include/features.h

   1 /* Copyright (C) 1991,1992,1993,1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006
   2         Free Software Foundation, Inc.
   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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _FEATURES_H
  21 #define _FEATURES_H     1
  22
  23 /* These are defined by the user (or the compiler)
  24    to specify the desired environment:
  25
  26    __STRICT_ANSI__      ISO Standard C.
  27    _ISOC99_SOURCE       Extensions to ISO C89 from ISO C99.
  28    _POSIX_SOURCE        IEEE Std 1003.1.
  29    _POSIX_C_SOURCE      If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
  30                         if >=199309L, add IEEE Std 1003.1b-1993;
  31                         if >=199506L, add IEEE Std 1003.1c-1995;
  32                         if >=200112L, all of IEEE 1003.1-2004
  33    _XOPEN_SOURCE        Includes POSIX and XPG things.  Set to 500 if
  34                         Single Unix conformance is wanted, to 600 for the
  35                         upcoming sixth 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    199506L.  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_ISOC99         Define ISO C99 things.
  60    __USE_POSIX          Define IEEE Std 1003.1 things.
  61    __USE_POSIX2         Define IEEE Std 1003.2 things.
  62    __USE_POSIX199309    Define IEEE Std 1003.1, and .1b things.
  63    __USE_POSIX199506    Define IEEE Std 1003.1, .1b, .1c and .1i things.
  64    __USE_XOPEN          Define XPG things.
  65    __USE_XOPEN_EXTENDED Define X/Open Unix things.
  66    __USE_UNIX98         Define Single Unix V2 things.
  67    __USE_XOPEN2K        Define XPG6 things.
  68    __USE_LARGEFILE      Define correct standard I/O things.
  69    __USE_LARGEFILE64    Define LFS things with separate names.
  70    __USE_FILE_OFFSET64  Define 64bit interface as default.
  71    __USE_BSD            Define 4.3BSD things.
  72    __USE_SVID           Define SVID things.
  73    __USE_MISC           Define things common to BSD and System V Unix.
  74    __USE_ATFILE         Define *at interfaces and AT_* constants for them.
  75    __USE_GNU            Define GNU extensions.
  76    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  77    __USE_FORTIFY_LEVEL  Additional security measures used, according to level.
  78    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  79
  80    The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
  81    defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
  82    only for compatibility.  All new code should use the other symbols
  83    to test for features.
  84
  85    All macros listed above as possibly being defined by this file are
  86    explicitly undefined if they are not explicitly defined.
  87    Feature-test macros that are not defined by the user or compiler
  88    but are implied by the other feature-test macros defined (or by the
  89    lack of any definitions) are defined by the file.  */
  90
  91
  92 /* Undefine everything, so we get a clean slate.  */
  93 #undef  __USE_ISOC99
  94 #undef  __USE_POSIX
  95 #undef  __USE_POSIX2
  96 #undef  __USE_POSIX199309
  97 #undef  __USE_POSIX199506
  98 #undef  __USE_XOPEN
  99 #undef  __USE_XOPEN_EXTENDED
 100 #undef  __USE_UNIX98
 101 #undef  __USE_XOPEN2K
 102 #undef  __USE_LARGEFILE
 103 #undef  __USE_LARGEFILE64
 104 #undef  __USE_FILE_OFFSET64
 105 #undef  __USE_BSD
 106 #undef  __USE_SVID
 107 #undef  __USE_MISC
 108 #undef  __USE_ATFILE
 109 #undef  __USE_GNU
 110 #undef  __USE_REENTRANT
 111 #undef  __USE_FORTIFY_LEVEL
 112 #undef  __FAVOR_BSD
 113 #undef  __KERNEL_STRICT_NAMES
 114
 115 /* Suppress kernel-name space pollution unless user expressedly asks
 116    for it.  */
 117 #ifndef _LOOSE_KERNEL_NAMES
 118 # define __KERNEL_STRICT_NAMES
 119 #endif
 120
 121 /* Always use ISO C things.  */
 122 #define __USE_ANSI      1
 123
 124 /* Convenience macros to test the versions of glibc and gcc.
 125    Use them like this:
 126    #if __GNUC_PREREQ (2,8)
 127    ... code requiring gcc 2.8 or later ...
 128    #endif
 129    Note - they won't work for gcc1 or glibc1, since the _MINOR macros
 130    were not defined then.  */
 131 #if defined __GNUC__ && defined __GNUC_MINOR__
 132 # define __GNUC_PREREQ(maj, min) \
 133         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
 134 #else
 135 # define __GNUC_PREREQ(maj, min) 0
 136 #endif
 137
 138
 139 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
 140 #if defined _BSD_SOURCE && \
 141     !(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
 142       defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
 143       defined _GNU_SOURCE || defined _SVID_SOURCE)
 144 # define __FAVOR_BSD    1
 145 #endif
 146
 147 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
 148 #ifdef _GNU_SOURCE
 149 # undef  _ISOC99_SOURCE
 150 # define _ISOC99_SOURCE 1
 151 # undef  _POSIX_SOURCE
 152 # define _POSIX_SOURCE  1
 153 # undef  _POSIX_C_SOURCE
 154 # define _POSIX_C_SOURCE        200112L
 155 # undef  _XOPEN_SOURCE
 156 # define _XOPEN_SOURCE  600
 157 # undef  _XOPEN_SOURCE_EXTENDED
 158 # define _XOPEN_SOURCE_EXTENDED 1
 159 # undef  _LARGEFILE64_SOURCE
 160 # define _LARGEFILE64_SOURCE    1
 161 # undef  _BSD_SOURCE
 162 # define _BSD_SOURCE    1
 163 # undef  _SVID_SOURCE
 164 # define _SVID_SOURCE   1
 165 # undef  _ATFILE_SOURCE
 166 # define _ATFILE_SOURCE 1
 167 #endif
 168
 169 /* If nothing (other than _GNU_SOURCE) is defined,
 170    define _BSD_SOURCE and _SVID_SOURCE.  */
 171 #if (!defined __STRICT_ANSI__ && !defined _ISOC99_SOURCE && \
 172      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \
 173      !defined _XOPEN_SOURCE && !defined _XOPEN_SOURCE_EXTENDED && \
 174      !defined _BSD_SOURCE && !defined _SVID_SOURCE)
 175 # define _BSD_SOURCE    1
 176 # define _SVID_SOURCE   1
 177 #endif
 178
 179 /* This is to enable the ISO C99 extension.  Also recognize the old macro
 180    which was used prior to the standard acceptance.  This macro will
 181    eventually go away and the features enabled by default once the ISO C99
 182    standard is widely adopted.  */
 183 #if (defined _ISOC99_SOURCE || defined _ISOC9X_SOURCE \
 184      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
 185 # define __USE_ISOC99   1
 186 #endif
 187
 188 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2
 189    (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined).  */
 190 #if ((!defined __STRICT_ANSI__ || (_XOPEN_SOURCE - 0) >= 500) && \
 191      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
 192 # define _POSIX_SOURCE  1
 193 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
 194 #  define _POSIX_C_SOURCE       2
 195 # elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
 196 #  define _POSIX_C_SOURCE       199506L
 197 # else
 198 #  define _POSIX_C_SOURCE       200112L
 199 # endif
 200 #endif
 201
 202 #if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
 203 # define __USE_POSIX    1
 204 #endif
 205
 206 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
 207 # define __USE_POSIX2   1
 208 #endif
 209
 210 #if (_POSIX_C_SOURCE - 0) >= 199309L
 211 # define __USE_POSIX199309      1
 212 #endif
 213
 214 #if (_POSIX_C_SOURCE - 0) >= 199506L
 215 # define __USE_POSIX199506      1
 216 #endif
 217
 218 #if (_POSIX_C_SOURCE - 0) >= 200112L
 219 # define __USE_XOPEN2K          1
 220 #endif
 221
 222 #ifdef  _XOPEN_SOURCE
 223 # define __USE_XOPEN    1
 224 # if (_XOPEN_SOURCE - 0) >= 500
 225 #  define __USE_XOPEN_EXTENDED  1
 226 #  define __USE_UNIX98  1
 227 #  undef _LARGEFILE_SOURCE
 228 #  define _LARGEFILE_SOURCE     1
 229 #  if (_XOPEN_SOURCE - 0) >= 600
 230 #   define __USE_XOPEN2K        1
 231 #   undef __USE_ISOC99
 232 #   define __USE_ISOC99         1
 233 #  endif
 234 # else
 235 #  ifdef _XOPEN_SOURCE_EXTENDED
 236 #   define __USE_XOPEN_EXTENDED 1
 237 #  endif
 238 # endif
 239 #endif
 240
 241 #ifdef _LARGEFILE_SOURCE
 242 # define __USE_LARGEFILE        1
 243 #endif
 244
 245 #ifdef _LARGEFILE64_SOURCE
 246 # define __USE_LARGEFILE64      1
 247 #endif
 248
 249 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
 250 # define __USE_FILE_OFFSET64    1
 251 #endif
 252
 253 #if defined _BSD_SOURCE || defined _SVID_SOURCE
 254 # define __USE_MISC     1
 255 #endif
 256
 257 #ifdef  _BSD_SOURCE
 258 # define __USE_BSD      1
 259 #endif
 260
 261 #ifdef  _SVID_SOURCE
 262 # define __USE_SVID     1
 263 #endif
 264
 265 #ifdef  _ATFILE_SOURCE
 266 # define __USE_ATFILE   1
 267 #endif
 268
 269 #ifdef  _GNU_SOURCE
 270 # define __USE_GNU      1
 271 #endif
 272
 273 #if defined _REENTRANT || defined _THREAD_SAFE
 274 # define __USE_REENTRANT        1
 275 #endif
 276
 277 #if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 \
 278     && __GNUC_PREREQ (4, 1) && defined __OPTIMIZE__ && __OPTIMIZE__ > 0
 279 # if _FORTIFY_SOURCE > 1
 280 #  define __USE_FORTIFY_LEVEL 2
 281 # else
 282 #  define __USE_FORTIFY_LEVEL 1
 283 # endif
 284 #else
 285 # define __USE_FORTIFY_LEVEL 0
 286 #endif
 287
 288 /* We do support the IEC 559 math functionality, real and complex.  */
 289 #define __STDC_IEC_559__                1
 290 #define __STDC_IEC_559_COMPLEX__        1
 291
 292 /* wchar_t uses ISO 10646-1 (2nd ed., published 2000-09-15) / Unicode 3.1.  */
 293 #define __STDC_ISO_10646__              200009L
 294
 295 /* This macro indicates that the installed library is the GNU C Library.
 296    For historic reasons the value now is 6 and this will stay from now
 297    on.  The use of this variable is deprecated.  Use __GLIBC__ and
 298    __GLIBC_MINOR__ now (see below) when you want to test for a specific
 299    GNU C library version and use the values in <gnu/lib-names.h> to get
 300    the sonames of the shared libraries.  */
 301 #undef  __GNU_LIBRARY__
 302 #define __GNU_LIBRARY__ 6
 303
 304 /* Major and minor version number of the GNU C library package.  Use
 305    these macros to test for features in specific releases.  */
 306 #define __GLIBC__       2
 307 #define __GLIBC_MINOR__ 4
 308
 309 #define __GLIBC_PREREQ(maj, min) \
 310         ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
 311
 312 /* Decide whether a compiler supports the long long datatypes.  */
 313 #if defined __GNUC__ \
 314     || (defined __PGI && defined __i386__ ) \
 315     || (defined __INTEL_COMPILER && (defined __i386__ || defined __ia64__)) \
 316     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
 317 # define __GLIBC_HAVE_LONG_LONG 1
 318 #endif
 319
 320 /* This is here only because every header file already includes this one.  */
 321 #ifndef __ASSEMBLER__
 322 # ifndef _SYS_CDEFS_H
 323 #  include <sys/cdefs.h>
 324 # endif
 325
 326 /* If we don't have __REDIRECT, prototypes will be missing if
 327    __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
 328 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
 329 #  define __USE_LARGEFILE       1
 330 #  define __USE_LARGEFILE64     1
 331 # endif
 332
 333 #endif  /* !ASSEMBLER */
 334
 335 /* Decide whether we can define 'extern inline' functions in headers.  */
 336 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
 337     && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__
 338 # define __USE_EXTERN_INLINES   1
 339 #endif
 340
 341
 342 /* This is here only because every header file already includes this one.
 343    Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
 344    <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
 345    that will always return failure (and set errno to ENOSYS).  */
 346 #include <gnu/stubs.h>
 347
 348
 349 #endif  /* features.h  */