GNU `make'

This file documents the GNU Make utility, which determines automatically which pieces of a large program need to be recompiled, and issues the commands to recompile them.

This is Edition 0.61, last updated 25 Dec 2005, of The GNU Make Manual, for make, Version 3.80+dbg.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”.

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Make

The GNU make utility automatically determines which pieces of a large program need to be recompiled, and issues the commands to recompile them.

This edition of the GNU Make Manual, last updated 25 Dec 2005, documents GNU make Version 3.80+dbg.

This manual describes make and contains the following chapters:

Overview: Overview of make.
Introduction: An introduction to make.
Makefiles: Makefiles tell make what to do.
Rules: Rules describe when a file must be remade.
Commands: Commands say how to remake a file.
Using Variables: You can use variables to avoid repetition.
Conditionals: Use or ignore parts of the makefile based on the values of variables.
Functions: Many powerful ways to manipulate text.
Invoking make: How to invoke make on the command line.
Implicit Rules: Use implicit rules to treat many files alike, based on their file names.
Archives: How make can update library archives.
Features: Features GNU make has over other makes.
Missing: What GNU make lacks from other makes.
Makefile Conventions: Conventions for writing makefiles for GNU programs.
Quick Reference: A quick reference for experienced users.
Error Messages: A list of common errors generated by make.
Complex Makefile: A real example of a straightforward, but nontrivial, makefile.
GNU Free Documentation License: License for copying this manual
Concept Index: Index of Concepts
Name Index: Index of Functions, Variables, & Directives

--- The Detailed Node Listing ---

Overview of make

An Introduction to Makefiles

Writing Makefiles

Makefile Contents: What makefiles contain.
Makefile Names: How to name your makefile.
Include: How one makefile can use another makefile.
MAKEFILES Variable: The environment can specify extra makefiles.
MAKEFILE_LIST Variable: Discover which makefiles have been read.
Special Variables: Other special variables.
Remaking Makefiles: How makefiles get remade.
Overriding Makefiles: How to override part of one makefile with another makefile.
Reading Makefiles: How makefiles are parsed.

Writing Rules

Rule Example: An example explained.
Rule Syntax: General syntax explained.
Prerequisite Types: There are two types of prerequisites.
Wildcards: Using wildcard characters such as `*'.
Directory Search: Searching other directories for source files.
Phony Targets: Using a target that is not a real file's name.
Force Targets: You can use a target without commands or prerequisites to mark other targets as phony.
Empty Targets: When only the date matters and the files are empty.
Special Targets: Targets with special built-in meanings.
Multiple Targets: When to make use of several targets in a rule.
Multiple Rules: How to use several rules with the same target.
Static Pattern: Static pattern rules apply to multiple targets and can vary the prerequisites according to the target name.
Double-Colon: How to use a special kind of rule to allow several independent rules for one target.
Automatic Prerequisites: How to automatically generate rules giving prerequisites from source files themselves.

Using Wildcard Characters in File Names

Searching Directories for Prerequisites

General Search: Specifying a search path that applies to every prerequisite.
Selective Search: Specifying a search path for a specified class of names.
Search Algorithm: When and how search paths are applied.
Commands/Search: How to write shell commands that work together with search paths.
Implicit/Search: How search paths affect implicit rules.
Libraries/Search: Directory search for link libraries.

Static Pattern Rules

Writing the Commands in Rules

Command Syntax: Command syntax features and pitfalls.
Echoing: How to control when commands are echoed.
Execution: How commands are executed.
Parallel: How commands can be executed in parallel.
Errors: What happens after a command execution error.
Interrupts: What happens when a command is interrupted.
Recursion: Invoking make from makefiles.
Sequences: Defining canned sequences of commands.
Empty Commands: Defining useful, do-nothing commands.

Recursive Use of make

How to Use Variables

Reference: How to use the value of a variable.
Flavors: Variables come in two flavors.
Advanced: Advanced features for referencing a variable.
Values: All the ways variables get their values.
Setting: How to set a variable in the makefile.
Appending: How to append more text to the old value of a variable.
Override Directive: How to set a variable in the makefile even if the user has set it with a command argument.
Defining: An alternate way to set a variable to a verbatim string.
Environment: Variable values can come from the environment.
Target-specific: Variable values can be defined on a per-target basis.
Pattern-specific: Target-specific variable values can be applied to a group of targets that match a pattern.

Advanced Features for Reference to Variables

Conditional Parts of Makefiles

Functions for Transforming Text

Syntax of Functions: How to write a function call.
Text Functions: General-purpose text manipulation functions.
File Name Functions: Functions for manipulating file names.
Foreach Function: Repeat some text with controlled variation.
If Function: Conditionally expand a value.
Call Function: Expand a user-defined function.
Value Function: Return the un-expanded value of a variable.
Eval Function: Evaluate the arguments as makefile syntax.
Origin Function: Find where a variable got its value.
Flavor Function: Find out the flavor of a variable.
Shell Function: Substitute the output of a shell command.
Make Control Functions: Functions that control how make runs.

How to Run make

Makefile Arguments: How to specify which makefile to use.
Goals: How to use goal arguments to specify which parts of the makefile to use.
Instead of Execution: How to use mode flags to specify what kind of thing to do with the commands in the makefile other than simply execute them.
Avoiding Compilation: How to avoid recompiling certain files.
Overriding: How to override a variable to specify an alternate compiler and other things.
Testing: How to proceed past some errors, to test compilation.
Options Summary: Summary of Options

Using Implicit Rules

Using Implicit: How to use an existing implicit rule to get the commands for updating a file.
Catalogue of Rules: A list of built-in implicit rules.
Implicit Variables: How to change what predefined rules do.
Chained Rules: How to use a chain of implicit rules.
Pattern Rules: How to define new implicit rules.
Last Resort: How to define commands for rules which cannot find any.
Suffix Rules: The old-fashioned style of implicit rule.
Implicit Rule Search: The precise algorithm for applying implicit rules.

Defining and Redefining Pattern Rules

Pattern Intro: An introduction to pattern rules.
Pattern Examples: Examples of pattern rules.
Automatic Variables: 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.

Using make to Update Archive Files

Implicit Rule for Archive Member Targets