C++ build automation with CMake

05 Oct 2023

If you’re developing a C++ project that requires multiple source files and dependencies, managing the build process manually can quickly become tedious and error-prone. Fortunately, there are tools available that can automate this process for you. One such tool is CMake.

CMake is an open-source cross-platform build system that uses a script-based configuration language. It allows you to define your project’s build rules and dependencies in a simple and platform-independent way. In this blog post, we will explore the basics of CMake and how you can use it to automate the build process for your C++ project.

What is CMake?
Installing CMake
Defining a CMake Project
Building the Project
Adding Dependencies
Conclusion

What is CMake?

CMake is a meta-build system that generates platform-specific build files (e.g. Makefiles, Visual Studio project files) based on a single high-level configuration file. It provides a unified interface to build tools and IDEs, making it easier to manage complex build configurations across different platforms.

With CMake, you can define the build rules, target dependencies, compiler flags, and other project-specific settings in a CMakeLists.txt file. This file serves as the entry point for CMake to generate the platform-specific build files.

Installing CMake

To install CMake on your system, you can download the latest version from the official website (https://cmake.org/download/) or use a package manager if your operating system supports it.

Once installed, you can verify the installation by opening a terminal or command prompt and running the following command:

cmake --version

This should display the version of CMake installed on your system.

Defining a CMake Project

To use CMake for your C++ project, you need to create a CMakeLists.txt file at the root of your project directory. This file is where you define the project-specific settings and build instructions.

Here’s a simple example of a CMakeLists.txt file:

cmake_minimum_required(VERSION 3.12)

project(MyProject)

# Add source files to the project
file(GLOB_RECURSE SOURCES "src/*.cpp")

# Create an executable target
add_executable(MyProject ${SOURCES})

In this example, we define a minimum required version of CMake, set the project name as “MyProject”, and specify the source files using the file command with the GLOB_RECURSE option to recursively find all .cpp files in the src directory.

The add_executable command creates an executable target named “MyProject” based on the specified source files.

Building the Project

To generate the platform-specific build files with CMake, you need to run the cmake command followed by the path to the directory containing the CMakeLists.txt file.

Assuming you’re in the root of your project directory, you can run the following commands:

mkdir build
cd build
cmake ..

This creates a build directory, navigates into it, and runs the cmake command to generate the build files.

Once the build files are generated, you can use the appropriate build tool (e.g. make, Ninja, Visual Studio) to compile your project. For example, if you’re using make, you can run:

make

This will build the project using the generated Makefile.

Adding Dependencies

CMake allows you to easily add dependencies to your project. Whether you’re using external libraries or other CMake projects, you can specify them in your CMakeLists.txt file.

Here’s an example of adding an external library to a CMake project using the find_package command:

find_package(Boost REQUIRED)

# Add Boost libraries to the project
target_link_libraries(MyProject PRIVATE Boost::boost)

In this example, we use the find_package command to locate the Boost library on the system. We then link the Boost libraries to our project using the target_link_libraries command.

CMake provides similar commands for other popular libraries, making it easy to manage dependencies in your C++ projects.

Conclusion

CMake is a powerful build automation tool that can simplify the build process for your C++ projects. By defining your project settings and dependencies in a CMakeLists.txt file, you can generate platform-specific build files and easily build your project on different platforms.

In this blog post, we’ve only scratched the surface of what CMake can do. There are many more advanced features and options available for configuring and customizing your build process.

So if you’re tired of manually managing complex build configurations, give CMake a try and see how it can streamline your C++ development workflow.

#programming #buildautomation

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