Как определить количество заданий на печать

type
  TForm1 = class(TForm)
    Label1: TLabel;
  private
    { Private declarations }
    procedure WM_SpoolerStatus(var Msg: TWMSPOOLERSTATUS);
      message WM_SPOOLERSTATUS;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.WM_SpoolerStatus(var Msg: TWMSPOOLERSTATUS);
begin
  Lable1.Caption := IntToStr(msg.JobsLeft) +
    ' Jobs currenly in spooler';
  msg.Result := 0;
end;