include/sys/stddef.h

   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 */