xref: /freebsd/contrib/tcpdump/funcattrs.h (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
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  * NORETURN, before a function declaration, means "this function
47  * never returns".  (It must go before the function declaration, e.g.
48  * "extern NORETURN func(...)" rather than after the function
49  * declaration, as the MSVC version has to go before the declaration.)
50  */
51 #if __has_attribute(noreturn) \
52     || ND_IS_AT_LEAST_GNUC_VERSION(2,5) \
53     || ND_IS_AT_LEAST_SUNC_VERSION(5,9) \
54     || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
55     || ND_IS_AT_LEAST_HP_C_VERSION(6,10)
56   /*
57    * Compiler with support for __attribute((noreturn)), or GCC 2.5 and
58    * later, or some compiler asserting compatibility with GCC 2.5 and
59    * later, or Solaris Studio 12 (Sun C 5.9) and later, or IBM XL C 10.1
60    * and later (do any earlier versions of XL C support this?), or HP aCC
61    * A.06.10 and later.
62    */
63   #define NORETURN __attribute((noreturn))
64 
65   /*
66    * However, GCC didn't support that for function *pointers* until GCC
67    * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
68    *
69    * Sun C/Oracle Studio C doesn't seem to support it, either.
70    */
71   #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401)) \
72       || (defined(__SUNPRO_C))
73     #define NORETURN_FUNCPTR
74   #else
75     #define NORETURN_FUNCPTR __attribute((noreturn))
76   #endif
77 #elif defined(_MSC_VER)
78   /*
79    * MSVC.
80    * It doesn't allow __declspec(noreturn) to be applied to function
81    * pointers.
82    */
83   #define NORETURN __declspec(noreturn)
84   #define NORETURN_FUNCPTR
85 #else
86   #define NORETURN
87   #define NORETURN_FUNCPTR
88 #endif
89 
90 /*
91  * WARN_UNUSED_RESULT, before a function declaration, means "the caller
92  * should use the result of this function" (even if it's just a success/
93  * failure indication).
94  */
95 #if __has_attribute(warn_unused_result) \
96     || ND_IS_AT_LEAST_GNUC_VERSION(3,4) \
97     || ND_IS_AT_LEAST_HP_C_VERSION(6,25)
98   #define WARN_UNUSED_RESULT __attribute((warn_unused_result))
99 #else
100   #define WARN_UNUSED_RESULT
101 #endif
102 
103 /*
104  * PRINTFLIKE(x,y), after a function declaration, means "this function
105  * does printf-style formatting, with the xth argument being the format
106  * string and the yth argument being the first argument for the format
107  * string".
108  */
109 #if __has_attribute(__format__) \
110     || ND_IS_AT_LEAST_GNUC_VERSION(2,3) \
111     || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
112     || ND_IS_AT_LEAST_HP_C_VERSION(6,10)
113   /*
114    * Compiler with support for it, or GCC 2.3 and later, or some compiler
115    * asserting compatibility with GCC 2.3 and later, or IBM XL C 10.1
116    * and later (do any earlier versions of XL C support this?),
117    * or HP aCC A.06.10 and later.
118    */
119   #define PRINTFLIKE(x,y) __attribute__((__format__(__printf__,x,y)))
120 
121   /*
122    * However, GCC didn't support that for function *pointers* until GCC
123    * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
124    * XL C 16.1 (and possibly some earlier versions, but not 12.1 or 13.1) has
125    * a similar bug, the bugfix for which was made in:
126    * * version 16.1.1.8 for Linux (25 June 2020), which fixes
127    *   https://www.ibm.com/support/pages/apar/LI81402
128    * * version 16.1.0.5 for AIX (5 May 2020), which fixes
129    *   https://www.ibm.com/support/pages/apar/IJ24678
130    *
131    * When testing versions, keep in mind that XL C 16.1 pretends to be both
132    * GCC 4.2 and Clang 4.0 at once.
133    */
134   #if (ND_IS_AT_LEAST_GNUC_VERSION(4,1) \
135        && !ND_IS_AT_LEAST_XL_C_VERSION(10,1)) \
136       || (ND_IS_AT_LEAST_XL_C_VERSION(16,1) \
137           && (ND_IS_AT_LEAST_XL_C_MODFIX(1, 8) && defined(__linux__)) \
138               || (ND_IS_AT_LEAST_XL_C_MODFIX(0, 5) && defined(_AIX)))
139     #define PRINTFLIKE_FUNCPTR(x,y) __attribute__((__format__(__printf__,x,y)))
140   #endif
141 #endif
142 
143 #if !defined(PRINTFLIKE)
144 #define PRINTFLIKE(x,y)
145 #endif
146 #if !defined(PRINTFLIKE_FUNCPTR)
147 #define PRINTFLIKE_FUNCPTR(x,y)
148 #endif
149 
150 /*
151  * For flagging arguments as format strings in MSVC.
152  */
153 #ifdef _MSC_VER
154  #include <sal.h>
155  #define FORMAT_STRING(p) _Printf_format_string_ p
156 #else
157  #define FORMAT_STRING(p) p
158 #endif
159 
160 #endif /* lib_funcattrs_h */
161