how do programs catch hotkeys like that? all window managers have this - fluxbox, kde, gnome I'm sure, and they catch your keypress no matter what program has active keyboard focus.
devices in /dev/input are all (or should be, anyhow) unreadable by any but root, so that idea is out the window.
there is a specific feature for that called grabbing, you just 'grab' the key sequence you're interested in and the X server will always send it to you (i.e. your window) (google xgrabkey)
They use Xlib:
http://tronche.com/gui/x/xlib/
Qv. chapters 11 & 12 about "event handling". Keyboard activity is an event.
C programming resources:
GNU C Function and Macro Index -- glibc reference manual
The C Book -- nice online learner guide
Current ISO draft standard
CCAN -- new CPAN like open source library repository
3 (different) GNU debugger tutorials: #1 -- #2 -- #3
cpwiki -- our wiki on sourceforge
