include/features.h

   1 /* Copyright (C) 1991-2013 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    <http://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    _POSIX_SOURCE        IEEE Std 1003.1.
  28    _POSIX_C_SOURCE      If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
  29                         if >=199309L, add IEEE Std 1003.1b-1993;
  30                         if >=199506L, add IEEE Std 1003.1c-1995;
  31                         if >=200112L, all of IEEE 1003.1-2004
  32                         if >=200809L, all of IEEE 1003.1-2008
  33    _XOPEN_SOURCE        Includes POSIX and XPG things.  Set to 500 if
  34                         Single Unix conformance is wanted, to 600 for the
  35                         sixth revision, to 700 for the seventh revision.
  36    _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
  37    _LARGEFILE_SOURCE    Some more functions for correct standard I/O.
  38    _LARGEFILE64_SOURCE  Additional functionality from LFS for large files.
  39    _FILE_OFFSET_BITS=N  Select default filesystem interface.
  40    _BSD_SOURCE          ISO C, POSIX, and 4.3BSD things.
  41    _SVID_SOURCE         ISO C, POSIX, and SVID things.
  42    _ATFILE_SOURCE       Additional *at interfaces.
  43    _GNU_SOURCE          All of the above, plus GNU extensions.
  44    _REENTRANT           Select additionally reentrant object.
  45    _THREAD_SAFE         Same as _REENTRANT, often used by other systems.
  46    _FORTIFY_SOURCE      If set to numeric value > 0 additional security
  47                         measures are defined, according to level.
  48
  49    The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  50    If none of these are defined, the default is to have _SVID_SOURCE,
  51    _BSD_SOURCE, and _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
  52    200112L.  If more than one of these are defined, they accumulate.
  53    For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  54    together give you ISO C, 1003.1, and 1003.2, but nothing else.
  55
  56    These are defined by this file and are used by the
  57    header files to decide what to declare or define:
  58
  59    __USE_ISOC11         Define ISO C11 things.
  60    __USE_ISOC99         Define ISO C99 things.
  61    __USE_ISOC95         Define ISO C90 AMD1 (C95) things.
  62    __USE_POSIX          Define IEEE Std 1003.1 things.
  63    __USE_POSIX2         Define IEEE Std 1003.2 things.
  64    __USE_POSIX199309    Define IEEE Std 1003.1, and .1b things.
  65    __USE_POSIX199506    Define IEEE Std 1003.1, .1b, .1c and .1i things.
  66    __USE_XOPEN          Define XPG things.
  67    __USE_XOPEN_EXTENDED Define X/Open Unix things.
  68    __USE_UNIX98         Define Single Unix V2 things.
  69    __USE_XOPEN2K        Define XPG6 things.
  70    __USE_XOPEN2KXSI     Define XPG6 XSI things.
  71    __USE_XOPEN2K8       Define XPG7 things.
  72    __USE_XOPEN2K8XSI    Define XPG7 XSI things.
  73    __USE_LARGEFILE      Define correct standard I/O things.
  74    __USE_LARGEFILE64    Define LFS things with separate names.
  75    __USE_FILE_OFFSET64  Define 64bit interface as default.
  76    __USE_BSD            Define 4.3BSD things.
  77    __USE_SVID           Define SVID things.
  78    __USE_MISC           Define things common to BSD and System V Unix.
  79    __USE_ATFILE         Define *at interfaces and AT_* constants for them.
  80    __USE_GNU            Define GNU extensions.
  81    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  82    __USE_FORTIFY_LEVEL  Additional security measures used, according to level.
  83    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  84
  85    The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
  86    defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
  87    only for compatibility.  All new code should use the other symbols
  88    to test for features.
  89
  90    All macros listed above as possibly being defined by this file are
  91    explicitly undefined if they are not explicitly defined.
  92    Feature-test macros that are not defined by the user or compiler
  93    but are implied by the other feature-test macros defined (or by the
  94    lack of any definitions) are defined by the file.  */
  95
  96
  97 /* Undefine everything, so we get a clean slate.  */
  98 #undef  __USE_ISOC11
  99 #undef  __USE_ISOC99
 100 #undef  __USE_ISOC95
 101 #undef  __USE_ISOCXX11
 102 #undef  __USE_POSIX
 103 #undef  __USE_POSIX2
 104 #undef  __USE_POSIX199309
 105 #undef  __USE_POSIX199506
 106 #undef  __USE_XOPEN
 107 #undef  __USE_XOPEN_EXTENDED
 108 #undef  __USE_UNIX98
 109 #undef  __USE_XOPEN2K
 110 #undef  __USE_XOPEN2KXSI
 111 #undef  __USE_XOPEN2K8
 112 #undef  __USE_XOPEN2K8XSI
 113 #undef  __USE_LARGEFILE
 114 #undef  __USE_LARGEFILE64
 115 #undef  __USE_FILE_OFFSET64
 116 #undef  __USE_BSD
 117 #undef  __USE_SVID
 118 #undef  __USE_MISC
 119 #undef  __USE_ATFILE
 120 #undef  __USE_GNU
 121 #undef  __USE_REENTRANT
 122 #undef  __USE_FORTIFY_LEVEL
 123 #undef  __FAVOR_BSD
 124 #undef  __KERNEL_STRICT_NAMES
 125
 126 /* Suppress kernel-name space pollution unless user expressedly asks
 127    for it.  */
 128 #ifndef _LOOSE_KERNEL_NAMES
 129 # define __KERNEL_STRICT_NAMES
 130 #endif
 131
 132 /* Convenience macros to test the versions of glibc and gcc.
 133    Use them like this:
 134    #if __GNUC_PREREQ (2,8)
 135    ... code requiring gcc 2.8 or later ...
 136    #endif
 137    Note - they won't work for gcc1 or glibc1, since the _MINOR macros
 138    were not defined then.  */
 139 #if defined __GNUC__ && defined __GNUC_MINOR__
 140 # define __GNUC_PREREQ(maj, min) \
 141         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
 142 #else
 143 # define __GNUC_PREREQ(maj, min) 0
 144 #endif
 145
 146
 147 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
 148 #if defined _BSD_SOURCE && \
 149     !(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
 150       defined _XOPEN_SOURCE || defined _GNU_SOURCE || defined _SVID_SOURCE)
 151 # define __FAVOR_BSD    1
 152 #endif
 153
 154 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
 155 #ifdef _GNU_SOURCE
 156 # undef  _ISOC95_SOURCE
 157 # define _ISOC95_SOURCE 1
 158 # undef  _ISOC99_SOURCE
 159 # define _ISOC99_SOURCE 1
 160 # undef  _ISOC11_SOURCE
 161 # define _ISOC11_SOURCE 1
 162 # undef  _POSIX_SOURCE
 163 # define _POSIX_SOURCE  1
 164 # undef  _POSIX_C_SOURCE
 165 # define _POSIX_C_SOURCE        200809L
 166 # undef  _XOPEN_SOURCE
 167 # define _XOPEN_SOURCE  700
 168 # undef  _XOPEN_SOURCE_EXTENDED
 169 # define _XOPEN_SOURCE_EXTENDED 1
 170 # undef  _LARGEFILE64_SOURCE
 171 # define _LARGEFILE64_SOURCE    1
 172 # undef  _BSD_SOURCE
 173 # define _BSD_SOURCE    1
 174 # undef  _SVID_SOURCE
 175 # define _SVID_SOURCE   1
 176 # undef  _ATFILE_SOURCE
 177 # define _ATFILE_SOURCE 1
 178 #endif
 179
 180 /* If nothing (other than _GNU_SOURCE) is defined,
 181    define _BSD_SOURCE and _SVID_SOURCE.  */
 182 #if (!defined __STRICT_ANSI__ && !defined _ISOC99_SOURCE && \
 183      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \
 184      !defined _XOPEN_SOURCE && !defined _BSD_SOURCE && !defined _SVID_SOURCE)
 185 # define _BSD_SOURCE    1
 186 # define _SVID_SOURCE   1
 187 #endif
 188
 189 /* This is to enable the ISO C11 extension.  */
 190 #if (defined _ISOC11_SOURCE \
 191      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
 192 # define __USE_ISOC11   1
 193 #endif
 194
 195 /* This is to enable the ISO C99 extension.  */
 196 #if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
 197      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
 198 # define __USE_ISOC99   1
 199 #endif
 200
 201 /* This is to enable the ISO C90 Amendment 1:1995 extension.  */
 202 #if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
 203      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L))
 204 # define __USE_ISOC95   1
 205 #endif
 206
 207 /* This is to enable compatibility for ISO C++11.
 208
 209    So far g++ does not provide a macro.  Check the temporary macro for
 210    now, too.  */
 211 #if ((defined __cplusplus && __cplusplus >= 201103L)                          \
 212      || defined __GXX_EXPERIMENTAL_CXX0X__)
 213 # define __USE_ISOCXX11 1
 214 #endif
 215
 216 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2
 217    (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined).  */
 218 #if ((!defined __STRICT_ANSI__ || (_XOPEN_SOURCE - 0) >= 500) && \
 219      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
 220 # define _POSIX_SOURCE  1
 221 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
 222 #  define _POSIX_C_SOURCE       2
 223 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
 224 #  define _POSIX_C_SOURCE       199506L
 225 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700
 226 #  define _POSIX_C_SOURCE       200112L
 227 # else
 228 #  define _POSIX_C_SOURCE       200809L
 229 # endif
 230 # define __USE_POSIX_IMPLICITLY 1
 231 #endif
 232
 233 #if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
 234 # define __USE_POSIX    1
 235 #endif
 236
 237 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
 238 # define __USE_POSIX2   1
 239 #endif
 240
 241 #if (_POSIX_C_SOURCE - 0) >= 199309L
 242 # define __USE_POSIX199309      1
 243 #endif
 244
 245 #if (_POSIX_C_SOURCE - 0) >= 199506L
 246 # define __USE_POSIX199506      1
 247 #endif
 248
 249 #if (_POSIX_C_SOURCE - 0) >= 200112L
 250 # define __USE_XOPEN2K          1
 251 # undef __USE_ISOC95
 252 # define __USE_ISOC95           1
 253 # undef __USE_ISOC99
 254 # define __USE_ISOC99           1
 255 #endif
 256
 257 #if (_POSIX_C_SOURCE - 0) >= 200809L
 258 # define __USE_XOPEN2K8         1
 259 # undef  _ATFILE_SOURCE
 260 # define _ATFILE_SOURCE 1
 261 #endif
 262
 263 #ifdef  _XOPEN_SOURCE
 264 # define __USE_XOPEN    1
 265 # if (_XOPEN_SOURCE - 0) >= 500
 266 #  define __USE_XOPEN_EXTENDED  1
 267 #  define __USE_UNIX98  1
 268 #  undef _LARGEFILE_SOURCE
 269 #  define _LARGEFILE_SOURCE     1
 270 #  if (_XOPEN_SOURCE - 0) >= 600
 271 #   if (_XOPEN_SOURCE - 0) >= 700
 272 #    define __USE_XOPEN2K8      1
 273 #    define __USE_XOPEN2K8XSI   1
 274 #   endif
 275 #   define __USE_XOPEN2K        1
 276 #   define __USE_XOPEN2KXSI     1
 277 #   undef __USE_ISOC95
 278 #   define __USE_ISOC95         1
 279 #   undef __USE_ISOC99
 280 #   define __USE_ISOC99         1
 281 #  endif
 282 # else
 283 #  ifdef _XOPEN_SOURCE_EXTENDED
 284 #   define __USE_XOPEN_EXTENDED 1
 285 #  endif
 286 # endif
 287 #endif
 288
 289 #ifdef _LARGEFILE_SOURCE
 290 # define __USE_LARGEFILE        1
 291 #endif
 292
 293 #ifdef _LARGEFILE64_SOURCE
 294 # define __USE_LARGEFILE64      1
 295 #endif
 296
 297 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
 298 # define __USE_FILE_OFFSET64    1
 299 #endif
 300
 301 #if defined _BSD_SOURCE || defined _SVID_SOURCE
 302 # define __USE_MISC     1
 303 #endif
 304
 305 #ifdef  _BSD_SOURCE
 306 # define __USE_BSD      1
 307 #endif
 308
 309 #ifdef  _SVID_SOURCE
 310 # define __USE_SVID     1
 311 #endif
 312
 313 #ifdef  _ATFILE_SOURCE
 314 # define __USE_ATFILE   1
 315 #endif
 316
 317 #ifdef  _GNU_SOURCE
 318 # define __USE_GNU      1
 319 #endif
 320
 321 #if defined _REENTRANT || defined _THREAD_SAFE
 322 # define __USE_REENTRANT        1
 323 #endif
 324
 325 #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
 326 # if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
 327 #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
 328 # elif !__GNUC_PREREQ (4, 1)
 329 #  warning _FORTIFY_SOURCE requires GCC 4.1 or later
 330 # elif _FORTIFY_SOURCE > 1
 331 #  define __USE_FORTIFY_LEVEL 2
 332 # else
 333 #  define __USE_FORTIFY_LEVEL 1
 334 # endif
 335 #endif
 336 #ifndef __USE_FORTIFY_LEVEL
 337 # define __USE_FORTIFY_LEVEL 0
 338 #endif
 339
 340 /* Get definitions of __STDC_* predefined macros, if the compiler has
 341    not preincluded this header automatically.  */
 342 #include <stdc-predef.h>
 343
 344 /* This macro indicates that the installed library is the GNU C Library.
 345    For historic reasons the value now is 6 and this will stay from now
 346    on.  The use of this variable is deprecated.  Use __GLIBC__ and
 347    __GLIBC_MINOR__ now (see below) when you want to test for a specific
 348    GNU C library version and use the values in <gnu/lib-names.h> to get
 349    the sonames of the shared libraries.  */
 350 #undef  __GNU_LIBRARY__
 351 #define __GNU_LIBRARY__ 6
 352
 353 /* Major and minor version number of the GNU C library package.  Use
 354    these macros to test for features in specific releases.  */
 355 #define __GLIBC__       2
 356 #define __GLIBC_MINOR__ 18
 357
 358 #define __GLIBC_PREREQ(maj, min) \
 359         ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
 360
 361 /* This is here only because every header file already includes this one.  */
 362 #ifndef __ASSEMBLER__
 363 # ifndef _SYS_CDEFS_H
 364 #  include <sys/cdefs.h>
 365 # endif
 366
 367 /* If we don't have __REDIRECT, prototypes will be missing if
 368    __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
 369 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
 370 #  define __USE_LARGEFILE       1
 371 #  define __USE_LARGEFILE64     1
 372 # endif
 373
 374 #endif  /* !ASSEMBLER */
 375
 376 /* Decide whether we can define 'extern inline' functions in headers.  */
 377 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
 378     && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
 379     && defined __extern_inline
 380 # define __USE_EXTERN_INLINES   1
 381 #endif
 382
 383
 384 /* This is here only because every header file already includes this one.
 385    Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
 386    <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
 387    that will always return failure (and set errno to ENOSYS).  */
 388 #include <gnu/stubs.h>
 389
 390
 391 #endif  /* features.h  */