​

typedef union

{

    unsigned char a;

    unsigned short b;

    unsigned int c;

} SHAREDATA;

​

int main(void)

{

    SHAREDATA var;

    var.c = 0x12345678;

    printf("%x\n", var.a);

    printf("%x\n", var.b);

    printf("%x\n", var.c);

    return 0;

}

​