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The C and C++ Include Header Files
/usr/include/features.h
$ cat -n /usr/include/features.h 1 /* Copyright (C) 1991-2024 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 _FEATURES_H 19 #define _FEATURES_H 1 20 21 /* These are defined by the user (or the compiler) 22 to specify the desired environment: 23 24 __STRICT_ANSI__ ISO Standard C. 25 _ISOC99_SOURCE Extensions to ISO C89 from ISO C99. 26 _ISOC11_SOURCE Extensions to ISO C99 from ISO C11. 27 _ISOC2X_SOURCE Extensions to ISO C99 from ISO C2X. 28 __STDC_WANT_LIB_EXT2__ 29 Extensions to ISO C99 from TR 27431-2:2010. 30 __STDC_WANT_IEC_60559_BFP_EXT__ 31 Extensions to ISO C11 from TS 18661-1:2014. 32 __STDC_WANT_IEC_60559_FUNCS_EXT__ 33 Extensions to ISO C11 from TS 18661-4:2015. 34 __STDC_WANT_IEC_60559_TYPES_EXT__ 35 Extensions to ISO C11 from TS 18661-3:2015. 36 __STDC_WANT_IEC_60559_EXT__ 37 ISO C2X interfaces defined only in Annex F. 38 39 _POSIX_SOURCE IEEE Std 1003.1. 40 _POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2; 41 if >=199309L, add IEEE Std 1003.1b-1993; 42 if >=199506L, add IEEE Std 1003.1c-1995; 43 if >=200112L, all of IEEE 1003.1-2004 44 if >=200809L, all of IEEE 1003.1-2008 45 _XOPEN_SOURCE Includes POSIX and XPG things. Set to 500 if 46 Single Unix conformance is wanted, to 600 for the 47 sixth revision, to 700 for the seventh revision. 48 _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions. 49 _LARGEFILE_SOURCE Some more functions for correct standard I/O. 50 _LARGEFILE64_SOURCE Additional functionality from LFS for large files. 51 _FILE_OFFSET_BITS=N Select default filesystem interface. 52 _ATFILE_SOURCE Additional *at interfaces. 53 _DYNAMIC_STACK_SIZE_SOURCE Select correct (but non compile-time constant) 54 MINSIGSTKSZ, SIGSTKSZ and PTHREAD_STACK_MIN. 55 _GNU_SOURCE All of the above, plus GNU extensions. 56 _DEFAULT_SOURCE The default set of features (taking precedence over 57 __STRICT_ANSI__). 58 59 _FORTIFY_SOURCE Add security hardening to many library functions. 60 Set to 1, 2 or 3; 3 performs stricter checks than 2, which 61 performs stricter checks than 1. 62 63 _REENTRANT, _THREAD_SAFE 64 Obsolete; equivalent to _POSIX_C_SOURCE=199506L. 65 66 The `-ansi' switch to the GNU C compiler, and standards conformance 67 options such as `-std=c99', define __STRICT_ANSI__. If none of 68 these are defined, or if _DEFAULT_SOURCE is defined, the default is 69 to have _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to 70 200809L, as well as enabling miscellaneous functions from BSD and 71 SVID. If more than one of these are defined, they accumulate. For 72 example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE together 73 give you ISO C, 1003.1, and 1003.2, but nothing else. 74 75 These are defined by this file and are used by the 76 header files to decide what to declare or define: 77 78 __GLIBC_USE (F) Define things from feature set F. This is defined 79 to 1 or 0; the subsequent macros are either defined 80 or undefined, and those tests should be moved to 81 __GLIBC_USE. 82 __USE_ISOC11 Define ISO C11 things. 83 __USE_ISOC99 Define ISO C99 things. 84 __USE_ISOC95 Define ISO C90 AMD1 (C95) things. 85 __USE_ISOCXX11 Define ISO C++11 things. 86 __USE_POSIX Define IEEE Std 1003.1 things. 87 __USE_POSIX2 Define IEEE Std 1003.2 things. 88 __USE_POSIX199309 Define IEEE Std 1003.1, and .1b things. 89 __USE_POSIX199506 Define IEEE Std 1003.1, .1b, .1c and .1i things. 90 __USE_XOPEN Define XPG things. 91 __USE_XOPEN_EXTENDED Define X/Open Unix things. 92 __USE_UNIX98 Define Single Unix V2 things. 93 __USE_XOPEN2K Define XPG6 things. 94 __USE_XOPEN2KXSI Define XPG6 XSI things. 95 __USE_XOPEN2K8 Define XPG7 things. 96 __USE_XOPEN2K8XSI Define XPG7 XSI things. 97 __USE_LARGEFILE Define correct standard I/O things. 98 __USE_LARGEFILE64 Define LFS things with separate names. 99 __USE_FILE_OFFSET64 Define 64bit interface as default. 100 __USE_MISC Define things from 4.3BSD or System V Unix. 101 __USE_ATFILE Define *at interfaces and AT_* constants for them. 102 __USE_DYNAMIC_STACK_SIZE Define correct (but non compile-time constant) 103 MINSIGSTKSZ, SIGSTKSZ and PTHREAD_STACK_MIN. 104 __USE_GNU Define GNU extensions. 105 __USE_FORTIFY_LEVEL Additional security measures used, according to level. 106 107 The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are 108 defined by this file unconditionally. `__GNU_LIBRARY__' is provided 109 only for compatibility. All new code should use the other symbols 110 to test for features. 111 112 All macros listed above as possibly being defined by this file are 113 explicitly undefined if they are not explicitly defined. 114 Feature-test macros that are not defined by the user or compiler 115 but are implied by the other feature-test macros defined (or by the 116 lack of any definitions) are defined by the file. 117 118 ISO C feature test macros depend on the definition of the macro 119 when an affected header is included, not when the first system 120 header is included, and so they are handled in 121 <bits/libc-header-start.h>, which does not have a multiple include 122 guard. Feature test macros that can be handled from the first 123 system header included are handled here. */ 124 125 126 /* Undefine everything, so we get a clean slate. */ 127 #undef __USE_ISOC11 128 #undef __USE_ISOC99 129 #undef __USE_ISOC95 130 #undef __USE_ISOCXX11 131 #undef __USE_POSIX 132 #undef __USE_POSIX2 133 #undef __USE_POSIX199309 134 #undef __USE_POSIX199506 135 #undef __USE_XOPEN 136 #undef __USE_XOPEN_EXTENDED 137 #undef __USE_UNIX98 138 #undef __USE_XOPEN2K 139 #undef __USE_XOPEN2KXSI 140 #undef __USE_XOPEN2K8 141 #undef __USE_XOPEN2K8XSI 142 #undef __USE_LARGEFILE 143 #undef __USE_LARGEFILE64 144 #undef __USE_FILE_OFFSET64 145 #undef __USE_MISC 146 #undef __USE_ATFILE 147 #undef __USE_DYNAMIC_STACK_SIZE 148 #undef __USE_GNU 149 #undef __USE_FORTIFY_LEVEL 150 #undef __KERNEL_STRICT_NAMES 151 #undef __GLIBC_USE_ISOC2X 152 #undef __GLIBC_USE_DEPRECATED_GETS 153 #undef __GLIBC_USE_DEPRECATED_SCANF 154 #undef __GLIBC_USE_C2X_STRTOL 155 156 /* Suppress kernel-name space pollution unless user expressedly asks 157 for it. */ 158 #ifndef _LOOSE_KERNEL_NAMES 159 # define __KERNEL_STRICT_NAMES 160 #endif 161 162 /* Convenience macro to test the version of gcc. 163 Use like this: 164 #if __GNUC_PREREQ (2,8) 165 ... code requiring gcc 2.8 or later ... 166 #endif 167 Note: only works for GCC 2.0 and later, because __GNUC_MINOR__ was 168 added in 2.0. */ 169 #if defined __GNUC__ && defined __GNUC_MINOR__ 170 # define __GNUC_PREREQ(maj, min) \ 171 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) 172 #else 173 # define __GNUC_PREREQ(maj, min) 0 174 #endif 175 176 /* Similarly for clang. Features added to GCC after version 4.2 may 177 or may not also be available in clang, and clang's definitions of 178 __GNUC(_MINOR)__ are fixed at 4 and 2 respectively. Not all such 179 features can be queried via __has_extension/__has_feature. */ 180 #if defined __clang_major__ && defined __clang_minor__ 181 # define __glibc_clang_prereq(maj, min) \ 182 ((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min)) 183 #else 184 # define __glibc_clang_prereq(maj, min) 0 185 #endif 186 187 /* Whether to use feature set F. */ 188 #define __GLIBC_USE(F) __GLIBC_USE_ ## F 189 190 /* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for 191 _DEFAULT_SOURCE. If _DEFAULT_SOURCE is present we do not 192 issue a warning; the expectation is that the source is being 193 transitioned to use the new macro. */ 194 #if (defined _BSD_SOURCE || defined _SVID_SOURCE) \ 195 && !defined _DEFAULT_SOURCE 196 # warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE" 197 # undef _DEFAULT_SOURCE 198 # define _DEFAULT_SOURCE 1 199 #endif 200 201 /* If _GNU_SOURCE was defined by the user, turn on all the other features. */ 202 #ifdef _GNU_SOURCE 203 # undef _ISOC95_SOURCE 204 # define _ISOC95_SOURCE 1 205 # undef _ISOC99_SOURCE 206 # define _ISOC99_SOURCE 1 207 # undef _ISOC11_SOURCE 208 # define _ISOC11_SOURCE 1 209 # undef _ISOC2X_SOURCE 210 # define _ISOC2X_SOURCE 1 211 # undef _POSIX_SOURCE 212 # define _POSIX_SOURCE 1 213 # undef _POSIX_C_SOURCE 214 # define _POSIX_C_SOURCE 200809L 215 # undef _XOPEN_SOURCE 216 # define _XOPEN_SOURCE 700 217 # undef _XOPEN_SOURCE_EXTENDED 218 # define _XOPEN_SOURCE_EXTENDED 1 219 # undef _LARGEFILE64_SOURCE 220 # define _LARGEFILE64_SOURCE 1 221 # undef _DEFAULT_SOURCE 222 # define _DEFAULT_SOURCE 1 223 # undef _ATFILE_SOURCE 224 # define _ATFILE_SOURCE 1 225 # undef _DYNAMIC_STACK_SIZE_SOURCE 226 # define _DYNAMIC_STACK_SIZE_SOURCE 1 227 #endif 228 229 /* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined, 230 define _DEFAULT_SOURCE. */ 231 #if (defined _DEFAULT_SOURCE \ 232 || (!defined __STRICT_ANSI__ \ 233 && !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE \ 234 && !defined _ISOC2X_SOURCE \ 235 && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \ 236 && !defined _XOPEN_SOURCE)) 237 # undef _DEFAULT_SOURCE 238 # define _DEFAULT_SOURCE 1 239 #endif 240 241 /* This is to enable the ISO C2X extension. */ 242 #if (defined _ISOC2X_SOURCE \ 243 || (defined __STDC_VERSION__ && __STDC_VERSION__ > 201710L)) 244 # define __GLIBC_USE_ISOC2X 1 245 #else 246 # define __GLIBC_USE_ISOC2X 0 247 #endif 248 249 /* This is to enable the ISO C11 extension. */ 250 #if (defined _ISOC11_SOURCE || defined _ISOC2X_SOURCE \ 251 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L)) 252 # define __USE_ISOC11 1 253 #endif 254 255 /* This is to enable the ISO C99 extension. */ 256 #if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ 257 || defined _ISOC2X_SOURCE \ 258 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)) 259 # define __USE_ISOC99 1 260 #endif 261 262 /* This is to enable the ISO C90 Amendment 1:1995 extension. */ 263 #if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \ 264 || defined _ISOC2X_SOURCE \ 265 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L)) 266 # define __USE_ISOC95 1 267 #endif 268 269 #ifdef __cplusplus 270 /* This is to enable compatibility for ISO C++17. */ 271 # if __cplusplus >= 201703L 272 # define __USE_ISOC11 1 273 # endif 274 /* This is to enable compatibility for ISO C++11. 275 Check the temporary macro for now, too. */ 276 # if __cplusplus >= 201103L || defined __GXX_EXPERIMENTAL_CXX0X__ 277 # define __USE_ISOCXX11 1 278 # define __USE_ISOC99 1 279 # endif 280 #endif 281 282 /* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE 283 is defined, use POSIX.1-2008 (or another version depending on 284 _XOPEN_SOURCE). */ 285 #ifdef _DEFAULT_SOURCE 286 # if !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE 287 # define __USE_POSIX_IMPLICITLY 1 288 # endif 289 # undef _POSIX_SOURCE 290 # define _POSIX_SOURCE 1 291 # undef _POSIX_C_SOURCE 292 # define _POSIX_C_SOURCE 200809L 293 #endif 294 295 #if ((!defined __STRICT_ANSI__ \ 296 || (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500)) \ 297 && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE) 298 # define _POSIX_SOURCE 1 299 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500 300 # define _POSIX_C_SOURCE 2 301 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600 302 # define _POSIX_C_SOURCE 199506L 303 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700 304 # define _POSIX_C_SOURCE 200112L 305 # else 306 # define _POSIX_C_SOURCE 200809L 307 # endif 308 # define __USE_POSIX_IMPLICITLY 1 309 #endif 310 311 /* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be 312 defined in all multithreaded code. GNU libc has not required this 313 for many years. We now treat them as compatibility synonyms for 314 _POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with 315 comprehensive support for multithreaded code. Using them never 316 lowers the selected level of POSIX conformance, only raises it. */ 317 #if ((!defined _POSIX_C_SOURCE || (_POSIX_C_SOURCE - 0) < 199506L) \ 318 && (defined _REENTRANT || defined _THREAD_SAFE)) 319 # define _POSIX_SOURCE 1 320 # undef _POSIX_C_SOURCE 321 # define _POSIX_C_SOURCE 199506L 322 #endif 323 324 #if (defined _POSIX_SOURCE \ 325 || (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1) \ 326 || defined _XOPEN_SOURCE) 327 # define __USE_POSIX 1 328 #endif 329 330 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE 331 # define __USE_POSIX2 1 332 #endif 333 334 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L 335 # define __USE_POSIX199309 1 336 #endif 337 338 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L 339 # define __USE_POSIX199506 1 340 #endif 341 342 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L 343 # define __USE_XOPEN2K 1 344 # undef __USE_ISOC95 345 # define __USE_ISOC95 1 346 # undef __USE_ISOC99 347 # define __USE_ISOC99 1 348 #endif 349 350 #if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L 351 # define __USE_XOPEN2K8 1 352 # undef _ATFILE_SOURCE 353 # define _ATFILE_SOURCE 1 354 #endif 355 356 #ifdef _XOPEN_SOURCE 357 # define __USE_XOPEN 1 358 # if (_XOPEN_SOURCE - 0) >= 500 359 # define __USE_XOPEN_EXTENDED 1 360 # define __USE_UNIX98 1 361 # undef _LARGEFILE_SOURCE 362 # define _LARGEFILE_SOURCE 1 363 # if (_XOPEN_SOURCE - 0) >= 600 364 # if (_XOPEN_SOURCE - 0) >= 700 365 # define __USE_XOPEN2K8 1 366 # define __USE_XOPEN2K8XSI 1 367 # endif 368 # define __USE_XOPEN2K 1 369 # define __USE_XOPEN2KXSI 1 370 # undef __USE_ISOC95 371 # define __USE_ISOC95 1 372 # undef __USE_ISOC99 373 # define __USE_ISOC99 1 374 # endif 375 # else 376 # ifdef _XOPEN_SOURCE_EXTENDED 377 # define __USE_XOPEN_EXTENDED 1 378 # endif 379 # endif 380 #endif 381 382 #ifdef _LARGEFILE_SOURCE 383 # define __USE_LARGEFILE 1 384 #endif 385 386 #ifdef _LARGEFILE64_SOURCE 387 # define __USE_LARGEFILE64 1 388 #endif 389 390 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64 391 # define __USE_FILE_OFFSET64 1 392 #endif 393 394 #include <features-time64.h> 395 396 #if defined _DEFAULT_SOURCE 397 # define __USE_MISC 1 398 #endif 399 400 #ifdef _ATFILE_SOURCE 401 # define __USE_ATFILE 1 402 #endif 403 404 #ifdef _DYNAMIC_STACK_SIZE_SOURCE 405 # define __USE_DYNAMIC_STACK_SIZE 1 406 #endif 407 408 #ifdef _GNU_SOURCE 409 # define __USE_GNU 1 410 #endif 411 412 #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 \ 413 && defined __OPTIMIZE__ && __OPTIMIZE__ > 0 414 # if !__GNUC_PREREQ (4, 1) 415 # warning _FORTIFY_SOURCE requires GCC 4.1 or later 416 # elif _FORTIFY_SOURCE > 2 && (__glibc_clang_prereq (9, 0) \ 417 || __GNUC_PREREQ (12, 0)) 418 419 # if _FORTIFY_SOURCE > 3 420 # warning _FORTIFY_SOURCE > 3 is treated like 3 on this platform 421 # endif 422 # define __USE_FORTIFY_LEVEL 3 423 # elif _FORTIFY_SOURCE > 1 424 # if _FORTIFY_SOURCE > 2 425 # warning _FORTIFY_SOURCE > 2 is treated like 2 on this platform 426 # endif 427 # define __USE_FORTIFY_LEVEL 2 428 # else 429 # define __USE_FORTIFY_LEVEL 1 430 # endif 431 #endif 432 #ifndef __USE_FORTIFY_LEVEL 433 # define __USE_FORTIFY_LEVEL 0 434 #endif 435 436 /* The function 'gets' existed in C89, but is impossible to use 437 safely. It has been removed from ISO C11 and ISO C++14. Note: for 438 compatibility with various implementations of <cstdio>, this test 439 must consider only the value of __cplusplus when compiling C++. */ 440 #if defined __cplusplus ? __cplusplus >= 201402L : defined __USE_ISOC11 441 # define __GLIBC_USE_DEPRECATED_GETS 0 442 #else 443 # define __GLIBC_USE_DEPRECATED_GETS 1 444 #endif 445 446 /* GNU formerly extended the scanf functions with modified format 447 specifiers %as, %aS, and %a[...] that allocate a buffer for the 448 input using malloc. This extension conflicts with ISO C99, which 449 defines %a as a standalone format specifier that reads a floating- 450 point number; moreover, POSIX.1-2008 provides the same feature 451 using the modifier letter 'm' instead (%ms, %mS, %m[...]). 452 453 We now follow C99 unless GNU extensions are active and the compiler 454 is specifically in C89 or C++98 mode (strict or not). For 455 instance, with GCC, -std=gnu11 will have C99-compliant scanf with 456 or without -D_GNU_SOURCE, but -std=c89 -D_GNU_SOURCE will have the 457 old extension. */ 458 #if (defined __USE_GNU \ 459 && (defined __cplusplus \ 460 ? (__cplusplus < 201103L && !defined __GXX_EXPERIMENTAL_CXX0X__) \ 461 : (!defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L))) 462 # define __GLIBC_USE_DEPRECATED_SCANF 1 463 #else 464 # define __GLIBC_USE_DEPRECATED_SCANF 0 465 #endif 466 467 /* ISO C2X added support for a 0b or 0B prefix on binary constants as 468 inputs to strtol-family functions (base 0 or 2). This macro is 469 used to condition redirection in headers to allow that redirection 470 to be disabled when building those functions, despite _GNU_SOURCE 471 being defined. */ 472 #if __GLIBC_USE (ISOC2X) 473 # define __GLIBC_USE_C2X_STRTOL 1 474 #else 475 # define __GLIBC_USE_C2X_STRTOL 0 476 #endif 477 478 /* Get definitions of __STDC_* predefined macros, if the compiler has 479 not preincluded this header automatically. */ 480 #include <stdc-predef.h> 481 482 /* This macro indicates that the installed library is the GNU C Library. 483 For historic reasons the value now is 6 and this will stay from now 484 on. The use of this variable is deprecated. Use __GLIBC__ and 485 __GLIBC_MINOR__ now (see below) when you want to test for a specific 486 GNU C library version and use the values in <gnu/lib-names.h> to get 487 the sonames of the shared libraries. */ 488 #undef __GNU_LIBRARY__ 489 #define __GNU_LIBRARY__ 6 490 491 /* Major and minor version number of the GNU C library package. Use 492 these macros to test for features in specific releases. */ 493 #define __GLIBC__ 2 494 #define __GLIBC_MINOR__ 39 495 496 #define __GLIBC_PREREQ(maj, min) \ 497 ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min)) 498 499 /* This is here only because every header file already includes this one. */ 500 #ifndef __ASSEMBLER__ 501 # ifndef _SYS_CDEFS_H 502 # include <sys/cdefs.h> 503 # endif 504 505 /* If we don't have __REDIRECT, prototypes will be missing if 506 __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */ 507 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT 508 # define __USE_LARGEFILE 1 509 # define __USE_LARGEFILE64 1 510 # endif 511 512 #endif /* !ASSEMBLER */ 513 514 /* Decide whether we can define 'extern inline' functions in headers. */ 515 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \ 516 && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \ 517 && defined __extern_inline 518 # define __USE_EXTERN_INLINES 1 519 #endif 520 521 522 /* This is here only because every header file already includes this one. 523 Get the definitions of all the appropriate `__stub_FUNCTION' symbols. 524 <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub 525 that will always return failure (and set errno to ENOSYS). */ 526 #include <gnu/stubs.h> 527 528 529 #endif /* features.h */
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