misc/sys/cdefs.h

   1 /* Copyright (C) 1992, 93, 94, 95, 96, 97, 98 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 _SYS_CDEFS_H
  20 #define _SYS_CDEFS_H    1
  21
  22 /* We are almost always included from features.h. */
  23 #ifndef _FEATURES_H
  24 #include <features.h>
  25 #endif
  26
  27 /* Some user header file might have defined this before.  */
  28 #undef  __P
  29
  30 #ifdef __GNUC__
  31
  32 /* GCC can always grok prototypes.  For C++ programs we add throw()
  33    to help it optimize the function calls.  But this works only with
  34    gcc 2.8.x and egcs.  */
  35 # if defined __cplusplus && __GNUC_MINOR__ >= 8
  36 #  define __THROW       throw ()
  37 # else
  38 #  define __THROW
  39 # endif
  40 # define __P(args)      args __THROW
  41 /* This macro will be used for functions which might take C++ callback
  42    functions.  */
  43 # define __PMT(args)    args
  44 # define __DOTS         , ...
  45
  46 #else   /* Not GCC.  */
  47
  48 # define __inline               /* No inline functions.  */
  49
  50 # if (defined __STDC__ && __STDC__) || defined __cplusplus
  51
  52 #  define __P(args)     args
  53 #  define __PMT(args)   args
  54 #  define __const       const
  55 #  define __signed      signed
  56 #  define __volatile    volatile
  57 #  define __DOTS        , ...
  58
  59 # else  /* Not ANSI C or C++.  */
  60
  61 #  define __P(args)     ()      /* No prototypes.  */
  62 #  define __PMT(args)   ()
  63 #  define __const               /* No ANSI C keywords.  */
  64 #  define __signed
  65 #  define __volatile
  66 #  define __DOTS
  67
  68 # endif /* ANSI C or C++.  */
  69
  70 #endif  /* GCC.  */
  71
  72 /* For these things, GCC behaves the ANSI way normally,
  73    and the non-ANSI way under -traditional.  */
  74
  75 #if defined __STDC__ && __STDC__
  76
  77 # define __CONCAT(x,y)  x ## y
  78 # define __STRING(x)    #x
  79
  80 /* This is not a typedef so `const __ptr_t' does the right thing.  */
  81 # define __ptr_t void *
  82 # define __long_double_t  long double
  83
  84 #else
  85
  86 # define __CONCAT(x,y)  x/**/y
  87 # define __STRING(x)    "x"
  88
  89 # define __ptr_t char *
  90 # define __long_double_t  long double
  91
  92 /* The BSD header files use the ANSI keywords unmodified (this means that
  93    old programs may lose if they use the new keywords as identifiers), but
  94    those names are not available under -traditional.  We define them to
  95    their __ versions, which are taken care of above.  */
  96 #ifdef  __USE_BSD
  97 # define const          __const
  98 # define signed         __signed
  99 # define volatile       __volatile
 100 #endif
 101
 102 #endif  /* __STDC__ */
 103
 104
 105 /* C++ needs to know that types and declarations are C, not C++.  */
 106 #ifdef  __cplusplus
 107 # define __BEGIN_DECLS  extern "C" {
 108 # define __END_DECLS    }
 109 #else
 110 # define __BEGIN_DECLS
 111 # define __END_DECLS
 112 #endif
 113
 114 /* __asm__ ("xyz") is used throughout the headers to rename functions
 115    at the assembly language level.  This is wrapped by the __REDIRECT
 116    macro, in order to support compilers that can do this some other
 117    way.  When compilers don't support asm-names at all, we have to do
 118    preprocessor tricks instead (which don't have exactly the right
 119    semantics, but it's the best we can do).
 120
 121    Example:
 122    int __REDIRECT(setpgrp, __P((__pid_t pid, __pid_t pgrp)), setpgid); */
 123
 124 #if defined __GNUC__ && __GNUC__ >= 2
 125
 126 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
 127 # define __ASMNAME(cname)  __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
 128 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
 129
 130 /*
 131 #elif __SOME_OTHER_COMPILER__
 132
 133 # define __attribute__(xyz)
 134 # define __REDIRECT(name, proto, alias) name proto; \
 135         _Pragma("let " #name " = " #alias)
 136 */
 137 #endif
 138
 139 /* GCC has various useful declarations that can be made with the
 140    `__attribute__' syntax.  All of the ways we use this do fine if
 141    they are omitted for compilers that don't understand it. */
 142 #if !defined __GNUC__ || __GNUC__ < 2
 143
 144 # define __attribute__(xyz)     /* Ignore. */
 145
 146 #endif
 147
 148 /* It is possible to compile containing GCC extensions even if GCC is
 149    run in pedantic mode if the uses are carefully marked using the
 150    `__extension__' keyword.  But this is not generally available before
 151    version 2.8.  */
 152 #if !defined __GNUC__ || __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
 153
 154 # define __extension__          /* Ignore */
 155
 156 #endif
 157
 158 /* __restrict is known in EGCS 1.2 and above. */
 159 #if !defined __GNUC__ || __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 92)
 160
 161 # define __restrict     /* Ignore */
 162
 163 #endif
 164
 165 #endif   /* sys/cdefs.h */