HIWORD是High Word的缩写,作用是取得某个4字节变量(即32位的值)在内存中处于高位的两个字节,即一个word长的数据;
LOWORD是Low Word的缩写,作用是取得某个4字节变量(即32位的值)在内存中处于低位的两个字节,即一个word长的数据;

Win32编程常用;

Win32窗口编程中,收到 WM_SIZE消息时,也就是窗口大小变化时,如下从消息的lParam参数可取出窗口的客户区宽度和长度,
          cxClient = LOWORD (lParam) ;
          cyClient = HIWORD (lParam) ;

收到 WM_MOUSEMOVE 消息时,如下取出鼠标的x和y坐标;
        pt.x=LOWORD (lParam) ;
        pt.y=HIWORD (lParam) ;

如果有一个数据0XCCDDEEFF ,如下则取出高位和低位,
    high = HIWORD(0XCCDDEEFF) ;
    low = LOWORD(0XCCDDEEFF) ;

下面输出相关的值看一下;

/*----------------------------------------
    2020.10.11, by bo
  ----------------------------------------*/
 
#include <windows.h>
 
LRESULT CALLBACK WndProc    (HWND, UINT, WPARAM, LPARAM) ;
 
int WINAPI WinMain (HINSTANCE hInstance, 
12-12 06:27