GUI-less app to capture key_press_events only

[Eric Lenio <eric lenio net>]

Hi, I'm new to Gtk2.

I have an unusual situation where I want my app to merely capture
key_press_events, without having any kind of GUI.  Is it possible
to do this with Gtk2?

If you're wondering why I don't just read from standard input,
it is because I want to capture when the control key is pressed.
That is, the control key is pressed by itself.  I also want to
do the same for the shift key and mod key.