Autoconf, Automake, and Libtool: Makefile syntax

| ## 4.2 Makefile syntax ``Makefile'`s have a rather particular syntax that can trouble new users. There are many implementations of `make`, some of which provide non-portable extensions. An abridged description of the syntax follows which, for portability, may be stricter than you may be used to. Comments start with a ``#'` and continue until the end of line. They may appear anywhere except in command sequences--if they do, they will be interpreted by the shell running the command. The following ``Makefile'` shows three individual targets with dependencies on each:
    target1:  dep1 dep2 ... depN
    <tab>	  cmd1
    <tab>	  cmd2
    <tab>	  ...
    <tab>	  cmdN

    target2:  dep4 dep5
    <tab>	  cmd1
    <tab>	  cmd2

    dep4 dep5:
    <tab>	  cmd1
Target rules start at the beginning of a line and are followed by a colon. Following the colon is a whitespace separated list of dependencies. A series of lines follow which contain shell commands to be run by a sub-shell (the default is the Bourne shell). Each of these lines must be prefixed by a horizontal tab character. This is the most common mistake made by new `make` users. These commands may be prefixed by an ``@'` character to prevent `make` from echoing the command line prior to executing it. They may also optionally be prefixed by a ``-'` character to allow the rule to continue if the command returns a non-zero exit code. The combination of both characters is permitted.

This document was generated by Gary V. Vaughan on February, 8 2006 using texi2html