如何从另一个类似typedef的结构中存储结构

Question

1. struct DISPLAY_INFO *display_info;

2. typedef struct DISPLAY_INFO;

   DISPLAY_INFO display_info_2;

Have to copy diplay_info_2 to display_info. How can I do it using memcpy .

Answer 1

Iff (if and only if) display_info points to a valid memory area , you can write

memcpy(display_info, &display_info_2, sizeof(DISPLAY_INFO));

eg

#include <stdio.h>

typedef struct DISPLAY_INFO{
    int val;
} DISPLAY_INFO;

int main() {

    DISPLAY_INFO *display_info;

    display_info = (DISPLAY_INFO*)malloc(sizeof(DISPLAY_INFO));

    DISPLAY_INFO display_info_2; // The object to be copied
    display_info_2.val = 42;

    memcpy(display_info, &display_info_2, sizeof(DISPLAY_INFO));

    printf("%d", display_info->val);

    free(display_info);

    return 0;
}

http://ideone.com/AUwDNw

Answer 2

您可以执行： *display_info = display_info_2 。