cdefs.h (34638B) - Raw
1 /* Copyright (C) 1992-2025 Free Software Foundation, Inc. 2 Copyright The GNU Toolchain Authors. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #ifndef _SYS_CDEFS_H 20 #define _SYS_CDEFS_H 1 21 22 /* We are almost always included from features.h. */ 23 #ifndef _FEATURES_H 24 # include <features.h> 25 #endif 26 27 /* The GNU libc does not support any K&R compilers or the traditional mode 28 of ISO C compilers anymore. Check for some of the combinations not 29 supported anymore. */ 30 #if defined __GNUC__ && !defined __STDC__ && !defined __cplusplus 31 # error "You need a ISO C or C++ conforming compiler to use the glibc headers" 32 #endif 33 34 /* Some user header file might have defined this before. */ 35 #undef __P 36 #undef __PMT 37 38 /* Compilers that lack __has_attribute may object to 39 #if defined __has_attribute && __has_attribute (...) 40 even though they do not need to evaluate the right-hand side of the &&. 41 Similarly for __has_builtin, etc. */ 42 #if (defined __has_attribute \ 43 && (!defined __clang_minor__ \ 44 || 3 < __clang_major__ + (5 <= __clang_minor__))) 45 # define __glibc_has_attribute(attr) __has_attribute (attr) 46 #else 47 # define __glibc_has_attribute(attr) 0 48 #endif 49 #ifdef __has_builtin 50 # define __glibc_has_builtin(name) __has_builtin (name) 51 #else 52 # define __glibc_has_builtin(name) 0 53 #endif 54 #ifdef __has_extension 55 # define __glibc_has_extension(ext) __has_extension (ext) 56 #else 57 # define __glibc_has_extension(ext) 0 58 #endif 59 60 #if defined __GNUC__ || defined __clang__ 61 62 /* All functions, except those with callbacks or those that 63 synchronize memory, are leaf functions. */ 64 # if __GNUC_PREREQ (4, 6) && !defined _LIBC 65 # define __LEAF , __leaf__ 66 # define __LEAF_ATTR __attribute__ ((__leaf__)) 67 # else 68 # define __LEAF 69 # define __LEAF_ATTR 70 # endif 71 72 /* GCC can always grok prototypes. For C++ programs we add throw() 73 to help it optimize the function calls. But this only works with 74 gcc 2.8.x and egcs. For gcc 3.4 and up we even mark C functions 75 as non-throwing using a function attribute since programs can use 76 the -fexceptions options for C code as well. */ 77 # if !defined __cplusplus \ 78 && (__GNUC_PREREQ (3, 4) || __glibc_has_attribute (__nothrow__)) 79 # define __THROW __attribute__ ((__nothrow__ __LEAF)) 80 # define __THROWNL __attribute__ ((__nothrow__)) 81 # define __NTH(fct) __attribute__ ((__nothrow__ __LEAF)) fct 82 # define __NTHNL(fct) __attribute__ ((__nothrow__)) fct 83 # else 84 # if defined __cplusplus && (__GNUC_PREREQ (2,8) || __clang_major__ >= 4) 85 # if __cplusplus >= 201103L 86 # define __THROW noexcept (true) 87 # else 88 # define __THROW throw () 89 # endif 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 # if __GNUC_PREREQ (4, 3) || __glibc_has_attribute (__cold__) 102 # define __COLD __attribute__ ((__cold__)) 103 # else 104 # define __COLD 105 # endif 106 107 #else /* Not GCC or clang. */ 108 109 # if (defined __cplusplus \ 110 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)) 111 # define __inline inline 112 # else 113 # define __inline /* No inline functions. */ 114 # endif 115 116 # define __THROW 117 # define __THROWNL 118 # define __NTH(fct) fct 119 # define __COLD 120 121 #endif /* GCC || clang. */ 122 123 /* These two macros are not used in glibc anymore. They are kept here 124 only because some other projects expect the macros to be defined. */ 125 #define __P(args) args 126 #define __PMT(args) args 127 128 /* For these things, GCC behaves the ANSI way normally, 129 and the non-ANSI way under -traditional. */ 130 131 #define __CONCAT(x,y) x ## y 132 #define __STRING(x) #x 133 134 /* This is not a typedef so `const __ptr_t' does the right thing. */ 135 #define __ptr_t void * 136 137 138 /* C++ needs to know that types and declarations are C, not C++. */ 139 #ifdef __cplusplus 140 # define __BEGIN_DECLS extern "C" { 141 # define __END_DECLS } 142 #else 143 # define __BEGIN_DECLS 144 # define __END_DECLS 145 #endif 146 147 148 /* The overloadable attribute was added on clang 2.6. */ 149 #if defined __clang_major__ \ 150 && (__clang_major__ + (__clang_minor__ >= 6) > 2) 151 # define __attribute_overloadable__ __attribute__((__overloadable__)) 152 #else 153 # define __attribute_overloadable__ 154 #endif 155 156 /* Fortify support. */ 157 #define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1) 158 #define __bos0(ptr) __builtin_object_size (ptr, 0) 159 160 /* Use __builtin_dynamic_object_size at _FORTIFY_SOURCE=3 when available. */ 161 #if __USE_FORTIFY_LEVEL == 3 && (__glibc_clang_prereq (9, 0) \ 162 || __GNUC_PREREQ (12, 0)) 163 # define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0) 164 # define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1) 165 #else 166 # define __glibc_objsize0(__o) __bos0 (__o) 167 # define __glibc_objsize(__o) __bos (__o) 168 #endif 169 170 #if __USE_FORTIFY_LEVEL > 0 171 /* Compile time conditions to choose between the regular, _chk and _chk_warn 172 variants. These conditions should get evaluated to constant and optimized 173 away. */ 174 175 #define __glibc_safe_len_cond(__l, __s, __osz) ((__l) <= (__osz) / (__s)) 176 #define __glibc_unsigned_or_positive(__l) \ 177 ((__typeof (__l)) 0 < (__typeof (__l)) -1 \ 178 || (__builtin_constant_p (__l) && (__l) > 0)) 179 180 /* Length is known to be safe at compile time if the __L * __S <= __OBJSZ 181 condition can be folded to a constant and if it is true, or unknown (-1) */ 182 #define __glibc_safe_or_unknown_len(__l, __s, __osz) \ 183 ((__builtin_constant_p (__osz) && (__osz) == (__SIZE_TYPE__) -1) \ 184 || (__glibc_unsigned_or_positive (__l) \ 185 && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \ 186 (__s), (__osz))) \ 187 && __glibc_safe_len_cond ((__SIZE_TYPE__) (__l), (__s), (__osz)))) 188 189 /* Conversely, we know at compile time that the length is unsafe if the 190 __L * __S <= __OBJSZ condition can be folded to a constant and if it is 191 false. */ 192 #define __glibc_unsafe_len(__l, __s, __osz) \ 193 (__glibc_unsigned_or_positive (__l) \ 194 && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \ 195 __s, __osz)) \ 196 && !__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), __s, __osz)) 197 198 /* To correctly instrument the fortify wrapper clang requires the 199 pass_object_size attribute, and the attribute has the restriction that the 200 argument needs to be 'const'. Furthermore, to make it usable with C 201 interfaces, clang provides the overload attribute, which provides a C++ 202 like function overload support. The overloaded fortify wrapper with the 203 pass_object_size attribute has precedence over the default symbol. 204 205 Also, clang does not support __va_arg_pack, so variadic functions are 206 expanded to issue va_arg implementations. The error function must not have 207 bodies (address takes are expanded to nonfortified calls), and with 208 __fortify_function compiler might still create a body with the C++ 209 mangling name (due to the overload attribute). In this case, the function 210 is defined with __fortify_function_error_function macro instead. 211 212 The argument size check is also done with a clang-only attribute, 213 __attribute__ ((__diagnose_if__ (...))), different than gcc which calls 214 symbol_chk_warn alias with uses __warnattr attribute. 215 216 The pass_object_size was added on clang 4.0, __diagnose_if__ on 5.0, 217 and pass_dynamic_object_size on 9.0. */ 218 #if defined __clang_major__ && __clang_major__ >= 5 219 # define __fortify_use_clang 1 220 221 # define __fortify_function_error_function static __attribute__((__unused__)) 222 223 # define __fortify_clang_pass_object_size_n(n) \ 224 __attribute__ ((__pass_object_size__ (n))) 225 # define __fortify_clang_pass_object_size0 \ 226 __fortify_clang_pass_object_size_n (0) 227 # define __fortify_clang_pass_object_size \ 228 __fortify_clang_pass_object_size_n (__USE_FORTIFY_LEVEL > 1) 229 230 # if __clang_major__ >= 9 231 # define __fortify_clang_pass_dynamic_object_size_n(n) \ 232 __attribute__ ((__pass_dynamic_object_size__ (n))) 233 # define __fortify_clang_pass_dynamic_object_size0 \ 234 __fortify_clang_pass_dynamic_object_size_n (0) 235 # define __fortify_clang_pass_dynamic_object_size \ 236 __fortify_clang_pass_dynamic_object_size_n (1) 237 # else 238 # define __fortify_clang_pass_dynamic_object_size_n(n) 239 # define __fortify_clang_pass_dynamic_object_size0 240 # define __fortify_clang_pass_dynamic_object_size 241 # endif 242 243 # define __fortify_clang_bos_static_lt_impl(bos_val, n, s) \ 244 ((bos_val) != -1ULL && (n) > (bos_val) / (s)) 245 # define __fortify_clang_bos_static_lt2(__n, __e, __s) \ 246 __fortify_clang_bos_static_lt_impl (__bos (__e), __n, __s) 247 # define __fortify_clang_bos_static_lt(__n, __e) \ 248 __fortify_clang_bos_static_lt2 (__n, __e, 1) 249 # define __fortify_clang_bos0_static_lt2(__n, __e, __s) \ 250 __fortify_clang_bos_static_lt_impl (__bos0 (__e), __n, __s) 251 # define __fortify_clang_bos0_static_lt(__n, __e) \ 252 __fortify_clang_bos0_static_lt2 (__n, __e, 1) 253 254 # define __fortify_clang_bosn_args(bos_fn, n, buf, div, complaint) \ 255 (__fortify_clang_bos_static_lt_impl (bos_fn (buf), n, div)), (complaint), \ 256 "warning" 257 258 # define __fortify_clang_warning(__c, __msg) \ 259 __attribute__ ((__diagnose_if__ ((__c), (__msg), "warning"))) 260 # define __fortify_clang_error(__c, __msg) \ 261 __attribute__ ((__diagnose_if__ ((__c), (__msg), "error"))) 262 # define __fortify_clang_warning_only_if_bos0_lt(n, buf, complaint) \ 263 __attribute__ ((__diagnose_if__ \ 264 (__fortify_clang_bosn_args (__bos0, n, buf, 1, complaint)))) 265 # define __fortify_clang_warning_only_if_bos0_lt2(n, buf, div, complaint) \ 266 __attribute__ ((__diagnose_if__ \ 267 (__fortify_clang_bosn_args (__bos0, n, buf, div, complaint)))) 268 # define __fortify_clang_warning_only_if_bos_lt(n, buf, complaint) \ 269 __attribute__ ((__diagnose_if__ \ 270 (__fortify_clang_bosn_args (__bos, n, buf, 1, complaint)))) 271 # define __fortify_clang_warning_only_if_bos_lt2(n, buf, div, complaint) \ 272 __attribute__ ((__diagnose_if__ \ 273 (__fortify_clang_bosn_args (__bos, n, buf, div, complaint)))) 274 275 # define __fortify_clang_prefer_this_overload \ 276 __attribute__ ((enable_if (1, ""))) 277 # define __fortify_clang_unavailable(__msg) \ 278 __attribute__ ((unavailable(__msg))) 279 280 # if __USE_FORTIFY_LEVEL == 3 281 # define __fortify_clang_overload_arg(__type, __attr, __name) \ 282 __type __attr const __fortify_clang_pass_dynamic_object_size __name 283 # define __fortify_clang_overload_arg0(__type, __attr, __name) \ 284 __type __attr const __fortify_clang_pass_dynamic_object_size0 __name 285 # else 286 # define __fortify_clang_overload_arg(__type, __attr, __name) \ 287 __type __attr const __fortify_clang_pass_object_size __name 288 # define __fortify_clang_overload_arg0(__type, __attr, __name) \ 289 __type __attr const __fortify_clang_pass_object_size0 __name 290 # endif 291 292 # define __fortify_clang_mul_may_overflow(size, n) \ 293 ((size | n) >= (((size_t)1) << (8 * sizeof (size_t) / 2))) 294 295 # define __fortify_clang_size_too_small(__bos, __dest, __len) \ 296 (__bos (__dest) != (size_t) -1 && __bos (__dest) < __len) 297 # define __fortify_clang_warn_if_src_too_large(__dest, __src) \ 298 __fortify_clang_warning (__fortify_clang_size_too_small (__glibc_objsize, \ 299 __dest, \ 300 __builtin_strlen (__src) + 1), \ 301 "destination buffer will always be overflown by source") 302 # define __fortify_clang_warn_if_dest_too_small(__dest, __len) \ 303 __fortify_clang_warning (__fortify_clang_size_too_small (__glibc_objsize, \ 304 __dest, \ 305 __len), \ 306 "function called with bigger length than the destination buffer") 307 # define __fortify_clang_warn_if_dest_too_small0(__dest, __len) \ 308 __fortify_clang_warning (__fortify_clang_size_too_small (__glibc_objsize0, \ 309 __dest, \ 310 __len), \ 311 "function called with bigger length than the destination buffer") 312 #else 313 # define __fortify_use_clang 0 314 # define __fortify_clang_warning(__c, __msg) 315 # define __fortify_clang_warning_only_if_bos0_lt(__n, __buf, __complaint) 316 # define __fortify_clang_warning_only_if_bos0_lt2(__n, __buf, __div, complaint) 317 # define __fortify_clang_warning_only_if_bos_lt(__n, __buf, __complaint) 318 # define __fortify_clang_warning_only_if_bos_lt2(__n, __buf, div, __complaint) 319 # define __fortify_clang_overload_arg(__type, __attr, __name) \ 320 __type __attr __name 321 # define __fortify_clang_overload_arg0(__type, __attr, __name) \ 322 __fortify_clang_overload_arg (__type, __attr, __name) 323 # define __fortify_clang_warn_if_src_too_large(__dest, __src) 324 # define __fortify_clang_warn_if_dest_too_small(__dest, __len) 325 # define __fortify_clang_warn_if_dest_too_small0(__dest, __len) 326 #endif 327 328 329 /* Fortify function f. __f_alias, __f_chk and __f_chk_warn must be 330 declared. */ 331 332 #if !__fortify_use_clang 333 # define __glibc_fortify(f, __l, __s, __osz, ...) \ 334 (__glibc_safe_or_unknown_len (__l, __s, __osz) \ 335 ? __ ## f ## _alias (__VA_ARGS__) \ 336 : (__glibc_unsafe_len (__l, __s, __osz) \ 337 ? __ ## f ## _chk_warn (__VA_ARGS__, __osz) \ 338 : __ ## f ## _chk (__VA_ARGS__, __osz))) 339 #else 340 # define __glibc_fortify(f, __l, __s, __osz, ...) \ 341 (__osz == (__SIZE_TYPE__) -1) \ 342 ? __ ## f ## _alias (__VA_ARGS__) \ 343 : __ ## f ## _chk (__VA_ARGS__, __osz) 344 #endif 345 346 /* Fortify function f, where object size argument passed to f is the number of 347 elements and not total size. */ 348 349 #if !__fortify_use_clang 350 # define __glibc_fortify_n(f, __l, __s, __osz, ...) \ 351 (__glibc_safe_or_unknown_len (__l, __s, __osz) \ 352 ? __ ## f ## _alias (__VA_ARGS__) \ 353 : (__glibc_unsafe_len (__l, __s, __osz) \ 354 ? __ ## f ## _chk_warn (__VA_ARGS__, (__osz) / (__s)) \ 355 : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s)))) 356 # else 357 # define __glibc_fortify_n(f, __l, __s, __osz, ...) \ 358 (__osz == (__SIZE_TYPE__) -1) \ 359 ? __ ## f ## _alias (__VA_ARGS__) \ 360 : __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s)) 361 #endif 362 363 #endif /* __USE_FORTIFY_LEVEL > 0 */ 364 365 #if __GNUC_PREREQ (4,3) 366 # define __warnattr(msg) __attribute__((__warning__ (msg))) 367 # define __errordecl(name, msg) \ 368 extern void name (void) __attribute__((__error__ (msg))) 369 #else 370 # define __warnattr(msg) 371 # define __errordecl(name, msg) extern void name (void) 372 #endif 373 374 /* Support for flexible arrays. 375 Headers that should use flexible arrays only if they're "real" 376 (e.g. only if they won't affect sizeof()) should test 377 #if __glibc_c99_flexarr_available. */ 378 #if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L && !defined __HP_cc 379 # define __flexarr [] 380 # define __glibc_c99_flexarr_available 1 381 #elif __GNUC_PREREQ (2,97) || defined __clang__ 382 /* GCC 2.97 and clang support C99 flexible array members as an extension, 383 even when in C89 mode or compiling C++ (any version). */ 384 # define __flexarr [] 385 # define __glibc_c99_flexarr_available 1 386 #elif defined __GNUC__ 387 /* Pre-2.97 GCC did not support C99 flexible arrays but did have 388 an equivalent extension with slightly different notation. */ 389 # define __flexarr [0] 390 # define __glibc_c99_flexarr_available 1 391 #else 392 /* Some other non-C99 compiler. Approximate with [1]. */ 393 # define __flexarr [1] 394 # define __glibc_c99_flexarr_available 0 395 #endif 396 397 398 /* __asm__ ("xyz") is used throughout the headers to rename functions 399 at the assembly language level. This is wrapped by the __REDIRECT 400 macro, in order to support compilers that can do this some other 401 way. When compilers don't support asm-names at all, we have to do 402 preprocessor tricks instead (which don't have exactly the right 403 semantics, but it's the best we can do). 404 405 Example: 406 int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */ 407 408 #if (defined __GNUC__ && __GNUC__ >= 2) || (__clang_major__ >= 4) 409 410 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias)) 411 # ifdef __cplusplus 412 # define __REDIRECT_NTH(name, proto, alias) \ 413 name proto __THROW __asm__ (__ASMNAME (#alias)) 414 # define __REDIRECT_NTHNL(name, proto, alias) \ 415 name proto __THROWNL __asm__ (__ASMNAME (#alias)) 416 # else 417 # define __REDIRECT_NTH(name, proto, alias) \ 418 name proto __asm__ (__ASMNAME (#alias)) __THROW 419 # define __REDIRECT_NTHNL(name, proto, alias) \ 420 name proto __asm__ (__ASMNAME (#alias)) __THROWNL 421 # endif 422 # define __ASMNAME(cname) __ASMNAME2 (__USER_LABEL_PREFIX__, cname) 423 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname 424 425 #ifndef __REDIRECT_FORTIFY 426 #define __REDIRECT_FORTIFY __REDIRECT 427 #endif 428 429 #ifndef __REDIRECT_FORTIFY_NTH 430 #define __REDIRECT_FORTIFY_NTH __REDIRECT_NTH 431 #endif 432 433 /* 434 #elif __SOME_OTHER_COMPILER__ 435 436 # define __REDIRECT(name, proto, alias) name proto; \ 437 _Pragma("let " #name " = " #alias) 438 */ 439 #endif 440 441 /* GCC and clang have various useful declarations that can be made with 442 the '__attribute__' syntax. All of the ways we use this do fine if 443 they are omitted for compilers that don't understand it. */ 444 #if !(defined __GNUC__ || defined __clang__) 445 # define __attribute__(xyz) /* Ignore */ 446 #endif 447 448 /* At some point during the gcc 2.96 development the `malloc' attribute 449 for functions was introduced. We don't want to use it unconditionally 450 (although this would be possible) since it generates warnings. */ 451 #if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__malloc__) 452 # define __attribute_malloc__ __attribute__ ((__malloc__)) 453 #else 454 # define __attribute_malloc__ /* Ignore */ 455 #endif 456 457 /* Tell the compiler which arguments to an allocation function 458 indicate the size of the allocation. */ 459 #if __GNUC_PREREQ (4, 3) 460 # define __attribute_alloc_size__(params) \ 461 __attribute__ ((__alloc_size__ params)) 462 #else 463 # define __attribute_alloc_size__(params) /* Ignore. */ 464 #endif 465 466 /* Tell the compiler which argument to an allocation function 467 indicates the alignment of the allocation. */ 468 #if __GNUC_PREREQ (4, 9) || __glibc_has_attribute (__alloc_align__) 469 # define __attribute_alloc_align__(param) \ 470 __attribute__ ((__alloc_align__ param)) 471 #else 472 # define __attribute_alloc_align__(param) /* Ignore. */ 473 #endif 474 475 /* At some point during the gcc 2.96 development the `pure' attribute 476 for functions was introduced. We don't want to use it unconditionally 477 (although this would be possible) since it generates warnings. */ 478 #if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__pure__) 479 # define __attribute_pure__ __attribute__ ((__pure__)) 480 #else 481 # define __attribute_pure__ /* Ignore */ 482 #endif 483 484 /* This declaration tells the compiler that the value is constant. */ 485 #if __GNUC_PREREQ (2,5) || __glibc_has_attribute (__const__) 486 # define __attribute_const__ __attribute__ ((__const__)) 487 #else 488 # define __attribute_const__ /* Ignore */ 489 #endif 490 491 #if __GNUC_PREREQ (2,7) || __glibc_has_attribute (__unused__) 492 # define __attribute_maybe_unused__ __attribute__ ((__unused__)) 493 #else 494 # define __attribute_maybe_unused__ /* Ignore */ 495 #endif 496 497 /* At some point during the gcc 3.1 development the `used' attribute 498 for functions was introduced. We don't want to use it unconditionally 499 (although this would be possible) since it generates warnings. */ 500 #if __GNUC_PREREQ (3,1) || __glibc_has_attribute (__used__) 501 # define __attribute_used__ __attribute__ ((__used__)) 502 # define __attribute_noinline__ __attribute__ ((__noinline__)) 503 #else 504 # define __attribute_used__ __attribute__ ((__unused__)) 505 # define __attribute_noinline__ /* Ignore */ 506 #endif 507 508 /* Since version 3.2, gcc allows marking deprecated functions. */ 509 #if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__deprecated__) 510 # define __attribute_deprecated__ __attribute__ ((__deprecated__)) 511 #else 512 # define __attribute_deprecated__ /* Ignore */ 513 #endif 514 515 /* Since version 4.5, gcc also allows one to specify the message printed 516 when a deprecated function is used. clang claims to be gcc 4.2, but 517 may also support this feature. */ 518 #if __GNUC_PREREQ (4,5) \ 519 || __glibc_has_extension (__attribute_deprecated_with_message__) 520 # define __attribute_deprecated_msg__(msg) \ 521 __attribute__ ((__deprecated__ (msg))) 522 #else 523 # define __attribute_deprecated_msg__(msg) __attribute_deprecated__ 524 #endif 525 526 /* At some point during the gcc 2.8 development the `format_arg' attribute 527 for functions was introduced. We don't want to use it unconditionally 528 (although this would be possible) since it generates warnings. 529 If several `format_arg' attributes are given for the same function, in 530 gcc-3.0 and older, all but the last one are ignored. In newer gccs, 531 all designated arguments are considered. */ 532 #if __GNUC_PREREQ (2,8) || __glibc_has_attribute (__format_arg__) 533 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x))) 534 #else 535 # define __attribute_format_arg__(x) /* Ignore */ 536 #endif 537 538 /* At some point during the gcc 2.97 development the `strfmon' format 539 attribute for functions was introduced. We don't want to use it 540 unconditionally (although this would be possible) since it 541 generates warnings. */ 542 #if __GNUC_PREREQ (2,97) || __glibc_has_attribute (__format__) 543 # define __attribute_format_strfmon__(a,b) \ 544 __attribute__ ((__format__ (__strfmon__, a, b))) 545 #else 546 # define __attribute_format_strfmon__(a,b) /* Ignore */ 547 #endif 548 549 /* The nonnull function attribute marks pointer parameters that 550 must not be NULL. This has the name __nonnull in glibc, 551 and __attribute_nonnull__ in files shared with Gnulib to avoid 552 collision with a different __nonnull in DragonFlyBSD 5.9. */ 553 #ifndef __attribute_nonnull__ 554 # if __GNUC_PREREQ (3,3) || __glibc_has_attribute (__nonnull__) 555 # define __attribute_nonnull__(params) __attribute__ ((__nonnull__ params)) 556 # else 557 # define __attribute_nonnull__(params) 558 # endif 559 #endif 560 #ifndef __nonnull 561 # define __nonnull(params) __attribute_nonnull__ (params) 562 #endif 563 564 /* The returns_nonnull function attribute marks the return type of the function 565 as always being non-null. */ 566 #ifndef __returns_nonnull 567 # if __GNUC_PREREQ (4, 9) || __glibc_has_attribute (__returns_nonnull__) 568 # define __returns_nonnull __attribute__ ((__returns_nonnull__)) 569 # else 570 # define __returns_nonnull 571 # endif 572 #endif 573 574 /* If fortification mode, we warn about unused results of certain 575 function calls which can lead to problems. */ 576 #if __GNUC_PREREQ (3,4) || __glibc_has_attribute (__warn_unused_result__) 577 # define __attribute_warn_unused_result__ \ 578 __attribute__ ((__warn_unused_result__)) 579 # if defined __USE_FORTIFY_LEVEL && __USE_FORTIFY_LEVEL > 0 580 # define __wur __attribute_warn_unused_result__ 581 # endif 582 #else 583 # define __attribute_warn_unused_result__ /* empty */ 584 #endif 585 #ifndef __wur 586 # define __wur /* Ignore */ 587 #endif 588 589 /* Forces a function to be always inlined. */ 590 #if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__always_inline__) 591 /* The Linux kernel defines __always_inline in stddef.h (283d7573), and 592 it conflicts with this definition. Therefore undefine it first to 593 allow either header to be included first. */ 594 # undef __always_inline 595 # define __always_inline __inline __attribute__ ((__always_inline__)) 596 #else 597 # undef __always_inline 598 # define __always_inline __inline 599 #endif 600 601 /* Associate error messages with the source location of the call site rather 602 than with the source location inside the function. */ 603 #if __GNUC_PREREQ (4,3) || __glibc_has_attribute (__artificial__) 604 # define __attribute_artificial__ __attribute__ ((__artificial__)) 605 #else 606 # define __attribute_artificial__ /* Ignore */ 607 #endif 608 609 /* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99 610 inline semantics, unless -fgnu89-inline is used. Using __GNUC_STDC_INLINE__ 611 or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions 612 older than 4.3 may define these macros and still not guarantee GNU inlining 613 semantics. 614 615 clang++ identifies itself as gcc-4.2, but has support for GNU inlining 616 semantics, that can be checked for by using the __GNUC_STDC_INLINE_ and 617 __GNUC_GNU_INLINE__ macro definitions. */ 618 #if (!defined __cplusplus || __GNUC_PREREQ (4,3) \ 619 || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \ 620 || defined __GNUC_GNU_INLINE__))) 621 # if defined __GNUC_STDC_INLINE__ || defined __cplusplus 622 # define __extern_inline extern __inline __attribute__ ((__gnu_inline__)) 623 # define __extern_always_inline \ 624 extern __always_inline __attribute__ ((__gnu_inline__)) 625 # else 626 # define __extern_inline extern __inline 627 # define __extern_always_inline extern __always_inline 628 # endif 629 #endif 630 631 #ifdef __extern_always_inline 632 # define __fortify_function __extern_always_inline __attribute_artificial__ 633 #endif 634 635 /* GCC 4.3 and above allow passing all anonymous arguments of an 636 __extern_always_inline function to some other vararg function. */ 637 #if __GNUC_PREREQ (4,3) 638 # define __va_arg_pack() __builtin_va_arg_pack () 639 # define __va_arg_pack_len() __builtin_va_arg_pack_len () 640 #endif 641 642 /* It is possible to compile containing GCC extensions even if GCC is 643 run in pedantic mode if the uses are carefully marked using the 644 `__extension__' keyword. But this is not generally available before 645 version 2.8. */ 646 #if !(__GNUC_PREREQ (2,8) || defined __clang__) 647 # define __extension__ /* Ignore */ 648 #endif 649 650 /* __restrict is known in EGCS 1.2 and above, and in clang. 651 It works also in C++ mode (outside of arrays), but only when spelled 652 as '__restrict', not 'restrict'. */ 653 #if !(__GNUC_PREREQ (2,92) || __clang_major__ >= 3) 654 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L 655 # define __restrict restrict 656 # else 657 # define __restrict /* Ignore */ 658 # endif 659 #endif 660 661 /* ISO C99 also allows to declare arrays as non-overlapping. The syntax is 662 array_name[restrict] 663 GCC 3.1 and clang support this. 664 This syntax is not usable in C++ mode. */ 665 #if (__GNUC_PREREQ (3,1) || __clang_major__ >= 3) && !defined __cplusplus 666 # define __restrict_arr __restrict 667 #else 668 # ifdef __GNUC__ 669 # define __restrict_arr /* Not supported in old GCC. */ 670 # else 671 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L 672 # define __restrict_arr restrict 673 # else 674 /* Some other non-C99 compiler. */ 675 # define __restrict_arr /* Not supported. */ 676 # endif 677 # endif 678 #endif 679 680 #if (__GNUC__ >= 3) || __glibc_has_builtin (__builtin_expect) 681 # define __glibc_unlikely(cond) __builtin_expect ((cond), 0) 682 # define __glibc_likely(cond) __builtin_expect ((cond), 1) 683 #else 684 # define __glibc_unlikely(cond) (cond) 685 # define __glibc_likely(cond) (cond) 686 #endif 687 688 #if (!defined _Noreturn \ 689 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \ 690 && !(__GNUC_PREREQ (4,7) \ 691 || (3 < __clang_major__ + (5 <= __clang_minor__)))) 692 # if __GNUC_PREREQ (2,8) 693 # define _Noreturn __attribute__ ((__noreturn__)) 694 # else 695 # define _Noreturn 696 # endif 697 #endif 698 699 #if __GNUC_PREREQ (8, 0) 700 /* Describes a char array whose address can safely be passed as the first 701 argument to strncpy and strncat, as the char array is not necessarily 702 a NUL-terminated string. */ 703 # define __attribute_nonstring__ __attribute__ ((__nonstring__)) 704 #else 705 # define __attribute_nonstring__ 706 #endif 707 708 /* Undefine (also defined in libc-symbols.h). */ 709 #undef __attribute_copy__ 710 #if __GNUC_PREREQ (9, 0) 711 /* Copies attributes from the declaration or type referenced by 712 the argument. */ 713 # define __attribute_copy__(arg) __attribute__ ((__copy__ (arg))) 714 #else 715 # define __attribute_copy__(arg) 716 #endif 717 718 #if (!defined _Static_assert && !defined __cplusplus \ 719 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \ 720 && (!(__GNUC_PREREQ (4, 6) || __clang_major__ >= 4) \ 721 || defined __STRICT_ANSI__)) 722 # define _Static_assert(expr, diagnostic) \ 723 extern int (*__Static_assert_function (void)) \ 724 [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })] 725 #endif 726 727 /* Gnulib avoids including these, as they don't work on non-glibc or 728 older glibc platforms. */ 729 #ifndef __GNULIB_CDEFS 730 # include <bits/wordsize.h> 731 # include <bits/long-double.h> 732 #endif 733 734 #if __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1 735 # ifdef __REDIRECT 736 737 /* Alias name defined automatically. */ 738 # define __LDBL_REDIR(name, proto) ... unused__ldbl_redir 739 # define __LDBL_REDIR_DECL(name) \ 740 extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128")); 741 # define __REDIRECT_LDBL(name, proto, alias) \ 742 name proto __asm (__ASMNAME ("__" #alias "ieee128")) 743 744 /* Alias name defined automatically, with leading underscores. */ 745 # define __LDBL_REDIR2_DECL(name) \ 746 extern __typeof (__##name) __##name \ 747 __asm (__ASMNAME ("__" #name "ieee128")); 748 749 /* Alias name defined manually. */ 750 # define __LDBL_REDIR1(name, proto, alias) ... unused__ldbl_redir1 751 # define __LDBL_REDIR1_DECL(name, alias) \ 752 extern __typeof (name) name __asm (__ASMNAME (#alias)); 753 754 # define __LDBL_REDIR1_NTH(name, proto, alias) \ 755 __REDIRECT_NTH (name, proto, alias) 756 # define __REDIRECT_NTH_LDBL(name, proto, alias) \ 757 __LDBL_REDIR1_NTH (name, proto, __##alias##ieee128) 758 759 /* Unused. */ 760 # define __LDBL_REDIR_NTH(name, proto) ... unused__ldbl_redir_nth 761 762 # else 763 _Static_assert (0, "IEEE 128-bits long double requires redirection on this platform"); 764 # endif 765 #elif defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH 766 # define __LDBL_COMPAT 1 767 # ifdef __REDIRECT 768 # define __LDBL_REDIR1(name, proto, alias) __REDIRECT (name, proto, alias) 769 # define __LDBL_REDIR(name, proto) \ 770 __LDBL_REDIR1 (name, proto, __nldbl_##name) 771 # define __LDBL_REDIR1_NTH(name, proto, alias) __REDIRECT_NTH (name, proto, alias) 772 # define __LDBL_REDIR_NTH(name, proto) \ 773 __LDBL_REDIR1_NTH (name, proto, __nldbl_##name) 774 # define __LDBL_REDIR2_DECL(name) \ 775 extern __typeof (__##name) __##name __asm (__ASMNAME ("__nldbl___" #name)); 776 # define __LDBL_REDIR1_DECL(name, alias) \ 777 extern __typeof (name) name __asm (__ASMNAME (#alias)); 778 # define __LDBL_REDIR_DECL(name) \ 779 extern __typeof (name) name __asm (__ASMNAME ("__nldbl_" #name)); 780 # define __REDIRECT_LDBL(name, proto, alias) \ 781 __LDBL_REDIR1 (name, proto, __nldbl_##alias) 782 # define __REDIRECT_NTH_LDBL(name, proto, alias) \ 783 __LDBL_REDIR1_NTH (name, proto, __nldbl_##alias) 784 # endif 785 #endif 786 #if (!defined __LDBL_COMPAT && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0) \ 787 || !defined __REDIRECT 788 # define __LDBL_REDIR1(name, proto, alias) name proto 789 # define __LDBL_REDIR(name, proto) name proto 790 # define __LDBL_REDIR1_NTH(name, proto, alias) name proto __THROW 791 # define __LDBL_REDIR_NTH(name, proto) name proto __THROW 792 # define __LDBL_REDIR2_DECL(name) 793 # define __LDBL_REDIR_DECL(name) 794 # ifdef __REDIRECT 795 # define __REDIRECT_LDBL(name, proto, alias) __REDIRECT (name, proto, alias) 796 # define __REDIRECT_NTH_LDBL(name, proto, alias) \ 797 __REDIRECT_NTH (name, proto, alias) 798 # endif 799 #endif 800 801 /* __glibc_macro_warning (MESSAGE) issues warning MESSAGE. This is 802 intended for use in preprocessor macros. 803 804 Note: MESSAGE must be a _single_ string; concatenation of string 805 literals is not supported. */ 806 #if __GNUC_PREREQ (4,8) || __glibc_clang_prereq (3,5) 807 # define __glibc_macro_warning1(message) _Pragma (#message) 808 # define __glibc_macro_warning(message) \ 809 __glibc_macro_warning1 (GCC warning message) 810 #else 811 # define __glibc_macro_warning(msg) 812 #endif 813 814 /* Generic selection (ISO C11) is a C-only feature, available in GCC 815 since version 4.9. Previous versions do not provide generic 816 selection, even though they might set __STDC_VERSION__ to 201112L, 817 when in -std=c11 mode. Thus, we must check for !defined __GNUC__ 818 when testing __STDC_VERSION__ for generic selection support. 819 On the other hand, Clang also defines __GNUC__, so a clang-specific 820 check is required to enable the use of generic selection. */ 821 #if !defined __cplusplus \ 822 && (__GNUC_PREREQ (4, 9) \ 823 || __glibc_has_extension (c_generic_selections) \ 824 || (!defined __GNUC__ && defined __STDC_VERSION__ \ 825 && __STDC_VERSION__ >= 201112L)) 826 # define __HAVE_GENERIC_SELECTION 1 827 #else 828 # define __HAVE_GENERIC_SELECTION 0 829 #endif 830 831 #if __GNUC_PREREQ (10, 0) 832 /* Designates a 1-based positional argument ref-index of pointer type 833 that can be used to access size-index elements of the pointed-to 834 array according to access mode, or at least one element when 835 size-index is not provided: 836 access (access-mode, <ref-index> [, <size-index>]) */ 837 # define __attr_access(x) __attribute__ ((__access__ x)) 838 /* For _FORTIFY_SOURCE == 3 we use __builtin_dynamic_object_size, which may 839 use the access attribute to get object sizes from function definition 840 arguments, so we can't use them on functions we fortify. Drop the access 841 attribute for such functions. */ 842 # if __USE_FORTIFY_LEVEL == 3 843 # define __fortified_attr_access(a, o, s) 844 # else 845 # define __fortified_attr_access(a, o, s) __attr_access ((a, o, s)) 846 # endif 847 # if __GNUC_PREREQ (11, 0) 848 # define __attr_access_none(argno) __attribute__ ((__access__ (__none__, argno))) 849 # else 850 # define __attr_access_none(argno) 851 # endif 852 #else 853 # define __fortified_attr_access(a, o, s) 854 # define __attr_access(x) 855 # define __attr_access_none(argno) 856 #endif 857 858 #if __GNUC_PREREQ (11, 0) 859 /* Designates dealloc as a function to call to deallocate objects 860 allocated by the declared function. */ 861 # define __attr_dealloc(dealloc, argno) \ 862 __attribute__ ((__malloc__ (dealloc, argno))) 863 # define __attr_dealloc_free __attr_dealloc (__builtin_free, 1) 864 #else 865 # define __attr_dealloc(dealloc, argno) 866 # define __attr_dealloc_free 867 #endif 868 869 /* Specify that a function such as setjmp or vfork may return 870 twice. */ 871 #if __GNUC_PREREQ (4, 1) 872 # define __attribute_returns_twice__ __attribute__ ((__returns_twice__)) 873 #else 874 # define __attribute_returns_twice__ /* Ignore. */ 875 #endif 876 877 /* Mark struct types as aliasable. Restricted to compilers that 878 support forward declarations of structs in the presence of the 879 attribute. */ 880 #if __GNUC_PREREQ (7, 1) || defined __clang__ 881 # define __attribute_struct_may_alias__ __attribute__ ((__may_alias__)) 882 #else 883 # define __attribute_struct_may_alias__ 884 #endif 885 886 #endif /* sys/cdefs.h */