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
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, 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    _BSD_SOURCE          ANSI, POSIX, and 4.3BSD things.
  30    _SVID_SOURCE         ANSI, POSIX, and SVID things.
  31    _GNU_SOURCE          All of the above, plus GNU extensions.
  32    _REENTRANT           Select additionally reentrant object.
  33    _THREAD_SAFE         Same as _REENTRANT, often used by other systems.
  34
  35    The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
  36    If none of these are defined, the default is all but _GNU_SOURCE.
  37    If more than one of these are defined, they accumulate.
  38    For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
  39    together give you ANSI C, 1003.1, and 1003.2, but nothing else.
  40
  41    These are defined by this file and are used by the
  42    header files to decide what to declare or define:
  43
  44    __USE_POSIX          Define IEEE Std 1003.1 things.
  45    __USE_POSIX2         Define IEEE Std 1003.2 things.
  46    __USE_BSD            Define 4.3BSD things.
  47    __USE_SVID           Define SVID things.
  48    __USE_MISC           Define things common to BSD and System V Unix.
  49    __USE_GNU            Define GNU extensions.
  50    __USE_REENTRANT      Define reentrant/thread-safe *_r functions.
  51    __FAVOR_BSD          Favor 4.3BSD things in cases of conflict.
  52
  53    The macro `__GNU_LIBRARY__' is defined by this file unconditionally.
  54
  55    All macros listed above as possibly being defined by this file are
  56    explicitly undefined if they are not explicitly defined.
  57    Feature-test macros that are not defined by the user or compiler
  58    but are implied by the other feature-test macros defined (or by the
  59    lack of any definitions) are defined by the file.  */
  60
  61
  62 /* Undefine everything, so we get a clean slate.  */
  63 #undef  __USE_POSIX
  64 #undef  __USE_POSIX2
  65 #undef  __USE_BSD
  66 #undef  __USE_SVID
  67 #undef  __USE_MISC
  68 #undef  __USE_GNU
  69 #undef  __USE_REENTRANT
  70 #undef  __FAVOR_BSD
  71 #undef  __KERNEL_STRICT_NAMES
  72
  73 /* Suppress kernel-name space pollution unless user expressedly asks
  74    for it: */
  75 #ifndef _LOOSE_KERNEL_NAMES
  76 # define __KERNEL_STRICT_NAMES
  77 #endif
  78
  79 /* Always use ANSI things.  */
  80 #define __USE_ANSI      1
  81
  82
  83 /* If _BSD_SOURCE was defined by the user, favor BSD over POSIX.  */
  84 #if defined (_BSD_SOURCE) && \
  85     !(defined (_POSIX_SOURCE) || defined (_POSIX_C_SOURCE) || \
  86       defined (_GNU_SOURCE) || defined (_SVID_SOURCE))
  87 #define __FAVOR_BSD     1
  88 #endif
  89
  90 /* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
  91 #ifdef _GNU_SOURCE
  92 #undef  _POSIX_SOURCE
  93 #define _POSIX_SOURCE   1
  94 #undef  _POSIX_C_SOURCE
  95 #define _POSIX_C_SOURCE 2
  96 #undef  _BSD_SOURCE
  97 #define _BSD_SOURCE     1
  98 #undef  _SVID_SOURCE
  99 #define _SVID_SOURCE    1
 100 #endif
 101
 102 /* If nothing (other than _GNU_SOURCE) is defined,
 103    define _BSD_SOURCE and _SVID_SOURCE.  */
 104 #if (!defined (__STRICT_ANSI__) && !defined (_POSIX_SOURCE) && \
 105      !defined (_POSIX_C_SOURCE) && !defined (_BSD_SOURCE) && \
 106      !defined (_SVID_SOURCE))
 107 #define _BSD_SOURCE     1
 108 #define _SVID_SOURCE    1
 109 #endif
 110
 111 /* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2.  */
 112 #if (!defined (__STRICT_ANSI__) && !defined (_POSIX_SOURCE) && \
 113      !defined (_POSIX_C_SOURCE))
 114 #define _POSIX_SOURCE   1
 115 #define _POSIX_C_SOURCE 2
 116 #endif
 117
 118 #if     defined (_POSIX_SOURCE) || _POSIX_C_SOURCE >= 1
 119 #define __USE_POSIX     1
 120 #endif
 121
 122 #if     defined (_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 2
 123 #define __USE_POSIX2    1
 124 #endif
 125
 126 #if defined (_BSD_SOURCE) || defined (_SVID_SOURCE)
 127 #define __USE_MISC      1
 128 #endif
 129
 130 #ifdef  _BSD_SOURCE
 131 #define __USE_BSD       1
 132 #endif
 133
 134 #ifdef  _SVID_SOURCE
 135 #define __USE_SVID      1
 136 #endif
 137
 138 #ifdef  _GNU_SOURCE
 139 #define __USE_GNU       1
 140 #endif
 141
 142 #if defined (_REENTRANT) || defined (_THREAD_SAFE)
 143 #define __USE_REENTRANT 1
 144 #endif
 145
 146
 147 /* This macro indicates that the installed library is the GNU C Library.
 148    For historic reasons the value now is 6 and this will stay from now
 149    on.  The use of this variable is deprecated.  Use __GLIBC__ and
 150    __GLIBC_MINOR__ now (see below) when you want to test for a specific
 151    GNU C library version and use the values in <gnu/lib-names.h> to get
 152    the sonames of the shared libraries.  */
 153 #undef  __GNU_LIBRARY__
 154 #define __GNU_LIBRARY__ 6
 155
 156 /* Major and minor version number of the GNU C library package.  Use
 157    these macros to test for features in specific releases.  */
 158 #define __GLIBC__       2
 159 #define __GLIBC_MINOR__ 0
 160
 161
 162 #if     !defined (__GNUC__) || __GNUC__ < 2
 163 /* In GCC version 2, (__extension__ EXPR) will not complain
 164    about GCC extensions used in EXPR under -ansi or -pedantic.  */
 165 #define __extension__
 166 #endif
 167
 168
 169 /* This is here only because every header file already includes this one.  */
 170 #ifndef __ASSEMBLER__
 171 #include <sys/cdefs.h>
 172 #endif
 173
 174 /* This is here only because every header file already includes this one.  */
 175 #ifndef _LIBC
 176 /* Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
 177    <stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
 178    which will always return failure (and set errno to ENOSYS).
 179
 180    We avoid including <stubs.h> when compiling the C library itself to
 181    avoid a dependency loop.  stubs.h depends on every object file.  If
 182    this #include were done for the library source code, then every object
 183    file would depend on stubs.h.  */
 184
 185 #include <stubs.h>
 186 #endif
 187
 188 #endif  /* features.h  */