c语言共用体的使用和long类型长度

#include <stdio.h>
#include <stdlib.h>

int main()
{
    long frame_size = 0x12345678;

    union
    {
        int a;
        long b;
        char c;
    }m;

    m.b = 0x12345678;

    printf("Hello world! frame_size is %x
",(char)frame_size); // 0x78

    printf(" hello world c is %x
",m.c);  // 0x78

    printf(" long size is  %x
",sizeof(long));  //

    return 0;
}

 

#include <stdio.h>
#include <stdlib.h>

union data
{
    int i;
    char c;
    float f;
    long video_data;
}a;

int n;

int main()
{

    a.video_data = 0x123456789;
    printf("union %x
",a.i);
    printf("union %x
",a.video_data);
    return 0;
}