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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 #else
32 # define AV_GCC_VERSION_AT_LEAST(x,y) 0
33 #endif
34 
35 #ifndef av_always_inline
36 #if AV_GCC_VERSION_AT_LEAST(3,1)
37 # define av_always_inline __attribute__((always_inline)) inline
38 #elif defined(_MSC_VER)
39 # define av_always_inline __forceinline
40 #else
41 # define av_always_inline inline
42 #endif
43 #endif
44 
45 #ifndef av_extern_inline
46 #if defined(__ICL) && __ICL >= 1210 || defined(__GNUC_STDC_INLINE__)
47 # define av_extern_inline extern inline
48 #else
49 # define av_extern_inline inline
50 #endif
51 #endif
52 
53 #if AV_GCC_VERSION_AT_LEAST(3,1)
54 # define av_noinline __attribute__((noinline))
55 #else
56 # define av_noinline
57 #endif
58 
59 #if AV_GCC_VERSION_AT_LEAST(3,1)
60 # define av_pure __attribute__((pure))
61 #else
62 # define av_pure
63 #endif
64 
65 #ifndef av_restrict
66 #define av_restrict restrict
67 #endif
68 
69 #if AV_GCC_VERSION_AT_LEAST(2,6)
70 # define av_const __attribute__((const))
71 #else
72 # define av_const
73 #endif
74 
75 #if AV_GCC_VERSION_AT_LEAST(4,3)
76 # define av_cold __attribute__((cold))
77 #else
78 # define av_cold
79 #endif
80 
81 #if AV_GCC_VERSION_AT_LEAST(4,1)
82 # define av_flatten __attribute__((flatten))
83 #else
84 # define av_flatten
85 #endif
86 
87 #if AV_GCC_VERSION_AT_LEAST(3,1)
88 # define attribute_deprecated __attribute__((deprecated))
89 #else
90 # define attribute_deprecated
91 #endif
92 
93 /**
94  * Disable warnings about deprecated features
95  * This is useful for sections of code kept for backward compatibility and
96  * scheduled for removal.
97  */
98 #ifndef AV_NOWARN_DEPRECATED
99 #if AV_GCC_VERSION_AT_LEAST(4,6)
100 # define AV_NOWARN_DEPRECATED(code) \
101  _Pragma("GCC diagnostic push") \
102  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"") \
103  code \
104  _Pragma("GCC diagnostic pop")
105 #else
106 # define AV_NOWARN_DEPRECATED(code) code
107 #endif
108 #endif
109 
110 
111 #if defined(__GNUC__)
112 # define av_unused __attribute__((unused))
113 #else
114 # define av_unused
115 #endif
116 
117 /**
118  * Mark a variable as used and prevent the compiler from optimizing it
119  * away. This is useful for variables accessed only from inline
120  * assembler without the compiler being aware.
121  */
122 #if AV_GCC_VERSION_AT_LEAST(3,1)
123 # define av_used __attribute__((used))
124 #else
125 # define av_used
126 #endif
127 
128 #if AV_GCC_VERSION_AT_LEAST(3,3)
129 # define av_alias __attribute__((may_alias))
130 #else
131 # define av_alias
132 #endif
133 
134 #if defined(__GNUC__) && !defined(__INTEL_COMPILER) && !defined(__clang__)
135 # define av_uninit(x) x=x
136 #else
137 # define av_uninit(x) x
138 #endif
139 
140 #ifdef __GNUC__
141 # define av_builtin_constant_p __builtin_constant_p
142 # define av_printf_format(fmtpos, attrpos) __attribute__((__format__(__printf__, fmtpos, attrpos)))
143 #else
144 # define av_builtin_constant_p(x) 0
145 # define av_printf_format(fmtpos, attrpos)
146 #endif
147 
148 #if AV_GCC_VERSION_AT_LEAST(2,5)
149 # define av_noreturn __attribute__((noreturn))
150 #else
151 # define av_noreturn
152 #endif
153 
154 #endif /* AVUTIL_ATTRIBUTES_H */