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CMake with C++ Tutorial

CMake is an open-source build system generator that helps manage the compilation process of projects that use C and C++. CMake simplifies the process of configuring, compiling, and linking C++ projects, especially across different platforms.

Prerequisites​

  1. C++ Compiler: Ensure a modern C++ compiler (e.g., GCC, Clang, or MSVC) is installed on your system.

  2. CMake: Verify that CMake is installed.

    cmake --version

    If not installed, you can download it from the CMake website.

1. Setting Up a Basic Project​

Create a directory for your project and navigate into it:

mkdir CMakeProject
cd CMakeProject

Step 1: Create a Simple C++ File​

Create a main C++ file, main.cpp, in the project directory:

#include <iostream>

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

Step 2: Create a CMakeLists.txt File​

Create a CMakeLists.txt file in the same directory to configure your build:

cmake_minimum_required(VERSION 3.10)
project(CMakeProject)

# Specify C++ standard
set(CMAKE_CXX_STANDARD 11)

# Add executable
add_executable(CMakeProject main.cpp)

In this CMakeLists.txt:

  • project(CMakeProject) names the project.
  • set(CMAKE_CXX_STANDARD 11) specifies the C++ standard.
  • add_executable creates an executable from main.cpp.

2. Building the Project​

To build the project:

  1. Create a build directory:

    mkdir build
    cd build

  2. Run cmake to generate build files:

    cmake ..

  3. Compile the project with:

    make

  4. Run the executable:

    ./CMakeProject

You should see Hello, CMake! printed to the console.

3. Organizing Code with Multiple Source Files​

As your project grows, you can separate code into different files.

Example: Adding a New Source File​

Create an additional file, hello.cpp, and its header file, hello.h.

hello.h​

#ifndef HELLO_H
#define HELLO_H

void sayHello();

#endif

hello.cpp​

#include <iostream>
#include "hello.h"

void sayHello() {
    std::cout << "Hello from a separate file!" << std::endl;
}

Update main.cpp​

Update main.cpp to call sayHello():

#include "hello.h"

int main() {
    sayHello();
    return 0;
}

Update CMakeLists.txt​

Modify CMakeLists.txt to include the new source file:

cmake_minimum_required(VERSION 3.10)
project(CMakeProject)

set(CMAKE_CXX_STANDARD 11)

# Add executable with multiple source files
add_executable(CMakeProject main.cpp hello.cpp)

Re-run the build steps in the build directory:

cmake ..
make
./CMakeProject

4. Adding Libraries​

You can split complex projects into libraries.

Step 1: Create a Library​

Add a new file mathlib.cpp and a header mathlib.h to act as a library.

mathlib.h​

#ifndef MATHLIB_H
#define MATHLIB_H

int add(int a, int b);

#endif

mathlib.cpp​

#include "mathlib.h"

int add(int a, int b) {
    return a + b;
}

Step 2: Update CMakeLists.txt to Create a Library​

Modify CMakeLists.txt to build mathlib as a library:

cmake_minimum_required(VERSION 3.10)
project(CMakeProject)

set(CMAKE_CXX_STANDARD 11)

# Add a library
add_library(mathlib mathlib.cpp)

# Link the library to the executable
add_executable(CMakeProject main.cpp hello.cpp)
target_link_libraries(CMakeProject mathlib)

Step 3: Update main.cpp to Use the Library​

Update main.cpp to use the add function:

#include "hello.h"
#include "mathlib.h"
#include <iostream>

int main() {
    sayHello();
    int result = add(3, 5);
    std::cout << "3 + 5 = " << result << std::endl;
    return 0;
}

Rebuild and run:

cmake ..
make
./CMakeProject

Summary​

This tutorial introduced the basics of using CMake with C++:

  1. Setting up a basic project with a CMakeLists.txt file.
  2. Building and running the project.
  3. Adding multiple source files to the project.
  4. Creating and linking a custom library.

CMake provides powerful tools to organize, build, and manage complex C++ projects across different platforms.

Content Review​

The content in this repository has been reviewed by chevp. Chevp is dedicated to ensuring that the information provided is accurate, relevant, and up-to-date, helping users to learn and implement programming skills effectively.

About the Reviewer​

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