Glossary

Automatic variables $@, $<, $^ and friends — set by Make inside each recipe to the target, first prerequisite, and all prerequisites. See Automatic Variables.

Built-in rules Pattern rules that ship with Make (compiling C, linking single objects, ...). Your own rules override them; your CC and CFLAGS customize them.

Default goal The target built by plain make: the first explicit rule in the file (unless .DEFAULT_GOAL is set).

Explicit rule A rule you wrote with a literal target name, as opposed to a pattern rule.

Parallel build make -jN — up to N recipes at once. Safe only with honest prerequisites.

Pattern rule A rule with % matching a stem, e.g. %.o: %.c builds every object file from its source. See Pattern Rules.

.PHONY A declaration that a target is a task, not a file — it always runs. See .PHONY Targets.

Prerequisite A file (or target) that must be up to date before the target builds. Listed after the colon.

Recipe The shell commands under a rule — each line starting with a tab. Echoed before running unless prefixed with @.

Recursive variable (=) Re-expanded on every use; picks up later changes to variables it references.

Rule Target + prerequisites + recipe. The unit of a Makefile.

Simple variable (:=) Expanded once, when the line is read.

Stem The part % matched in a pattern rule: for %.o: %.c building main.o, the stem is main.

Target The thing a rule builds — a file, or a task name declared .PHONY. Written before the colon.