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 previous lesson, we saw how to define targets and attach properties to them. We learned that the `PUBLIC`, `PRIVATE`, and `INTERFACE` keywords control how these properties are shared with direct consumers. A consumer that links to our library will inherit its `PUBLIC` and `INTERFACE` properties, but not its `PRIVATE` ones.


This is the key to building modular components, but it's only half the story. Real-world projects are not simple, linear chains of dependencies. They are complex webs, where an application might depend on a library, which in turn depends on several other libraries, and so on.


This lesson explores how CMake manages these **indirect relationships**. We'll see how `target_link_libraries()` does more than just specify a link; it builds a **dependency graph**.


By understanding this graph, you'll see how CMake automatically handles  transitive dependencies and solves the age-old problem of link order, freeing you from one of the most tedious aspects of C++ development.


## Indirect Dependencies through Targets


In addition to properties being `PUBLIC`, `PRIVATE`, or `INTERFACE`, the links between our targets can also have these visibility settings.  For example, when we specify that `GreeterApp` depends on `GreeterLib`, we can declare that relationship `PUBLIC`:


```javascript
//<cmake>
target_link_libraries(GreeterApp PUBLIC GreeterLib)
```


Setting the visibility of the relationships between targets is what enables CMake to do a lot of heavy lifting once our projects get large. It allows us to define only the **direct** dependencies, whilst CMake handles all the **indirect** dependencies automatically.


For example, let's imagine we introduce another header-only library, `Calendar`, that depends on `Date`.  Compiling `Date`'s header files requires C++20, so `Calendar` needs to keep track of that requirement.  Our `Date` properly specifies that requirement using a `target_compile_features()` with `INTERFACE` visibility, so it will automatically be propagated to `Calendar` when we link them using `target_link_libraries()`.


However, what if another library, such as `GreeterLib` links to `Calendar`?


<Img hasTransparency invertible file="cmake-transitive.png" alt="Diagram showing a transitive dependency" width="1200" height="349" blurHash="L87-ZwWBWBay~qj[j[t7RjRjWBj[" />


Now, `GreeterLib` also requires C++20 to compile successfully.  This is true even when:

- `GreeterLib` doesn't directly link to `Date`, it only links to `Calendar`.  It may not even know that `Date` exists and it shouldn't need to.  From `GreeterLib`'s perspective, it just wants to use `Calendar` and doesn't care about its internal implementation details.
- `Calendar` doesn't directly specify that it needs C++20.  It only inherits that requirement from `Date`.

In spite of both of these constraints, `GreeterLib` still has a transitive dependency on `Date`, so it needs to respect its requirements and use C++20.


These webs of dependencies can get extremely complex in larger projects, with dozens of targets and hundreds of direct and indirect connections between them.  Managing this dependency graph is one of the strengths of CMake.


<Definition>


### Graphs


This web of dependences is an example of a **graph**.  A graph is a data structure that comprising or **nodes** and **edges** that connect them.


In this implementation of a graph, the nodes represent CMake targets created with commands like `add_executable()` and `add_library()`.  The edges represent the dependencies between those targets, created using commands like `target_link_libraries()`.


**Graph theory** is the field of mathematics and computer science that studies graphs, and the algorithms for analysing and solving problems that can be represented as graphs.


</Definition>


<Pw>


## Visibility of Relationships


The `target_link_libraries()` command is the engine that allows CMake to construct this dependency graph.  Let's imagine we have this command:


```c++
#<cmake>
target_link_libraries(Calendar PUBLIC Date)
```


When you write this, you are declaring that `Calendar` depends on target `Date`.  Accordingly, CMake will now ensure that `Calendar` inherits all of `Date`'s `PUBLIC` and `INTERFACE` properties, including the C++20 requirement.


Furthermore, because we used the `PUBLIC` keyword in the `target_link_libraries()` call itself, that means this relationship between `Calendar` and `Date` is also visible and inheritable.  It means that any target that links to `Calendar` will now also be transitively linked to `Date`, and will also inherit `Date`'s `PUBLIC` and `INTERFACE` properties in much the same way that `Calendar` did.


Let's continue to build our graph by declaring that `GreeterLib` depends on `Calendar`: 


```c++
#<cmake>
target_link_libraries(Calendar PUBLIC Date)

target_link_libraries(GreeterLib Calendar)#<h>
```


Not only will CMake understand it needs to link `GreeterLib` to `Calendar`, it will also understand that there is now an indirect, transitive relationship between `GreeterLib` and `Date` that it needs to manage.


<Img hasTransparency invertible file="cmake-transitive-automatic.png" alt="Diagram showing a transitive dependency being managed automatically" width="1200" height="567" blurHash="L06kVC4n00%M009FD%_300D%M{%M" />


### Default Visibility of Relationships


When we do not specify the visibility of a relationship within `target_link_libraries()`, the relationship is `PRIVATE` by default:


```c++
#<cmake>
# These are equivalent
target_link_libraries(B C)
target_link_libraries(B PRIVATE C)
```


This means that targets that link to B will **not** be aware that B links to C, and will therefore **not** inherit C's properties:


```c++
#<cmake>
# A PRIVATE relationship
target_link_libraries(B C)

# This links A to B, but does NOT link A to C
# This is because B's relationship to C is PRIVATE
target_link_libraries(A B)
```


We walk through a practical example of where `PRIVATE` relationships are useful in the next lesson.


## Automatic Link Ordering


One of the most frustrating problems in traditional C/C++ builds is managing the **link order**. When you call the linker directly, the order in which you list your libraries matters. If library `A` uses functions from library `B`, you typically need to link them in the order `A`, then `B`.


Manually tracking these dependencies and ensuring the correct order for a project with dozens of libraries is a tedious and fragile process.


CMake completely solves this problem. It doesn't think in terms of a linear list of libraries.  As we've seen earlier in the chapter, it thinks in terms of a **dependency graph**.


<Img hasTransparency invertible file="cmake-dependency-graph.png" alt="Diagram showing a dependency graph" width="1200" height="594" blurHash="L168EX~q0000xu9F_3?b9F%M4n9F" />


Every time you use `target_link_libraries(A B)`, you are adding a connection to this graph, from `A` to `B`. When it's time to generate the final link command, CMake analyses the graph to generate a linear list of all the libraries.  The algorithm that generate this list of targets ensures that they are ordered in a way that satisfies all of the dependencies.


Our only job is to accurately describe the direct dependencies for each target. CMake handles the rest. If `App` links to `Renderer`, and `Renderer` links to `Core`, CMake knows that the final link command must list them in an order that respects that chain.


<Advanced>


### Directed Acyclic Graphs (DAGs) and Topological Sorting


The dependency graph that is constructed by CMake (and most other build systems) is a **directed acyclic graph**, or **DAG**.

- They are **directed** as the direction of dependencies (**edges**, in graph theory) between targets (called **nodes** or **vertices**) matters.  Linking `Core` to `Physics` is different from linking `Physics` to `Core`.
- A **cycle** within a graph is a situation where you can start at a node, such as `Physics`, and follow a series of connections that lead back to `Physics`.  An **acyclic** graph is one that does **not** have any such **cycles**.

DAG's are widely used in computer science, as the algorithms that act upon them solve many common problems.  For example, the algorithm that enables automatic link ordering is called **topological sort**.  It analyses the DAG to create a linear list of targets that respects the dependency chain.  If `Physics` depends on `Core`, then `Physics` would come after `Core` in the topologically sorted list.


</Advanced>


### Circular Dependencies


If our dependency graph contained a cycle, that would represent a **circular dependency**.  For example, if `Physics` depends on `Core`, which depends on `Math`, which depends on `Physics`, then we introduce a cycle:


<Img hasTransparency invertible file="cmake-circular-dependency.png" alt="Diagram showing a circular dependency" width="1200" height="651" blurHash="LDATi,~q9F4n4nIU?b?bD%M{IUM{" />


CMake, and most other build systems, cannot resolve circular dependencies.  If we create one, we will get an error:


```c++
#<cmake>
target_link_libraries(A B)
target_link_libraries(B A)
```


```plain text
//<oe>
CMake Error: The inter-target dependency graph contains the following cycle:
  - "A" links to "B"
  - "B" links to "A"
This is not allowed.
```


Circular dependencies like this are almost always a sign of a design flaw in your project, which should be fixed regardless of any CMake limitations.  Breaking a circular dependency typically involve one of the following options:

- If the two components are so tightly coupled that reliance on this circular dependency is pervasive through one or both of the libraries, they can be merged into a single component
- If the circular dependency is required for only a small piece of functionality, that part can be refactored so it exists entirely within one of the libraries, or within a new, third library that they both can use

## Summary


This lesson pulled back the curtain on how CMake manages the complex web of relationships in a project. By thinking in terms of a graph rather than a list, CMake automates some of the most difficult parts of C++ build configuration.

- **Dependency Graph**: Every `target_link_libraries()` call adds a directed edge to a graph. CMake uses this graph to understand the complete structure of your project.
- **Transitive Dependencies**: When a link is `PUBLIC`, the dependency is passed on to consumers. If `App` links to `LibA`, and `LibA` **publicly** links to `LibB`, `App` automatically gets linked to `LibB` as well.
- **Automatic Link Order**: CMake performs a topological sort on the dependency graph to determine the correct order for libraries on the linker command line, solving a common and frustrating build problem.
- **No Circular Dependencies**: A direct or indirect dependency of a target on itself forms a cycle in the graph. CMake will report this as a fatal error, which usually indicates a flaw in your project's design.

<Preview>


### Advanced Target Modeling


We've established the core principle of modern CMake: projects are a dependency graph of targets, and usage requirements flow automatically through that graph. We know how to model libraries built from our own 
source code and even simple header-only dependencies.


In the next lesson, we will explore advanced target types that solve common problems.

- We'll learn how to use `INTERFACE` libraries as "property bags" to group and apply common settings
- We'll discover `ALIAS` targets to create clean names for our components
- We'll see how to wrap pre-compiled binaries in `IMPORTED` targets, integrating them seamlessly into our dependency graph.

</Preview>


</Pw>

Property Groups, Aliases, and Imports

`target_link_libraries` Documentation

Using CMake Dependencies Effectively

Modern CMake with target_link_libraries

Transitive link dependencies with cmake

Directed acyclic graph

Topological sorting

Visualizing CMake Project Dependencies with Graphviz

A deep dive into CMake's dependency management. Learn how `target_link_libraries` builds a dependency graph, automatically resolves transitive dependencies, and uses topological sorting to ensure correct link order, preventing common linker errors.

CMake's Dependency Graph: Managing Transitive Links and Link Order

Directed Acyclic Graphs (DAGs) and Topological Sorting

Indirect Relationships and the Dependency Graph

Understanding the Basics

Practical Applications

Common Mistakes

Next Steps

Additional Resources

Assessment Preparation

Managing C++ Projects Using CMake