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Defining and Redefining Pattern Rules
You define an implicit rule by writing a "pattern rule". A pattern
rule looks like an ordinary rule, except that its target contains the
character `%' (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
dependencies likewise use `%' to show how their names relate to the
Thus, a pattern rule `%.o : %.c' says how to make any file `STEM.o'
from another file `STEM.c'.
Note that expansion using `%' in pattern rules occurs *after* any
variable or function expansions, which take place when the makefile is
read. Note: How to Use Variables, and Note: Functions
for Transforming Text.
- Pattern Intro
- An introduction to pattern rules.
- Pattern Examples
- Examples of pattern rules.
- How to use automatic variables in the
commands 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.
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