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/*
* File : container_of.c
* Author : Jérémy Zurcher <jeremy@asynk.ch>
* Date : 2009/11/01
* License :
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#include "stdio.h"
#include "stdlib.h"
#include "stddef.h"
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
#define containerof(ptr, type, member) ( { (type*)(((char*)ptr)-offsetof(type,member)); } )
struct node
{
int data1;
int data2;
int data3;
int data4;
int data5;
};
static void _check(int cond, const char *msg)
{
if(!cond)
{
fprintf(stderr,"%s failed\n",msg);
exit(EXIT_FAILURE);
}
}
int main(int argc, char *argv[])
{
struct node n;
_check((&n==container_of( &n.data1, struct node, data1)),"1 container_of");
_check((&n==container_of( &n.data2, struct node, data2)),"2 container_of");
_check((&n==container_of( &n.data3, struct node, data3)),"3 container_of");
_check((&n==container_of( &n.data4, struct node, data4)),"4 container_of");
_check((&n==container_of( &n.data5, struct node, data5)),"5 container_of");
_check((&n==containerof( &n.data1, struct node, data1)),"1 containerof");
_check((&n==containerof( &n.data2, struct node, data2)),"2 containerof");
_check((&n==containerof( &n.data3, struct node, data3)),"3 containerof");
_check((&n==containerof( &n.data4, struct node, data4)),"4 containerof");
_check((&n==containerof( &n.data5, struct node, data5)),"5 containerof");
printf("success\n");
return EXIT_SUCCESS;
}
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