详解大端模式和小端模式

http://blog.csdn.net/ce123_zhouwei/article/details/6971544


一个小程序判断机器的大小端

#include <stdio.h>

int main(void)
{
    union {
        int s;
        char c[sizeof(int)];
    }un;
    un.s = 0x12345678;

    printf("%p,%p,%p,%p\n",un.c[0],un.c[1],un.c[2],un.c[3]);
    printf("%p,%p,%p,%p\n",&un.c[0],&un.c[1],&un.c[2],&un.c[3]);
# if __BYTE_ORDER == __LITTLE_ENDIAN
    printf("little endian\n");
# elif __BYTE_ORDER == __BIG_ENDIAN
    printf("big endian\n");
# else
    # error "__BYTE_ORDER neither  __LITTLE_ENDIAN nor __BIG_ENDIAN!!!"
# endif
    return 0;
}