联合体 字节序 验证

    union u_buff
    {
        uint32_t value;
        struct
        {
            uint8_t buff[4];
        };
    };

    union u_buff data;
    memset( &data, 0, sizeof(data) );

    data.buff[0] = 0x78;
    data.buff[1] = 0x56;
    data.buff[2] = 0x34;
    data.buff[3] = 0x12;
    xil_printf( "data=0x%X.\n", data.value );

运行结果：

data=0x12345678.