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/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright 2017 Toomas Soome <tsoome@me.com>
*/
#ifndef _SYS_CONTAINEROF_H
#define _SYS_CONTAINEROF_H
/*
* __containerof macro for private use in illumos.
*
* __containerof(ptr, type, member) will return pointer to the data
* structure of given type, calculated based on the offset of 'member'
* in the structure 'type'.
*
* For this macro to work, we should be certain of the pointer type.
*/
#include <sys/stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
#if !defined(__containerof)
/*
* The extension to support statements and declarations in expressions,
* https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html, is available
* in gcc >= 3.1.
* We perform the assignment below to try and provide additional type safety.
*/
#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
#define __containerof(m, s, name) ( \
{ \
const volatile __typeof(((s *)0)->name) *__m = (m); \
(void *)((uintptr_t)__m - (uintptr_t)offsetof(s, name)); \
})
#else
#define __containerof(m, s, name) \
(void *)((uintptr_t)(m) - (uintptr_t)offsetof(s, name))
#endif
#endif
#ifdef __cplusplus
}
#endif
#endif /* _SYS_CONTAINEROF_H */
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