m4: Comments
3.3 Comments in 'm4' input
==========================
Comments in 'm4' are normally delimited by the characters '#' and
newline. All characters between the comment delimiters are ignored, but
the entire comment (including the delimiters) is passed through to the
output--comments are _not_ discarded by 'm4'.
Comments cannot be nested, so the first newline after a '#' ends the
comment. The commenting effect of the begin-comment string can be
inhibited by quoting it.
$ m4
`quoted text' # `commented text'
=>quoted text # `commented text'
`quoting inhibits' `#' `comments'
=>quoting inhibits # comments
The comment delimiters can be changed to any string at any time,
using the builtin macro 'changecom'. ⇒Changecom, for more
information.