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正确使用GetMessage

GetMessage function

Retrieves a message from the calling thread’s message queue. The function dispatches incoming sent messages until a posted message is available for retrieval.

Unlike GetMessage, the PeekMessage function does not wait for a message to be posted before returning.

 

这样使用是不太对的：

Because the return value can be nonzero, zero, or -1, avoid code like this:

while (GetMessage( lpMsg, hWnd, 0, 0)) …
 

The possibility of a -1 return value in the case that hWnd is an invalid parameter (such as referring to a window that has already been destroyed) means that such code can lead to fatal application errors. Instead, use code like this:

要像这样用哦！

 while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0)
    {
        if (bRet == -1)
        {
            // handle the error and possibly exit
        }
        else
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }