procedure WinMain; 
  const szClassName='Shablon';
  var   wndClass:TWndClassEx;
        hWnd: THandle;
        msg:TMsg;
begin
  wndClass.cbSize:=sizeof(wndClass);
  wndClass.style:=cs_hredraw or cs_vredraw;
  wndClass.lpfnWndProc:=@WndProc;
  wndClass.cbClsExtra:=0;
  wndClass.cbWndExtra:=0;
  wndClass.hInstance:=hPrevInst; //[Warning] Symbol 'HPrevInst' is deprecated
 ...