VOID PASCAL ClientToScreen(HWND hWnd, LPPOINT pPt)

  This function translates a point's coordinates from coordinates
which represent an offset from a window's client area to absolute
screen coordinates.

Parameters
  hWnd is a handle to a window whose client rectangle will be used in the
   transformation.
  pPt is a pointer to a POINT structure whose coordinates we will transform.

Returns
  Nothing.