misc/sys/cdefs.h

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