What happens to the DC when I free a canvas?

In this code I would expe开发者_如何学Cct a call to ReleaseDC to happen in MyCanvas.Free, but this code runs fine, how come?

And what happens to TCanvas' own DC?

var GlobalDC: THandle;

procedure TForm1.FormCreate(Sender: TObject);
begin
   GlobalDC:= GetDC(0);
end;

function LoopMeOften(const X, Y: Integer): TColor;
var
  MyCanvas: TCanvas;
begin
  MyCanvas := TCanvas.Create;
  MyCanvas.Handle := GlobalDC;
  Result := GetPixel(MyCanvas.Handle, X, Y);
  MyCanvas.Free;
end;

TCanvas does not have its own DC, it neither acquires nor releases a DC. Its descendant TControlCanvas does.

From TCanvas.Handle Property

TCanvas does not own the HDC. Applications must create an HDC and set the Handle property. Applications must release the HDC when the canvas no longer needs it.