判断大端小端机器的两种方法 - hzh512的博客

作者在 2011-09-03 10:52:21 发布以下内容

第一种，使用位段：

#include <stdio.h>

struct data
{
    unsigned int a:3;
    unsigned int b:2;
    unsigned int c:3;
};

int main()
{
    struct data abc;
    unsigned char* s = (unsigned char*) &abc;
    *s = 0x99;
    if(abc.a == 1)
        printf("you are using big_endian machine\n");
    else
        printf("you are using little_endian machine\n");
}

第2种方法：

union data
{
    struct t {
        char a;
        char b;
    } d;
    short c;
};

int main()
{
    union data x;
    x.c = 0x0102;
    if(sizeof(short) == 2)
    {
        if(x.d.a == 1 && x.d.b == 2)
            printf("your machine is big-endian\n");
        else
            if(x.d.a == 2 && x.d.b == 1)
                printf("your machine is little-endian\n");
            else
                printf("unknown\n");
    }
    else
        printf("sizeof(short) = %d\n", sizeof(short));
    return 0;
}