xref: /freebsd/include/assert.h (revision 73e0d6b44038d1c7764c5013a54ae17a8f680a69)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #include <sys/cdefs.h>
38 
39 /*
40  * Unlike other ANSI header files, <assert.h> may usefully be included
41  * multiple times, with and without NDEBUG defined.
42  */
43 
44 #undef assert
45 #undef _assert
46 #undef __assert_unreachable
47 
48 #ifdef NDEBUG
49 #define	assert(e)	((void)0)
50 #define	_assert(e)	((void)0)
51 #if __BSD_VISIBLE
52 #define	__assert_unreachable()	__unreachable()
53 #endif	/* __BSD_VISIBLE */
54 #else
55 #ifdef __cplusplus
56 #if __cplusplus < 202002L
57 /*
58  * C++ modes prior to C++20 cannot simultaneously satisfy all three
59  * desirable properties of the sanitiser:
60  *
61  *   Approach                       No double-eval  Lambda support  Arity check
62  *   -----------------------------  --------------  --------------  -----------
63  *   sizeof(cast(expression))       yes             no              yes
64  *   static_cast<bool>(expression)  no              yes             no
65  *   (void)bool(expression)         no              yes             no
66  *
67  *   NOTE: C++20 introduced lambdas in unevaluated contexts; see P0315R4.
68  *
69  * Since no approach satisfies all three below C++20, the least harmful
70  * choice is to forgo the check entirely rather than silently break one
71  * of the remaining guarantees.
72  *
73  */
74 #define	__assert_sanitize(...)	((void)0)
75 #else
76 #define	__assert_sanitize(...)	(void)sizeof(((bool(*)(bool))0)(__VA_ARGS__))
77 #endif /* __cplusplus < 202002L */
78 #else
79 #define	__assert_sanitize(...)	(void)sizeof(((_Bool(*)(_Bool))0)(__VA_ARGS__))
80 #endif /* __cplusplus */
81 #define	assert(...)	(__assert_sanitize(__VA_ARGS__),       \
82 			    (__VA_ARGS__) ? (void)0 :          \
83 			    __assert(__func__, __FILE__,       \
84 			    __LINE__, #__VA_ARGS__))
85 #define	_assert(...)	assert(__VA_ARGS__)
86 #if __BSD_VISIBLE
87 #define	__assert_unreachable()	assert(0 && "unreachable segment reached")
88 #endif	/* __BSD_VISIBLE */
89 #endif /* NDEBUG */
90 
91 #ifndef __STDC_VERSION_ASSERT_H__
92 #define	__STDC_VERSION_ASSERT_H__ 202311L
93 
94 /*
95  * Static assertions.  In principle we could define static_assert for
96  * C++ older than C++11, but this breaks if _Static_assert is
97  * implemented as a macro.
98  *
99  * C++ template parameters may contain commas, even if not enclosed in
100  * parentheses, causing the _Static_assert macro to be invoked with more
101  * than two parameters.
102  *
103  * C23 defines static_assert and its obsolescent alternative spelling,
104  * _Static_assert, as keywords.
105  */
106 #if __ISO_C_VISIBLE >= 2011 && !defined(__cplusplus) && \
107     __STDC_VERSION__ < 202311L
108 #define	static_assert	_Static_assert
109 #endif
110 
111 __BEGIN_DECLS
112 void __assert(const char *, const char *, int, const char *) __dead2;
113 __END_DECLS
114 
115 #endif /* !__STDC_VERSION_ASSERT_H__ */
116