An introduction to the build pipeline, and how we can orchestrate it manually

Before working with CMake, it's useful to understand the tools it orchestrates. This lesson guides you through setting up a C++ toolchain.

Building C++ Programs

Walking through the steps of the C++ compilation process, from source code to machine code.

The Compilation Pipeline

The linker's role in the build process, how it resolves symbols to combine object files, and how to troubleshoot common errors.

Object Files and the Linking Process

The difference between static and dynamic libraries, how to create them, and the trade-offs between them.

Static and Shared Libraries

The C++ Build Process

Recommended approaches for managing large projects and the libraries that they depend on

Learn how to structure your C++ projects for scalability and maintainability, from basic directory layouts to managing multiple modules.

Organizing a C++ Project

Learn to manage third-party libraries in C++, covering include/library paths, static vs. shared libraries, versioning, and platform differences.

Managing Libraries and Dependencies

An introduction to traditional build tools like Makefiles and IDE projects, highlighting the maintenance, scalability, and cross-platform challenges that result

Automated Build Systems and Their Limitations

Project Structure and Dependency Management

Setting up CMake and creating your first project

An introduction to CMake, the cross-platform, open-source meta-build system that solves the core challenges of C++ project management.

Why CMake?

A step-by-step guide to installing CMake. We'll explore command-line, GUI, and IDE workflows, and how to configure your compiler.

Setting Up a CMake Environment

Creating the bare minimum `CMakeLists.txt` file and build up to a project with an executable and a library, learning the fundamental commands along the way.

Writing a CMakeLists File

Learn the two-stage process of building a CMake project. This lesson covers configuring, generating, building, running, and troubleshooting common errors.

Building and Running CMake Projects

Learn how to organize large C++ projects in CMake using subdirectories and the `add_subdirectory()` command to create modular, maintainable builds.

CMake Project Structure and Subdirectories

Introducing CMake

Exploring CMake's programming features, caching mechanisms, and interactions with the file system

A primer on the fundamental building blocks of the CMake language: variables, string interpolation, and logging messages.

CMake Variables and Logging

Discover the CMake Cache, the mechanism for storing persistent user-configurable options, and learn how to create and manage cached variables.

The CMake Cache

Exploring CMake's command syntax and its list data type, including how to create, manipulate, and use lists in your projects.

CMake Commands, Arguments, and Lists

Transform your static build descriptions into dynamic scripts with CMake's control flow commands, if() and foreach().

CMake Conditionals and Loops

Exploring CMake's `file()` command, covering how to read, write, copy, and glob files, and how to manipulate paths.

Working with the File System

Learn to create reusable logic with CMake functions and macros, and how to organize them into modules for clean, scalable build systems.

Modularizing CMake Code

CMake Language and Fundamentals

Learn more about targets, and how their properties and links are the foundation of modern CMake

Learn to work with target properties - understanding their purpose, setting and updating them, and retrieving them when your build requires it

Target Properties

Learn about target types, and how the `PUBLIC`, `PRIVATE`, and `INTERFACE` keywords control how properties are shared.

Relationships Between Targets

Discover how CMake's `target_link_libraries()` command builds a dependency graph, and how it uses this graph to automatically manage transitive dependencies and link order.

Indirect Relationships and the Dependency Graph

Learn to use abstract target types like `INTERFACE`, `ALIAS`, and `IMPORTED` to model complex project needs, organize build properties, and integrate pre-compiled binaries.

Using `INTERFACE`, `ALIAS`, and `IMPORTED` Libraries

Adding support for user-configurable library types and an initial introduction to target installation.

Using Shared Libraries

Targets and Dependencies

Learn how to manage multiple build configurations within the same project, and how to create scripts that adapt to the environment

Learn how CMake manages different build configurations like Debug and Release, the difference between generator types, and how to apply settings conditionally using modern techniques.

Build Configurations (Debug, Release, etc.)

Learn the tools and patterns needed to write portable CMakeLists.txt files that work seamlessly across platforms and compilers

Cross-Platform Configurations

Learn to write architecture-aware CMake scripts for 32/64-bit systems and Apple's Universal Binaries (Intel/ARM).

Handling Different Architectures

Learn to build for different operating systems and architectures using CMake's cross-compilation support and toolchain files.

Cross-Compilation and Toolchain Files

Platforms and Build Configurations

Learn how to add external libraries to our build, and how to create our own packages for others to use

Learn to find and use pre-installed libraries with `find_package()`, understanding Module vs. Config mode and the power of imported targets

Finding Dependencies using `find_package()`

Learn how to make your libraries consumable by other projects using CMake by turning your build-tree into a distributable install-tree.

Creating a Consumable Package

Learn how to consume a CMake package you've installed, completing the producer-consumer cycle. We'll cover using `find_package()` and how to point CMake to your library's location

Using Installed Packages

Learn how to create self-contained, reproducible builds by fetching dependencies from source using `FetchContent()` and `ExternalProject_Add()`.

Fetching External Dependencies

Creating and Consuming Packages

Integrating the vcpkg and Conan package managers to handle external dependencies

Learn to manage C++ dependencies effortlessly with the vcpkg package manager and its seamless CMake integration using toolchain files and manifests.

Integrating CMake and vcpkg

Learn the day-to-day commands for managing dependencies with vcpkg and how to guarantee reproducible builds using baselines and version overrides

vcpkg Commands and Versioning

Combine vcpkg with CMake's cross-compilation capabilities. Learn to use triplets to target different architectures and chain-load toolchain files

Cross-Compiling with vcpkg

Discover Conan, the binary-first C++ package manager, and learn how to integrate it with CMake using profiles and lockfiles for fast, reproducible builds.

Using Conan with CMake

Learn to cross-compile C++ projects with Conan, using build and host profiles to manage dependencies for different platforms.

Cross-Compilation with Conan

Package Managers

Introducing presets, allowing us to simplify our workflow and share common configurations across our team

Learn the fundamentals of CMake Presets. This lesson introduces `CMakePresets.json` to simplify complex build commands.

CMake Presets

Learn to structure your CMake presets with inheritance and customize them for your local environment using `CMakeUserPresets.json`.

User Presets and Inheritance

Learn to make your CMake presets portable by using environment variables and conditional logic to adapt to different machine configurations.

Environment Variables and Conditional Presets

Learn how to extend the build process beyond simple compilation by integrating external tools and custom commands

Learn how to use generator expressions `$<...>` for build-time conditional logic.

Generator Expressions and Conditional Logic

Learn how to attach commands to specific points in a target's build lifecycle using `add_custom_command(TARGET)` for tasks like post-build file copying.

Integrating Tools with `add_custom_command()`

Learn to integrate code generators like Protobuf into your build process using `add_custom_command()`, creating automated file-level dependencies in CMake.

Generating Files with Protobuf and `add_custom_command()`

Custom Commands

An introduction to automating common workflow chores by creating custom targets

Learn to create standalone, non-code targets using add_custom_target() for utility tasks like code formatting and documentation generation.

Custom Targets and Build Utilities

Using the Clang-Format tool to automatically enforce a consistent coding style, and integrating it into our build using a custom CMake target

Using Clang-Format

An introduction to file sets and the `target_sources()` command, allowing us to manage our header files in a more controlled way

Using File Sets

A step-by-step guide to integrating Doxygen into your CMake build process for automated C++ documentation.

Generating Documentation with Doxygen

Custom Targets

Integrate automated tests into a CMake project using CTest, GoogleTest, and GoogleMock

Learn the fundamentals of automated testing in C++ with CTest. Create your first test suite, register tests with `add_test()`, and run them with the `ctest` command.

Automated Testing and CTest

Learn to refactor manual C++ tests into a professional test suite using the GoogleTest framework, managed by vcpkg and integrated with CTest.

Integrating GoogleTest with CMake

Learn to use a wide range of assertions, write data-driven parameterized tests, and isolate dependencies with Google Mock.

Assertions and Parameterized Tests

Learn how to isolate dependencies that our project uses, and then how to replace those dependencies at test time using Google Mock.

Dependency Injection and Mocking

Learn the standard pattern for testing application logic by refactoring it into a linkable library

Testing Executables

Move beyond individual tests to manage a full test suite. Learn to organize tests, run tests in parallel, filter by labels, and measure our code coverage

Managing a Test Suite

Automated Testing

Using static and dynamic analysis in CMake projects to automatically detect memory bugs, performance issues, and problematic code

Learn to find memory bugs at runtime by integrating AddressSanitizer (ASan) into a CMake project

Using AddressSanitizer (ASan)

Adding benchmarks to our build to measure the performance of our code, and track how it changes over time

Using Google Benchmark

Integrating Clang-Tidy to enforce good practices and find bugs before we even compile

Using Clang-Tidy

Automated Analysis

Automating the entire development lifecycle using Git for souce control, GitHub Actions for cloud builds, and CPack to create distributable packages and installers.

An introduction to Git, the version control system that underpins modern collaborative software development and automated build pipelines.

Source Control with Git

Learn how to automate your build and test process with Continuous Integration (CI) and a build server. This lesson provides a guide to creating a GitHub Actions workflow for a CMake project.

Build Servers and Continuous Integration

Learn to package your C++ projects using CMake's CPack. This lesson covers creating developer ZIP archives and professional Windows MSI installers with components.

Packaging with CPack

Learn to automate the packaging process by integrating CPack with a multi-platform GitHub Actions workflow

Packaging with GitHub Actions

Learn to automate the creation of a professional Windows installer by integrating CPack, the WiX Toolset, and a multi-platform GitHub Actions workflow.

Creating Installers with CPack and GitHub Actions

Learn to automate the release process using a GitHub Actions workflow that builds, packages, and publishes artifacts to a GitHub Release

Deployment with GitHub Releases

Continuous Integration and Packaging

If you have a basic grasp of C++ but find the build process intimidating, this course is for you. We assume you know the language, but not how to manage large projects.

Manage complex, cross-platform builds using industry-standard tools. Create scalable build systems that automate the entire development lifecycle.

This course is a comprehensive deep-dive into the entire C++ build ecosystem, centered around the power and flexibility of modern CMake. We leave no stone unturned.

Start with a foundational understanding of compilers, linkers, static vs. shared libraries, and object files.

The Full Build Pipeline

Learn every aspect of the CMake language, from variables and control flow to functions, modules, and generator expressions.

Complete CMake Language Mastery

Master the modern target-centric paradigm, including properties, usage requirements, and abstract targets.

Advanced Target Management

Explore every method for handling dependencies, from `find_package` and `FetchContent` to vcpkg and Conan, including versioning and cross-compilation.

In-Depth Dependency Management

Integrate a full suite of professional tools for testing (CTest, GoogleTest), analysis (ASan, Clang-Tidy), and packaging (CPack).

Total Workflow Automation

Build a fully automated deployment pipeline that takes your code from a Git push to a published GitHub Release with multi-platform installers.

End-to-End CI/CD and Deployment

What You'll Learn

Become a software engineer with C++.  Starting from the basics, we guide you step by step along the way

Intro to C++ Programming

If you're completely new to programming or want a thorough introduction, consider starting with our free introductory course:

New to Programming?

Managing C++ Projects Using CMake

In the last lesson, we successfully built our first CMake project. It worked, but all our build logic was crammed into a single `CMakeLists.txt` file.


```c++
#<cmake>
# 1. Set the minimum CMake version and project name
cmake_minimum_required(VERSION 3.16)
project(Greeter)

# 2. Define the library target
add_library(GreeterLib src/Greeter.cpp)

# 3. Add usage requirements to the library
target_include_directories(GreeterLib PUBLIC
  ${PROJECT_SOURCE_DIR}/include
)
target_compile_features(GreeterLib PUBLIC cxx_std_20)

# 4. Define the executable target
add_executable(GreeterApp src/main.cpp)

# 5. Add usage requirements to the executable
target_compile_features(GreeterApp PUBLIC cxx_std_20)

# 6. Link the library to the executable
target_link_libraries(GreeterApp GreeterLib)
```


For a tiny project, that's fine. But what happens when our project grows? Imagine adding a physics engine, a rendering module, a networking library, and a separate test suite. A single `CMakeLists.txt` would quickly become a long, unmaintainable file.


There is also a more practical problem - how can we share our library with other projects if the build configuration for our library is mixed with the configuration for a load of other targets within the same `CMakeLists.txt` file?


A core principle of good software design is _**modularity**_. This applies to our build scripts just as much as it does to our C++ code. A scalable project needs a scalable build structure.


In this lesson, we'll learn the two steps for for achieving this:

1. Breaking a project into self-contained, reusable components each with their own `CMakeLists.txt` file
2. Bringing these components back together into a complete project using `add_subdirectory()` commands

## From Monolith to Modular


The goal is to structure our project so that each component (like a library or an executable) is entirely self-contained. All its source code, public headers, and build instructions should live together in a single directory.


This makes the component:

- **Maintainable**: The logic for a component is in one place.
- **Reusable**: You could copy the component's directory into a new project and use it instantly.
- **Scalable**: Adding new components doesn't increase the complexity of existing ones.

To do this, we'll refactor our simple `Greeter` project into a structure that treats the `GreeterLib` library and the `GreeterApp` executable as two distinct, modular components.


## The Modular Project Structure


Here is the structure for our refactored project, which we'll set up in this lesson:


```c++
//<nh>
greeter/
 ├─ include/
 │  └─ greeter
 │    └─ Greeter.h
 ├─ src/
 │  └─ Greeter.cpp
 └─ CMakeLists.txt

app/
 ├─ src/
 │  └─ main.cpp
 └─ CMakeLists.txt
 
CMakeLists.txt
```


Each major component gets its own dedicated directory and `CMakeLists.txt` file.  In our top level directory, we have three things:

- The `/greeter` directory for our library.
- The `/app` directory for our executable
- A top level `CMakeLists.txt` to orchestrate everything

Each of our two components has its own dedicated `CMakeLists.txt` file, as well as the usual subfolders like `/src`, `/include`, and more can be added as needed.


Within our library's `/include` directory, we've also added an intermediate `greeter` directory for our header files.  We'll explain the reason for this later in this lesson.


Let's walk through each of our three `CMakeLists.txt` files.


### The Root `CMakeLists.txt`


The top-level `CMakeLists.txt` becomes extremely simple. Its only job is to define project-wide settings and then pull in the components using `add_subdirectory()`.


<CodeFile path="CMakeLists.txt" status="New">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.16)

# Name the overall project
project(Greeter)

# Bring in our components
add_subdirectory(greeter) # The library #<h>
add_subdirectory(app)     # The executable #<h>
```


</CodeFile>


This top level `CMakeLists.txt` is now extremely high level, which is what we want for a file in such an important location as the root of our project.  It simply declares what components our project has, and each new component we add requires a single line, keeping complexity to a minimum.


It doesn't care about the implementation details of how those components are built - those are lower level details stored deeper in our project structure.


The single line that loads these components is the `add_subdirectory()` command.  This command looks for a `CMakeLists.txt` file in that location, and incorporates it into our build.


### The Library's `CMakeLists.txt`


The `greeter/CMakeLists.txt` file is responsible for defining the library in its directory.


Let's use it to define our `GreeterLib` target, alongside its source files, include directories, and it's usage of the C++20 standard:


<CodeFile path="greeter/CMakeLists.txt" status="New">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.16)

add_library(GreeterLib src/Greeter.cpp)
target_include_directories(GreeterLib PUBLIC
  ${CMAKE_CURRENT_SOURCE_DIR}/include
)
target_compile_features(GreeterLib PUBLIC cxx_std_20)
```


</CodeFile>


Note that we're now using the `CMAKE_CURRENT_SOURCE_DIR` variable for our include directories, where previously we were using `PROJECT_SOURCE_DIR`.


The `CMAKE_CURRENT_SOURCE_DIR` variable is the directory where the _**current**_ `CMakeLists.txt` file is.  Given we're using this variable in a `CMakeLists.txt` file stored in the `greeter/` directory, then its value will be the path to that directory.


The `PROJECT_SOURCE_DIR` variable is the directory where the `CMakeLists.txt` file containing the `project()` command is.  In our case, the only `CMakeLists.txt` file in our hierarchy containing a `project()` command is within the top level directory.


So, if we were to use that variable in any `CMakeLists.txt` file loaded by an `add_subdirectory()` command in that file, it would contain the path to the root of our project.


With these changes, our library is now completely reusable.  If we want to share it with other projects, we just share our entire `greeter` directory.  Any other project that wants to use our library involves three simple steps:

- copy this directory into their project's file structure
- add an `add_subdirectory()` command to their `CMakeLists.txt` file to make CMake aware of it
- add a `target_link_libraries()` command for any target that wants to use the library

### The Application's `CMakeLists.txt`


Finally, let's look at the application's `CMakeLists.txt` file.  Again, it's quite simple - it just needs to define itself, it's C++ standard, and link against the `GreeterLib` library.


<CodeFile path="app/CMakeLists.txt" status="New">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.16)

add_executable(GreeterApp src/main.cpp)
target_compile_features(GreeterApp PUBLIC cxx_std_20)
target_link_libraries(GreeterApp GreeterLib)
```


</CodeFile>


<Pw>


## Namespaced Includes


Our project structure has added an intermediate `/greeter` directory between our library's `/include` directory and its header files.


The reason this is a common convention is that, as our project grows to contain multiple libraries, we want our `#include` directives to specify which library they're importing a specific header from.


This makes it clear what our code is importing, and also mitigates against naming conflicts, where two or more libraries have header files with the same name.


Let's update our `main.cpp` and our library's source file to match the new, namespaced directory structure:


<CodeViewer>


<CodeFile path="CMakeLists.txt">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.16)

project(Greeter)

add_subdirectory(greeter)
add_subdirectory(app)
```


</CodeFile>


<CodeFile path="greeter/CMakeLists.txt">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.16)

add_library(GreeterLib src/Greeter.cpp)
target_include_directories(GreeterLib PUBLIC
  ${CMAKE_CURRENT_SOURCE_DIR}/include
)
target_compile_features(GreeterLib PUBLIC cxx_std_20)
```


</CodeFile>


<CodeFile path="greeter/include/greeter/Greeter.h" status="Moved">


```c++
#pragma once
#include <string>

// A simple function that returns a greeting
std::string get_greeting();
```


</CodeFile>


<CodeFile path="greeter/src/Greeter.cpp" status="Updated">


```c++
#include <greeter/Greeter.h> // Namespaced include //<h>

std::string get_greeting() {
  return "Hello from the modular Greeter library!";
}
```


</CodeFile>


<CodeFile path="app/src/main.cpp" status="Updated" defaultOpen>


```c++
#include <iostream>
#include <greeter/Greeter.h> // Namespaced include //<h>

int main() {
  std::cout << get_greeting();
  return 0;
}
```


</CodeFile>


<CodeFile path="app/CMakeLists.txt">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.16)

add_executable(GreeterApp src/main.cpp)
target_compile_features(GreeterApp PUBLIC cxx_std_20)
target_link_libraries(GreeterApp GreeterLib)
```


</CodeFile>


</CodeViewer>


Remember, we can configure our include directories however we want.  A library providing the option for namespaced includes is nice, but we don't have to use it if we don't want to.  We can still add this specific `/include/greeter` path as an include directory for any target:


<CodeFile path="app/CMakeLists.txt">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.16)

add_executable(GreeterApp src/main.cpp)
target_compile_features(GreeterApp PUBLIC cxx_std_20)
target_link_libraries(GreeterApp GreeterLib)

target_include_directories(GreeterApp PUBLIC #<h>
  ${PROJECT_SOURCE_DIR}/greeter/include/greeter #<h>
)#<h>
```


</CodeFile>


Now, source files within our `GreeterApp` target can omit the `/greeter` namespace if they prefer:


<CodeFile path="app/src/main.cpp" status="Updated" defaultOpen>


```c++
#include <iostream>

// Either of these will work
#include <greeter/Greeter.h>//<h>
#include <Greeter.h>//<h>

int main() {
  std::cout << get_greeting();
  return 0;
}
```


</CodeFile>


This specific implementation in `app/CMakeLists.txt` isn't great, as it means we no longer have a clean module separation.  `GreeterApp` now needs to know where `GreeterLib` lives within our project's directory structure (`${PROJECT_SOURCE_DIR}/greeter`) and where that library stores its header files (`include/greeter`).


```c++
#<cmake>
target_include_directories(GreeterApp PUBLIC
  # GreeterApp shouldn't know about this path
  ${PROJECT_SOURCE_DIR}/greeter/include/greeter #<w>
)
```


If either of those things change, `GreeterApp` will stop working.  By the end of the course, we'll have learned more robust ways to solve problems like this.


## Building and Running


Let's verify our new modular structure is working using the same steps we walked through in the previous lesson.  Within our `/build` directory, we can generate our project files using the command:


```c++
//<ti>
cmake ..
```


This will process our top-level `CMakeLists.txt` file.  This will, in turn, load in the `CMakeLists.txt` files in the other directories identified by our `add_subdirectory()` commands, and process those too.


When it's successful, we can build our project using the same command as before.  Again, we would do this from the `/build` directory:


```c++
//<ti>
cmake --build .
```


Our new modular structure will slightly change where our compiled files are located.  Before, our `GreeterApp` executable was located in the base `/build` directory.  Now, it will be located in `/build/app`.


We'll learn how to control our output locations soon but, for now, we can just run it from that location using `./app/GreeterApp` (or `./app/GreeterApp.exe` on Windows):


```c++
//<ti>
./app/GreeterApp
```


```c++
//<o>
Hello from the modular Greeter library!
```


## Summary


In this lesson, we refactored our project to a modular, component-based structure.

- **The Goal**: To create self-contained components that can be easily maintained, reused, and scaled.
- **The Structure**: Each component (library, executable) lives in its own directory with its own `include`, `src`, and `CMakeLists.txt` files.
- **The** **`add_subdirectory()`** **Command**: The root `CMakeLists.txt` acts as an orchestrator, using this command to bring components into the build.

You now have a scalable template for organizing any C++ project, no matter how large it becomes. This modular approach is the key to managing complexity in a growing codebase.


<Preview>


### CMake Fundamentals and Language Basics


We've designed a great project structure, but our ability to write the `CMakeLists.txt` files that power it is still basic. We've seen a few commands, but CMake includes an entire suite of capabilities.  It's akin to a programming language in it's own right, including variables, conditional logic, loops, functions, and more.


To write truly powerful and flexible build scripts, we need to understand the CMake language itself. In the next chapter, we'll explore this core syntax.


</Preview>


</Pw>

add_subdirectory() Docs

CMake Tutorial - Adding a Library

An Introduction to Modern CMake

In CMake, what is the difference between CMAKE_SOURCE_DIR and PROJECT_SOURCE_DIR?

Mastering CMake

Master CMake project organization with this guide on using subdirectories. Learn how to refactor your project, use the add_subdirectory() command to create modular components, and manage scopes and paths for scalable, maintainable builds.

CMake Project Structure and Subdirectories

Understanding the Basics

Practical Applications

Common Mistakes

Next Steps

Additional Resources

Assessment Preparation

Managing C++ Projects Using CMake