linux内核container_of宏获取结构体地址

先mark一下　linux内核container_of宏

/*
 * =====================================================================================
 *
 *       Filename:  contion_of.cpp
 *
 *    Description:  
 *
 *        Version:  1.0
 *        Created:  2016年05月29日 17时00分20秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  
 *   Organization:  
 *
 * =====================================================================================
 */
#include 
#include 

/**
 * container_of - cast a member of a structure out to the containing structure
 * @ptr:    the pointer to the member.
 * @type:   the type of the container struct this is embedded in.
 * @member: the name of the member within the struct.
 *
 **/
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

#define container_of(ptr, type, member) ({\
    const typeof( ((type *)0)->member ) *__mptr = (ptr);\
    (type *)( (char *)__mptr - offsetof(type,member) );})

struct A{
    unsigned int c;
    char a;
    char b;
};

int main(int argc, char** argv){

    struct A tmp;
    tmp.c = 100;
    tmp.b = 'c';
    char *a = &tmp.b;
    struct A *p = container_of(a,struct A,b);
    printf("tmp.c = %u ,A.c = %u\n",tmp.c,p->c);
    return 0;
}