How to use xtrace?

From: BlueOwl (blueowl_at_centrum.cz)
Date: 04/28/05 

Date: Thu, 28 Apr 2005 13:55:10 +0200

I need to trace program flow (trace user function calls).
I have found a script xtrace from glibc which promises to do that. But if I
run it doesn't print anything except programs output.
How should I use it. It is neccessary to recompile the program with a
special option?

Or does there exist any other similar tool to xtrace?

Jirka