You define an implicit rule by writing a pattern rule. A pattern
rule looks like an ordinary rule, except that its target contains the
%’ (exactly one of them). The target is considered a
pattern for matching file names; the ‘
%’ can match any nonempty
substring, while other characters match only themselves. The prerequisites
likewise use ‘
%’ to show how their names relate to the target name.
Thus, a pattern rule ‘
%.o : %.c’ says how to make any file
stem.o from another file
Note that expansion using ‘
%’ in pattern rules occurs
after any variable or function expansions, which take place
when the makefile is read. See How to Use
Variables, and Functions for Transforming Text.
|• Pattern Intro||An introduction to pattern rules.|
|• Pattern Examples||Examples of pattern rules.|
|• Automatic Variables||How to use automatic variables in the
recipe of implicit rules.
|• Pattern Match||How patterns match.|
|• Match-Anything Rules||Precautions you should take prior to
defining rules that can match any target file whatever.
|• Canceling Rules||How to override or cancel built-in rules.|