CMake basics

Learn build configuration with CMake.

What is CMake?

CMake is a build system generator for C++ projects. It does not compile directly; instead it produces Makefiles or Ninja files that build the project. It is cross-platform: the same build file works on Linux, macOS and Windows.

Every CMake project has a CMakeLists.txt at its root. The three basic commands are: cmake_minimum_required(VERSION 3.20) for the minimum version, project(MyApp) for the project name, and add_executable(myapp main.cpp) to define an executable target. After writing this file you run cmake . to generate build files.

project and add_executable

The project(MyApp) command names the project and sets the default language (C/C++). You can specify the language explicitly with project(MyApp LANGUAGES CXX). This command also defines the PROJECT_NAME variable.

The add_executable(myapp main.cpp) command defines an executable target named myapp. You can list source files one by one: add_executable(myapp main.cpp utils.cpp). The target name usually matches the project name. CMake compiles this target and produces the executable.

Exercise Write your first CMakeLists.txt

Write a CMakeLists.txt. Define the version with cmake_minimum_required(VERSION 3.20), the project name with project(MyApp), and the executable target with add_executable(myapp main.cpp).

Show example solution

cmake_minimum_required(VERSION 3.20)
project(MyApp)
add_executable(myapp main.cpp)

Test yourself

What does CMake produce?
- An executable directly
- C++ source code
- Build files (Makefile or Ninja)
- A class diagram
Show answer

Build files (Makefile or Ninja) — CMake produces Make or Ninja build files; they compile the project.

Complete the version command

____(VERSION 3.20)

Show answer

cmake_minimum_required(VERSION 3.20)

Match the command to its role

cmake_minimum_required

Minimum version
project(MyApp)

Sets project name
add_executable

Executable target
CMakeLists.txt

Build file

Next lesson: CMakeLists.txt

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