c语言结构体及成员的互换，并且打印结构体地址和成员地址

#include <stdio.h>#define offsetof(TYPE , MEMBER)((size_t) &((TYPE *)0)->MEMBER)//container_of是给定结构体某个成员的地址反推其结构体地址#define container_of(ptr , type , member)({            \const typeof(((type *)0)->member)*__mptr = (ptr);      \(type *)((char *)__mptr - offsetof(type , member));})//#define container(ptr , type , member)(type *)((char *)ptr - offsetof(type , member)) // 返回结构体地址#define container(ptr , type , member)(type *)((char *)ptr)   //返回成员的地址struct tag_test{        int i;        char s[32];        void *p;};#define print_addr(var) printf(" "#var": %p\n", var)int main(void){        struct tag_test tstr;        struct tag_test *ca = container_of(&(tstr.p) , struct tag_test , p);        //struct tag_test *ca2 = container(&(tstr.p) , struct tag_test , p);        struct tag_test *ca2 = (struct tag_test *)((char *)&(tstr.p)); //打印p成员的地址        print_addr(&tstr);        print_addr(ca);        print_addr(ca2);        return 0;}