C的offsetof和container_of

#include <stdio.h>

#include <stddef.h>

// #define offsetof(s, m)   (size_t)&(((s *)0)->m)

 

struct A

{

        int a;

        int b;

};

 

int main()

{

        printf("%d\n", offsetof(struct A, b));

        return 0;

}

http://blog.csdn.net/pengzhixi/article/details/4275887

 

#define container_of(ptr, type, member) \

  ((type *) ((char *) (ptr) - offsetof(type, member)))