How to get the topmost window through xlib programming

Hi All,

Is there any option to get the topmost window or currently active window
through anu xlib API . Because i think, through XQueryTree we can get all
the Alive windows(windows that are not closed) only. So is there any means
to get the topmost window, also is it possible to check whether the windowID
that i am having is top most window or not?


Thanks in advance

Regards
Karthik