include/features.h

   1 /* Copyright (C) 1991-1993,1995-2003, 2004 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    _GNU_SOURCE          All of the above, plus GNU extensions.
  42    _REENTRANT           Select additionally reentrant object.
  43    _THREAD_SAFE         Same as _REENTRANT, often used by other systems.
  44    _FORTIFY_SOURCE      If set to numeric value > 0 additional security
  45                         measures are defined, according to level.
  46
  47    The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  48    If none of these are defined, the default is to have _SVID_SOURCE,
  49    _BSD_SOURCE, and _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
  50    199506L.  If more than one of these are defined, they accumulate.
  51    For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  52    together give you ISO C, 1003.1, and 1003.2, but nothing else.
  53
  54    These are defined by this file and are used by the
  55    header files to decide what to declare or define:
  56
  57    __USE_ISOC99         Define ISO C99 things.
  58    __USE_POSIX          Define IEEE Std 1003.1 things.
  59    __USE_POSIX2         Define IEEE Std 1003.2 things.
  60    __USE_POSIX199309    Define IEEE Std 1003.1, and .1b things.
  61    __USE_POSIX199506    Define IEEE Std 1003.1, .1b, .1c and .1i things.
  62    __USE_XOPEN          Define XPG things.
  63    __USE_XOPEN_EXTENDED Define X/Open Unix things.
  64    __USE_UNIX98         Define Single Unix V2 things.
  65    __USE_XOPEN2K        Define XPG6 things.
  66    __USE_LARGEFILE      Define correct standard I/O things.
  67    __USE_LARGEFILE64    Define LFS things with separate names.
  68    __USE_FILE_OFFSET64  Define 64bit interface as default.
  69    __USE_BSD            Define 4.3BSD things.
  70    __USE_SVID           Define SVID things.
  71    __USE_MISC           Define things common to BSD and System V Unix.
  72    __USE_GNU            Define GNU extensions.
  73    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  74    __USE_FORTIFY_LEVEL  Additional security measures used, according to level.
  75    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  76
  77    The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
  78    defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
  79    only for compatibility.  All new code should use the other symbols
  80    to test for features.
  81
  82    All macros listed above as possibly being defined by this file are
  83    explicitly undefined if they are not explicitly defined.
  84    Feature-test macros that are not defined by the user or compiler
  85    but are implied by the other feature-test macros defined (or by the
  86    lack of any definitions) are defined by the file.  */
  87
  88
  89 /* Undefine everything, so we get a clean slate.  */
  90 #undef  __USE_ISOC99
  91 #undef  __USE_POSIX
  92 #undef  __USE_POSIX2
  93 #undef  __USE_POSIX199309
  94 #undef  __USE_POSIX199506
  95 #undef  __USE_XOPEN
  96 #undef  __USE_XOPEN_EXTENDED
  97 #undef  __USE_UNIX98
  98 #undef  __USE_XOPEN2K
  99 #undef  __USE_LARGEFILE
 100 #undef  __USE_LARGEFILE64
 101 #undef  __USE_FILE_OFFSET64
 102 #undef  __USE_BSD
 103 #undef  __USE_SVID
 104 #undef  __USE_MISC
 105 #undef  __USE_GNU
 106 #undef  __USE_REENTRANT
 107 #undef  __USE_FORTIFY_LEVEL
 108 #undef  __FAVOR_BSD
 109 #undef  __KERNEL_STRICT_NAMES
 110
 111 /* Suppress kernel-name space pollution unless user expressedly asks
 112    for it.  */
 113 #ifndef _LOOSE_KERNEL_NAMES
 114 # define __KERNEL_STRICT_NAMES
 115 #endif
 116
 117 /* Always use ISO C things.  */
 118 #define __USE_ANSI      1
 119
 120 /* Convenience macros to test the versions of glibc and gcc.
 121    Use them like this:
 122    #if __GNUC_PREREQ (2,8)
 123    ... code requiring gcc 2.8 or later ...
 124    #endif
 125    Note - they won't work for gcc1 or glibc1, since the _MINOR macros
 126    were not defined then.  */
 127 #if defined __GNUC__ && defined __GNUC_MINOR__
 128 # define __GNUC_PREREQ(maj, min) \
 129         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
 130 #else
 131 # define __GNUC_PREREQ(maj, min) 0
 132 #endif
 133
 134
 135 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
 136 #if defined _BSD_SOURCE && \
 137     !(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
 138       defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
 139       defined _GNU_SOURCE || defined _SVID_SOURCE)
 140 # define __FAVOR_BSD    1
 141 #endif
 142
 143 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
 144 #ifdef _GNU_SOURCE
 145 # undef  _ISOC99_SOURCE
 146 # define _ISOC99_SOURCE 1
 147 # undef  _POSIX_SOURCE
 148 # define _POSIX_SOURCE  1
 149 # undef  _POSIX_C_SOURCE
 150 # define _POSIX_C_SOURCE        199506L
 151 # undef  _XOPEN_SOURCE
 152 # define _XOPEN_SOURCE  600
 153 # undef  _XOPEN_SOURCE_EXTENDED
 154 # define _XOPEN_SOURCE_EXTENDED 1
 155 # undef  _LARGEFILE64_SOURCE
 156 # define _LARGEFILE64_SOURCE    1
 157 # undef  _BSD_SOURCE
 158 # define _BSD_SOURCE    1
 159 # undef  _SVID_SOURCE
 160 # define _SVID_SOURCE   1
 161 #endif
 162
 163 /* If nothing (other than _GNU_SOURCE) is defined,
 164    define _BSD_SOURCE and _SVID_SOURCE.  */
 165 #if (!defined __STRICT_ANSI__ && !defined _ISOC99_SOURCE && \
 166      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \
 167      !defined _XOPEN_SOURCE && !defined _XOPEN_SOURCE_EXTENDED && \
 168      !defined _BSD_SOURCE && !defined _SVID_SOURCE)
 169 # define _BSD_SOURCE    1
 170 # define _SVID_SOURCE   1
 171 #endif
 172
 173 /* This is to enable the ISO C99 extension.  Also recognize the old macro
 174    which was used prior to the standard acceptance.  This macro will
 175    eventually go away and the features enabled by default once the ISO C99
 176    standard is widely adopted.  */
 177 #if (defined _ISOC99_SOURCE || defined _ISOC9X_SOURCE \
 178      || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
 179 # define __USE_ISOC99   1
 180 #endif
 181
 182 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2
 183    (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined).  */
 184 #if (!defined __STRICT_ANSI__ && !defined _POSIX_SOURCE && \
 185      !defined _POSIX_C_SOURCE)
 186 # define _POSIX_SOURCE  1
 187 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
 188 #  define _POSIX_C_SOURCE       2
 189 # else
 190 #  define _POSIX_C_SOURCE       199506L
 191 # endif
 192 #endif
 193
 194 #if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
 195 # define __USE_POSIX    1
 196 #endif
 197
 198 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
 199 # define __USE_POSIX2   1
 200 #endif
 201
 202 #if (_POSIX_C_SOURCE - 0) >= 199309L
 203 # define __USE_POSIX199309      1
 204 #endif
 205
 206 #if (_POSIX_C_SOURCE - 0) >= 199506L
 207 # define __USE_POSIX199506      1
 208 #endif
 209
 210 #if (_POSIX_C_SOURCE - 0) >= 200112L
 211 # define __USE_XOPEN2K          1
 212 #endif
 213
 214 #ifdef  _XOPEN_SOURCE
 215 # define __USE_XOPEN    1
 216 # if (_XOPEN_SOURCE - 0) >= 500
 217 #  define __USE_XOPEN_EXTENDED  1
 218 #  define __USE_UNIX98  1
 219 #  undef _LARGEFILE_SOURCE
 220 #  define _LARGEFILE_SOURCE     1
 221 #  if (_XOPEN_SOURCE - 0) >= 600
 222 #   define __USE_XOPEN2K        1
 223 #   undef __USE_ISOC99
 224 #   define __USE_ISOC99         1
 225 #  endif
 226 # else
 227 #  ifdef _XOPEN_SOURCE_EXTENDED
 228 #   define __USE_XOPEN_EXTENDED 1
 229 #  endif
 230 # endif
 231 #endif
 232
 233 #ifdef _LARGEFILE_SOURCE
 234 # define __USE_LARGEFILE        1
 235 #endif
 236
 237 #ifdef _LARGEFILE64_SOURCE
 238 # define __USE_LARGEFILE64      1
 239 #endif
 240
 241 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
 242 # define __USE_FILE_OFFSET64    1
 243 #endif
 244
 245 #if defined _BSD_SOURCE || defined _SVID_SOURCE
 246 # define __USE_MISC     1
 247 #endif
 248
 249 #ifdef  _BSD_SOURCE
 250 # define __USE_BSD      1
 251 #endif
 252
 253 #ifdef  _SVID_SOURCE
 254 # define __USE_SVID     1
 255 #endif
 256
 257 #ifdef  _GNU_SOURCE
 258 # define __USE_GNU      1
 259 #endif
 260
 261 #if defined _REENTRANT || defined _THREAD_SAFE
 262 # define __USE_REENTRANT        1
 263 #endif
 264
 265 #if _FORTIFY_SOURCE > 0 && __GNUC_PREREQ (4, 1) && __OPTIMIZE__ > 0
 266 # if _FORTIFY_SOURCE == 1
 267 #  define __USE_FORTIFY_LEVEL 1
 268 # elif _FORTIFY_SOURCE > 1
 269 #  define __USE_FORTIFY_LEVEL 2
 270 # endif
 271 #endif
 272
 273 /* We do support the IEC 559 math functionality, real and complex.  */
 274 #define __STDC_IEC_559__                1
 275 #define __STDC_IEC_559_COMPLEX__        1
 276
 277 /* wchar_t uses ISO 10646-1 (2nd ed., published 2000-09-15) / Unicode 3.1.  */
 278 #define __STDC_ISO_10646__              200009L
 279
 280 /* This macro indicates that the installed library is the GNU C Library.
 281    For historic reasons the value now is 6 and this will stay from now
 282    on.  The use of this variable is deprecated.  Use __GLIBC__ and
 283    __GLIBC_MINOR__ now (see below) when you want to test for a specific
 284    GNU C library version and use the values in <gnu/lib-names.h> to get
 285    the sonames of the shared libraries.  */
 286 #undef  __GNU_LIBRARY__
 287 #define __GNU_LIBRARY__ 6
 288
 289 /* Major and minor version number of the GNU C library package.  Use
 290    these macros to test for features in specific releases.  */
 291 #define __GLIBC__       2
 292 #define __GLIBC_MINOR__ 4
 293
 294 #define __GLIBC_PREREQ(maj, min) \
 295         ((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
 296
 297 /* Decide whether a compiler supports the long long datatypes.  */
 298 #if defined __GNUC__ \
 299     || (defined __PGI && defined __i386__ ) \
 300     || (defined __INTEL_COMPILER && (defined __i386__ || defined __ia64__)) \
 301     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
 302 # define __GLIBC_HAVE_LONG_LONG 1
 303 #endif
 304
 305 /* This is here only because every header file already includes this one.  */
 306 #ifndef __ASSEMBLER__
 307 # ifndef _SYS_CDEFS_H
 308 #  include <sys/cdefs.h>
 309 # endif
 310
 311 /* If we don't have __REDIRECT, prototypes will be missing if
 312    __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
 313 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
 314 #  define __USE_LARGEFILE       1
 315 #  define __USE_LARGEFILE64     1
 316 # endif
 317
 318 #endif  /* !ASSEMBLER */
 319
 320 /* Decide whether we can define 'extern inline' functions in headers.  */
 321 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
 322     && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__
 323 # define __USE_EXTERN_INLINES   1
 324 #endif
 325
 326
 327 /* This is here only because every header file already includes this one.
 328    Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
 329    <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
 330    that will always return failure (and set errno to ENOSYS).  */
 331 #include <gnu/stubs.h>
 332
 333
 334 #endif  /* features.h  */