class ParvusKernel
{
public:
	LRESULT CALLBACK WindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam);
	
	bool initialize(HINSTANCE hinstance, HINSTANCE hprevinstance, LPSTR lpcmdline, int ncmdshow);
...

private:
...
	//main handle
	HWND main_window_handle;

	//window instance
	HINSTANCE main_instance;

	WNDCLASSEX winclass; // this will hold the class we create
	HWND	   hwnd;	 // generic window handle
	MSG		   msg;		 // generic message

};

bool ParvusKernel::initialize(HINSTANCE hinstance, HINSTANCE hprevinstance, LPSTR lpcmdline, int ncmdshow)
{
	main_window_handle = NULL;
	main_instance = NULL;

	// first fill in the window class structure
	winclass.cbSize         = sizeof(WNDCLASSEX);
	winclass.style			= CS_DBLCLKS | CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
	winclass.lpfnWndProc	= &ParvusKernel::WindowProc;
	winclass.cbClsExtra		= 0;
	winclass.cbWndExtra		= 0;
	winclass.hInstance		= hinstance;
	winclass.hIcon			= LoadIcon(NULL, IDI_APPLICATION);
	winclass.hCursor		= LoadCursor(NULL, IDC_ARROW);
	winclass.hbrBackground	= (HBRUSH)GetStockObject(BLACK_BRUSH);
	winclass.lpszMenuName	= NULL;
	winclass.lpszClassName	= WINDOW_CLASS_NAME;
	winclass.hIconSm        = LoadIcon(NULL, IDI_APPLICATION);		


	switch(windowType)
	{
	case 0:
		{
			// register the window class
			RegisterClassEx(&winclass);				

			// create the window
			hwnd = CreateWindowEx(NULL, // extended style
				WINDOW_CLASS_NAME,     // class
				"Parvus Alpha 1", // title
				WS_POPUP | WS_VISIBLE,
				0,0,	    // initial x,y
				400,400,  // initial width, height
				NULL,	    // handle to parent 
				NULL,	    // handle to menu
				hinstance,// instance of this application
				NULL);// extra creation params

			//save the handle and instance
			main_window_handle = hwnd;
			main_instance = hinstance;

			break;

		}
	case 1:
		{
			//TODO: Add full screen creation code here.
			break;
		}
	}
}

1>\parvus_kernel.cpp(18) : error C2440: '=' : cannot convert from 'LRESULT (__stdcall ParvusKernel::* )(HWND,UINT,WPARAM,LPARAM)' to 'WNDPROC'
1>        There is no context in which this conversion is possible