Make Comments

A comment consists of the text starting with a # sign and continuing through to the end of the line. Make will understand a comment anywhere within a Makefile, except within the command part of a rule. Although you can put a comment inside a multi-line variable assignment, it is generally a bad idea because it is hard to tell whether the following line is still part of the comment or not¹.

     libm4_a_SOURCES         = builtin.c debug.c error.c eval.c hash.c \
                               # Do the next 2 lines continue this comment? \
                               input.c ltdl.c macro.c module.c output.c \
                               path.c regex.c symtab.c utility.c
     

     Example 5.15: Ambiguous comment endings are bad