Efficiency coding; a simple top-level window

This is a discussion on Efficiency coding; a simple top-level window within the Windows Programming forums, part of the Platform Specific Boards category; I'd like to know how other programmers go about creating a simple window in Win32. If there's anything in my ...

  1. #1
    mustang benny bennyandthejets's Avatar
    Join Date
    Jul 2002
    Posts
    1,401

    Efficiency coding; a simple top-level window

    I'd like to know how other programmers go about creating a simple window in Win32. If there's anything in my code that could be made more efficient, or which has been superseded, I'd love to know, thanks.

    Code:
    #include <windows.h>
    
    int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow);
    LRESULT CALLBACK WndProc(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam);
    
    int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow)
    {
    	WNDCLASSEX wcx;
    	
    	wcx.cbClsExtra=0;
    	wcx.cbSize=sizeof(WNDCLASSEX);
    	wcx.cbWndExtra=0;
    	wcx.hbrBackground=(HBRUSH)(COLOR_BTNFACE+1);
    	wcx.hCursor=LoadCursor(NULL,IDC_ARROW);
    	wcx.hIcon=LoadIcon(NULL,IDI_APPLICATION);
    	wcx.hIconSm=NULL;
    	wcx.hInstance=hInstance;
    	wcx.lpfnWndProc=WndProc;
    	wcx.lpszClassName="clsAccess";
    	wcx.lpszMenuName=NULL;
    	wcx.style=0;
    
    	if (!RegisterClassEx(&wcx))
    		exit(1);
    
    	HWND hwnd;
    
    	hwnd=CreateWindow("clsAccess","Access Manager",
    				WS_OVERLAPPEDWINDOW,
    				0,0,0,0,NULL,NULL,hInstance,NULL);
    
    	if (!hwnd)
    		exit(2);
    
    	ShowWindow(hwnd,SW_SHOW);
    	UpdateWindow(hwnd);
    
    	MSG msg;
    
    	while (GetMessage(&msg,hwnd,0,0)>0)
    	{
    		TranslateMessage(&msg);
    		DispatchMessage(&msg);
    	}
    
    	return msg.wParam;
    }
    
    LRESULT CALLBACK WndProc(HWND hwnd,UINT msg,WPARAM wParam,LPARAM lParam)
    {
    	switch (msg)
    	{
    	case WM_DESTROY:
    		PostQuitMessage(0);
    		return 0;
    
    	case WM_CREATE:
    		SetWindowPos(hwnd,NULL,
    			GetSystemMetrics(SM_CXSCREEN)/4,
    			GetSystemMetrics(SM_CYSCREEN)/4,
    			GetSystemMetrics(SM_CXSCREEN)/2,
    			GetSystemMetrics(SM_CYSCREEN)/2,
    			SWP_NOOWNERZORDER);
    		break;
    
    	default:
    		break;
    	}
    
    	return DefWindowProc(hwnd,msg,wParam,lParam);
    }
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
    Windows XP Pro

    Code Tags
    Programming FAQ
    Tutorials

  2. #2
    &TH of undefined behavior Fordy's Avatar
    Join Date
    Aug 2001
    Posts
    5,789
    More efficient? If your finding that slow then I guess it's more to do with the os than your code

    Though as you seem to be in C++ (with variables declared throughout the block and not at the top), why not

    WNDCLASSEX wcx = {0};

    Then you dont need to keep assigning NULL or zero to the relevant members of that struct.

    Also, why bother calling exit() when you can use a simple return with that value you want and allow the compiler generated code to destroy the process.

    None of these are real efficiency tips...you would never in a million years notice a benefit from my suggestions

  3. #3
    mustang benny bennyandthejets's Avatar
    Join Date
    Jul 2002
    Posts
    1,401
    It's not for speed, it's just general things that I should be doing. Looks like it's okay though. Thanks.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
    Windows XP Pro

    Code Tags
    Programming FAQ
    Tutorials

  4. #4
    I lurk
    Join Date
    Aug 2002
    Posts
    1,361
    Warning

    Because the return value can be nonzero, zero, or -1, avoid code like this:
    Code:
    while (GetMessage( lpMsg, hWnd, 0, 0)) 
    ...
    The possibility of a -1 return value means that such code can lead to fatal application errors. Instead, use code like this:
    Code:
    BOOL bRet;
    
    while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0)
    { 
        if (bRet == -1)
        {
            // handle the error and possibly exit
        }
        else
        {
            TranslateMessage(&msg); 
            DispatchMessage(&msg); 
        }
    }

  5. #5
    mustang benny bennyandthejets's Avatar
    Join Date
    Jul 2002
    Posts
    1,401
    Eibro, thanks for the tip. Now here's a tip for you: go back and read my code.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
    Windows XP Pro

    Code Tags
    Programming FAQ
    Tutorials

  6. #6
    Registered User
    Join Date
    Jan 2003
    Posts
    648
    Hahahaha!

    But the documentation for GetMessage() says that sucess could be anything non-zero or -1. So -5 could be success. I'd recommend using Eibro's code anyways.
    Last edited by Speedy5; 07-09-2003 at 09:05 AM.

  7. #7
    I lurk
    Join Date
    Aug 2002
    Posts
    1,361
    Originally posted by bennyandthejets
    Eibro, thanks for the tip. Now here's a tip for you: go back and read my code.
    Again, here's a tip for you: Do what I suggested. That was quoted straight from MSDN.

  8. #8
    mustang benny bennyandthejets's Avatar
    Join Date
    Jul 2002
    Posts
    1,401
    I was indignant until I read Speedy5's addition to his/her original post. I had forgotten that non-zero included negatives too. Sorry Eibro. I haven't run into any problems in the past with that one. Has anyone?

    EDIT: Being a follower of the Church of MSDN doesn't make everything you say correct. Speedy5's explanation had substance to it.
    Last edited by bennyandthejets; 07-09-2003 at 09:18 AM.
    benforbes@optusnet.com.au
    Microsoft Visual Studio .NET 2003 Enterprise Architect
    Windows XP Pro

    Code Tags
    Programming FAQ
    Tutorials

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Adding buttons, edit boxes, etc to the window
    By rainmanddw in forum Windows Programming
    Replies: 1
    Last Post: 04-10-2006, 03:07 PM
  2. Simple window program
    By baniakjr in forum C++ Programming
    Replies: 5
    Last Post: 03-11-2006, 02:46 PM
  3. Errors with simple window handler
    By Chapmad in forum Windows Programming
    Replies: 11
    Last Post: 08-30-2004, 01:44 PM
  4. Tab Controls - API
    By -KEN- in forum Windows Programming
    Replies: 7
    Last Post: 06-02-2002, 09:44 AM
  5. opengl code not working
    By Unregistered in forum Windows Programming
    Replies: 4
    Last Post: 02-14-2002, 09:01 PM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21