How do I catch keyboard events in X11?

I'm writing an LCD controller, and one feature 开发者_开发技巧I want to add is the ability to catch keyboard strokes so that you can do stuff like instant messaging over the LCD. I found xsnoop.c but it's outdated. I'm using xorg-x11-server 1.6.4-0.1.fc11 on Fedora 11. I'm also using Qt. I didn't find anything in the docs that might help, but figured I'd mention it.

Any hints?

I've just tried compiling xsnoop.c and there was a line

 #include <vroot.h>

which needs to be just removed, but apart from that it works.