features.h

   1 /* Copyright (C) 1991, 92, 93, 95, 96 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
  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__      ANSI Standard C.
  27    _POSIX_SOURCE        IEEE Std 1003.1.
  28    _POSIX_C_SOURCE      If ==1, like _POSIX_SOURCE; if ==2 add IEEE Std 1003.2.
  29    _XOPEN_SOURCE        Includes POSIX and XPG things.
  30    _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
  31    _BSD_SOURCE          ANSI, POSIX, and 4.3BSD things.
  32    _SVID_SOURCE         ANSI, POSIX, and SVID things.
  33    _GNU_SOURCE          All of the above, plus GNU extensions.
  34    _REENTRANT           Select additionally reentrant object.
  35    _THREAD_SAFE         Same as _REENTRANT, often used by other systems.
  36
  37    The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  38    If none of these are defined, the default is all but _GNU_SOURCE.
  39    If more than one of these are defined, they accumulate.
  40    For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  41    together give you ANSI C, 1003.1, and 1003.2, but nothing else.
  42
  43    These are defined by this file and are used by the
  44    header files to decide what to declare or define:
  45
  46    __USE_POSIX          Define IEEE Std 1003.1 things.
  47    __USE_POSIX2         Define IEEE Std 1003.2 things.
  48    __USE_XOPEN          Define XPG things.
  49    __USE_XOPEN_EXTENDED Define X/Open Unix things.
  50    __USE_BSD            Define 4.3BSD things.
  51    __USE_SVID           Define SVID things.
  52    __USE_MISC           Define things common to BSD and System V Unix.
  53    __USE_GNU            Define GNU extensions.
  54    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  55    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  56
  57    The macro `__GNU_LIBRARY__' is defined by this file unconditionally.
  58
  59    All macros listed above as possibly being defined by this file are
  60    explicitly undefined if they are not explicitly defined.
  61    Feature-test macros that are not defined by the user or compiler
  62    but are implied by the other feature-test macros defined (or by the
  63    lack of any definitions) are defined by the file.  */
  64
  65
  66 /* Undefine everything, so we get a clean slate.  */
  67 #undef  __USE_POSIX
  68 #undef  __USE_POSIX2
  69 #undef  __USE_XOPEN
  70 #undef  __USE_XOPEN_EXTENDED
  71 #undef  __USE_BSD
  72 #undef  __USE_SVID
  73 #undef  __USE_MISC
  74 #undef  __USE_GNU
  75 #undef  __USE_REENTRANT
  76 #undef  __FAVOR_BSD
  77 #undef  __KERNEL_STRICT_NAMES
  78
  79 /* Suppress kernel-name space pollution unless user expressedly asks
  80    for it.  */
  81 #ifndef _LOOSE_KERNEL_NAMES
  82 # define __KERNEL_STRICT_NAMES
  83 #endif
  84
  85 /* Always use ANSI things.  */
  86 #define __USE_ANSI      1
  87
  88
  89 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
  90 #if defined (_BSD_SOURCE) && \
  91     !(defined (_POSIX_SOURCE) || defined (_POSIX_C_SOURCE) || \
  92       defined (_XOPEN_SOURCE) || defined (_XOPEN_SOURCE_DEFINED) || \
  93       defined (_GNU_SOURCE) || defined (_SVID_SOURCE))
  94 # define __FAVOR_BSD    1
  95 #endif
  96
  97 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
  98 #ifdef _GNU_SOURCE
  99 #undef  _POSIX_SOURCE
 100 #define _POSIX_SOURCE   1
 101 #undef  _POSIX_C_SOURCE
 102 #define _POSIX_C_SOURCE 2
 103 #undef  _XOPEN_SOURCE
 104 #define _XOPEN_SOURCE   1
 105 #undef  _XOPEN_SOURCE_EXTENDED
 106 #define _XOPEN_SOURCE_EXTENDED  1
 107 #undef  _BSD_SOURCE
 108 #define _BSD_SOURCE     1
 109 #undef  _SVID_SOURCE
 110 #define _SVID_SOURCE    1
 111 #endif
 112
 113 /* If nothing (other than _GNU_SOURCE) is defined,
 114    define _BSD_SOURCE and _SVID_SOURCE.  */
 115 #if (!defined (__STRICT_ANSI__) && !defined (_POSIX_SOURCE) && \
 116      !defined (_POSIX_C_SOURCE) && !defined (_XOPEN_SOURCE) && \
 117      !defined (_XOPEN_SOURCE_EXTENDED) && !defined (_BSD_SOURCE) && \
 118      !defined (_SVID_SOURCE))
 119 #define _BSD_SOURCE     1
 120 #define _SVID_SOURCE    1
 121 #endif
 122
 123 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2.  */
 124 #if (!defined (__STRICT_ANSI__) && !defined (_POSIX_SOURCE) && \
 125      !defined (_POSIX_C_SOURCE))
 126 #define _POSIX_SOURCE   1
 127 #define _POSIX_C_SOURCE 2
 128 #endif
 129
 130 #if     (defined (_POSIX_SOURCE) || _POSIX_C_SOURCE >= 1 || \
 131          defined (_XOPEN_SOURCE))
 132 #define __USE_POSIX     1
 133 #endif
 134
 135 #if     (defined (_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 2 || \
 136          defined (_XOPEN_SOURCE))
 137 #define __USE_POSIX2    1
 138 #endif
 139
 140 #ifdef  _XOPEN_SOURCE
 141 #define __USE_XOPEN     1
 142 #ifdef  _XOPEN_SOURCE_EXTENDED
 143 #define __USE_XOPEN_EXTENDED    1
 144 #endif
 145 #endif
 146
 147 #if defined (_BSD_SOURCE) || defined (_SVID_SOURCE)
 148 #define __USE_MISC      1
 149 #endif
 150
 151 #ifdef  _BSD_SOURCE
 152 #define __USE_BSD       1
 153 #endif
 154
 155 #ifdef  _SVID_SOURCE
 156 #define __USE_SVID      1
 157 #endif
 158
 159 #ifdef  _GNU_SOURCE
 160 #define __USE_GNU       1
 161 #endif
 162
 163 #if defined (_REENTRANT) || defined (_THREAD_SAFE)
 164 #define __USE_REENTRANT 1
 165 #endif
 166
 167
 168 /* This macro indicates that the installed library is the GNU C Library.
 169    For historic reasons the value now is 6 and this will stay from now
 170    on.  The use of this variable is deprecated.  Use __GLIBC__ and
 171    __GLIBC_MINOR__ now (see below) when you want to test for a specific
 172    GNU C library version and use the values in <gnu/lib-names.h> to get
 173    the sonames of the shared libraries.  */
 174 #undef  __GNU_LIBRARY__
 175 #define __GNU_LIBRARY__ 6
 176
 177 /* Major and minor version number of the GNU C library package.  Use
 178    these macros to test for features in specific releases.  */
 179 #define __GLIBC__       2
 180 #define __GLIBC_MINOR__ 0
 181
 182
 183 #if     !defined (__GNUC__) || __GNUC__ < 2
 184 /* In GCC version 2, (__extension__ EXPR) will not complain
 185    about GCC extensions used in EXPR under -ansi or -pedantic.  */
 186 #define __extension__
 187 #endif
 188
 189
 190 /* This is here only because every header file already includes this one.  */
 191 #ifndef __ASSEMBLER__
 192 #include <sys/cdefs.h>
 193 #endif
 194
 195 /* This is here only because every header file already includes this one.  */
 196 #ifndef _LIBC
 197 /* Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
 198    <stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
 199    which will always return failure (and set errno to ENOSYS).
 200
 201    We avoid including <stubs.h> when compiling the C library itself to
 202    avoid a dependency loop.  stubs.h depends on every object file.  If
 203    this #include were done for the library source code, then every object
 204    file would depend on stubs.h.  */
 205
 206 #include <stubs.h>
 207 #endif
 208
 209 #endif  /* features.h  */