Source code cross referencing tools?

All: Does anyone know of a tool that will take an arbitrary list of source files (say C) and cross reference the variables and routines among the source files? Here?s the problem. I?m trying to adapt and extract a small portion of a large project for a smaller project. The header files spider all over the place and the code calls functions in several modules. In all, there?s several hundred of source files in the large project and I think I?ll probably need fragments of about 15 of them. Does this make sense to anyone? I want to take the source file I?m interested in and find out where the variables and functions are declared in other modules. Rich -- Rich Cini Collector of Classic Computers Build Master and lead engineer, Altair32 Emulator http://www.altair32.com http://highgate.comm.sfu.ca/~rcini/classiccmp