XLib - GetWindowTitle & SetWindowTitle

function GetWindowTitle(handle:TWindow): String;
var
  title: TXTextProperty;
begin
  title.value    := nil;
  title.encoding := XA_STRING;
  title.format   := 8;
  title.nitems   := 0;

  XGetWMName(display, handle, @title);
  if (title.value <> nil) and (title.nitmems <> 0) then
  begin
    SetLength(Result, title.nitems);
    Move(title.value^[0], Result[1], title.nitems);
  end;
end;

procedure SetWindowTitle(handle:TWindow; Text:String);
var
  title: TXTextProperty;
begin
  title.value    := PChar(Text);
  title.encoding := XA_STRING;
  title.format   := 8;
  title.nitems   := Length(Text);

  XSetWMName(display, handle, @title);
  XFlush(display);
end;