Phony in Makefile refers to a specific target that is not associated with a file. It is primarily used for defining tasks or actions that need to be executed, regardless of whether there is a file with the same name. The « phony » targets are usually used for organizing and managing complex build processes in software development.

Phony targets are declared with the .PHONY special target in the Makefile. By specifying a target as phony, it tells Make that the target is not a file and should always be considered out-of-date, triggering the associated commands to be executed.

How To define a phony target in Makefile, you can make use of the .PHONY special target as follows:

« `makefile
.PHONY: target_name
« `

Here, ‘target_name’ should be replaced with the actual name of the phony target you want to define. Multiple phony targets can be specified using whitespace or newline characters.

For example, let’s say we have a Makefile with a phony target called ‘clean’. We want to execute the ‘clean’ action every time, irrespective of the existence of a file named ‘clean’.

« `makefile
.PHONY: clean

clean:
rm -rf build/
« `

In this example, ‘clean’ is declared as a phony target, and the associated command removes the ‘build/’ directory.

Why

The purpose of using phony targets in Makefile is to define tasks or actions that do not represent actual files, but rather are used for organizing the build process and performing operations like cleaning, testing, or generating documentation. By using phony targets, it allows developers to easily execute specific actions without worrying about file dependencies.

Phony targets are particularly useful in scenarios where the same name might be used for a file and a target, but they serve different purposes. Without declaring the target as phony, Make would consider the target up-to-date if a file with the same name exists, leading to incorrect build results.

Or

Currently, phony targets in Makefile are widely used in software development for tasks such as cleaning build artifacts, running tests, generating documentation, and more. They provide a convenient way to manage the build process and ensure specific actions are executed when needed, regardless of file dependencies.

Phony targets can be used in combination with other dependencies to create more complex build workflows. For example, a phony target ‘all’ can depend on multiple actual targets to build an entire project. When running ‘make all’, it will execute all the necessary build steps.

Who

In the context of Makefile, the usage of phony targets is primarily done by software developers and build automation tools. Developers define phony targets in the Makefile to specify actions that are not associated with actual files but are essential for the build and maintenance of the project.

Other relevant entities or tools that can be associated with phony targets in Makefile include build systems such as GNU Make, CMake, or any other tool that utilizes Makefile for building software projects. These build systems provide support for phony targets to enhance the build process and enable developers to define custom actions.