Doxygen is a documentation system for C, C++ and IDL. It can generate
an on-line class browser (in HTML) and/or an off-line reference manual
(in LaTeX) from a set of documented source files. There is also
support for generating man lpages and for converting the generated
output into Postscript, hyperlinked PDF or compressed HTML. The
documentation is extracted directly from the sources.

Doxygen can also be configured to extract the code-structure from
undocumented source files. This can be very useful to quickly find
your way in large source distributions.