1/* $NetBSD: stddef.h,v 1.2 2025/04/01 00:33:55 riastradh Exp $ */
2
3/*-
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)stddef.h 8.1 (Berkeley) 6/2/93
32 */
33
34/*
35 * C99, 7.17: Common definitions <stddef.h>
36 * C11, 7.19: Common definitoins <stddef.h>
37 * C23, 7.21: Common definitions <stddef.h>
38 */
39
40#ifndef _SYS_STDDEF_H_
41#define _SYS_STDDEF_H_
42
43/*
44 * C23 `2. The macro
45 *
46 * __STDC_VERSION_STDDEF_H__
47 *
48 * is an integer constant expression with a value equivalent
49 * to 202311L.'
50 */
51#if defined(_NETBSD_SOURCE) || defined(_ISOC23_SOURCE) || \
52 (__STDC_VERSION__ - 0) >= 202311L
53#define __STDC_VERSION_STDDEF_H__ 202311L
54#endif
55
56#include <sys/cdefs.h>
57#include <sys/featuretest.h>
58#include <machine/ansi.h>
59
60/*
61 * C23 `3. The types are
62 *
63 * ptrdiff_t
64 *
65 * which is the signed integer type of the result of
66 * subtracting two pointers;
67 *
68 * size_t
69 *
70 * which is the unsigned integer type of the result of the
71 * sizeof operator;
72 *
73 * max_align_t
74 *
75 * which is an object type whose alignment is the greatest
76 * fundamental alignment;
77 *
78 * wchar_t
79 *
80 * which is an integer type whose range of values can
81 * represent distinct codes for all members of the largest
82 * extended chracter set specified among the supported
83 * locales; [...] and
84 *
85 * nullptr_t
86 *
87 * which is the type of the nullptr predefined constant, see
88 * below.'
89 */
90#ifdef _BSD_PTRDIFF_T_
91typedef _BSD_PTRDIFF_T_ ptrdiff_t;
92#undef _BSD_PTRDIFF_T_
93#endif
94
95#ifdef _BSD_SIZE_T_
96typedef _BSD_SIZE_T_ size_t;
97#undef _BSD_SIZE_T_
98#endif
99
100#if (__STDC_VERSION__ - 0) >= 201112L || (__cplusplus - 0) >= 201103L
101typedef union {
102 void *_v;
103 long double _ld;
104 long long int _ll;
105} max_align_t;
106#endif
107
108#if defined(_BSD_WCHAR_T_) && !defined(__cplusplus)
109typedef _BSD_WCHAR_T_ wchar_t;
110#undef _BSD_WCHAR_T_
111#endif
112
113#if (__STDC_VERSION__ - 0) >= 202311L
114typedef typeof_unqual(nullptr) nullptr_t;
115#endif
116
117/*
118 * C23 `4. The macros are
119 *
120 * NULL
121 *
122 * which expands to an implementation-defined null pointer
123 * constant;
124 *
125 * unreachable()
126 *
127 * which expands to a void expression that invokes undefined
128 * behavior if it is reached during execution; and
129 *
130 * offsetof(type, member-designator)
131 *
132 * which expands to an integer constant expression that has
133 * type size_t, the value of which is the offset in bytes, to
134 * the subobject (designated by member-designator), from the
135 * beginning of any object of type type.'
136 */
137
138#include <sys/null.h>
139
140#if (__STDC_VERSION__ - 0) >= 202311L
141#define unreachable() __unreachable() /* sys/cdefs.h */
142#endif
143
144#if __GNUC_PREREQ__(4, 0)
145#define offsetof(type, member) __builtin_offsetof(type, member)
146#elif !defined(__cplusplus)
147#define offsetof(type, member) ((size_t)(unsigned long)(&((type *)0)->member))
148#else
149#if !__GNUC_PREREQ__(3, 4)
150#define __offsetof__(a) a
151#endif
152#define offsetof(type, member) __offsetof__((reinterpret_cast<size_t> \
153 (&reinterpret_cast<const volatile char &>(static_cast<type *>(0)->member))))
154#endif
155
156#endif /* _SYS_STDDEF_H_ */