GLOBAL is a source code tag system that works the same way across diverse
environments.  Supported languages are C, C++, Yacc, Java, PHP and Assembly.
You can locate a specified function in the source files and move there easily.
It is useful for hacking a large project containing many subdirectories,
many '#ifdef' and many main() functions, like MH, X or BSD kernel.

WWW: http://www.gnu.org/software/global/