How do I extract a list of function prototypes from C++ code?

[kitepilot at kitepilot.com]

Hello there... 

I have this extensive C++ code base from which I want to know every function 
prototype.
Yes, I can write a script to get them, but from experience *I KNOW* that it 
will take me longer than I anticipate and more effort than I want to commit 
to writing such a script. 

I am using the IBM XL C/C++ compiler (2007), which doesn't seem to have an 
option to produce for me such a listing. 

Does anybody know of something out there to accomplish this?
Thanks!
Enrique