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🛠️ CMake Tutorial: Build C++ Projects Easily

What is CMake?

CMake is an open-source, cross-platform build system generator. It helps you manage the build process of your C++ (and other language) projects, generating native build files for systems like Make, Ninja, or Visual Studio.

Why Use CMake?

  • Portability: Works on Linux, Windows, macOS.
  • Scalability: Handles small and large projects.
  • Flexibility: Supports many compilers and IDEs.
  • Modern Features: Supports out-of-source builds, testing, packaging, and more.

1. Basic Project Structure

my_project/
├── CMakeLists.txt
├── main.cpp

2. Writing a Simple CMakeLists.txt

main.cpp 

#include <iostream>
int main() {
    std::cout << "Hello, CMake!" << std::endl;
    return 0;
}

CMakeLists.txt 

cmake_minimum_required(VERSION 3.10)
project(HelloCMake)
add_executable(hello_cmake main.cpp)

  • cmake_minimum_required: Specifies the minimum CMake version.
  • project: Names your project.
  • add_executable: Defines an executable target.

3. Building and Running

From your project root:

$ mkdir build
$ cd build
$ cmake ..
$ make
  • The binary will be in the build/ directory (e.g., build/hello_cmake).

Run it: 

$ ./hello_cmake

4. Adding a Library

Suppose you have a helper library:

helper.h 

#pragma once
int add(int a, int b);

helper.cpp 

#include "helper.h"
int add(int a, int b) { return a + b; }

Update your CMakeLists.txt: 

cmake_minimum_required(VERSION 3.10)
project(HelloCMake)
add_library(helper helper.cpp)
add_executable(hello_cmake main.cpp)
target_link_libraries(hello_cmake PRIVATE helper)

5. Useful CMake Tips

  • Use target_include_directories to add include paths.
  • Use set(CMAKE_CXX_STANDARD 17) to set the C++ standard.
  • Out-of-source builds keep your source directory clean.
  • Use cmake --build . for a portable build command.

6. Further Resources

Summary

CMake is a powerful tool for managing C++ builds. With simple configuration files and support for all major platforms, it’s a must-learn for modern C++ development!