include/features.h

   1 /* Copyright (C) 1991,1992,1993,1995-2006,2007 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #ifndef _FEATURES_H
  20 #define _FEATURES_H     1
  21
  22 /* These are defined by the user (or the compiler)
  23    to specify the desired environment:
  24
  25    __STRICT_ANSI__      ISO Standard C.
  26    _ISOC99_SOURCE       Extensions to ISO C89 from ISO C99.
  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    _XOPEN_SOURCE        Includes POSIX and XPG things.  Set to 500 if
  33                         Single Unix conformance is wanted, to 600 for the
  34                         upcoming sixth revision.
  35    _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
  36    _LARGEFILE_SOURCE    Some more functions for correct standard I/O.
  37    _LARGEFILE64_SOURCE  Additional functionality from LFS for large files.
  38    _FILE_OFFSET_BITS=N  Select default filesystem interface.
  39    _BSD_SOURCE          ISO C, POSIX, and 4.3BSD things.
  40    _SVID_SOURCE         ISO C, POSIX, and SVID things.
  41    _ATFILE_SOURCE       Additional *at interfaces.
  42    _GNU_SOURCE          All of the above, plus GNU extensions.
  43    _REENTRANT           Select additionally reentrant object.
  44    _THREAD_SAFE         Same as _REENTRANT, often used by other systems.
  45    _FORTIFY_SOURCE      If set to numeric value > 0 additional security
  46                         measures are defined, according to level.
  47
  48    The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  49    If none of these are defined, the default is to have _SVID_SOURCE,
  50    _BSD_SOURCE, and _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
  51    200112L.  If more than one of these are defined, they accumulate.
  52    For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  53    together give you ISO C, 1003.1, and 1003.2, but nothing else.
  54
  55    These are defined by this file and are used by the
  56    header files to decide what to declare or define:
  57
  58    __USE_ISOC99         Define ISO C99 things.
  59    __USE_POSIX          Define IEEE Std 1003.1 things.
  60    __USE_POSIX2         Define IEEE Std 1003.2 things.
  61    __USE_POSIX199309    Define IEEE Std 1003.1, and .1b things.
  62    __USE_POSIX199506    Define IEEE Std 1003.1, .1b, .1c and .1i things.
  63    __USE_XOPEN          Define XPG things.
  64    __USE_XOPEN_EXTENDED Define X/Open Unix things.
  65    __USE_UNIX98         Define Single Unix V2 things.
  66    __USE_XOPEN2K        Define XPG6 things.
  67    __USE_LARGEFILE      Define correct standard I/O things.
  68    __USE_LARGEFILE64    Define LFS things with separate names.
  69    __USE_FILE_OFFSET64  Define 64bit interface as default.
  70    __USE_BSD            Define 4.3BSD things.
  71    __USE_SVID           Define SVID things.
  72    __USE_MISC           Define things common to BSD and System V Unix.
  73    __USE_ATFILE         Define *at interfaces and AT_* constants for them.
  74    __USE_GNU            Define GNU extensions.
  75    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  76    __USE_FORTIFY_LEVEL  Additional security measures used, according to level.
  77    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  78
  79    The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
  80    defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
  81    only for compatibility.  All new code should use the other symbols
  82    to test for features.
  83
  84    All macros listed above as possibly being defined by this file are
  85    explicitly undefined if they are not explicitly defined.
  86    Feature-test macros that are not defined by the user or compiler
  87    but are implied by the other feature-test macros defined (or by the
  88    lack of any definitions) are defined by the file.  */
  89
  90
  91 /* Undefine everything, so we get a clean slate.  */
  92 #undef  __USE_ISOC99
  93 #undef  __USE_POSIX
  94 #undef  __USE_POSIX2
  95 #undef  __USE_POSIX199309
  96 #undef  __USE_POSIX199506
  97 #undef  __USE_XOPEN
  98 #undef  __USE_XOPEN_EXTENDED
  99 #undef  __USE_UNIX98
 100 #undef  __USE_XOPEN2K
 101 #undef  __USE_LARGEFILE
 102 #undef  __USE_LARGEFILE64
 103 #undef  __USE_FILE_OFFSET64
 104 #undef  __USE_BSD
 105 #undef  __USE_SVID
 106 #undef  __USE_MISC
 107 #undef  __USE_ATFILE
 108 #undef  __USE_GNU
 109 #undef  __USE_REENTRANT
 110 #undef  __USE_FORTIFY_LEVEL
 111 #undef  __FAVOR_BSD
 112 #undef  __KERNEL_STRICT_NAMES
 113
 114 /* Suppress kernel-name space pollution unless user expressedly asks
 115    for it.  */
 116 #ifndef _LOOSE_KERNEL_NAMES
 117 # define __KERNEL_STRICT_NAMES
 118 #endif
 119
 120 /* Always use ISO C things.  */
 121 #define __USE_ANSI      1
 122
 123 /* Convenience macros to test the versions of glibc and gcc.
 124    Use them like this:
 125    #if __GNUC_PREREQ (2,8)
 126    ... code requiring gcc 2.8 or later ...
 127    #endif
 128    Note - they won't work for gcc1 or glibc1, since the _MINOR macros
 129    were not defined then.  */
 130 #if defined __GNUC__ && defined __GNUC_MINOR__
 131 # define __GNUC_PREREQ(maj, min) \
 132         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
 133 #else
 134 # define __GNUC_PREREQ(maj, min) 0
 135 #endif
 136
 137
 138 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
 139 #if defined _BSD_SOURCE && \
 140     !(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
 141       defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
 142       defined _GNU_SOURCE || defined _SVID_SOURCE)
 143 # define __FAVOR_BSD    1
 144 #endif
 145
 146 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
 147 #ifdef _GNU_SOURCE
 148 # undef  _ISOC99_SOURCE
 149 # define _ISOC99_SOURCE 1
 150 # undef  _POSIX_SOURCE
 151 # define _POSIX_SOURCE  1
 152 # undef  _POSIX_C_SOURCE
 153 # define _POSIX_C_SOURCE        200112L
 154 # undef  _XOPEN_SOURCE
 155 # define _XOPEN_SOURCE  600
 156 # undef  _XOPEN_SOURCE_EXTENDED
 157 # define _XOPEN_SOURCE_EXTENDED 1
 158 # undef  _LARGEFILE64_SOURCE
 159 # define _LARGEFILE64_SOURCE    1
 160 # undef  _BSD_SOURCE
 161 # define _BSD_SOURCE    1
 162 # undef  _SVID_SOURCE
 163 # define _SVID_SOURCE   1
 164 # undef  _ATFILE_SOURCE
 165 # define _ATFILE_SOURCE 1
 166 #endif
 167
 168 /* If nothing (other than _GNU_SOURCE) is defined,
 169    define _BSD_SOURCE and _SVID_SOURCE.  */
 170 #if (!defined __STRICT_ANSI__ && !defined _ISOC99_SOURCE && \
 171      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \
 172      !defined _XOPEN_SOURCE && !defined _XOPEN_SOURCE_EXTENDED && \
 173      !defined _BSD_SOURCE && !defined _SVID_SOURCE)
 174 # define _BSD_SOURCE    1
 175 # define _SVID_SOURCE   1
 176 #endif
 177
 178 /* This is to enable the ISO C99 extension.  Also recognize the old macro
 179    which was used prior to the standard acceptance.  This macro will
 180    eventually go away and the features enabled by default once the ISO C99
 181    standard is widely adopted.  */
 182 #if (defined _ISOC99_SOURCE || defined _ISOC9X_SOURCE \
 183      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
 184 # define __USE_ISOC99   1
 185 #endif
 186
 187 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2
 188    (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined).  */
 189 #if ((!defined __STRICT_ANSI__ || (_XOPEN_SOURCE - 0) >= 500) && \
 190      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
 191 # define _POSIX_SOURCE  1
 192 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
 193 #  define _POSIX_C_SOURCE       2
 194 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
 195 #  define _POSIX_C_SOURCE       199506L
 196 # else
 197 #  define _POSIX_C_SOURCE       200112L
 198 # endif
 199 #endif
 200
 201 #if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
 202 # define __USE_POSIX    1
 203 #endif
 204
 205 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
 206 # define __USE_POSIX2   1
 207 #endif
 208
 209 #if (_POSIX_C_SOURCE - 0) >= 199309L
 210 # define __USE_POSIX199309      1
 211 #endif
 212
 213 #if (_POSIX_C_SOURCE - 0) >= 199506L
 214 # define __USE_POSIX199506      1
 215 #endif
 216
 217 #if (_POSIX_C_SOURCE - 0) >= 200112L
 218 # define __USE_XOPEN2K          1
 219 #endif
 220
 221 #ifdef  _XOPEN_SOURCE
 222 # define __USE_XOPEN    1
 223 # if (_XOPEN_SOURCE - 0) >= 500
 224 #  define __USE_XOPEN_EXTENDED  1
 225 #  define __USE_UNIX98  1
 226 #  undef _LARGEFILE_SOURCE
 227 #  define _LARGEFILE_SOURCE     1
 228 #  if (_XOPEN_SOURCE - 0) >= 600
 229 #   define __USE_XOPEN2K        1
 230 #   undef __USE_ISOC99
 231 #   define __USE_ISOC99         1
 232 #  endif
 233 # else
 234 #  ifdef _XOPEN_SOURCE_EXTENDED
 235 #   define __USE_XOPEN_EXTENDED 1
 236 #  endif
 237 # endif
 238 #endif
 239
 240 #ifdef _LARGEFILE_SOURCE
 241 # define __USE_LARGEFILE        1
 242 #endif
 243
 244 #ifdef _LARGEFILE64_SOURCE
 245 # define __USE_LARGEFILE64      1
 246 #endif
 247
 248 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
 249 # define __USE_FILE_OFFSET64    1
 250 #endif
 251
 252 #if defined _BSD_SOURCE || defined _SVID_SOURCE
 253 # define __USE_MISC     1
 254 #endif
 255
 256 #ifdef  _BSD_SOURCE
 257 # define __USE_BSD      1
 258 #endif
 259
 260 #ifdef  _SVID_SOURCE
 261 # define __USE_SVID     1
 262 #endif
 263
 264 #ifdef  _ATFILE_SOURCE
 265 # define __USE_ATFILE   1
 266 #endif
 267
 268 #ifdef  _GNU_SOURCE
 269 # define __USE_GNU      1
 270 #endif
 271
 272 #if defined _REENTRANT || defined _THREAD_SAFE
 273 # define __USE_REENTRANT        1
 274 #endif
 275
 276 #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 \
 277     && __GNUC_PREREQ (4, 1) && defined __OPTIMIZE__ && __OPTIMIZE__ > 0
 278 # if _FORTIFY_SOURCE > 1
 279 #  define __USE_FORTIFY_LEVEL 2
 280 # else
 281 #  define __USE_FORTIFY_LEVEL 1
 282 # endif
 283 #else
 284 # define __USE_FORTIFY_LEVEL 0
 285 #endif
 286
 287 /* We do support the IEC 559 math functionality, real and complex.  */
 288 #define __STDC_IEC_559__                1
 289 #define __STDC_IEC_559_COMPLEX__        1
 290
 291 /* wchar_t uses ISO 10646-1 (2nd ed., published 2000-09-15) / Unicode 3.1.  */
 292 #define __STDC_ISO_10646__              200009L
 293
 294 /* This macro indicates that the installed library is the GNU C Library.
 295    For historic reasons the value now is 6 and this will stay from now
 296    on.  The use of this variable is deprecated.  Use __GLIBC__ and
 297    __GLIBC_MINOR__ now (see below) when you want to test for a specific
 298    GNU C library version and use the values in <gnu/lib-names.h> to get
 299    the sonames of the shared libraries.  */
 300 #undef  __GNU_LIBRARY__
 301 #define __GNU_LIBRARY__ 6
 302
 303 /* Major and minor version number of the GNU C library package.  Use
 304    these macros to test for features in specific releases.  */
 305 #define __GLIBC__       2
 306 #define __GLIBC_MINOR__ 6
 307
 308 #define __GLIBC_PREREQ(maj, min) \
 309         ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
 310
 311 /* Decide whether a compiler supports the long long datatypes.  */
 312 #if defined __GNUC__ \
 313     || (defined __PGI && defined __i386__ ) \
 314     || (defined __INTEL_COMPILER && (defined __i386__ || defined __ia64__)) \
 315     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
 316 # define __GLIBC_HAVE_LONG_LONG 1
 317 #endif
 318
 319 /* This is here only because every header file already includes this one.  */
 320 #ifndef __ASSEMBLER__
 321 # ifndef _SYS_CDEFS_H
 322 #  include <sys/cdefs.h>
 323 # endif
 324
 325 /* If we don't have __REDIRECT, prototypes will be missing if
 326    __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
 327 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
 328 #  define __USE_LARGEFILE       1
 329 #  define __USE_LARGEFILE64     1
 330 # endif
 331
 332 #endif  /* !ASSEMBLER */
 333
 334 /* Decide whether we can define 'extern inline' functions in headers.  */
 335 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
 336     && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__
 337 # define __USE_EXTERN_INLINES   1
 338 #endif
 339
 340
 341 /* This is here only because every header file already includes this one.
 342    Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
 343    <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
 344    that will always return failure (and set errno to ENOSYS).  */
 345 #include <gnu/stubs.h>
 346
 347
 348 #endif  /* features.h  */