[X11] get information from window like xprop

[Andreas Volz <lists brachttal net>]

Hi,

I like to get information from a X-window like xprop does it in gtk2.
Are there functions for this or should I get the X-window-widget and
do some X programming? I need for example (xprop output):

...
WM_CLASS(STRING) = "main_window", "Sylpheed"
...

And I like to click on a window which properties I want to get, like
xprop does it. Can you give some hints or should I look into xprop
source?

regards
Andreas