WM_QUIT return values

This is a discussion on WM_QUIT return values within the Windows Programming forums, part of the Platform Specific Boards category; In my program, under WM_DESTROY, I use PostQuitMessage(0). After my message loop, in WinMain(), I return msg.wParam. The exit code ...

  1. #1
    mustang benny bennyandthejets's Avatar
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    WM_QUIT return values

    In my program, under WM_DESTROY, I use PostQuitMessage(0). After my message loop, in WinMain(), I return msg.wParam. The exit code for my program however, is always -1080664280 (0xBF965F28). Is this behaviour normal? According to MSDN my exit code should be 0.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
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  2. #2
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    Should be zero. Post up the code and we'll have a look.

  3. #3
    mustang benny bennyandthejets's Avatar
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    Here's the important stuff, should be enough:

    Code:
    LRESULT CALLBACK WndProc(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam)
    {
    	switch (msg)
    	{
    	case WM_DESTROY:
    		PostQuitMessage(0);
    		return 0;
    Code:
    while (GetMessage(&msg,hwnd,0,0)>0)
    	{
    		TranslateMessage(&msg);
    		DispatchMessage(&msg);
    	}
    
    	return msg.wParam;
    Code:
    The thread 0x170 has exited with code -1080664280 (0xBF965F28)
    I've confirmed that it IS exiting through WM_DESTROY.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
    Windows XP Pro

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  4. #4
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    Put a breakpoint on the return statement. Look at the msg structure. What msg does it have? It should be 0x12 or 18 ( decimal ). Everything else should be 0.

  5. #5
    mustang benny bennyandthejets's Avatar
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    The message is 0! Weird. I think it may be because my message loop will exit if GetMessage() doesn't return a positive value. Eibro told me to change this. I'll try it and see.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
    Windows XP Pro

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  6. #6
    mustang benny bennyandthejets's Avatar
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    I added the following check to my loop:

    Code:
    while ((bRet=GetMessage(&msg,hwnd,0,0))!=0)
    	{
    		if (bRet==-1)
    			exit(1);
    		TranslateMessage(&msg);
    		DispatchMessage(&msg);
    	}
    
    	return msg.wParam;
    And sure enough it exited with code 1. Apparently that means there's some horrible error like hwnd being invalid. Could that be possible in this case?
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
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  7. #7
    It's full of stars adrianxw's Avatar
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    If it returns -1 call GetLastError() and see what that says.
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

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