1 #include <stdio.h> 2 3 union endian_u 4 { 5 /*最大成员的长度就是联合成员的长度。联合可以在定义时直接进行初始化，但这个初始化必须是联合第一个成员的类型，所以把unsigned short sval放在第一个成员的原因*/ 6 unsigned short sval; 7 unsigned char cval[2]; 8 }; 9 10 int main(int argc, char *argv[]) 11 { 12 char *info = "unknow endian"; 13 union endian_u t = { 0x1234 }; 14 15 if (t.cval[0] == 0x12 && t.cval[1] == 0x34) 16 info = "big-endian"; 17 else if (t.cval[0] == 0x34 && t.cval[1] == 0x12) 18 info = "little-endian"; 19 20 printf("host is %s. ", info); 21 22 return 0; 23 }