Router Problem

Hello everyone. I know that I have posted a lot in the last day or so but I am totally stumped... I wrote a windows router/handler for a windows wrapper class and have run into a few errors (most of which are minor). The major problem is here:

p_wnd = reinterpret_cast<CWND*>(LPCREATESTRUCT(lParam)->lpCreateParams);
    instance = LPCREATESTRUCT(lParam)->hInstance;

    SetWindowLong(hwnd, GWL_USERDATA, reinterpret_cast<long>(p_wnd));
 

The lpCreateParams member of the LPCREATESTRUCT is always zero and thus the SetWindowLong function fails and returns zero as well (even after the error code is reset). I am not clear if I have to pass a pointer in the CreateWindowEx function that allows use of this member... but here is my window creation code:

void CWND::CreateWND(int showCmd)
{
  DWORD		dwExStyle;		// Window Extended Style

	DWORD		dwStyle;			// Window Style

	
	HWND hwnd;
  
  // Setup the windows class

  m_wndClass.cbSize = sizeof(WNDCLASSEX);
  m_wndClass.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
  m_wndClass.lpfnWndProc = CWND::MessageRouter; // window procedure

  m_wndClass.cbClsExtra = 0;
  m_wndClass.cbWndExtra = 0;
  m_wndClass.hInstance = m_instance;
  m_wndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);  // default app icon

  m_wndClass.hCursor = LoadCursor(NULL, IDC_ARROW);    // default cursor

  m_wndClass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);; // windows default black

  m_wndClass.lpszClassName = m_className; // class name

  m_wndClass.hIconSm = LoadIcon(NULL, IDI_WINLOGO); 
  
  RECT windowRect;							// Grabs Rectangle Upper Left / Lower Right Values

	windowRect.left = (long)0;						// Set Left Value To 0

	windowRect.right = (long)m_width;						// Set Right Value To Requested Width

	windowRect.top = (long)0;							// Set Top Value To 0

	windowRect.bottom = (long)m_height;						// Set Bottom Value To Requested Height  

  
  // register the class

  if (!RegisterClassEx(&m_wndClass))
        { MessageBox(NULL, "Class Registration Failed!", "ERROR!", MB_OK | MB_ICONEXCLAMATION); }
  
  if (m_fullscreen)								// Attempt Fullscreen Mode?

	{
    DEVMODE dmScreenSettings;					// Device Mode

		memset(&dmScreenSettings, 0, sizeof(dmScreenSettings));		// Makes Sure Memory's Cleared

		dmScreenSettings.dmSize = sizeof(dmScreenSettings);		// Size Of The Devmode Structure

		dmScreenSettings.dmPelsWidth	= m_width;			// Selected Screen Width

		dmScreenSettings.dmPelsHeight	= m_height;			// Selected Screen Height

		dmScreenSettings.dmBitsPerPel	= m_bpp;		 		  // Selected Bits Per Pixel

		dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;
		
		// Try To Set Selected Mode And Get Results.  NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.

		if(ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
		{
		  // If The Mode Fails, Offer Two Options.  Quit Or Run In A Window.

			if (MessageBox(NULL, "The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Using windowed mode instead.",
          "ERROR", MB_OK | MB_ICONEXCLAMATION) == IDOK)
			{
			  	m_fullscreen = false;
			}
		}
	}
	
	if (m_fullscreen)								// Are We Still In Fullscreen Mode?

	{
	  dwExStyle = WS_EX_APPWINDOW;	// Window Extended Style

		dwStyle = WS_POPUP;						// Windows Style

	}
	else
	{
    dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;			// Window Extended Style

		dwStyle = WS_OVERLAPPEDWINDOW;					// Windows Style

	}
	
	// Adjust Window To True Requested Size

	AdjustWindowRectEx(&windowRect, dwStyle, FALSE, dwExStyle);

  // Create the window

  hwnd = CreateWindowEx(dwExStyle,     // Extended Style

             m_className,            
             m_className,             
             dwStyle | WS_CLIPSIBLINGS | WS_CLIPCHILDREN,
             0,                          // X

             0,                          // Y

             m_width,                    // Height

             m_height,                   // Width

             NULL,                       // Handle to parent

             NULL,                       // Handle to menu

             m_instance,                // Application Instance

             NULL);                      // No Extra Params

  
  // Check to see if window creation failed

  if(!hwnd)
      { MessageBox(NULL, "Window Creation Failed!", "ERROR!", MB_OK | MB_ICONEXCLAMATION); }
  
  // Show and update the window

  ShowWindow(hwnd, showCmd);
  UpdateWindow(hwnd);
}
 

And here is the router in its entirity:

// Class message router: this function is static and will rout messages

// to the correct class instance

LRESULT CALLBACK CWND::MessageRouter(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
  CWND *p_wnd = 0;
  HINSTANCE instance;

  if(msg == WM_NCCREATE)
  {
    // retrieve Window instance from window creation data and associate

    p_wnd = reinterpret_cast<CWND*>(LPCREATESTRUCT(lParam)->lpCreateParams);
    instance = LPCREATESTRUCT(lParam)->hInstance;

    SetWindowLong(hwnd, GWL_USERDATA, reinterpret_cast<long>(p_wnd));

	  // save window handle

    if(p_wnd)
    {
      p_wnd->SetHWND(hwnd);
      p_wnd->SetInstance(instance);
    }
  }
  else
  {
    // retrieve associated Window instance

    p_wnd = reinterpret_cast<CWND*>(GetWindowLong(hwnd, GWL_USERDATA));
  }
  
  if(p_wnd)
  {
    t_messageIterator i;
    
    // retrieve the associated message handler

    i = p_wnd->GetMessageHandler(msg);
    return (i->second)(p_wnd, hwnd, wParam, lParam); 
  }
    
  return DefWindowProc(hwnd, msg, wParam, lParam);
}
 

It is imperative that I get this router up and running and I would appreciate any help that someone can offer... [edited by - Premonition on April 26, 2004 8:15:55 PM]