01. CMake Tutorial

CMake

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Prerequisites

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1. What is CMake?

This tutorial explains how to build a simple C++ program (main.cpp) using CMake, with a clear explanation of every command and option.

The goal is not just to run commands, but to understand what each part actually does.

Flow:

CMakeLists.txt
   ↓
CMake (configure)
   ↓
Build system (Makefile / Ninja / MSBuild)
   ↓
Compiler (g++, clang)
   ↓
Executable

2. Tutorial

2-1. Project Structure

project/ ├── CMakeLists.txt └── main.cpp

2-2. Context

main.cpp ```cpp #include int main() { std::cout << "Hello CMake!" << std::endl;

return 0;  } ```

CMakeLists.txt ```cmake cmake_minimum_required(VERSION 3.10) project(MyApp)

add_executable(MyApp main.cpp)

#### <b>2-3. Context Detail</b>


##### 1. `cmake_minimum_required(VERSION 3.10)`

* Specifies the **minimum required version of CMake**
* Ensures compatibility and avoids unexpected behavior

##### 2. `project(MyApp)`

* Defines the **project name**
* Internally sets variables like:

  * `PROJECT_NAME`
  * `PROJECT_SOURCE_DIR`

##### 3. `add_executable(MyApp main.cpp)`

**This is one of the most important commands**

**Meaning:**

* Create an executable file named `MyApp`
* Compile `main.cpp`
* Link everything into a runnable program

**Equivalent concept (low-level):**

```bash
g++ main.cpp -o MyApp

2-4. Build Process

Build Directory → Run CMake → Build Project → Run

1. Create Build Directory

mkdir build
cd build

• Separates source files and build artifacts
• Prevents clutter in your project
• This is called an out-of-source build (industry standard)

2. Run CMake

cmake ..

• cmake → run the CMake configuration process
• .. → path to the directory containing CMakeLists.txt

What happens internally:

• Detects compiler (e.g., g++, clang)

• Generates build files:

  • Makefile (Linux)
  • .sln / .vcxproj (Windows)

3. Build the Project

cmake --build .

• --build → tells CMake to actually compile
• . → current build directory

4. Run the Program

./MyApp

(Windows: MyApp.exe)

Full Command Summary

mkdir build
cd build
cmake ..
cmake --build .
./MyApp

3. Important CMake Options

3.1 -DCMAKE_BUILD_TYPE=Release

cmake -DCMAKE_BUILD_TYPE=Release ..

3.2 -DCMAKE_CXX_COMPILER=g++

cmake -DCMAKE_CXX_COMPILER=g++ ..