include/ansidecl.h

   1 /* Compiler compatibility macros
   2    Copyright (C) 1991-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2 of the License, or
   8 (at your option) any later version.
   9
  10 This program 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
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  18
  19 /* For ease of writing code which uses GCC extensions but needs to be
  20    portable to other compilers, we provide the GCC_VERSION macro that
  21    simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
  22    wrappers around __attribute__.  Also, __extension__ will be #defined
  23    to nothing if it doesn't work.  See below.  */
  24
  25 #ifndef _ANSIDECL_H
  26 #define _ANSIDECL_H     1
  27
  28 #ifdef __cplusplus
  29 extern "C" {
  30 #endif
  31
  32 /* Every source file includes this file,
  33    so they will all get the switch for lint.  */
  34 /* LINTLIBRARY */
  35
  36 /* Using MACRO(x,y) in cpp #if conditionals does not work with some
  37    older preprocessors.  Thus we can't define something like this:
  38
  39 #define HAVE_GCC_VERSION(MAJOR, MINOR) \
  40   (__GNUC__ > (MAJOR) || (__GNUC__ == (MAJOR) && __GNUC_MINOR__ >= (MINOR)))
  41
  42 and then test "#if HAVE_GCC_VERSION(2,7)".
  43
  44 So instead we use the macro below and test it against specific values.  */
  45
  46 /* This macro simplifies testing whether we are using gcc, and if it
  47    is of a particular minimum version. (Both major & minor numbers are
  48    significant.)  This macro will evaluate to 0 if we are not using
  49    gcc at all.  */
  50 #ifndef GCC_VERSION
  51 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
  52 #endif /* GCC_VERSION */
  53
  54 /* inline requires special treatment; it's in C99, and GCC >=2.7 supports
  55    it too, but it's not in C89.  */
  56 #undef inline
  57 #if (!defined(__cplusplus) && __STDC_VERSION__ >= 199901L) || defined(__cplusplus) || (defined(__SUNPRO_C) && defined(__C99FEATURES__))
  58 /* it's a keyword */
  59 #else
  60 # if GCC_VERSION >= 2007
  61 #  define inline __inline__   /* __inline__ prevents -pedantic warnings */
  62 # else
  63 #  define inline  /* nothing */
  64 # endif
  65 #endif
  66
  67 /* Define macros for some gcc attributes.  This permits us to use the
  68    macros freely, and know that they will come into play for the
  69    version of gcc in which they are supported.  */
  70
  71 #if (GCC_VERSION < 2007)
  72 # define __attribute__(x)
  73 #endif
  74
  75 /* Attribute __malloc__ on functions was valid as of gcc 2.96. */
  76 #ifndef ATTRIBUTE_MALLOC
  77 # if (GCC_VERSION >= 2096)
  78 #  define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
  79 # else
  80 #  define ATTRIBUTE_MALLOC
  81 # endif /* GNUC >= 2.96 */
  82 #endif /* ATTRIBUTE_MALLOC */
  83
  84 /* Attributes on labels were valid as of gcc 2.93 and g++ 4.5.  For
  85    g++ an attribute on a label must be followed by a semicolon.  */
  86 #ifndef ATTRIBUTE_UNUSED_LABEL
  87 # ifndef __cplusplus
  88 #  if GCC_VERSION >= 2093
  89 #   define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
  90 #  else
  91 #   define ATTRIBUTE_UNUSED_LABEL
  92 #  endif
  93 # else
  94 #  if GCC_VERSION >= 4005
  95 #   define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED ;
  96 #  else
  97 #   define ATTRIBUTE_UNUSED_LABEL
  98 #  endif
  99 # endif
 100 #endif
 101
 102 /* Similarly to ARG_UNUSED below.  Prior to GCC 3.4, the C++ frontend
 103    couldn't parse attributes placed after the identifier name, and now
 104    the entire compiler is built with C++.  */
 105 #ifndef ATTRIBUTE_UNUSED
 106 #if GCC_VERSION >= 3004
 107 #  define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
 108 #else
 109 #define ATTRIBUTE_UNUSED
 110 #endif
 111 #endif /* ATTRIBUTE_UNUSED */
 112
 113 /* Before GCC 3.4, the C++ frontend couldn't parse attributes placed after the
 114    identifier name.  */
 115 #if ! defined(__cplusplus) || (GCC_VERSION >= 3004)
 116 # define ARG_UNUSED(NAME) NAME ATTRIBUTE_UNUSED
 117 #else /* !__cplusplus || GNUC >= 3.4 */
 118 # define ARG_UNUSED(NAME) NAME
 119 #endif /* !__cplusplus || GNUC >= 3.4 */
 120
 121 #ifndef ATTRIBUTE_NORETURN
 122 #define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
 123 #endif /* ATTRIBUTE_NORETURN */
 124
 125 /* Attribute `nonnull' was valid as of gcc 3.3.  */
 126 #ifndef ATTRIBUTE_NONNULL
 127 # if (GCC_VERSION >= 3003)
 128 #  define ATTRIBUTE_NONNULL(m) __attribute__ ((__nonnull__ (m)))
 129 # else
 130 #  define ATTRIBUTE_NONNULL(m)
 131 # endif /* GNUC >= 3.3 */
 132 #endif /* ATTRIBUTE_NONNULL */
 133
 134 /* Attribute `returns_nonnull' was valid as of gcc 4.9.  */
 135 #ifndef ATTRIBUTE_RETURNS_NONNULL
 136 # if (GCC_VERSION >= 4009)
 137 #  define ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
 138 # else
 139 #  define ATTRIBUTE_RETURNS_NONNULL
 140 # endif /* GNUC >= 4.9 */
 141 #endif /* ATTRIBUTE_RETURNS_NONNULL */
 142
 143 /* Attribute `pure' was valid as of gcc 3.0.  */
 144 #ifndef ATTRIBUTE_PURE
 145 # if (GCC_VERSION >= 3000)
 146 #  define ATTRIBUTE_PURE __attribute__ ((__pure__))
 147 # else
 148 #  define ATTRIBUTE_PURE
 149 # endif /* GNUC >= 3.0 */
 150 #endif /* ATTRIBUTE_PURE */
 151
 152 /* Use ATTRIBUTE_PRINTF when the format specifier must not be NULL.
 153    This was the case for the `printf' format attribute by itself
 154    before GCC 3.3, but as of 3.3 we need to add the `nonnull'
 155    attribute to retain this behavior.  */
 156 #ifndef ATTRIBUTE_PRINTF
 157 #define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n))) ATTRIBUTE_NONNULL(m)
 158 #define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
 159 #define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
 160 #define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
 161 #define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
 162 #define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
 163 #endif /* ATTRIBUTE_PRINTF */
 164
 165 /* Use ATTRIBUTE_FPTR_PRINTF when the format attribute is to be set on
 166    a function pointer.  Format attributes were allowed on function
 167    pointers as of gcc 3.1.  */
 168 #ifndef ATTRIBUTE_FPTR_PRINTF
 169 # if (GCC_VERSION >= 3001)
 170 #  define ATTRIBUTE_FPTR_PRINTF(m, n) ATTRIBUTE_PRINTF(m, n)
 171 # else
 172 #  define ATTRIBUTE_FPTR_PRINTF(m, n)
 173 # endif /* GNUC >= 3.1 */
 174 # define ATTRIBUTE_FPTR_PRINTF_1 ATTRIBUTE_FPTR_PRINTF(1, 2)
 175 # define ATTRIBUTE_FPTR_PRINTF_2 ATTRIBUTE_FPTR_PRINTF(2, 3)
 176 # define ATTRIBUTE_FPTR_PRINTF_3 ATTRIBUTE_FPTR_PRINTF(3, 4)
 177 # define ATTRIBUTE_FPTR_PRINTF_4 ATTRIBUTE_FPTR_PRINTF(4, 5)
 178 # define ATTRIBUTE_FPTR_PRINTF_5 ATTRIBUTE_FPTR_PRINTF(5, 6)
 179 #endif /* ATTRIBUTE_FPTR_PRINTF */
 180
 181 /* Use ATTRIBUTE_NULL_PRINTF when the format specifier may be NULL.  A
 182    NULL format specifier was allowed as of gcc 3.3.  */
 183 #ifndef ATTRIBUTE_NULL_PRINTF
 184 # if (GCC_VERSION >= 3003)
 185 #  define ATTRIBUTE_NULL_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
 186 # else
 187 #  define ATTRIBUTE_NULL_PRINTF(m, n)
 188 # endif /* GNUC >= 3.3 */
 189 # define ATTRIBUTE_NULL_PRINTF_1 ATTRIBUTE_NULL_PRINTF(1, 2)
 190 # define ATTRIBUTE_NULL_PRINTF_2 ATTRIBUTE_NULL_PRINTF(2, 3)
 191 # define ATTRIBUTE_NULL_PRINTF_3 ATTRIBUTE_NULL_PRINTF(3, 4)
 192 # define ATTRIBUTE_NULL_PRINTF_4 ATTRIBUTE_NULL_PRINTF(4, 5)
 193 # define ATTRIBUTE_NULL_PRINTF_5 ATTRIBUTE_NULL_PRINTF(5, 6)
 194 #endif /* ATTRIBUTE_NULL_PRINTF */
 195
 196 /* Attribute `sentinel' was valid as of gcc 3.5.  */
 197 #ifndef ATTRIBUTE_SENTINEL
 198 # if (GCC_VERSION >= 3005)
 199 #  define ATTRIBUTE_SENTINEL __attribute__ ((__sentinel__))
 200 # else
 201 #  define ATTRIBUTE_SENTINEL
 202 # endif /* GNUC >= 3.5 */
 203 #endif /* ATTRIBUTE_SENTINEL */
 204
 205
 206 #ifndef ATTRIBUTE_ALIGNED_ALIGNOF
 207 # if (GCC_VERSION >= 3000)
 208 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m) __attribute__ ((__aligned__ (__alignof__ (m))))
 209 # else
 210 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m)
 211 # endif /* GNUC >= 3.0 */
 212 #endif /* ATTRIBUTE_ALIGNED_ALIGNOF */
 213
 214 /* Useful for structures whose layout must match some binary specification
 215    regardless of the alignment and padding qualities of the compiler.  */
 216 #ifndef ATTRIBUTE_PACKED
 217 # define ATTRIBUTE_PACKED __attribute__ ((packed))
 218 #endif
 219
 220 /* Attribute `hot' and `cold' was valid as of gcc 4.3.  */
 221 #ifndef ATTRIBUTE_COLD
 222 # if (GCC_VERSION >= 4003)
 223 #  define ATTRIBUTE_COLD __attribute__ ((__cold__))
 224 # else
 225 #  define ATTRIBUTE_COLD
 226 # endif /* GNUC >= 4.3 */
 227 #endif /* ATTRIBUTE_COLD */
 228 #ifndef ATTRIBUTE_HOT
 229 # if (GCC_VERSION >= 4003)
 230 #  define ATTRIBUTE_HOT __attribute__ ((__hot__))
 231 # else
 232 #  define ATTRIBUTE_HOT
 233 # endif /* GNUC >= 4.3 */
 234 #endif /* ATTRIBUTE_HOT */
 235
 236 /* Attribute 'no_sanitize_undefined' was valid as of gcc 4.9.  */
 237 #ifndef ATTRIBUTE_NO_SANITIZE_UNDEFINED
 238 # if (GCC_VERSION >= 4009)
 239 #  define ATTRIBUTE_NO_SANITIZE_UNDEFINED __attribute__ ((no_sanitize_undefined))
 240 # else
 241 #  define ATTRIBUTE_NO_SANITIZE_UNDEFINED
 242 # endif /* GNUC >= 4.9 */
 243 #endif /* ATTRIBUTE_NO_SANITIZE_UNDEFINED */
 244
 245 /* Attribute 'nonstring' was valid as of gcc 8.  */
 246 #ifndef ATTRIBUTE_NONSTRING
 247 # if GCC_VERSION >= 8000
 248 #  define ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
 249 # else
 250 #  define ATTRIBUTE_NONSTRING
 251 # endif
 252 #endif
 253
 254 /* Attribute `alloc_size' was valid as of gcc 4.3.  */
 255 #ifndef ATTRIBUTE_RESULT_SIZE_1
 256 # if (GCC_VERSION >= 4003)
 257 #  define ATTRIBUTE_RESULT_SIZE_1 __attribute__ ((alloc_size (1)))
 258 # else
 259 #  define ATTRIBUTE_RESULT_SIZE_1
 260 #endif
 261 #endif
 262
 263 #ifndef ATTRIBUTE_RESULT_SIZE_2
 264 # if (GCC_VERSION >= 4003)
 265 #  define ATTRIBUTE_RESULT_SIZE_2 __attribute__ ((alloc_size (2)))
 266 # else
 267 #  define ATTRIBUTE_RESULT_SIZE_2
 268 #endif
 269 #endif
 270
 271 #ifndef ATTRIBUTE_RESULT_SIZE_1_2
 272 # if (GCC_VERSION >= 4003)
 273 #  define ATTRIBUTE_RESULT_SIZE_1_2 __attribute__ ((alloc_size (1, 2)))
 274 # else
 275 #  define ATTRIBUTE_RESULT_SIZE_1_2
 276 #endif
 277 #endif
 278
 279 /* Attribute `warn_unused_result' was valid as of gcc 3.3.  */
 280 #ifndef ATTRIBUTE_WARN_UNUSED_RESULT
 281 # if GCC_VERSION >= 3003
 282 #  define ATTRIBUTE_WARN_UNUSED_RESULT __attribute__ ((warn_unused_result))
 283 # else
 284 #  define ATTRIBUTE_WARN_UNUSED_RESULT
 285 # endif
 286 #endif
 287
 288 /* We use __extension__ in some places to suppress -pedantic warnings
 289    about GCC extensions.  This feature didn't work properly before
 290    gcc 2.8.  */
 291 #if GCC_VERSION < 2008
 292 #define __extension__
 293 #endif
 294
 295 /* This is used to declare a const variable which should be visible
 296    outside of the current compilation unit.  Use it as
 297      EXPORTED_CONST int i = 1;
 298    This is because the semantics of const are different in C and C++.
 299    "extern const" is permitted in C but it looks strange, and gcc
 300    warns about it when -Wc++-compat is not used.  */
 301 #ifdef __cplusplus
 302 #define EXPORTED_CONST extern const
 303 #else
 304 #define EXPORTED_CONST const
 305 #endif
 306
 307 /* Be conservative and only use enum bitfields with C++ or GCC.
 308    FIXME: provide a complete autoconf test for buggy enum bitfields.  */
 309
 310 #ifdef __cplusplus
 311 #define ENUM_BITFIELD(TYPE) enum TYPE
 312 #elif (GCC_VERSION > 2000)
 313 #define ENUM_BITFIELD(TYPE) __extension__ enum TYPE
 314 #else
 315 #define ENUM_BITFIELD(TYPE) unsigned int
 316 #endif
 317
 318 #if defined(__cplusplus) && __cpp_constexpr >= 200704
 319 #define CONSTEXPR constexpr
 320 #else
 321 #define CONSTEXPR
 322 #endif
 323
 324 /* A macro to disable the copy constructor and assignment operator.
 325    When building with C++11 and above, the methods are explicitly
 326    deleted, causing a compile-time error if something tries to copy.
 327    For C++03, this just declares the methods, causing a link-time
 328    error if the methods end up called (assuming you don't
 329    define them).  For C++03, for best results, place the macro
 330    under the private: access specifier, like this,
 331
 332    class name_lookup
 333    {
 334      private:
 335        DISABLE_COPY_AND_ASSIGN (name_lookup);
 336    };
 337
 338    so that most attempts at copy are caught at compile-time.  */
 339
 340 #if defined(__cplusplus) && __cplusplus >= 201103
 341 #define DISABLE_COPY_AND_ASSIGN(TYPE)           \
 342   TYPE (const TYPE&) = delete;                  \
 343   void operator= (const TYPE &) = delete
 344   #else
 345 #define DISABLE_COPY_AND_ASSIGN(TYPE)           \
 346   TYPE (const TYPE&);                           \
 347   void operator= (const TYPE &)
 348 #endif /* __cplusplus >= 201103 */
 349
 350 #ifdef __cplusplus
 351 }
 352 #endif
 353
 354 #endif  /* ansidecl.h   */