When working on a project, one of the important tasks is managing the build artifacts generated during the build process. Build artifacts can include object files, executables, libraries, and other temporary files. These artifacts can take up disk space and clutter your project directory, so it’s good practice to include a cleanup mechanism.

CMake is a popular build system that allows you to manage the build process in a platform-independent manner. It provides several built-in functionalities, including ways to handle build artifacts. In this article, we’ll explore some techniques to manage build artifacts and perform cleanup using CMake.

Setting Output Directories

CMake supports specifying the output directories for different types of build artifacts. This allows you to organize your build files in a structured manner. You can use the following CMake variables to set the output directories:

• CMAKE_ARCHIVE_OUTPUT_DIRECTORY: Specifies the directory where library files (.a, .lib) will be placed.
• CMAKE_LIBRARY_OUTPUT_DIRECTORY: Specifies the directory where shared library files (.so, .dylib) will be placed.
• CMAKE_RUNTIME_OUTPUT_DIRECTORY: Specifies the directory where executable files will be placed.

Here’s an example of setting the output directories using these variables:

# Set the output directories
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

By default, CMake sets these variables to the ${CMAKE_BINARY_DIR} directory, which represents the build directory.

Adding Cleanup Targets

CMake allows you to define custom targets and add commands to be executed when building those targets. We can utilize this feature to add cleanup targets that remove the build artifacts.

Here’s an example of defining a cleanup target in CMake:

# Define cleanup target
add_custom_target(clean
    COMMAND ${CMAKE_COMMAND} -E remove_directory ${CMAKE_BINARY_DIR}/lib
    COMMAND ${CMAKE_COMMAND} -E remove_directory ${CMAKE_BINARY_DIR}/bin
)

In this example, we define a target named clean. It invokes the remove_directory command provided by CMake to remove the lib and bin directories, which represent the library and executable output directories, respectively.

Adding Cleanup to the Build Process

To automatically clean up the build artifacts before building the project, we can add the cleanup target as a dependency to the build targets.

Here’s an example of adding the cleanup target as a dependency to the all target:

# Add cleanup target as dependency to `all` target
add_custom_target(all DEPENDS clean)

Now, whenever we build the all target, the cleanup target will be executed first.

Running Cleanup Command

You can also run the cleanup command manually using the following command:

cmake --build . --target clean

This command invokes the build system (Make, Ninja, etc.) in the current directory and builds the clean target.

Conclusion

Managing build artifacts and performing cleanup is an important part of the development process. With CMake, you can easily set output directories for different types of build artifacts and add cleanup targets. Automating the cleanup process helps in keeping the project directory clean and avoids unnecessary disk space usage.

By utilizing these techniques, you can effectively manage build artifacts and keep your project organized and tidy.

#CMake #BuildArtifacts