When working on a software project, you may find the need to include external libraries to leverage their functionality. CMake, a widely used build system, provides a simple and efficient way to integrate these libraries into your project.

This blog post will guide you through the process of adding external libraries using CMake, ensuring that your project is properly configured and can build successfully.

Table of Contents

• What is CMake?
• Finding and Installing External Libraries
• Using Find Modules
• Configuring CMakeLists.txt
• Building the Project

What is CMake?

CMake is an open-source build system used to manage the build process of software projects. It allows developers to define the build configuration in a platform-independent manner using CMakeLists.txt files. CMake generates build files (e.g., Makefiles, Visual Studio solution files) based on the specified build configuration.

Finding and Installing External Libraries

Before integrating an external library into your project, you need to identify the appropriate library for your needs. You can usually find libraries on websites like GitHub or through package managers.

Once you have chosen a library, you need to install it on your system. The installation process varies depending on the library and the operating system you are using. Some libraries may require additional dependencies or build steps, so be sure to follow the library’s documentation for installation instructions.

Using Find Modules

CMake provides Find Modules to aid in automatically locating installed libraries on your system. These modules are provided for many popular libraries, allowing CMake to find the necessary headers, libraries, and other dependencies.

To use a Find Module, simply include it in your CMakeLists.txt file using the find_package() command. For example, to include the Boost library, you can add the following line to your CMakeLists.txt:

find_package(Boost REQUIRED)

CMake will search for the Boost library on your system and set the appropriate variables (e.g., Boost_INCLUDE_DIRS) that you can use in your project.

Configuring CMakeLists.txt

To integrate an external library into your CMake project, you need to add the necessary configuration to your CMakeLists.txt file.

1. Specify the required CMake version at the beginning of your CMakeLists.txt file:

   cmake_minimum_required(VERSION 3.10)
   

2. Use the project() command to define your project:

   project(MyProject)
   

3. Specify the source code files of your project:

   add_executable(MyProject main.cpp other_file.cpp)
   

4. Use the include_directories() command to set the include directories for your project. This is useful when the library requires additional header files not included in the default include paths:

   include_directories(${Boost_INCLUDE_DIRS})
   

5. Link the necessary libraries to your project using the target_link_libraries() command. This ensures that the libraries are properly linked during the build process:

   target_link_libraries(MyProject ${Boost_LIBRARIES})
   

Building the Project

Once you have configured your CMakeLists.txt file, you can build your project using CMake.

1. Create a build directory and navigate into it:

   mkdir build
   cd build
   

2. Run CMake from within the build directory, specifying the path to the root CMakeLists.txt file:

   cmake ..
   

3. Finally, build the project using your preferred build system (e.g., make or cmake --build .).

By following these steps, you can easily integrate external libraries into your CMake project. With CMake’s flexibility and the ability to use Find Modules, managing external libraries becomes straightforward, allowing you to harness the power of various libraries in your software projects.

#CMake #ExternalLibraries