QApplication focus from other friend instance

I try QApplication::setActiveWindow(this);
and other flag ...

but i can only make this and run ok.
How to make focus QApplication from linux & mac?

Code:

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if(instance.isRunning())
	{
   #if defined Q_WS_WIN
   /* focus this QApplication instance from other QApplication*/
   HWND hWnd = FindWindowW( 0, (LPCWSTR) titles.utf16() );
   ShowWindow( hWnd, SW_RESTORE );
   SetForegroundWindow( hWnd );
   #endif
  /* send the file to other instance..... */

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