Tom's wiki

Make

POSIX specification

A program builder that uses Makefile for instructions. Often used as a task runner.

Learn

• A Tutorial on Portable Makefiles
• https://makefiletutorial.com (non-POSIX)

Notes

• A target is out-of-date if it is older than any of its prerequisites.
• The first non-special target is run if no target is specified.
• The $@ macro expands to the target name.
• The $< macro expands to the first prerequisite.
• @ before a command stops it from being printed.
• Each command is run in a new shell.
• The default shell is /bin/sh (can be changed with the SHELL macro).
• Macros can be overwritten with arguments in the key=value form, e.g. make CC=gcc.

Best practices

• Stick to the POSIX standard.
• Add .POSIX: to the top of the Makefile to get reliable POSIX behavior.
• Add .SUFFIXES: to the top of the Makefile to clear the builtin C rules.
• Add .PHONY: to non-file targets such as clean (non-POSIX).
• Use = to define macros and $() to expand them.
• Use macro name conventions:
  • CC - compiler to use
  • CFLAGS - compiler flags
  • LDFLAGS - linker flags
  • LDLIBS - libraries to link