invocation

# override variables
make CFLAGS='-g -O'

arguments

• -B always make, force compiling of all targets

variables

• CC = gcc will be expanded when it is used
• CC := gcc will be expanded when it is set
• CC ?= gcc will be set when it doesn't already have a value, may be overwritten by any environment
• CFLAGS += -ansi append

automatic variables

• $@ file name of target
• $* stem of matching, target: dir/a.foo.b, pattern: a.%.b, stem: dir/foo
• $< name of first prerequisite
• $? names of all the prerequisites that are newer than the target
• $^ names of all the prerequisites, with spaces between them
• $+ names of all the prerequisites, with spaces between them, with duplicates
• following two work with <, ?, ... in place of @ as well:
• $(@F) dir part of the file name of the target, without trailing slash
• $(@D) file-within-directory part of the file name of the target

functions

sources   := $(wildcard *.src)
targets   := $(sources:.src=.trg)
filtered  := $(filter-out broken.src, $(sources))
term_cols := $(shell tput cols)

special targets

• .DELETE_ON_ERROR
• .NOTPARALLEL affects all targets in file
• .PHONY
• .IGNORE old way to ignore errors in recipe

commands

• - before command ignores its errors
• @ don't display command

pattern

loops

subdirs := $(wildcard */)

.PHONY: all
all: $(subdirs)

.PHONY: $(subdirs)
$(subdirs):
    $(MAKE) -C $@

conventions

variables

uppercase letters are traditional, however gnu recommends lowercase for internal purposes and uppercase for variables that control implicit rules or parameters intended to be overwritten by caller.

gnu standard targets

• all
• dist create distribution tar file
• check run tests which require build but no installation
• installcheck perform tests after install, don't assume $(bindir) is in path
• install
• install-strip strip removes information such as debugging symbols
• uninstall
• clean don't delete config files
• distclean like a fresh checkout
• mostlyclean like clean, but leave costly files
• maintainer-clean distclean plus more: may need other tools to rebuild, not intended for normal users
• html, pdf, install-html, install-pdf doc in other format than info