include/features.h

   1 /* Copyright (C) 1991, 92, 93, 95, 96, 97 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 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    _ISOC9X_SOURCE       Extensions to ISO C 89 from ISO C 9x.
  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    _XOPEN_SOURCE        Includes POSIX and XPG things.  Set to 500 if
  31                         Single Unix conformance is wanted.
  32    _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
  33    _LARGEFILE_SOURCE    Some more functions for correct standard I/O.
  34    _LARGEFILE64_SOURCE  Additional functionality from LFS for large files.
  35    _FILE_OFFSET_BITS=N  Select default filesystem interface.
  36    _BSD_SOURCE          ISO C, POSIX, and 4.3BSD things.
  37    _SVID_SOURCE         ISO C, POSIX, and SVID things.
  38    _GNU_SOURCE          All of the above, plus GNU extensions.
  39    _REENTRANT           Select additionally reentrant object.
  40    _THREAD_SAFE         Same as _REENTRANT, often used by other systems.
  41
  42    The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  43    If none of these are defined, the default is all but _GNU_SOURCE.
  44    If more than one of these are defined, they accumulate.
  45    For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  46    together give you ISO C, 1003.1, and 1003.2, but nothing else.
  47
  48    These are defined by this file and are used by the
  49    header files to decide what to declare or define:
  50
  51    __USE_ISOC9X         Define ISO C 9X things.
  52    __USE_POSIX          Define IEEE Std 1003.1 things.
  53    __USE_POSIX2         Define IEEE Std 1003.2 things.
  54    __USE_POSIX199309    Define IEEE Std 1003.1b things.
  55    __USE_XOPEN          Define XPG things.
  56    __USE_XOPEN_EXTENDED Define X/Open Unix things.
  57    __USE_UNIX98         Define Single Unix V2 things.
  58    __USE_LARGEFILE64    Define LFS things with separate names.
  59    __USE_FILE_OFFSET64  Define 64bit interface as default.
  60    __USE_BSD            Define 4.3BSD things.
  61    __USE_SVID           Define SVID things.
  62    __USE_MISC           Define things common to BSD and System V Unix.
  63    __USE_GNU            Define GNU extensions.
  64    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  65    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  66
  67    The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
  68    defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
  69    only for compatibility.  All new code should use the other symbols
  70    to test for features.
  71
  72    All macros listed above as possibly being defined by this file are
  73    explicitly undefined if they are not explicitly defined.
  74    Feature-test macros that are not defined by the user or compiler
  75    but are implied by the other feature-test macros defined (or by the
  76    lack of any definitions) are defined by the file.  */
  77
  78
  79 /* Undefine everything, so we get a clean slate.  */
  80 #undef  __USE_ISOC9X
  81 #undef  __USE_POSIX
  82 #undef  __USE_POSIX2
  83 #undef  __USE_POSIX199309
  84 #undef  __USE_XOPEN
  85 #undef  __USE_XOPEN_EXTENDED
  86 #undef  __USE_UNIX98
  87 #undef  __USE_LARGEFILE
  88 #undef  __USE_LARGEFILE64
  89 #undef  __USE_FILE_OFFSET64
  90 #undef  __USE_BSD
  91 #undef  __USE_SVID
  92 #undef  __USE_MISC
  93 #undef  __USE_GNU
  94 #undef  __USE_REENTRANT
  95 #undef  __FAVOR_BSD
  96 #undef  __KERNEL_STRICT_NAMES
  97
  98 /* Suppress kernel-name space pollution unless user expressedly asks
  99    for it.  */
 100 #ifndef _LOOSE_KERNEL_NAMES
 101 # define __KERNEL_STRICT_NAMES
 102 #endif
 103
 104 /* Always use ISO C things.  */
 105 #define __USE_ANSI      1
 106
 107
 108 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
 109 #if defined _BSD_SOURCE && \
 110     !(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
 111       defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
 112       defined _GNU_SOURCE || defined _SVID_SOURCE)
 113 # define __FAVOR_BSD    1
 114 #endif
 115
 116 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
 117 #ifdef _GNU_SOURCE
 118 # undef  _ISOC9X_SOURCE
 119 # define _ISOC9X_SOURCE 1
 120 # undef  _POSIX_SOURCE
 121 # define _POSIX_SOURCE  1
 122 # undef  _POSIX_C_SOURCE
 123 # define _POSIX_C_SOURCE        199506L
 124 # undef  _XOPEN_SOURCE
 125 # define _XOPEN_SOURCE  500
 126 # undef  _XOPEN_SOURCE_EXTENDED
 127 # define _XOPEN_SOURCE_EXTENDED 1
 128 # undef  _LARGEFILE64_SOURCE
 129 # define _LARGEFILE64_SOURCE    1
 130 # undef  _BSD_SOURCE
 131 # define _BSD_SOURCE    1
 132 # undef  _SVID_SOURCE
 133 # define _SVID_SOURCE   1
 134 #endif
 135
 136 /* If nothing (other than _GNU_SOURCE) is defined,
 137    define _BSD_SOURCE and _SVID_SOURCE.  */
 138 #if (!defined __STRICT_ANSI__ && !defined _ISOC9X_SOURCE && \
 139      !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \
 140      !defined _XOPEN_SOURCE && !defined _XOPEN_SOURCE_EXTENDED && \
 141      !defined _BSD_SOURCE && !defined _SVID_SOURCE)
 142 # define _BSD_SOURCE    1
 143 # define _SVID_SOURCE   1
 144 #endif
 145
 146 /* This is to enable the ISO C 9x extension.  It will go away as soon
 147    as this standard is officially released.  */
 148 #ifdef _ISOC9X_SOURCE
 149 # define __USE_ISOC9X   1
 150 #endif
 151
 152 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2
 153    (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined).  */
 154 #if (!defined __STRICT_ANSI__ && !defined _POSIX_SOURCE && \
 155      !defined _POSIX_C_SOURCE)
 156 # define _POSIX_SOURCE  1
 157 # if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) != 500
 158 #  define _POSIX_C_SOURCE       2
 159 # else
 160 #  define _POSIX_C_SOURCE       199506L
 161 # endif
 162 #endif
 163
 164 #if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
 165 # define __USE_POSIX    1
 166 #endif
 167
 168 #if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
 169 # define __USE_POSIX2   1
 170 #endif
 171
 172 #if (_POSIX_C_SOURCE - 0) >= 199309L
 173 # define __USE_POSIX199309      1
 174 #endif
 175
 176 #ifdef  _XOPEN_SOURCE
 177 # define __USE_XOPEN    1
 178 # if (_XOPEN_SOURCE - 0) == 500
 179 #  define __USE_XOPEN_EXTENDED  1
 180 #  define __USE_UNIX98  1
 181 #  undef _LARGEFILE_SOURCE
 182 #  define _LARGEFILE_SOURCE     1
 183 # else
 184 #  ifdef _XOPEN_SOURCE_EXTENDED
 185 #   define __USE_XOPEN_EXTENDED 1
 186 #  endif
 187 # endif
 188 #endif
 189
 190 #ifdef _LARGEFILE_SOURCE
 191 # define __USE_LARGEFILE        1
 192 #endif
 193
 194 #ifdef _LARGEFILE64_SOURCE
 195 # define __USE_LARGEFILE64      1
 196 #endif
 197
 198 #if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
 199 # define __USE_FILE_OFFSET64    1
 200 #endif
 201
 202 #if defined _BSD_SOURCE || defined _SVID_SOURCE
 203 # define __USE_MISC     1
 204 #endif
 205
 206 #ifdef  _BSD_SOURCE
 207 # define __USE_BSD      1
 208 #endif
 209
 210 #ifdef  _SVID_SOURCE
 211 # define __USE_SVID     1
 212 #endif
 213
 214 #ifdef  _GNU_SOURCE
 215 # define __USE_GNU      1
 216 #endif
 217
 218 #if defined _REENTRANT || defined _THREAD_SAFE
 219 # define __USE_REENTRANT        1
 220 #endif
 221
 222 /* We do support the IEC 559 math functionality, real and complex.  */
 223 #define __STDC_IEC_559__                1
 224 #define __STDC_IEC_559_COMPLEX__        1
 225
 226 /* This macro indicates that the installed library is the GNU C Library.
 227    For historic reasons the value now is 6 and this will stay from now
 228    on.  The use of this variable is deprecated.  Use __GLIBC__ and
 229    __GLIBC_MINOR__ now (see below) when you want to test for a specific
 230    GNU C library version and use the values in <gnu/lib-names.h> to get
 231    the sonames of the shared libraries.  */
 232 #undef  __GNU_LIBRARY__
 233 #define __GNU_LIBRARY__ 6
 234
 235 /* Major and minor version number of the GNU C library package.  Use
 236    these macros to test for features in specific releases.  */
 237 #define __GLIBC__       2
 238 #define __GLIBC_MINOR__ 1
 239
 240 /* This is here only because every header file already includes this one.  */
 241 #ifndef __ASSEMBLER__
 242 # include <sys/cdefs.h>
 243
 244 /* If we don't have __REDIRECT, prototypes will be missing if
 245    __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
 246 # if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
 247 #  define __USE_LARGEFILE
 248 #  define __USE_LARGEFILE64
 249 # endif
 250
 251 #endif  /* !ASSEMBLER */
 252
 253 /* Decide whether we can define 'extern inline' functions in headers.  */
 254 #if defined __GNUC__ && (__GNUC__ > 2 || __GNUC__ == 2 && __GNUC_MINOR__ >= 7)\
 255     && defined __OPTIMIZE__ && !defined __OPTIMIZE_SIZE__
 256 # define __USE_EXTERN_INLINES   1
 257 #endif
 258
 259 /* This is here only because every header file already includes this one.  */
 260 #ifndef _LIBC
 261 /* Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
 262    <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
 263    which will always return failure (and set errno to ENOSYS).
 264
 265    We avoid including <gnu/stubs.h> when compiling the C library itself to
 266    avoid a dependency loop.  stubs.h depends on every object file.  If
 267    this #include were done for the library source code, then every object
 268    file would depend on stubs.h.  */
 269
 270 # include <gnu/stubs.h>
 271 #endif
 272
 273 #endif  /* features.h  */