]> The Tcpdump Group git mirrors - tcpdump/blob - funcattrs.h
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[tcpdump] / funcattrs.h
1 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
2 /*
3 * Copyright (c) 1993, 1994, 1995, 1996, 1997
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by the Computer Systems
17 * Engineering Group at Lawrence Berkeley Laboratory.
18 * 4. Neither the name of the University nor of the Laboratory may be used
19 * to endorse or promote products derived from this software without
20 * specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #ifndef lib_funcattrs_h
36 #define lib_funcattrs_h
37
38 #include "compiler-tests.h"
39
40 /*
41 * Attributes to apply to functions and their arguments, using various
42 * compiler-specific extensions.
43 */
44
45 /*
46 * This was introduced by Clang:
47 *
48 * https://clang.llvm.org/docs/LanguageExtensions.html#has-attribute
49 *
50 * in some version (which version?); it has been picked up by GCC 5.0.
51 */
52 #ifndef __has_attribute
53 /*
54 * It's a macro, so you can check whether it's defined to check
55 * whether it's supported.
56 *
57 * If it's not, define it to always return 0, so that we move on to
58 * the fallback checks.
59 */
60 #define __has_attribute(x) 0
61 #endif
62
63 /*
64 * NORETURN, before a function declaration, means "this function
65 * never returns". (It must go before the function declaration, e.g.
66 * "extern NORETURN func(...)" rather than after the function
67 * declaration, as the MSVC version has to go before the declaration.)
68 */
69 #if __has_attribute(noreturn) \
70 || ND_IS_AT_LEAST_GNUC_VERSION(2,5) \
71 || ND_IS_AT_LEAST_SUNC_VERSION(5,9) \
72 || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
73 || ND_IS_AT_LEAST_HP_C_VERSION(6,10)
74 /*
75 * Compiler with support for __attribute((noreturn)), or GCC 2.5 and
76 * later, or Solaris Studio 12 (Sun C 5.9) and later, or IBM XL C 10.1
77 * and later (do any earlier versions of XL C support this?), or
78 * HP aCC A.06.10 and later.
79 */
80 #define NORETURN __attribute((noreturn))
81
82 /*
83 * However, GCC didn't support that for function *pointers* until GCC
84 * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
85 *
86 * Sun C/Oracle Studio C doesn't seem to support it, either.
87 */
88 #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401)) \
89 || (defined(__SUNPRO_C))
90 #define NORETURN_FUNCPTR
91 #else
92 #define NORETURN_FUNCPTR __attribute((noreturn))
93 #endif
94 #elif defined(_MSC_VER)
95 /*
96 * MSVC.
97 * It doesn't allow __declspec(noreturn) to be applied to function
98 * pointers.
99 */
100 #define NORETURN __declspec(noreturn)
101 #define NORETURN_FUNCPTR
102 #else
103 #define NORETURN
104 #define NORETURN_FUNCPTR
105 #endif
106
107 /*
108 * PRINTFLIKE(x,y), after a function declaration, means "this function
109 * does printf-style formatting, with the xth argument being the format
110 * string and the yth argument being the first argument for the format
111 * string".
112 */
113 #if __has_attribute(__format__) \
114 || ND_IS_AT_LEAST_GNUC_VERSION(2,3) \
115 || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
116 || ND_IS_AT_LEAST_HP_C_VERSION(6,10)
117 /*
118 * Compiler with support for it, or GCC 2.3 and later, or IBM XL C 10.1
119 * and later (do any earlier versions of XL C support this?),
120 * or HP aCC A.06.10 and later.
121 */
122 #define PRINTFLIKE(x,y) __attribute__((__format__(__printf__,x,y)))
123
124 /*
125 * However, GCC didn't support that for function *pointers* until GCC
126 * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
127 */
128 #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401))
129 #define PRINTFLIKE_FUNCPTR(x,y)
130 #else
131 #define PRINTFLIKE_FUNCPTR(x,y) __attribute__((__format__(__printf__,x,y)))
132 #endif
133 #else
134 #define PRINTFLIKE(x,y)
135 #define PRINTFLIKE_FUNCPTR(x,y)
136 #endif
137
138 /*
139 * For flagging arguments as format strings in MSVC.
140 */
141 #ifdef _MSC_VER
142 #include <sal.h>
143 #define FORMAT_STRING(p) _Printf_format_string_ p
144 #else
145 #define FORMAT_STRING(p) p
146 #endif
147
148 #endif /* lib_funcattrs_h */