Hi all,
Whilst browsing MSDN to refresh my memory on the GetMessage function, i found some code (and documentation!) which appeared to have been written by someone who may or may not have been influenced by various illegal substances. Whatever he/she was on, I want some. It must make coding a lot of fun!
To summarise;
Return value
Type: BOOL
If the function retrieves a message other than WM_QUIT, the return value is nonzero.
If the function retrieves the WM_QUIT message, the return value is zero.
If there is an error, the return value is -1. For example, the function fails if hWnd is an invalid window handle or lpMsg is an invalid pointer. To get extended error information, call GetLastError.
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:
BOOL bRet; while( (bRet = GetMessage( &msg, hWnd, 0, 0 )) != 0) { if (bRet == -1) { // handle the error and possibly exit } else { TranslateMessage(&msg); DispatchMessage(&msg); } }
... say wha?!
My head hurts :(