Add container_of macro

This commit is contained in:
Justin R. Cutler 2016-04-08 21:16:07 -04:00
parent 0eed022034
commit cd1b95aea3
1 changed files with 27 additions and 0 deletions

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threadless/container_of.h Normal file
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/* threadless.io
* Copyright (c) 2016 Justin R. Cutler
* Licensed under the MIT License. See LICENSE file in the project root for
* full license information.
*/
/** @file
* container_of macro definition
* @author Justin R. Cutler <justin.r.cutler@gmail.com>
*/
#ifndef THREADLESS_CONTAINER_OF_H
#define THREADLESS_CONTAINER_OF_H
/* offsetof */
#include <stddef.h>
/** Get a pointer to the containing structure of a member
* @param ptr address of @p member within a @p type
* @param type type of container
* @param member name of the member in @p type
* @returns pointer to containing @p type
*/
#define container_of(ptr, type, member) ( \
(type *)((char *)(1 ? (ptr) : &((type *)0)->member) \
- offsetof(type, member)) \
)
#endif /* THREADLESS_CONTAINER_OF_H */