if (GetSystemMetrics(SM_SWAPBUTTON)>0 )
     {
      mouse_event(MOUSEEVENTF_RIGHTDOWN, 1, 0, 0, 0);
      mouse_event(MOUSEEVENTF_RIGHTUP, 1, 0, 0, 0);
     }
     else
     {
      mouse_event(MOUSEEVENTF_LEFTDOWN, 1, 0, 0, 0);
      mouse_event(MOUSEEVENTF_LEFTUP, 1, 0, 0, 0);
     }