libavutil/attributes.h

   1 /*
   2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * Macro definitions for various function/variable attributes
  24  */
  25
  26 #ifndef AVUTIL_ATTRIBUTES_H
  27 #define AVUTIL_ATTRIBUTES_H
  28
  29 #ifdef __GNUC__
  30 #    define AV_GCC_VERSION_AT_LEAST(x,y) (__GNUC__ > (x) || __GNUC__ == (x) && __GNUC_MINOR__ >= (y))
  31 #    define AV_GCC_VERSION_AT_MOST(x,y)  (__GNUC__ < (x) || __GNUC__ == (x) && __GNUC_MINOR__ <= (y))
  32 #else
  33 #    define AV_GCC_VERSION_AT_LEAST(x,y) 0
  34 #    define AV_GCC_VERSION_AT_MOST(x,y)  0
  35 #endif
  36
  37 #ifdef __has_builtin
  38 #    define AV_HAS_BUILTIN(x) __has_builtin(x)
  39 #else
  40 #    define AV_HAS_BUILTIN(x) 0
  41 #endif
  42
  43 #ifdef __has_attribute
  44 #    define AV_HAS_ATTRIBUTE(x) __has_attribute(x)
  45 #else
  46 #    define AV_HAS_ATTRIBUTE(x) 0
  47 #endif
  48
  49 #if defined(__cplusplus) && defined(__has_cpp_attribute)
  50 #    define AV_HAS_STD_ATTRIBUTE(x) __has_cpp_attribute(x)
  51 #elif !defined(__cplusplus) && defined(__has_c_attribute)
  52 #    define AV_HAS_STD_ATTRIBUTE(x) __has_c_attribute(x)
  53 #else
  54 #    define AV_HAS_STD_ATTRIBUTE(x) 0
  55 #endif
  56
  57 #ifndef av_always_inline
  58 #if AV_GCC_VERSION_AT_LEAST(3,1) || defined(__clang__)
  59 #    define av_always_inline __attribute__((always_inline)) inline
  60 #elif defined(_MSC_VER)
  61 #    define av_always_inline __forceinline
  62 #else
  63 #    define av_always_inline inline
  64 #endif
  65 #endif
  66
  67 #ifndef av_extern_inline
  68 #if defined(__ICL) && __ICL >= 1210 || defined(__GNUC_STDC_INLINE__)
  69 #    define av_extern_inline extern inline
  70 #else
  71 #    define av_extern_inline inline
  72 #endif
  73 #endif
  74
  75 #if AV_HAS_STD_ATTRIBUTE(nodiscard)
  76 #    define av_warn_unused_result [[nodiscard]]
  77 #elif AV_GCC_VERSION_AT_LEAST(3,4) || defined(__clang__)
  78 #    define av_warn_unused_result __attribute__((warn_unused_result))
  79 #else
  80 #    define av_warn_unused_result
  81 #endif
  82
  83 #if AV_GCC_VERSION_AT_LEAST(3,1) || defined(__clang__)
  84 #    define av_noinline __attribute__((noinline))
  85 #elif defined(_MSC_VER)
  86 #    define av_noinline __declspec(noinline)
  87 #else
  88 #    define av_noinline
  89 #endif
  90
  91 #if AV_GCC_VERSION_AT_LEAST(3,1) || defined(__clang__)
  92 #    define av_pure __attribute__((pure))
  93 #else
  94 #    define av_pure
  95 #endif
  96
  97 #if AV_GCC_VERSION_AT_LEAST(2,6) || defined(__clang__)
  98 #    define av_const __attribute__((const))
  99 #else
 100 #    define av_const
 101 #endif
 102
 103 #if AV_GCC_VERSION_AT_LEAST(4,3) || defined(__clang__)
 104 #    define av_cold __attribute__((cold))
 105 #else
 106 #    define av_cold
 107 #endif
 108
 109 #if AV_GCC_VERSION_AT_LEAST(4,1) && !defined(__llvm__)
 110 #    define av_flatten __attribute__((flatten))
 111 #else
 112 #    define av_flatten
 113 #endif
 114
 115 #if AV_HAS_STD_ATTRIBUTE(deprecated)
 116 #    define attribute_deprecated [[deprecated]]
 117 #elif AV_GCC_VERSION_AT_LEAST(3,1) || defined(__clang__)
 118 #    define attribute_deprecated __attribute__((deprecated))
 119 #elif defined(_MSC_VER)
 120 #    define attribute_deprecated __declspec(deprecated)
 121 #else
 122 #    define attribute_deprecated
 123 #endif
 124
 125 /**
 126  * Disable warnings about deprecated features
 127  * This is useful for sections of code kept for backward compatibility and
 128  * scheduled for removal.
 129  */
 130 #ifndef AV_NOWARN_DEPRECATED
 131 #if AV_GCC_VERSION_AT_LEAST(4,6) || defined(__clang__)
 132 #    define AV_NOWARN_DEPRECATED(code) \
 133         _Pragma("GCC diagnostic push") \
 134         _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"") \
 135         code \
 136         _Pragma("GCC diagnostic pop")
 137 #elif defined(_MSC_VER)
 138 #    define AV_NOWARN_DEPRECATED(code) \
 139         __pragma(warning(push)) \
 140         __pragma(warning(disable : 4996)) \
 141         code; \
 142         __pragma(warning(pop))
 143 #else
 144 #    define AV_NOWARN_DEPRECATED(code) code
 145 #endif
 146 #endif
 147
 148 #if AV_HAS_STD_ATTRIBUTE(maybe_unused)
 149 #    define av_unused [[maybe_unused]]
 150 #elif defined(__GNUC__) || defined(__clang__)
 151 #    define av_unused __attribute__((unused))
 152 #else
 153 #    define av_unused
 154 #endif
 155
 156 /**
 157  * Mark a variable as used and prevent the compiler from optimizing it
 158  * away.  This is useful for variables accessed only from inline
 159  * assembler without the compiler being aware.
 160  */
 161 #if AV_GCC_VERSION_AT_LEAST(3,1) || defined(__clang__)
 162 #    define av_used __attribute__((used))
 163 #else
 164 #    define av_used
 165 #endif
 166
 167 #if AV_GCC_VERSION_AT_LEAST(3,3) || defined(__clang__)
 168 #   define av_alias __attribute__((may_alias))
 169 #else
 170 #   define av_alias
 171 #endif
 172
 173 #if (defined(__GNUC__) || defined(__clang__)) && !defined(__INTEL_COMPILER)
 174 #    define av_uninit(x) x=x
 175 #else
 176 #    define av_uninit(x) x
 177 #endif
 178
 179 #if defined(__GNUC__) || defined(__clang__)
 180 #    define av_builtin_constant_p __builtin_constant_p
 181 #else
 182 #    define av_builtin_constant_p(x) 0
 183 #endif
 184
 185 // for __MINGW_PRINTF_FORMAT and __MINGW_SCANF_FORMAT
 186 #ifdef __MINGW32__
 187 #    include <stdio.h>
 188 #endif
 189
 190 #ifdef __MINGW_PRINTF_FORMAT
 191 #    define AV_PRINTF_FMT __MINGW_PRINTF_FORMAT
 192 #elif AV_HAS_ATTRIBUTE(format)
 193 #    define AV_PRINTF_FMT __printf__
 194 #endif
 195
 196 #ifdef __MINGW_SCANF_FORMAT
 197 #    define AV_SCANF_FMT __MINGW_SCANF_FORMAT
 198 #elif AV_HAS_ATTRIBUTE(format)
 199 #    define AV_SCANF_FMT __scanf__
 200 #endif
 201
 202 #ifdef AV_PRINTF_FMT
 203 #    define av_printf_format(fmtpos, attrpos) __attribute__((format(AV_PRINTF_FMT, fmtpos, attrpos)))
 204 #else
 205 #    define av_printf_format(fmtpos, attrpos)
 206 #endif
 207
 208 #ifdef AV_SCANF_FMT
 209 #    define av_scanf_format(fmtpos, attrpos) __attribute__((format(AV_SCANF_FMT, fmtpos, attrpos)))
 210 #else
 211 #    define av_scanf_format(fmtpos, attrpos)
 212 #endif
 213
 214 #if AV_HAS_STD_ATTRIBUTE(noreturn)
 215 #    define av_noreturn [[noreturn]]
 216 #elif AV_GCC_VERSION_AT_LEAST(2,5) || defined(__clang__)
 217 #    define av_noreturn __attribute__((noreturn))
 218 #else
 219 #    define av_noreturn
 220 #endif
 221
 222 #endif /* AVUTIL_ATTRIBUTES_H */