xref: /illumos-gate/usr/src/uts/common/sys/stddef.h (revision c5bab7026b8e0ac44b25ee08507ea360f177d844)
1 /*
2  * This file and its contents are supplied under the terms of the
3  * Common Development and Distribution License ("CDDL"), version 1.0.
4  * You may only use this file in accordance with the terms of version
5  * 1.0 of the CDDL.
6  *
7  * A full copy of the text of the CDDL should have accompanied this
8  * source.  A copy of the CDDL is also available via the Internet at
9  * http://www.illumos.org/license/CDDL.
10  */
11 
12 /*
13  * Copyright 2017 Toomas Soome <tsoome@me.com>
14  */
15 
16 #ifndef _SYS_STDDEF_H
17 #define	_SYS_STDDEF_H
18 
19 /*
20  * Commonly used macros and definitions.
21  */
22 
23 #ifdef __cplusplus
24 extern "C" {
25 #endif
26 
27 #if !defined(offsetof)
28 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
29 #define	offsetof(s, m)	__builtin_offsetof(s, m)
30 #else
31 #if __cplusplus >= 199711L
32 #define	offsetof(s, m)	(std::size_t)(&(((s *)NULL)->m))
33 #else
34 #define	offsetof(s, m)	((size_t)(&(((s *)NULL)->m)))
35 #endif
36 #endif
37 #endif /* !offsetof */
38 
39 
40 /*
41  * We must not expose container_of() to userland, but we want it
42  * to be available for kernel and boot programs.
43  */
44 #if defined(_KERNEL) || defined(_BOOT)
45 #if !defined(container_of)
46 #define	container_of(m, s, name)			\
47 	(void *)((uintptr_t)(m) - (uintptr_t)offsetof(s, name))
48 #endif
49 #endif
50 
51 #ifdef __cplusplus
52 }
53 #endif
54 
55 #endif /* _SYS_STDDEF_H */
56