1) && !defined(__GNUG__) 296 #define __restrict_arr __restrict 297 #else 298 #ifdef __GNUC__ 299 #define __restrict_arr 300 #else 301 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901 302 #define __restrict_arr restrict 303 #else 304 #define __restrict_arr 305 #endif 306 #endif 307 #endif 308 309 /* 310 * GNU C version 2.96 adds explicit branch prediction so that 311 * the CPU back-end can hint the processor and also so that 312 * code blocks can be reordered such that the predicted path 313 * sees a more linear flow, thus improving cache behavior, etc. 314 * 315 * The following two macros provide us with a way to utilize this 316 * compiler feature. Use __predict_true() if you expect the expression 317 * to evaluate to true, and __predict_false() if you expect the 318 * expression to evaluate to false. 319 * 320 * A few notes about usage: 321 * 322 * * Generally, __predict_false() error condition checks (unless 323 * you have some _strong_ reason to do otherwise, in which case 324 * document it), and/or __predict_true() `no-error' condition 325 * checks, assuming you want to optimize for the no-error case. 326 * 327 * * Other than that, if you don't know the likelihood of a test 328 * succeeding from empirical or other `hard' evidence, don't 329 * make predictions. 330 * 331 * * These are meant to be used in places that are run `a lot'. 332 * It is wasteful to make predictions in code that is run 333 * seldomly (e.g. at subsystem initialization time) as the 334 * basic block reordering that this affects can often generate 335 * larger code. 336 */ 337 #if __GNUC_PREREQ__(2, 96) 338 #define __predict_true(exp) __builtin_expect((exp), 1) 339 #define __predict_false(exp) __builtin_expect((exp), 0) 340 #else 341 #define __predict_true(exp) (exp) 342 #define __predict_false(exp) (exp) 343 #endif 344 345 /* 346 * We define this here since <stddef.h>, <sys/queue.h>, and <sys/types.h> 347 * require it. 348 */ 349 #if __GNUC_PREREQ__(4, 1) 350 #define __offsetof(type, field) __builtin_offsetof(type, field) 351 #else 352 #ifndef __cplusplus 353 #define __offsetof(type, field) \ 354 ((__size_t)(__uintptr_t)((const volatile void *)&((type *)0)->field)) 355 #else 356 #define __offsetof(type, field) \ 357 (__offsetof__ (reinterpret_cast <__size_t> \ 358 (&reinterpret_cast <const volatile char &> \ 359 (static_cast<type *> (0)->field)))) 360 #endif 361 #endif 362 363 /* 364 * Given the pointer x to the member m of the struct s, return a pointer to 365 * the containing structure. When using GCC, we first assign pointer x to 366 * a local variable, to check that its type is compatible with member m. 367 */ 368 #if __GNUC_PREREQ__(3, 1) 369 #define __containerof(x, s, m) ({ \ 370 const volatile __typeof(((s *)NULL)->m) *__x = (x); \ 371 __DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m)); \ 372 }) 373 #else 374 #define __containerof(x, s, m) \ 375 __DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m)) 376 #endif 377 378 /* 379 * Compiler-dependent macros to declare that functions take printf-like 380 * or scanf-like arguments. They are null except for versions of gcc 381 * that are known to support the features properly (old versions of gcc-2 382 * didn't permit keeping the keywords out of the application namespace). 383 * 384 * The printf0like macro for GCC 2 uses DragonFly specific compiler extensions. 385 */ 386 #if !__GNUC_PREREQ__(2, 7) 387 #define __printflike(fmtarg, firstvararg) 388 #define __scanflike(fmtarg, firstvararg) 389 #define __printf0like(fmtarg, firstvararg) 390 #define __format_arg(fmtarg) 391 #define __strfmonlike(fmtarg, firstvararg) 392 #define __strftimelike(fmtarg, firstvararg) 393 394 #elif __GNUC_PREREQ__(3, 0) 395 #define __printflike(fmtarg, firstvararg) \ 396 __attribute__((__nonnull__(fmtarg), \ 397 __format__ (__printf__, fmtarg, firstvararg))) 398 #define __printf0like(fmtarg, firstvararg) \ 399 __attribute__((__format__ (__printf__, fmtarg, firstvararg))) 400 #define __scanflike(fmtarg, firstvararg) \ 401 __attribute__((__format__ (__scanf__, fmtarg, firstvararg))) 402 #define __format_arg(fmtarg) \ 403 __attribute__((__format_arg__ (fmtarg))) 404 #define __strfmonlike(fmtarg, firstvararg) \ 405 __attribute__((__format__ (__strfmon__, fmtarg, firstvararg))) 406 #define __strftimelike(fmtarg, firstvararg) \ 407 __attribute__((__format__ (__strftime__, fmtarg, firstvararg))) 408 409 #else 410 #define __printflike(fmtarg, firstvararg) \ 411 __attribute__((__format__ (__printf__, fmtarg, firstvararg))) 412 #define __printf0like(fmtarg, firstvararg) \ 413 __attribute__((__format__ (__printf0__, fmtarg, firstvararg))) 414 #define __scanflike(fmtarg, firstvararg) \ 415 __attribute__((__format__ (__scanf__, fmtarg, firstvararg))) 416 #define __format_arg(fmtarg) \ 417 __attribute__((__format_arg__ (fmtarg))) 418 #define __strfmonlike(fmtarg, firstvararg) \ 419 __attribute__((__format__ (__strfmon__, fmtarg, firstvararg))) 420 #define __strftimelike(fmtarg, firstvararg) \ 421 __attribute__((__format__ (__strftime__, fmtarg, firstvararg))) 422 #endif 423 424 #if !__GNUC_PREREQ__(3, 0) 425 #define __ARRAY_ZERO 0 426 #else 427 #define __ARRAY_ZERO 428 #endif 429 430 /* 431 * A convenient constructor macro, GCC 4.3.0 added priority support to 432 * constructors, provide a compatible interface for both. 433 */ 434 #if __GNUC_PREREQ__(4, 3) 435 #define __constructor(prio) __attribute__((constructor(prio))) 436 #else 437 #define __constructor(prio) __attribute__((constructor)) 438 #endif 439 440 /* 441 * Handy GCC based macros: 442 * 443 * __cachealign: 444 * 445 * The __cachealign macro can be used for cache line aligning structures 446 * of small to medium size. It aligns the particular structure or 447 * storage type to a system default cache line alignment, thus giving us 448 * a much more better cache utilization by making the hardware work at 449 * its best burst speeds. 450 * 451 * __usereg: 452 * 453 * The __usereg macro can/should be used when a function contains 454 * arguments not more than 3. It can be very useful to us due to the 455 * message-passing nature of the kernel. 456 * 457 * !!NOTE - USAGE INFORMATION!! 458 * 459 * The __cachealign macro should not be used for data structures that are 460 * as big struct proc, struct vnode, struct thread, and other structs which 461 * are as big as them; simply because it will be useless in that case. 462 * 463 * The __usereg macro should be used whenever possible, i.e., when a function 464 * does not exceed more than 3 arguments, and should not be used for vararg 465 * type functions. 466 * 467 * In other words, AVOID MISUSE OF THESE MACROS. :-) 468 */ 469 #ifdef __GNUC__ 470 #define __cachealign __attribute__((__aligned__(__VM_CACHELINE_SIZE))) 471 #define __usereg __attribute__((__regparm__(3))) 472 #else 473 #define __cachealign 474 #define __usereg 475 #endif 476 477 #ifdef __GNUC__ 478 #define __strong_reference(sym,aliassym) \ 479 extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym))) 480 #define __weak_reference(sym,aliassym) \ 481 __strong_reference(sym,aliassym) __attribute__ ((__weak__)) 482 #define __weak_reference_asm(sym,alias) \ 483 __asm__(".weak " #alias); \ 484 __asm__(".equ " #alias ", " #sym) 485 #define __warn_references(sym,msg) \ 486 __asm__(".section .gnu.warning." #sym); \ 487 __asm__(".asciz \"" msg "\""); \ 488 __asm__(".previous") 489 #define __sym_compat(sym,impl,verid) \ 490 __asm__(".symver " #impl ", " #sym "@" #verid) 491 #define __sym_default(sym,impl,verid) \ 492 __asm__(".symver " #impl ", " #sym "@@@" #verid) 493 #endif /* __GNUC__ */ 494 495 #if defined(__GNUC__) 496 #define __IDSTRING(name,string) __asm__(".ident\t\"" string "\"") 497 #endif 498 499 #ifndef __RCSID 500 #define __RCSID(s) struct __hack 501 #endif 502 503 #ifndef __RCSID_SOURCE 504 #define __RCSID_SOURCE(s) struct __hack 505 #endif 506 507 #ifndef __SCCSID 508 #define __SCCSID(s) struct __hack 509 #endif 510 511 #ifndef __FBSDID 512 #define __FBSDID(s) struct __hack 513 #endif 514 515 #ifndef __COPYRIGHT 516 #define __COPYRIGHT(s) struct __hack 517 #endif 518 519 #ifndef __DECONST 520 #define __DECONST(type, var) ((type)(__uintptr_t)(const void *)(var)) 521 #endif 522 523 #ifndef __DEVOLATILE 524 #define __DEVOLATILE(type, var) ((type)(__uintptr_t)(volatile void *)(var)) 525 #endif 526 527 #ifndef __DEQUALIFY 528 #define __DEQUALIFY(type, var) ((type)(__uintptr_t)(const volatile void *)(var)) 529 #endif 530 531 /* 532 * Keywords added in C11. 533 */ 534 535 #if !__GNUC_PREREQ__(2, 95) 536 #define __alignof(x) __offsetof(struct { char __a; x __b; }, __b) 537 #endif 538 539 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L 540 541 #if !__has_extension(c_alignas) 542 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \ 543 __has_extension(cxx_alignas) 544 #define _Alignas(x) alignas(x) 545 #else 546 /* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */ 547 #define _Alignas(x) __aligned(x) 548 #endif 549 #endif 550 551 #if defined(__cplusplus) && __cplusplus >= 201103L 552 #define _Alignof(x) alignof(x) 553 #else 554 #define _Alignof(x) __alignof(x) 555 #endif 556 557 #if !defined(_Noreturn) 558 #define _Noreturn __dead2 559 #endif 560 561 #if !__has_extension(c_static_assert) 562 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \ 563 __has_extension(cxx_static_assert) 564 #define _Static_assert(x, y) static_assert(x, y) 565 #elif !__GNUC_PREREQ__(4, 6) 566 #define _Static_assert(x, y) struct __hack 567 #ifdef _KERNEL 568 #define CTASSERT(x) _CTASSERT(x, __LINE__) 569 #define _CTASSERT(x, y) __CTASSERT(x, y) 570 #define __CTASSERT(x, y) typedef char __assert ## y[(x) ? 1 : -1] 571 #endif 572 #endif 573 574 /* 575 * GCC 4.7 has -std=c++11 but does not support thread_local. 576 */ 577 #if !__has_extension(c_thread_local) 578 #if (defined(__cplusplus) && __cplusplus >= 201103L && __GNUC_PREREQ__(4, 8)) || \ 579 __has_extension(cxx_thread_local) 580 #define _Thread_local thread_local 581 #else 582 #define _Thread_local __thread 583 #endif 584 #endif 585 #endif 586 587 #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */ 588 589 #if defined(_KERNEL) && !defined(CTASSERT) 590 #define CTASSERT(x) _Static_assert(x, \ 591 "compile-time assertion failed") 592 #endif 593 594 /* 595 * Emulation of C11 _Generic(). Unlike the previously defined C11 596 * keywords, it is not possible to implement this using exactly the same 597 * syntax. Therefore implement something similar under the name 598 * __generic(). Unlike _Generic(), this macro can only distinguish 599 * between a single type, so it requires nested invocations to 600 * distinguish multiple cases. 601 */ 602 603 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L 604 #define __generic(expr, t, yes, no) \ 605 _Generic(expr, t: yes, default: no) 606 #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus) 607 #define __generic(expr, t, yes, no) \ 608 __builtin_choose_expr( \ 609 __builtin_types_compatible_p(__typeof(expr), t), yes, no) 610 #endif 611 612 /*- 613 * POSIX.1 requires that the macros we test be defined before any standard 614 * header file is included. 615 * 616 * Here's a quick run-down of the versions: 617 * defined(_POSIX_SOURCE) 1003.1-1988 618 * _POSIX_C_SOURCE == 1 1003.1-1990 619 * _POSIX_C_SOURCE == 2 1003.2-1992 C Language Binding Option 620 * _POSIX_C_SOURCE == 199309 1003.1b-1993 621 * _POSIX_C_SOURCE == 199506 1003.1c-1995, 1003.1i-1995, 622 * and the omnibus ISO/IEC 9945-1: 1996 623 * _POSIX_C_SOURCE == 200112 1003.1-2001 624 * _POSIX_C_SOURCE == 200809 1003.1-2008 625 * 626 * In addition, the X/Open Portability Guide, which is now the Single UNIX 627 * Specification, defines a feature-test macro which indicates the version of 628 * that specification, and which subsumes _POSIX_C_SOURCE. 629 * 630 * Our macros begin with two underscores to avoid namespace screwage. 631 */ 632 633 /* Deal with IEEE Std. 1003.1-1990, in which _POSIX_C_SOURCE == 1. */ 634 #if defined(_POSIX_C_SOURCE) && (_POSIX_C_SOURCE - 0) == 1 635 #undef _POSIX_C_SOURCE /* Probably illegal, but beyond caring now. */ 636 #define _POSIX_C_SOURCE 199009 637 #endif 638 639 /* Deal with IEEE Std. 1003.2-1992, in which _POSIX_C_SOURCE == 2. */ 640 #if defined(_POSIX_C_SOURCE) && (_POSIX_C_SOURCE - 0) == 2 641 #undef _POSIX_C_SOURCE 642 #define _POSIX_C_SOURCE 199209 643 #endif 644 645 /* Deal with various X/Open Portability Guides and Single UNIX Spec. */ 646 #ifdef _XOPEN_SOURCE 647 #if _XOPEN_SOURCE - 0 >= 700 648 #define __XSI_VISIBLE 700 649 #undef _POSIX_C_SOURCE 650 #define _POSIX_C_SOURCE 200809 651 #elif _XOPEN_SOURCE - 0 >= 600 652 #define __XSI_VISIBLE 600 653 #undef _POSIX_C_SOURCE 654 #define _POSIX_C_SOURCE 200112 655 #elif _XOPEN_SOURCE - 0 >= 500 656 #define __XSI_VISIBLE 500 657 #undef _POSIX_C_SOURCE 658 #define _POSIX_C_SOURCE 199506 659 #endif 660 #endif 661 662 /* 663 * Deal with all versions of POSIX. The ordering relative to the tests above is 664 * important. 665 */ 666 #if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE) 667 #define _POSIX_C_SOURCE 198808 668 #endif 669 #ifdef _POSIX_C_SOURCE 670 #if (_POSIX_C_SOURCE - 0) >= 200809 671 #define __POSIX_VISIBLE 200809 672 #define __ISO_C_VISIBLE 1999 673 #elif (_POSIX_C_SOURCE - 0) >= 200112 674 #define __POSIX_VISIBLE 200112 675 #define __ISO_C_VISIBLE 1999 676 #elif (_POSIX_C_SOURCE - 0) >= 199506 677 #define __POSIX_VISIBLE 199506 678 #define __ISO_C_VISIBLE 1990 679 #elif (_POSIX_C_SOURCE - 0) >= 199309 680 #define __POSIX_VISIBLE 199309 681 #define __ISO_C_VISIBLE 1990 682 #elif (_POSIX_C_SOURCE - 0) >= 199209 683 #define __POSIX_VISIBLE 199209 684 #define __ISO_C_VISIBLE 1990 685 #elif (_POSIX_C_SOURCE - 0) >= 199009 686 #define __POSIX_VISIBLE 199009 687 #define __ISO_C_VISIBLE 1990 688 #else 689 #define __POSIX_VISIBLE 198808 690 #define __ISO_C_VISIBLE 0 691 #endif /* _POSIX_C_SOURCE */ 692 #else 693 /*- 694 * Deal with _ANSI_SOURCE: 695 * If it is defined, and no other compilation environment is explicitly 696 * requested, then define our internal feature-test macros to zero. This 697 * makes no difference to the preprocessor (undefined symbols in preprocessing 698 * expressions are defined to have value zero), but makes it more convenient for 699 * a test program to print out the values. 700 * 701 * If a program mistakenly defines _ANSI_SOURCE and some other macro such as 702 * _POSIX_C_SOURCE, we will assume that it wants the broader compilation 703 * environment (and in fact we will never get here). 704 */ 705 #if defined(_ANSI_SOURCE) /* Hide almost everything. */ 706 #define __POSIX_VISIBLE 0 707 #define __XSI_VISIBLE 0 708 #define __BSD_VISIBLE 0 709 #define __ISO_C_VISIBLE 1990 710 #define __EXT1_VISIBLE 0 711 #elif defined(_C99_SOURCE) /* Localism to specify strict C99 env. */ 712 #define __POSIX_VISIBLE 0 713 #define __XSI_VISIBLE 0 714 #define __BSD_VISIBLE 0 715 #define __ISO_C_VISIBLE 1999 716 #define __EXT1_VISIBLE 0 717 #elif defined(_C11_SOURCE) /* Localism to specify strict C11 env. */ 718 #define __POSIX_VISIBLE 0 719 #define __XSI_VISIBLE 0 720 #define __BSD_VISIBLE 0 721 #define __ISO_C_VISIBLE 2011 722 #define __EXT1_VISIBLE 0 723 #else /* Default environment: show everything. */ 724 #define __POSIX_VISIBLE 200809 725 #define __XSI_VISIBLE 700 726 #define __BSD_VISIBLE 1 727 #define __ISO_C_VISIBLE 2011 728 #define __EXT1_VISIBLE 1 729 #endif 730 #endif 731 732 /* User override __EXT1_VISIBLE */ 733 #if defined(__STDC_WANT_LIB_EXT1__) 734 #undef __EXT1_VISIBLE 735 #if __STDC_WANT_LIB_EXT1__ 736 #define __EXT1_VISIBLE 1 737 #else 738 #define __EXT1_VISIBLE 0 739 #endif 740 #endif /* __STDC_WANT_LIB_EXT1__ */ 741 742 #ifndef __BSD_VISIBLE 743 #define __BSD_VISIBLE 0 744 #endif 745 #ifndef __EXT1_VISIBLE 746 #define __EXT1_VISIBLE 0 747 #endif 748 749 /* 750 * GLOBL macro exists to preserve __start_set_* and __stop_set_* sections 751 * of kernel modules which are discarded from binutils 2.17.50+ otherwise. 752 */ 753 754 #define __GLOBL1(sym) __asm__(".globl " #sym) 755 #define __GLOBL(sym) __GLOBL1(sym) 756 757 #endif /* !_SYS_CDEFS_H_ */ 758