19.5 Pitfalls

The use of the # to place comments into an mc file for eventual transfer to your configuration file may not work as expected. The # is not special to m4 , so m4 continues to process a line even though that line is a comment. So instead of

# Here we define $m as our domain

(which would see define as an m4 keyword), use single quotes to insulate all such comments from m4 interpretation:

# `Here we define $m as our domain'