include/ansidecl.h

   1 /* ANSI and traditional C compatability macros
   2    Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
   3    2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, 2013
   4    Free Software Foundation, Inc.
   5    This file is part of the GNU C Library.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  20
  21 /* ANSI and traditional C compatibility macros
  22
  23    ANSI C is assumed if __STDC__ is #defined.
  24
  25    Macro                ANSI C definition       Traditional C definition
  26    -----                ---- - ----------       ----------- - ----------
  27    PTR                  `void *'                `char *'
  28    const                not defined             `'
  29    volatile             not defined             `'
  30    signed               not defined             `'
  31
  32    For ease of writing code which uses GCC extensions but needs to be
  33    portable to other compilers, we provide the GCC_VERSION macro that
  34    simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
  35    wrappers around __attribute__.  Also, __extension__ will be #defined
  36    to nothing if it doesn't work.  See below.  */
  37
  38 #ifndef _ANSIDECL_H
  39 #define _ANSIDECL_H     1
  40
  41 #ifdef __cplusplus
  42 extern "C" {
  43 #endif
  44
  45 /* Every source file includes this file,
  46    so they will all get the switch for lint.  */
  47 /* LINTLIBRARY */
  48
  49 /* Using MACRO(x,y) in cpp #if conditionals does not work with some
  50    older preprocessors.  Thus we can't define something like this:
  51
  52 #define HAVE_GCC_VERSION(MAJOR, MINOR) \
  53   (__GNUC__ > (MAJOR) || (__GNUC__ == (MAJOR) && __GNUC_MINOR__ >= (MINOR)))
  54
  55 and then test "#if HAVE_GCC_VERSION(2,7)".
  56
  57 So instead we use the macro below and test it against specific values.  */
  58
  59 /* This macro simplifies testing whether we are using gcc, and if it
  60    is of a particular minimum version. (Both major & minor numbers are
  61    significant.)  This macro will evaluate to 0 if we are not using
  62    gcc at all.  */
  63 #ifndef GCC_VERSION
  64 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
  65 #endif /* GCC_VERSION */
  66
  67 #if defined (__STDC__) || defined(__cplusplus) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(_WIN32)
  68 /* All known AIX compilers implement these things (but don't always
  69    define __STDC__).  The RISC/OS MIPS compiler defines these things
  70    in SVR4 mode, but does not define __STDC__.  */
  71 /* eraxxon@alumni.rice.edu: The Compaq C++ compiler, unlike many other
  72    C++ compilers, does not define __STDC__, though it acts as if this
  73    was so. (Verified versions: 5.7, 6.2, 6.3, 6.5) */
  74
  75 #define PTR             void *
  76
  77 #undef const
  78 #undef volatile
  79 #undef signed
  80
  81 /* inline requires special treatment; it's in C99, and GCC >=2.7 supports
  82    it too, but it's not in C89.  */
  83 #undef inline
  84 #if __STDC_VERSION__ >= 199901L || defined(__cplusplus) || (defined(__SUNPRO_C) && defined(__C99FEATURES__))
  85 /* it's a keyword */
  86 #else
  87 # if GCC_VERSION >= 2007
  88 #  define inline __inline__   /* __inline__ prevents -pedantic warnings */
  89 # else
  90 #  define inline  /* nothing */
  91 # endif
  92 #endif
  93
  94 #else   /* Not ANSI C.  */
  95
  96 #define PTR             char *
  97
  98 /* some systems define these in header files for non-ansi mode */
  99 #undef const
 100 #undef volatile
 101 #undef signed
 102 #undef inline
 103 #define const
 104 #define volatile
 105 #define signed
 106 #define inline
 107
 108 #endif  /* ANSI C.  */
 109
 110 /* Define macros for some gcc attributes.  This permits us to use the
 111    macros freely, and know that they will come into play for the
 112    version of gcc in which they are supported.  */
 113
 114 #if (GCC_VERSION < 2007)
 115 # define __attribute__(x)
 116 #endif
 117
 118 /* Attribute __malloc__ on functions was valid as of gcc 2.96. */
 119 #ifndef ATTRIBUTE_MALLOC
 120 # if (GCC_VERSION >= 2096)
 121 #  define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
 122 # else
 123 #  define ATTRIBUTE_MALLOC
 124 # endif /* GNUC >= 2.96 */
 125 #endif /* ATTRIBUTE_MALLOC */
 126
 127 /* Attributes on labels were valid as of gcc 2.93 and g++ 4.5.  For
 128    g++ an attribute on a label must be followed by a semicolon.  */
 129 #ifndef ATTRIBUTE_UNUSED_LABEL
 130 # ifndef __cplusplus
 131 #  if GCC_VERSION >= 2093
 132 #   define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
 133 #  else
 134 #   define ATTRIBUTE_UNUSED_LABEL
 135 #  endif
 136 # else
 137 #  if GCC_VERSION >= 4005
 138 #   define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED ;
 139 #  else
 140 #   define ATTRIBUTE_UNUSED_LABEL
 141 #  endif
 142 # endif
 143 #endif
 144
 145 /* Similarly to ARG_UNUSED below.  Prior to GCC 3.4, the C++ frontend
 146    couldn't parse attributes placed after the identifier name, and now
 147    the entire compiler is built with C++.  */
 148 #ifndef ATTRIBUTE_UNUSED
 149 #if GCC_VERSION >= 3004
 150 #  define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
 151 #else
 152 #define ATTRIBUTE_UNUSED
 153 #endif
 154 #endif /* ATTRIBUTE_UNUSED */
 155
 156 /* Before GCC 3.4, the C++ frontend couldn't parse attributes placed after the
 157    identifier name.  */
 158 #if ! defined(__cplusplus) || (GCC_VERSION >= 3004)
 159 # define ARG_UNUSED(NAME) NAME ATTRIBUTE_UNUSED
 160 #else /* !__cplusplus || GNUC >= 3.4 */
 161 # define ARG_UNUSED(NAME) NAME
 162 #endif /* !__cplusplus || GNUC >= 3.4 */
 163
 164 #ifndef ATTRIBUTE_NORETURN
 165 #define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
 166 #endif /* ATTRIBUTE_NORETURN */
 167
 168 /* Attribute `nonnull' was valid as of gcc 3.3.  */
 169 #ifndef ATTRIBUTE_NONNULL
 170 # if (GCC_VERSION >= 3003)
 171 #  define ATTRIBUTE_NONNULL(m) __attribute__ ((__nonnull__ (m)))
 172 # else
 173 #  define ATTRIBUTE_NONNULL(m)
 174 # endif /* GNUC >= 3.3 */
 175 #endif /* ATTRIBUTE_NONNULL */
 176
 177 /* Attribute `returns_nonnull' was valid as of gcc 4.9.  */
 178 #ifndef ATTRIBUTE_RETURNS_NONNULL
 179 # if (GCC_VERSION >= 4009)
 180 #  define ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
 181 # else
 182 #  define ATTRIBUTE_RETURNS_NONNULL
 183 # endif /* GNUC >= 4.9 */
 184 #endif /* ATTRIBUTE_RETURNS_NONNULL */
 185
 186 /* Attribute `pure' was valid as of gcc 3.0.  */
 187 #ifndef ATTRIBUTE_PURE
 188 # if (GCC_VERSION >= 3000)
 189 #  define ATTRIBUTE_PURE __attribute__ ((__pure__))
 190 # else
 191 #  define ATTRIBUTE_PURE
 192 # endif /* GNUC >= 3.0 */
 193 #endif /* ATTRIBUTE_PURE */
 194
 195 /* Use ATTRIBUTE_PRINTF when the format specifier must not be NULL.
 196    This was the case for the `printf' format attribute by itself
 197    before GCC 3.3, but as of 3.3 we need to add the `nonnull'
 198    attribute to retain this behavior.  */
 199 #ifndef ATTRIBUTE_PRINTF
 200 #define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n))) ATTRIBUTE_NONNULL(m)
 201 #define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
 202 #define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
 203 #define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
 204 #define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
 205 #define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
 206 #endif /* ATTRIBUTE_PRINTF */
 207
 208 /* Use ATTRIBUTE_FPTR_PRINTF when the format attribute is to be set on
 209    a function pointer.  Format attributes were allowed on function
 210    pointers as of gcc 3.1.  */
 211 #ifndef ATTRIBUTE_FPTR_PRINTF
 212 # if (GCC_VERSION >= 3001)
 213 #  define ATTRIBUTE_FPTR_PRINTF(m, n) ATTRIBUTE_PRINTF(m, n)
 214 # else
 215 #  define ATTRIBUTE_FPTR_PRINTF(m, n)
 216 # endif /* GNUC >= 3.1 */
 217 # define ATTRIBUTE_FPTR_PRINTF_1 ATTRIBUTE_FPTR_PRINTF(1, 2)
 218 # define ATTRIBUTE_FPTR_PRINTF_2 ATTRIBUTE_FPTR_PRINTF(2, 3)
 219 # define ATTRIBUTE_FPTR_PRINTF_3 ATTRIBUTE_FPTR_PRINTF(3, 4)
 220 # define ATTRIBUTE_FPTR_PRINTF_4 ATTRIBUTE_FPTR_PRINTF(4, 5)
 221 # define ATTRIBUTE_FPTR_PRINTF_5 ATTRIBUTE_FPTR_PRINTF(5, 6)
 222 #endif /* ATTRIBUTE_FPTR_PRINTF */
 223
 224 /* Use ATTRIBUTE_NULL_PRINTF when the format specifier may be NULL.  A
 225    NULL format specifier was allowed as of gcc 3.3.  */
 226 #ifndef ATTRIBUTE_NULL_PRINTF
 227 # if (GCC_VERSION >= 3003)
 228 #  define ATTRIBUTE_NULL_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
 229 # else
 230 #  define ATTRIBUTE_NULL_PRINTF(m, n)
 231 # endif /* GNUC >= 3.3 */
 232 # define ATTRIBUTE_NULL_PRINTF_1 ATTRIBUTE_NULL_PRINTF(1, 2)
 233 # define ATTRIBUTE_NULL_PRINTF_2 ATTRIBUTE_NULL_PRINTF(2, 3)
 234 # define ATTRIBUTE_NULL_PRINTF_3 ATTRIBUTE_NULL_PRINTF(3, 4)
 235 # define ATTRIBUTE_NULL_PRINTF_4 ATTRIBUTE_NULL_PRINTF(4, 5)
 236 # define ATTRIBUTE_NULL_PRINTF_5 ATTRIBUTE_NULL_PRINTF(5, 6)
 237 #endif /* ATTRIBUTE_NULL_PRINTF */
 238
 239 /* Attribute `sentinel' was valid as of gcc 3.5.  */
 240 #ifndef ATTRIBUTE_SENTINEL
 241 # if (GCC_VERSION >= 3005)
 242 #  define ATTRIBUTE_SENTINEL __attribute__ ((__sentinel__))
 243 # else
 244 #  define ATTRIBUTE_SENTINEL
 245 # endif /* GNUC >= 3.5 */
 246 #endif /* ATTRIBUTE_SENTINEL */
 247
 248
 249 #ifndef ATTRIBUTE_ALIGNED_ALIGNOF
 250 # if (GCC_VERSION >= 3000)
 251 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m) __attribute__ ((__aligned__ (__alignof__ (m))))
 252 # else
 253 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m)
 254 # endif /* GNUC >= 3.0 */
 255 #endif /* ATTRIBUTE_ALIGNED_ALIGNOF */
 256
 257 /* Useful for structures whose layout must much some binary specification
 258    regardless of the alignment and padding qualities of the compiler.  */
 259 #ifndef ATTRIBUTE_PACKED
 260 # define ATTRIBUTE_PACKED __attribute__ ((packed))
 261 #endif
 262
 263 /* Attribute `hot' and `cold' was valid as of gcc 4.3.  */
 264 #ifndef ATTRIBUTE_COLD
 265 # if (GCC_VERSION >= 4003)
 266 #  define ATTRIBUTE_COLD __attribute__ ((__cold__))
 267 # else
 268 #  define ATTRIBUTE_COLD
 269 # endif /* GNUC >= 4.3 */
 270 #endif /* ATTRIBUTE_COLD */
 271 #ifndef ATTRIBUTE_HOT
 272 # if (GCC_VERSION >= 4003)
 273 #  define ATTRIBUTE_HOT __attribute__ ((__hot__))
 274 # else
 275 #  define ATTRIBUTE_HOT
 276 # endif /* GNUC >= 4.3 */
 277 #endif /* ATTRIBUTE_HOT */
 278
 279 /* We use __extension__ in some places to suppress -pedantic warnings
 280    about GCC extensions.  This feature didn't work properly before
 281    gcc 2.8.  */
 282 #if GCC_VERSION < 2008
 283 #define __extension__
 284 #endif
 285
 286 /* This is used to declare a const variable which should be visible
 287    outside of the current compilation unit.  Use it as
 288      EXPORTED_CONST int i = 1;
 289    This is because the semantics of const are different in C and C++.
 290    "extern const" is permitted in C but it looks strange, and gcc
 291    warns about it when -Wc++-compat is not used.  */
 292 #ifdef __cplusplus
 293 #define EXPORTED_CONST extern const
 294 #else
 295 #define EXPORTED_CONST const
 296 #endif
 297
 298 /* Be conservative and only use enum bitfields with C++ or GCC.
 299    FIXME: provide a complete autoconf test for buggy enum bitfields.  */
 300
 301 #ifdef __cplusplus
 302 #define ENUM_BITFIELD(TYPE) enum TYPE
 303 #elif (GCC_VERSION > 2000)
 304 #define ENUM_BITFIELD(TYPE) __extension__ enum TYPE
 305 #else
 306 #define ENUM_BITFIELD(TYPE) unsigned int
 307 #endif
 308
 309 #ifdef __cplusplus
 310 }
 311 #endif
 312
 313 #endif  /* ansidecl.h   */