include/sys/cdefs.h

   1 /* Copyright (C) 1992-2001, 2002, 2004, 2005, 2006, 2007
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  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 /* The GNU libc does not support any K&R compilers or the traditional mode
  28    of ISO C compilers anymore.  Check for some of the combinations not
  29    anymore supported.  */
  30 #if defined __GNUC__ && !defined __STDC__
  31 # error "You need a ISO C conforming compiler to use the glibc headers"
  32 #endif
  33
  34 /* Some user header file might have defined this before.  */
  35 #undef  __P
  36 #undef  __PMT
  37
  38 #ifdef __GNUC__
  39
  40 /* All functions, except those with callbacks or those that
  41    synchronize memory, are leaf functions.  */
  42 # if __GNUC_PREREQ (4, 6) && !defined _LIBC
  43 #  define __LEAF , __leaf__
  44 #  define __LEAF_ATTR __attribute__ ((__leaf__))
  45 # else
  46 #  define __LEAF
  47 #  define __LEAF_ATTR
  48 # endif
  49
  50 /* GCC can always grok prototypes.  For C++ programs we add throw()
  51    to help it optimize the function calls.  But this works only with
  52    gcc 2.8.x and egcs.  For gcc 3.2 and up we even mark C functions
  53    as non-throwing using a function attribute since programs can use
  54    the -fexceptions options for C code as well.  */
  55 # if !defined __cplusplus && __GNUC_PREREQ (3, 3)
  56 #  define __THROW       __attribute__ ((__nothrow__ __LEAF))
  57 #  define __THROWNL     __attribute__ ((__nothrow__))
  58 #  define __NTH(fct)    __attribute__ ((__nothrow__ __LEAF)) fct
  59 # else
  60 #  if defined __cplusplus && __GNUC_PREREQ (2,8)
  61 #   define __THROW      throw ()
  62 #   define __THROWNL    throw ()
  63 #   define __NTH(fct)   __LEAF_ATTR fct throw ()
  64 #  else
  65 #   define __THROW
  66 #   define __THROWNL
  67 #   define __NTH(fct)   fct
  68 #  endif
  69 # endif
  70
  71 #else   /* Not GCC.  */
  72
  73 # define __inline               /* No inline functions.  */
  74
  75 # define __THROW
  76 # define __THROWNL
  77 # define __NTH(fct)     fct
  78
  79 #endif  /* GCC.  */
  80
  81 /* These two macros are not used in glibc anymore.  They are kept here
  82    only because some other projects expect the macros to be defined.  */
  83 #define __P(args)       args
  84 #define __PMT(args)     args
  85
  86 /* For these things, GCC behaves the ANSI way normally,
  87    and the non-ANSI way under -traditional.  */
  88
  89 #define __CONCAT(x,y)   x ## y
  90 #define __STRING(x)     #x
  91
  92 /* This is not a typedef so `const __ptr_t' does the right thing.  */
  93 #define __ptr_t void *
  94 #define __long_double_t  long double
  95
  96
  97 /* C++ needs to know that types and declarations are C, not C++.  */
  98 #ifdef  __cplusplus
  99 # define __BEGIN_DECLS  extern "C" {
 100 # define __END_DECLS    }
 101 #else
 102 # define __BEGIN_DECLS
 103 # define __END_DECLS
 104 #endif
 105
 106
 107 /* The standard library needs the functions from the ISO C90 standard
 108    in the std namespace.  At the same time we want to be safe for
 109    future changes and we include the ISO C99 code in the non-standard
 110    namespace __c99.  The C++ wrapper header take case of adding the
 111    definitions to the global namespace.  */
 112 #if defined __cplusplus && defined _GLIBCPP_USE_NAMESPACES
 113 # define __BEGIN_NAMESPACE_STD  namespace std {
 114 # define __END_NAMESPACE_STD    }
 115 # define __USING_NAMESPACE_STD(name) using std::name;
 116 # define __BEGIN_NAMESPACE_C99  namespace __c99 {
 117 # define __END_NAMESPACE_C99    }
 118 # define __USING_NAMESPACE_C99(name) using __c99::name;
 119 #else
 120 /* For compatibility we do not add the declarations into any
 121    namespace.  They will end up in the global namespace which is what
 122    old code expects.  */
 123 # define __BEGIN_NAMESPACE_STD
 124 # define __END_NAMESPACE_STD
 125 # define __USING_NAMESPACE_STD(name)
 126 # define __BEGIN_NAMESPACE_C99
 127 # define __END_NAMESPACE_C99
 128 # define __USING_NAMESPACE_C99(name)
 129 #endif
 130
 131
 132 #if __GNUC_PREREQ (4,3)
 133 # define __warndecl(name, msg) \
 134   extern void name (void) __attribute__((__warning__ (msg)))
 135 # define __warnattr(msg) __attribute__((__warning__ (msg)))
 136 # define __errordecl(name, msg) \
 137   extern void name (void) __attribute__((__error__ (msg)))
 138 #else
 139 # define __warndecl(name, msg) extern void name (void)
 140 # define __warnattr(msg)
 141 # define __errordecl(name, msg) extern void name (void)
 142 #endif
 143
 144 /* Support for flexible arrays.  */
 145 #if __GNUC_PREREQ (2,97)
 146 /* GCC 2.97 supports C99 flexible array members.  */
 147 # define __flexarr      []
 148 #else
 149 # ifdef __GNUC__
 150 #  define __flexarr     [0]
 151 # else
 152 #  if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
 153 #   define __flexarr    []
 154 #  else
 155 /* Some other non-C99 compiler.  Approximate with [1].  */
 156 #   define __flexarr    [1]
 157 #  endif
 158 # endif
 159 #endif
 160
 161
 162 /* __asm__ ("xyz") is used throughout the headers to rename functions
 163    at the assembly language level.  This is wrapped by the __REDIRECT
 164    macro, in order to support compilers that can do this some other
 165    way.  When compilers don't support asm-names at all, we have to do
 166    preprocessor tricks instead (which don't have exactly the right
 167    semantics, but it's the best we can do).
 168
 169    Example:
 170    int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
 171
 172 #if defined __GNUC__ && __GNUC__ >= 2
 173
 174 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
 175 # ifdef __cplusplus
 176 #  define __REDIRECT_NTH(name, proto, alias) \
 177      name proto __THROW __asm__ (__ASMNAME (#alias))
 178 #  define __REDIRECT_NTHNL(name, proto, alias) \
 179      name proto __THROWNL __asm__ (__ASMNAME (#alias))
 180 # else
 181 #  define __REDIRECT_NTH(name, proto, alias) \
 182      name proto __asm__ (__ASMNAME (#alias)) __THROW
 183 #  define __REDIRECT_NTHNL(name, proto, alias) \
 184      name proto __asm__ (__ASMNAME (#alias)) __THROWNL
 185 # endif
 186 # define __ASMNAME(cname)  __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
 187 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
 188
 189 /*
 190 #elif __SOME_OTHER_COMPILER__
 191
 192 # define __REDIRECT(name, proto, alias) name proto; \
 193         _Pragma("let " #name " = " #alias)
 194 */
 195 #endif
 196
 197 /* GCC has various useful declarations that can be made with the
 198    `__attribute__' syntax.  All of the ways we use this do fine if
 199    they are omitted for compilers that don't understand it. */
 200 #if !defined __GNUC__ || __GNUC__ < 2
 201 # define __attribute__(xyz)     /* Ignore */
 202 #endif
 203
 204 /* We make this a no-op unless it can be used as both a variable and
 205    a type attribute.  gcc 2.8 is known to support both.  */
 206 #if __GNUC_PREREQ (2,8)
 207 # define __attribute_aligned__(size) __attribute__ ((__aligned__ (size)))
 208 #else
 209 # define __attribute_aligned__(size) /* Ignore */
 210 #endif
 211
 212 /* At some point during the gcc 2.96 development the `malloc' attribute
 213    for functions was introduced.  We don't want to use it unconditionally
 214    (although this would be possible) since it generates warnings.  */
 215 #if __GNUC_PREREQ (2,96)
 216 # define __attribute_malloc__ __attribute__ ((__malloc__))
 217 #else
 218 # define __attribute_malloc__ /* Ignore */
 219 #endif
 220
 221 /* Tell the compiler which arguments to an allocation function
 222    indicate the size of the allocation.  */
 223 #if __GNUC_PREREQ (4, 3)
 224 # define __attribute_alloc_size__(params) \
 225   __attribute__ ((__alloc_size__ params))
 226 #else
 227 # define __attribute_alloc_size__(params) /* Ignore.  */
 228 #endif
 229
 230 /* At some point during the gcc 2.96 development the `pure' attribute
 231    for functions was introduced.  We don't want to use it unconditionally
 232    (although this would be possible) since it generates warnings.  */
 233 #if __GNUC_PREREQ (2,96)
 234 # define __attribute_pure__ __attribute__ ((__pure__))
 235 #else
 236 # define __attribute_pure__ /* Ignore */
 237 #endif
 238
 239 #if __GNUC_PREREQ (2,96)
 240 # define __attribute_const__ __attribute__((__const__))
 241 #else
 242 # define __attribute_const__     /* unimplemented */
 243 #endif
 244
 245 /* At some point during the gcc 3.1 development the `used' attribute
 246    for functions was introduced.  We don't want to use it unconditionally
 247    (although this would be possible) since it generates warnings.  */
 248 #if __GNUC_PREREQ (3,1)
 249 # define __attribute_used__ __attribute__ ((__used__))
 250 # define __attribute_noinline__ __attribute__ ((__noinline__))
 251 #else
 252 # define __attribute_used__ __attribute__ ((__unused__))
 253 # define __attribute_noinline__ /* Ignore */
 254 #endif
 255
 256 /* gcc allows marking deprecated functions.  */
 257 #if __GNUC_PREREQ (3,2) && !defined(__UCLIBC_HIDE_DEPRECATED__)
 258 # define __attribute_deprecated__ __attribute__ ((__deprecated__))
 259 #else
 260 # define __attribute_deprecated__ /* Ignore */
 261 #endif
 262
 263 /* At some point during the gcc 2.8 development the `format_arg' attribute
 264    for functions was introduced.  We don't want to use it unconditionally
 265    (although this would be possible) since it generates warnings.
 266    If several `format_arg' attributes are given for the same function, in
 267    gcc-3.0 and older, all but the last one are ignored.  In newer gccs,
 268    all designated arguments are considered.  */
 269 #if __GNUC_PREREQ (2,8)
 270 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
 271 #else
 272 # define __attribute_format_arg__(x) /* Ignore */
 273 #endif
 274
 275 /* At some point during the gcc 2.97 development the `strfmon' format
 276    attribute for functions was introduced.  We don't want to use it
 277    unconditionally (although this would be possible) since it
 278    generates warnings.  */
 279 #if __GNUC_PREREQ (2,97)
 280 # define __attribute_format_strfmon__(a,b) \
 281   __attribute__ ((__format__ (__strfmon__, a, b)))
 282 #else
 283 # define __attribute_format_strfmon__(a,b) /* Ignore */
 284 #endif
 285
 286 /* The nonull function attribute allows to mark pointer parameters which
 287    must not be NULL.  */
 288 #if __GNUC_PREREQ (3,3)
 289 # define __nonnull(params) __attribute__ ((__nonnull__ params))
 290 #else
 291 # define __nonnull(params)
 292 #endif
 293
 294 /* If fortification mode, we warn about unused results of certain
 295    function calls which can lead to problems.  */
 296 #if __GNUC_PREREQ (3,4)
 297 # define __attribute_warn_unused_result__ \
 298    __attribute__ ((__warn_unused_result__))
 299 #else
 300 # define __attribute_warn_unused_result__ /* empty */
 301 #endif
 302 #ifndef __wur
 303 # define __wur /* Ignore */
 304 #endif
 305
 306 /* Forces a function to be always inlined.  */
 307 #if __GNUC_PREREQ (3,2)
 308 # define __always_inline __inline __attribute__ ((__always_inline__))
 309 #else
 310 # define __always_inline __inline
 311 #endif
 312
 313 /* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
 314    inline semantics, unless -fgnu89-inline is used.
 315    For -std=gnu99, forcing gnu_inline attribute does not change behavior,
 316    but may silence spurious warnings (such as in GCC 4.2).  */
 317 #if !defined __cplusplus || __GNUC_PREREQ (4,3)
 318 # if defined __GNUC_STDC_INLINE__ || defined __GNUC_GNU_INLINE__ || defined __cplusplus
 319 #  define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
 320 #  if __GNUC_PREREQ (4,3)
 321 #   define __extern_always_inline \
 322   extern __always_inline __attribute__ ((__gnu_inline__, __artificial__))
 323 #  else
 324 #   define __extern_always_inline \
 325   extern __always_inline __attribute__ ((__gnu_inline__))
 326 #  endif
 327 # else
 328 #  define __extern_inline extern __inline
 329 #  define __extern_always_inline extern __always_inline
 330 # endif
 331 #endif
 332
 333 /* Undefine (also defined in libc-symbols.h).  */
 334 #undef __attribute_copy__
 335 #if __GNUC_PREREQ (9, 0)
 336 /* Copies attributes from the declaration or type referenced by
 337    the argument.  */
 338 # define __attribute_copy__(arg) __attribute__ ((__copy__ (arg)))
 339 #else
 340 # define __attribute_copy__(arg)
 341 #endif
 342
 343
 344 /* GCC 4.3 and above allow passing all anonymous arguments of an
 345    __extern_always_inline function to some other vararg function.  */
 346 #if __GNUC_PREREQ (4,3)
 347 # define __va_arg_pack() __builtin_va_arg_pack ()
 348 # define __va_arg_pack_len() __builtin_va_arg_pack_len ()
 349 #endif
 350
 351 /* It is possible to compile containing GCC extensions even if GCC is
 352    run in pedantic mode if the uses are carefully marked using the
 353    `__extension__' keyword.  But this is not generally available before
 354    version 2.8.  */
 355 #if !__GNUC_PREREQ (2,8)
 356 # define __extension__          /* Ignore */
 357 #endif
 358
 359 /* __restrict is known in EGCS 1.2 and above. */
 360 #if !__GNUC_PREREQ (2,92)
 361 # define __restrict     /* Ignore */
 362 #endif
 363
 364 /* ISO C99 also allows to declare arrays as non-overlapping.  The syntax is
 365      array_name[restrict]
 366    GCC 3.1 supports this.  */
 367 #if __GNUC_PREREQ (3,1) && !defined __GNUG__
 368 # define __restrict_arr __restrict
 369 #else
 370 # ifdef __GNUC__
 371 #  define __restrict_arr        /* Not supported in old GCC.  */
 372 # else
 373 #  if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
 374 #   define __restrict_arr       restrict
 375 #  else
 376 /* Some other non-C99 compiler.  */
 377 #   define __restrict_arr       /* Not supported.  */
 378 #  endif
 379 # endif
 380 #endif
 381
 382 #endif   /* sys/cdefs.h */