把鼠标限制在窗口内

玩魔兽和LOL时注意到即时游戏窗口最小化，鼠标仍限制在窗口内，这具体是怎么实现的呢？

Msdn上有个例子

Confining a Cursor:

RECT rcClip;           // new area for ClipCursor
RECT rcOldClip;        // previous area for ClipCursor
 
// Record the area in which the cursor can move. 
 
GetClipCursor(&rcOldClip); 
 
// Get the dimensions of the application's window. 
 
GetWindowRect(hwnd, &rcClip); 
 
// Confine the cursor to the application's window. 
 
ClipCursor(&rcClip); 
 
   // 
   // Process input from the confined cursor. 
   // 
 
// Restore the cursor to its previous area. 
 
ClipCursor(&rcOldClip);