Programm Handle hohlen

#include <windows.h>
#include <time.h>


LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int RegisterWC(WNDCLASS *, HINSTANCE *);
int InitDialog(HWND *, HINSTANCE *, int *);

const char szApp[]="Infoholer";

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrev, PSTR szCmdLine, int nCmdShow)
{
	HWND hWnd;
	MSG msg;
	WNDCLASS wc;

	RegisterWC(&wc, &hInstance);
	InitDialog(&hWnd, &hInstance, &nCmdShow);

	while(GetMessage(&msg, NULL, 0, 0))
	{
		DispatchMessage(&msg);
	}

	return (int)msg.wParam;
}


LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	static int TIMER_ID;
	static HWND edit;
	static POINT p;

	switch(message)
	{
	case WM_KEYDOWN:
		{
			GetCursorPos(&p);

			InvalidateRect(hWnd, NULL, false);
			return 0;
		}
	case WM_PAINT:
		{
			HDC hDC;
			PAINTSTRUCT ps;
            char szNummer[20];

			hDC = BeginPaint(hWnd, &ps);
			{
				HWND hZiel = WindowFromPoint(p);
				wsprintf(szNummer, "%d", (int)hZiel);
				TextOut(hDC, 2, 2, szNummer, strlen(szNummer));

			}
			EndPaint(hWnd, &ps);


			return 0;
		}
	case WM_DESTROY:
	case WM_CLOSE:
		{
			PostQuitMessage(0);

			return 0;
		}
	default:
		{
			return DefWindowProc(hWnd, message, wParam, lParam);
		}
	}

	return 0;
}

int RegisterWC(WNDCLASS *wc, HINSTANCE *hInstance)
{
	wc->cbClsExtra = 0;
	wc->cbWndExtra = 0;
	wc->hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wc->hCursor = LoadCursor(NULL, IDC_ARROW);
	wc->hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wc->hInstance = *hInstance;
	wc->lpfnWndProc = WndProc;
	wc->lpszClassName = szApp;
	wc->lpszMenuName = NULL;
	wc->style = CS_VREDRAW | CS_HREDRAW;

	RegisterClass(wc);

	return 0;
}

int InitDialog(HWND *hWnd, HINSTANCE *hInstance, int *nCmdShow)
{
	*hWnd = CreateWindow(szApp, szApp, WS_OVERLAPPED | WS_SYSMENU,
		CW_USEDEFAULT, CW_USEDEFAULT,
		CW_USEDEFAULT, CW_USEDEFAULT,
        NULL, NULL, *hInstance, NULL);

	ShowWindow(*hWnd, *nCmdShow);
	UpdateWindow(*hWnd);

	return 0;
}