There's another program out there that generates the source code listing
format found in the Lions book:
[taken from
http://cardit.et.tudelft.nl/~knop/#programs]
Cdg - a C-source Documentation Generator
Cdg produces output in a format similar to the layout used in "Source
Code and Commentary on UNIX level 6" by John Lions. This format consists
of a two-column listing of the sources where all lines are numbered, 100
lines per page. The listing is followed by an extensive cross reference
table.