What is Makefile in Linux?
If you’re familiar with programming on Linux systems, then you have probably heard of Makefile. It is a file that contains instructions on how to compile and build programs in the Linux environment. Makefile automates the process of building and compiling programs in the Linux environment, and it can be a powerful tool for developers who work on large projects.
In this article, we will explore the concept of Makefile in Linux in detail. We will discuss the various aspects of Makefile, including its syntax, workflow, and different types of rules. We will also cover the practical commands related to Makefile, and discuss the alternative tools that can be used instead of Makefile. By the end of this article, you will have a better understanding of what Makefile is and why it is so important in Linux development.
What is Makefile?
According to Tutorialspoint, Makefile is a file that contains instructions for the make utility to build and compile programs in the Linux environment. It is a powerful tool that automates the process of compiling and building programs by executing the necessary commands automatically.
Makefile is a universal tool that can be used to build any program written in any programming language in the Linux environment. It is used by developers to simplify the process of building large programs and libraries.
Brief History of Makefile in Linux
As reported by SIS, Makefile was created in the early days of Unix as a way to automate the build process of programs. It was developed by Stuart Feldman at Bell Labs in 1976. Since then, it has become an essential tool for developers working on Unix and Linux systems.
According to Opensource.com, Makefile in Linux is used to build and compile programs written in different programming languages, including C, C++, Java, Python, and more. It is a vital tool for developers working on large projects with multiple files and dependencies.
In the next section, we will explore how Makefile works in more detail.
How Makefile Works
Makefile works by automating the process of building and compiling programs in the Linux environment. In this section, we will explore the workflow of Makefile, the role of dependency tree, targets, and prerequisites.
Overview of the Makefile Workflow
As explained by Data Flair, Makefile works by executing a set of commands that are specified in the Makefile. The Makefile contains a list of targets, prerequisites, and recipes that are used to build and compile a program. When a target is specified, Makefile looks for the dependencies of that target and executes the necessary commands to build the target.
Dependency Tree and Its Role in Makefile
According to Makefile Tutorial, Makefile creates a dependency tree that is used to determine the order in which the targets are built. The dependency tree contains all the targets and their dependencies. When a target is specified, Makefile looks for the dependencies of that target and builds them first before building the target itself. This ensures that the program is built in the correct order and all the dependencies are satisfied.
Explanation of Targets and Prerequisites
Targets are the objects that are built by Makefile. As explained by SIS, targets are specified in the Makefile and can be files or actions. When a target is specified, Makefile looks for the dependencies of that target and executes the necessary commands to build the target.
Prerequisites are the files or actions that are required to build a target. According to Tutorialspoint, prerequisites are specified in the Makefile and can be files or targets themselves. When a target is specified, Makefile looks for the dependencies of that target and builds them first before building the target itself.
In the next section, we will explore the syntax of Makefile commands in more detail.
Syntax of Makefile Commands
In this section, we will explore the syntax of Makefile commands in more detail. We will cover the basic commands, advanced commands, and rules.
Basic Makefile Commands and Their Functions
According to Makefile Tutorial, there are several basic commands that are commonly used in Makefile. These include:
CC
: Specifies the C compiler to be usedCFLAGS
: Specifies the compilation flags to be usedLDFLAGS
: Specifies the linker flags to be usedRM
: Specifies the command to be used to delete files
These commands are used to specify the compiler, compilation flags, linker flags, and file deletion commands respectively.
Advanced Makefile Commands
In addition to the basic commands, Makefile also supports several advanced commands. According to Data Flair, some of the advanced commands that can be used in Makefile include:
VPATH
: Specifies the directories to search for fileswildcard
: Searches for files that match a patternforeach
: Loops over a list of itemsif
: Conditionally executes a command
These advanced commands can be very useful for developers working on large projects with multiple files and dependencies.
Rules and How to Write Them
As explained by Opensource.com, Makefile uses rules to specify how to build targets. A rule consists of a target, prerequisites, and a recipe. The target is the object that is being built, the prerequisites are the files or actions that are required to build the target, and the recipe is the set of commands that are executed to build the target.
Rules are written in the following format:
target: prerequisites
recipe
The target and prerequisites are separated by a colon, and the recipe is indented with a tab.
In the next section, we will explore the different types of rules that can be used in Makefile.
Types of Rules in Makefile
In this section, we will explore the different types of rules that can be used in Makefile. We will cover the different types of targets, phony targets, and default targets.
Types of Targets
As explained by Tutorialspoint, there are two types of targets in Makefile: files and actions.
File targets are used to build files, while action targets are used to execute commands that do not produce a file. File targets are specified by the name of the file to be built, while action targets are specified by a name that describes the action to be performed.
Phony Targets and Their Uses
Phony targets are targets that do not represent files. According to SIS, phony targets are used to group other targets together and to specify actions that do not produce a file.
Phony targets are specified in the Makefile using the .PHONY
target. For example:
.PHONY: clean
clean:
rm *.o
In this example, the clean
target is a phony target that specifies the command to delete all object files. The .PHONY
target indicates that clean
is not a file target, but rather a target that groups other targets together.
Default Targets and How to Specify Them
The default target is the target that is built when no target is specified on the command line. According to Makefile Tutorial, the default target is specified in the Makefile using the .DEFAULT_GOAL
target.
For example:
.DEFAULT_GOAL := target
In this example, the target
is specified as the default target. When make
is run without specifying a target, target
will be built.
In the next section, we will explore some advanced features of Makefile.
Advanced Features of Makefile
In this section, we will explore some advanced features of Makefile. We will cover the use of variables, functions, and conditional statements.
Variables and Their Uses
Variables can be used in Makefile to store values that are used in multiple places. According to Makefile Tutorial, variables are defined in the Makefile using the =
or :=
operators.
The =
operator is used to define a variable that is recursively expanded, while the :=
operator is used to define a variable that is simply expanded.
For example:
CC = gcc
CFLAGS = -Wall -Werror
In this example, CC
and CFLAGS
variables are defined with the =
operator. These variables can be used later in the Makefile to specify the compiler and compilation flags.
Functions and Their Uses
Functions can be used in Makefile to perform operations on variables. According to Data Flair, Makefile supports several built-in functions that can be used to manipulate variables.
For example:
OBJS = $(patsubst %.c,%.o,$(wildcard *.c))
In this example, the patsubst
function is used to replace the .c
extension with .o
extension for all files in the current directory.
Conditional Statements and Their Uses
Conditional statements can be used in Makefile to execute commands based on a condition. According to Makefile Tutorial, Makefile supports several conditional statements that can be used to check if a variable has a certain value.
For example:
ifeq ($(CC),gcc)
CFLAGS += -std=gnu99
endif
In this example, the ifeq
statement checks if the CC
variable is set to gcc
. If the condition is true, the -std=gnu99
flag is added to CFLAGS
.
In the next section, we will explore some practical commands related to Makefile.
Practical Commands Related to Makefile
In this section, we will explore some practical commands related to Makefile. We will cover the make
command, the make clean
command, and the make install
command.
The make
Command
According to Tutorialspoint, the make
command is used to build the targets specified in the Makefile. When the make
command is run, Makefile creates a dependency tree and takes the necessary actions to build the specified targets.
For example, if the Makefile specifies that the target
depends on file1.c
and file2.c
, Makefile will compile file1.c
and file2.c
and then build the target
.
The make clean
Command
The make clean
command is used to delete all object files and other files that are created during the build process. According to SIS, the make clean
command is often used when rebuilding a project from scratch.
For example:
clean:
rm *.o
In this example, the clean
target is used to delete all object files. When make clean
is run, all object files are deleted.
The make install
Command
The make install
command is used to install the built program onto the system. According to Data Flair, the make install
command is often used in conjunction with the PREFIX
variable to specify the installation directory.
For example:
PREFIX = /usr/local
install:
cp program $(PREFIX)/bin
In this example, the PREFIX
variable is set to /usr/local
. When make install
is run, the program
is copied to /usr/local/bin
.
In the next section, we will explore some alternatives to Make.
Alternatives to Make
In this section, we will explore some alternatives to Make. We will cover CMake, Ninja, and SCons.
CMake
CMake is a cross-platform build system generator that is used to build, test, and package software. According to Makefile Tutorial, CMake uses a separate configuration file to define the build process, making it easier to manage complex build processes.
CMake supports a wide range of programming languages, including C, C++, Java, and Python. CMake can also generate Makefiles, allowing it to be used in conjunction with Make.
Ninja
Ninja is a build system that is designed to be fast and efficient. According to OpenSource, Ninja uses a build file that is similar to Makefile, but with a simpler syntax and faster execution.
Ninja is often used in conjunction with CMake, as CMake can generate Ninja build files. Ninja is also compatible with Makefiles, allowing it to be used in conjunction with Make.
SCons
SCons is a build system that is designed to be easy to use and configure. According to Makefile Tutorial, SCons uses a Python-based configuration file to define the build process, making it easy to manage complex build processes.
SCons supports a wide range of programming languages, including C, C++, Java, and Python. SCons can also generate Makefiles, allowing it to be used in conjunction with Make.
In the next section, we will provide a summary of the key points discussed in this article.
Summary
In this article, we have explored the topic of Makefile in Linux. We began by defining what Makefile is and how it is used, and then we explored the syntax of Makefile commands, including targets, prerequisites, and recipes.
We then covered the advanced features of Makefile, including the use of variables, functions, and conditional statements. We also explored some practical commands related to Makefile, including the make
, make clean
, and make install
commands.
Finally, we discussed some alternatives to Make, including CMake, Ninja, and SCons.
Makefile is an essential tool for any developer working in a Unix or Linux environment. By using Makefile, developers can automate the build process and save time and effort. With the knowledge gained from this article, developers can create efficient and effective Makefiles that can be used to build a wide range of programs.
In the next section, we will provide some final thoughts on Makefile in Linux.
Final Thoughts
In this article, we have explored the topic of Makefile in Linux. Makefile is a powerful tool that is used to automate the build process of software projects. With the knowledge gained from this article, developers can create efficient and effective Makefiles that can be used to build a wide range of programs.
We began by defining what Makefile is and how it is used, and then we explored the syntax of Makefile commands, including targets, prerequisites, and recipes. We also covered the advanced features of Makefile, including the use of variables, functions, and conditional statements.
We then explored some practical commands related to Makefile, including the make
, make clean
, and make install
commands. We also discussed some alternatives to Make, including CMake, Ninja, and SCons.
We hope that this article has been informative and helpful. If you have any questions or comments, please feel free to leave them below. And don’t forget to check out our other great content on Linux and programming!
Thank you for reading!
Questions & Answers
What is Makefile in Linux?
Makefile is a tool used to automate the build process of software projects.
Who uses Makefile in Linux?
Developers with Unix/Linux environment knowledge use Makefile to compile programs.
How does Makefile work in Linux?
Makefile uses shell commands to update files that have changes and keep the source file up-to-date.
What are the advanced features of Makefile?
The advanced features of Makefile include variables, functions, and conditional statements.
How can Makefile be used with CMake in Linux?
CMake can generate Makefiles, allowing it to be used in conjunction with Make.
What are some alternatives to Make in Linux?
Some alternatives to Make in Linux include CMake, Ninja, and SCons.