Linux 判断机器的字节顺序

#include <fcntl.h>
int main(void)
{
    typedef union un{
        short s;
        char c[sizeof(short)];
    }un;
    un myun;
    myun.s = 0x0102;
    if(sizeof(short) == 2){
        if(myun.c[0] == 1 && myun.c[1] == 2)
                printf("big-endian\r\n");
        else if(myun.c[0] == 2 && myun.c[1] == 1)
                printf("little-endian\r\n");
        else
                printf("unkown\r\n");
       
    }
    return 0;
}
摘自《Unix 网络编程》