#include<stdio.h>
#include<string.h>
#include<malloc.h>
typedef struct _flex_array{
        int len;
        char str;
        char buff[];
}flex_array;

int main(int argc,char **argv)
{
        char *info = "this is a flex array!";
        int info_size = strlen(info);
        printf("info_size:%d,struct size:%d\n",info_size,sizeof(flex_array));
        // info_size:21,struct size:8

        flex_array *p = (flex_array *)malloc(sizeof(flex_array) + strlen(info));
        p->len = info_size;
        memcpy(p->buff,info,p->len);

        printf("p:%d,info:%s\n",sizeof(*p),p->buff);
        // p:8,info:this is a flex array!

        free(p);
        return 0;
}