Ticking Dialog

The smallest possible "live number on screen" demo. A dialog starts a 1 ms timer in WM_INITDIALOG; each tick calls Update to repaint, and a loop_function (invoked from the app's main loop) writes the current GetTickCount() value into a static control via SetText. It is a useful reference for understanding how fast Windows will actually let you refresh a window - the 1 ms request gets coalesced by the message queue to roughly the display's refresh rate - and for building simple counters, elapsed-time displays, or animation loops.

//---------------------------------------------------------------------------
#include "Headers/Functions.H" //----------------------------------------------------
#include "Dialogs/MainDialog.H"
//---------------------------------------------------------------------------


/////////////////////////////////////////////////////////////////////////////

extern int WINAPI WinMain (HWND hInst, HWND hPrev, LPSTR Cmd, int nCmdShow)
{
	hInstance=hInst;
	DialogBox(hInstance,MAKEINTRESOURCE(100),0,Clock);
	return 0;
}

/////////////////////////////////////////////////////////////////////////////


extern char *loop_function (int i)
{
SetText(clock,str(GetTickCount()));
return "Dialog Title";  //Dialog Title Here
}

extern int Clock (HWND hDlg, int Msg, int wParam, int lParam)
{
	for(;;)
	{
		if(Msg==WM_INITDIALOG)
		{
			hWnd=hDlg;
			SetTimer(hWnd,1,1,NULL);
         /* Refresh Delay Here ^ */
               //-------------(Dialog Definitions)---------(Start)

			clock=GetDlgItem(hDlg,101);

               //-------------(Dialog Definitions)----------(End)
			CenterWindow(hWnd);
			Update(hDlg);
			break;
		}

		if(Msg==WM_TIMER)
		{
			Update(hDlg);
			break;
		}

		if(Msg==WM_CLOSE)
		{
			KillTimer(hWnd,1);
			EndDialog(hDlg,0);

		}
		break;
	}
	return 0;
}

The comment above the timer period marks the one knob that matters: lower it for a faster counter, raise it if the window is eating too much CPU. For sub-millisecond timing use QueryPerformanceCounter instead of GetTickCount, which wraps after about 49 days and only ticks at ~15 ms resolution on older systems.