// This example will show you a faster method how you can obtain
// the text of the specified window’s title bar under Windows NT/2000 systems.
// (c)1999 Ashot Oganesyan K, SmartLine, Inc
// mailto:ashot@aha.ru, http://www.protect-me.com, http://www.codepile.com

// The function copies the text of the specified window’s title bar
// (if it has one) into a buffer. The InternalGetWindowText function is
// much faster than the documented GetWindowText because it uses INT 2E interrupt

// NT-Specific!
// Here is the prototype for InternalGetWindowText:

InternalGetWindowText(
hWnd: HWND; {a handle to a window or control with text}
lpString: PChar; {a pointer to a buffer to receive the string (UNICODE!!!)}
nMaxCount: Integer {the maximum number of characters to copy}
): Integer; {returns the length of the copied string}

function NT_InternalGetWindowText(Wnd: HWND): string;
type
  TInternalGetWindowText = function(Wnd: HWND; lpString: PWideChar;
    nMaxCount: Integer): Integer;
  stdcall;
var
  hUserDll: THandle;
  InternalGetWindowText: TInternalGetWindowText;
  lpString: array[0..MAX_PATH] of WideChar; //Buffer for window caption
  oemStr: PChar;
begin
  Result   := '';
  hUserDll := GetModuleHandle('user32.dll');
  if (hUserDll > 0) then
  begin @InternalGetWindowText := GetProcAddress(hUserDll, 'InternalGetWindowText');
    if Assigned(InternalGetWindowText) then
    begin
      InternalGetWindowText(Wnd, lpString, SizeOf(lpString));
      Result := string(lpString);
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  ShowMessage(NT_InternalGetWindowText(Form1.Handle));
end;