FFmpeg  4.0
attributes.h
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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 #ifndef av_always_inline
38 #if AV_GCC_VERSION_AT_LEAST(3,1)
39 # define av_always_inline __attribute__((always_inline)) inline
40 #elif defined(_MSC_VER)
41 # define av_always_inline __forceinline
42 #else
43 # define av_always_inline inline
44 #endif
45 #endif
46 
47 #ifndef av_extern_inline
48 #if defined(__ICL) && __ICL >= 1210 || defined(__GNUC_STDC_INLINE__)
49 # define av_extern_inline extern inline
50 #else
51 # define av_extern_inline inline
52 #endif
53 #endif
54 
55 #if AV_GCC_VERSION_AT_LEAST(3,4)
56 # define av_warn_unused_result __attribute__((warn_unused_result))
57 #else
58 # define av_warn_unused_result
59 #endif
60 
61 #if AV_GCC_VERSION_AT_LEAST(3,1)
62 # define av_noinline __attribute__((noinline))
63 #elif defined(_MSC_VER)
64 # define av_noinline __declspec(noinline)
65 #else
66 # define av_noinline
67 #endif
68 
69 #if AV_GCC_VERSION_AT_LEAST(3,1) || defined(__clang__)
70 # define av_pure __attribute__((pure))
71 #else
72 # define av_pure
73 #endif
74 
75 #if AV_GCC_VERSION_AT_LEAST(2,6) || defined(__clang__)
76 # define av_const __attribute__((const))
77 #else
78 # define av_const
79 #endif
80 
81 #if AV_GCC_VERSION_AT_LEAST(4,3) || defined(__clang__)
82 # define av_cold __attribute__((cold))
83 #else
84 # define av_cold
85 #endif
86 
87 #if AV_GCC_VERSION_AT_LEAST(4,1) && !defined(__llvm__)
88 # define av_flatten __attribute__((flatten))
89 #else
90 # define av_flatten
91 #endif
92 
93 #if AV_GCC_VERSION_AT_LEAST(3,1)
94 # define attribute_deprecated __attribute__((deprecated))
95 #elif defined(_MSC_VER)
96 # define attribute_deprecated __declspec(deprecated)
97 #else
98 # define attribute_deprecated
99 #endif
100 
101 /**
102  * Disable warnings about deprecated features
103  * This is useful for sections of code kept for backward compatibility and
104  * scheduled for removal.
105  */
106 #ifndef AV_NOWARN_DEPRECATED
107 #if AV_GCC_VERSION_AT_LEAST(4,6)
108 # define AV_NOWARN_DEPRECATED(code) \
109  _Pragma("GCC diagnostic push") \
110  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"") \
111  code \
112  _Pragma("GCC diagnostic pop")
113 #elif defined(_MSC_VER)
114 # define AV_NOWARN_DEPRECATED(code) \
115  __pragma(warning(push)) \
116  __pragma(warning(disable : 4996)) \
117  code; \
118  __pragma(warning(pop))
119 #else
120 # define AV_NOWARN_DEPRECATED(code) code
121 #endif
122 #endif
123 
124 #if defined(__GNUC__) || defined(__clang__)
125 # define av_unused __attribute__((unused))
126 #else
127 # define av_unused
128 #endif
129 
130 /**
131  * Mark a variable as used and prevent the compiler from optimizing it
132  * away. This is useful for variables accessed only from inline
133  * assembler without the compiler being aware.
134  */
135 #if AV_GCC_VERSION_AT_LEAST(3,1) || defined(__clang__)
136 # define av_used __attribute__((used))
137 #else
138 # define av_used
139 #endif
140 
141 #if AV_GCC_VERSION_AT_LEAST(3,3) || defined(__clang__)
142 # define av_alias __attribute__((may_alias))
143 #else
144 # define av_alias
145 #endif
146 
147 #if (defined(__GNUC__) || defined(__clang__)) && !defined(__INTEL_COMPILER)
148 # define av_uninit(x) x=x
149 #else
150 # define av_uninit(x) x
151 #endif
152 
153 #if defined(__GNUC__) || defined(__clang__)
154 # define av_builtin_constant_p __builtin_constant_p
155 # define av_printf_format(fmtpos, attrpos) __attribute__((__format__(__printf__, fmtpos, attrpos)))
156 #else
157 # define av_builtin_constant_p(x) 0
158 # define av_printf_format(fmtpos, attrpos)
159 #endif
160 
161 #if AV_GCC_VERSION_AT_LEAST(2,5) || defined(__clang__)
162 # define av_noreturn __attribute__((noreturn))
163 #else
164 # define av_noreturn
165 #endif
166 
167 #endif /* AVUTIL_ATTRIBUTES_H */
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