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

We can now format our code and generate documentation with single commands, but an important question remains: how do we know our code actually **works**? And how do we ensure it **keeps working** as we refactor, optimize, and add new features?


The answer is **automated testing**. In this chapter, we'll integrate a testing workflow into our project. We'll start with the fundamentals, using CMake's built-in testing framework, **CTest**, to create and run our first simple tests.


## The Benefits of Automated Testing


Before we write any test code, it's important to understand the value it provides. Automated tests have many benefits:

- **A Safety Net Against Regressions**: A **regression** is when a change to the code unintentionally breaks existing functionality. A test suite acts as a safety net. After every change, you can run your tests to get immediate feedback. If the tests are comprehensive and they all pass, you can be more confident you haven't broken anything.
- **Confidence to Refactor**: Code often needs to be **refactored** - restructured and improved without changing its external behavior. Without tests, refactoring is a high-risk activity. With a good test suite, you can make bold changes, knowing that you can instantly verify that the new implementation behaves identically to the old one.
- **Executable Documentation**: Tests are a form of documentation that cannot go out of date. A well-written test clearly demonstrates how a piece of code is intended to be used and what its expected behavior is, including for edge cases that might be missed in traditional documentation.

Throughout this chapter, we'll use our `Greeter` project as a practical testbed to learn how to implement these ideas with CMake and CTest.


## Creating a Test Sub-Project


Just as we separate our library (`greeter/`) from our application (`app/`), it's a standard practice to keep test code separate from production code. We'll create a new `tests/` directory for this purpose.


```plain text
//<nh>
Greeter/
├─ app/
├─ greeter/
├─ tests/                 //<h>
│  ├─ CMakeLists.txt     //<h>
│  └─ main.cpp           //<h>
└─ CMakeLists.txt
```


We'll cover what goes in these new files soon.  To integrate this new component, we need to make two changes to our existing root `CMakeLists.txt`:

1. Add `add_subdirectory(tests)` to tell CMake to process the new `CMakeLists.txt` file inside the `tests/` directory.
2. Add the `enable_testing()` command. This is the master switch that activates all of CMake's testing features, including the `add_test()` command we'll use shortly and the CTest framework itself.

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


```c++
#<cmake>
cmake_minimum_required(VERSION 3.23)
project(Greeter)

add_subdirectory(greeter)
add_subdirectory(app)

enable_testing() #<h>
add_subdirectory(tests) #<h>
```


</CodeFile>


## Writing a Test Driver


Our first test will verify that the `get_greeting()` function in our `GreeterLib` returns the correct string. To do this, we need to create a simple C++ program whose only job is to run this test. This is often called a **test driver** or a **test runner**.


First, let's define the build target for this executable in `tests/CMakeLists.txt`. We'll call the target `GreeterTests` and link it against our `GreeterLib` so it can access the `get_greeting()` function.


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


```c++
#<cmake>
cmake_minimum_required(VERSION 3.23)

add_executable(GreeterTests main.cpp)

# Our test needs access to the library it's testing
target_link_libraries(GreeterTests PRIVATE GreeterLib)
```


</CodeFile>


Next, let's write the C++ code for our test driver in `tests/main.cpp`. This is quite a lot of code to create a simple test but, in the next lesson, we'll introduce an external testing library that makes this easier.


For now, our test file might be verbose, but the logic is simple:


<CodeFile path="tests/main.cpp" status="New">


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

int main() {
  const std::string expected{
    "Hello from the modular greeter library"
  };
  const std::string actual{get_greeting()};

  if (actual != expected) {
    std::cerr << "Test Failed:"
              << "\n  Expected: " << expected
              << "\n  Actual:   " << actual;
    return EXIT_FAILURE;
  }

  std::cout << "Test Passed!";
  return EXIT_SUCCESS;
}
```


</CodeFile>


We call the function we want to test, and compare the actual result to the expected result.


If they don't match, print an error and return a non-zero exit code from our `main` function.  Something like `return 1` would work, but `return EXIT_FAILURE` gives us similar behavior with more descriptive syntax.


If they do match, print a success message and return `0` (or `EXIT_SUCCESS`).


This convention of using the program's exit code to signal success or failure is fundamental to how CTest and most command-line testing tools work.


For reference, here is the function we're testing.  It's important that the string we're returning here **exactly** matches the `expected` value in the test:


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


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

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


</CodeFile>


<Pw>


## Registering Tests with `add_test()`


We've created a test executable, but CMake's testing framework doesn't know about it yet. We need to formally register it as a test case. We do this with the `add_test()` command.


<CodeFile path="tests/CMakeLists.txt" status="Updated">


```c++
#<cmake>
cmake_minimum_required(VERSION 3.23)

add_executable(GreeterTests main.cpp)
target_link_libraries(GreeterTests PRIVATE GreeterLib)

add_test(#<h>
  NAME Greeter.API.get_greeting#<h>
  COMMAND GreeterTests#<h>
) #<h>
```


</CodeFile>


Let's break down this command:

- `NAME Greeter.API.get_greeting`: This gives our test a unique, human-readable name for reporting purposes. This is the name you'll see in the CTest output. It's a good practice to use a hierarchical naming scheme (e.g., `ComponentName.Subsystem.TestName`) to keep your tests organized.
- `COMMAND GreeterTests`: This specifies the command to run for this test. In this case, it's just our `GreeterTests` executable target.

## Running Tests with `ctest`


With our test registered, we can now run it. From our build directory, we should first configure and build the project in the usual way:


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


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


We can then run the `ctest` command, also from our build directory:


```c++
//<ti>
ctest
```


CTest will find all the tests registered with `add_test()` and run them, providing a summary of the results:


```c++
//<o>
Test project D:/Projects/cmake/build
    Start 1: Greeter.API.get_greeting
1/1 Test #1: Greeter.API.get_greeting ... Passed  0.01 sec

100% tests passed, 0 tests failed out of 1

Total Test time (real) =   0.01 sec
```


## Creating Test Presets


As our testing requirements get more complex, our `ctest` commands will also get longer, and inputting them will become a chore.  Just as we did for configuring and building, we can use presets to create simple, named workflows for testing.


We do this by adding a `testPresets` array to our `CMakePresets.json` file.


<CodeFile path="CMakePresets.json" status="Updated">


```json
{
  "version": 3,
  "configurePresets": [{
    "name": "default",
    "binaryDir": "${sourceDir}/build"
  }],
  "buildPresets": [{
    "name": "default",
    "configurePreset": "default"
  }],
  "testPresets": [{//<h>
    "name": "default",//<h>
    "displayName": "Run All Tests",//<h>
    "configurePreset": "default"//<h>
  }]//<h>
}
```


</CodeFile>

- `"name"`: The unique name for the test preset.
- `"displayName"`: A friendly name for our preset that can be used by IDEs and other tools.
- `"configurePreset"`: Similar to our build presets, this links our test preset to the configure preset it requires.  It tells CTest which build directory to run the tests from by pointing to the corresponding configure preset.

With this preset defined, we can now configure, build, and test our project from the **root directory** with a consistent set of commands:


```c++
//<ti>
cmake --preset=default
```


```c++
//<ti>
cmake --build --preset=default
```


```c++
//<ti>
ctest --preset=default
```


```c++
//<o>
Test project D:/Projects/cmake/build
    Start 1: Greeter.API.get_greeting
1/1 Test #1: Greeter.API.get_greeting ... Passed  0.01 sec

100% tests passed, 0 tests failed out of 1

Total Test time (real) =   0.01 sec
```


## Analyzing Failures


Let's see what happens when a test fails. We'll intentionally introduce a bug into our `GreeterLib` by changing the greeting string.


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


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

std::string get_greeting() {
  return "Hello from the buggy greeter library"; //<e>
}
```


</CodeFile>


Now, let's rebuild and run our test preset:


```c++
//<ti>
cmake --build --preset=default
```


```c++
//<ti>
ctest --preset=default
```


The summary now correctly reports the failure:


```c++
//<o>
Test project D:/Projects/cmake/build
    Start 1: Greeter.API.get_greeting
1/1 Test #1: Greeter.API.get_greeting ... Failed  0.04 sec

0% tests passed, 1 tests failed out of 1

Total Test time (real) =   0.04 sec

The following tests FAILED:
          1 - Greeter.API.get_greeting (Failed)
Errors while running CTest
Output from these tests are in: D:/Projects/cmake/build/Testing/Temporary/LastTest.log
Use "--rerun-failed --output-on-failure" to re-run the failed cases verbosely.
```


### Verbose Output


This is good, but it doesn't tell us **why** the test failed.  It does generate a log file which explains the failure, but most people prefer to see the reason directly in the terminal rather than opening a log file.


We can set this up with command-line flag `--output-on-failure` like our error report suggested, but a more common way is to add this to our test preset, or to create a new test preset for debugging tests.


With either approach, we'd add an `output` key, whose value is an object with `outputOnFailure` set to `true`:


<CodeFile path="CMakePresets.json" status="Updated">


```json
{
  "version": 3,
  "configurePresets": [ ... ],
  "buildPresets": [ ... ],
  "testPresets": [
    {
      "name": "default",
      "displayName": "Run All Tests",
      "configurePreset": "default"
    },
    {//<h>
      "name": "debug-tests",//<h>
      "displayName": "Run Tests (Output on Failure)",//<h>
      "configurePreset": "default",//<h>
      "output": { "outputOnFailure": true }//<h>
    }//<h>
  ]
}
```


</CodeFile>


Now, when we run our new preset, CTest will print the `stdout` and `stderr` from any test that fails.


```c++
//<ti>
ctest --preset=debug-tests
```


This time, we get the detailed error message we wrote in our test driver in `/tests/main.cpp`, making it much easier to see the problem:


```c++
//<o>
Test project D:/Projects/cmake/build
    Start 1: Greeter.API.get_greeting
1/1 Test #1: Greeter.API.get_greeting ... Failed  0.01 sec
Test Failed:
  Expected: Hello from the modular greeter library
  Actual:   Hello from the buggy greeter library


0% tests passed, 1 tests failed out of 1

Total Test time (real) =   0.01 sec

The following tests FAILED:
          1 - Greeter.API.get_greeting (Failed)
Errors while running CTest
```


Let's fix our bug in `Greeter.cpp` and ensure our tests pass once more before moving on:


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


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

std::string get_greeting() {
  return "Hello from the modular greeter library"; //<h>
}
```


</CodeFile>


## Summary


In this lesson, we took our first steps into automated testing with CTest, CMake's testing framework.

- **Why Test?**: We learned that automated tests are an important tool for ensuring code correctness, preventing regressions, and enabling confident refactoring.
- **The CTest Workflow**: The process involves enabling testing with `enable_testing()`, creating a test driver executable, and registering it as a test case with `add_test()`.
- **Test Drivers**: A test driver is a simple program that returns `0` for success and a non-zero value for failure. This exit code is how CTest determines the pass/fail status.
- **Presets for Testing**: We saw how `testPresets` in `CMakePresets.json` can simplify the testing workflow, providing named shortcuts for running tests with specific configurations.

This was a quick crash-tour of CTest and how we can use it.  It's a powerful tool with many more options, which are listed on the [official docs](https://cmake.org/cmake/help/latest/manual/ctest.1.html).


For now, the most pressing concern is that our test driver makes writing tests extremely tedious.  For every check, we have to write a verbose `if/else` blocks, manually create strings to report successes and explain failures, and then write `std::cerr` statements to let people see those reports.


<Preview>


### Using a Testing Framework


What if we had a library that provided simple, expressive macros to handle all this boilerplate for us? We'd much prefer to just write something like `EXPECT_EQ(actual, expected)` and have the framework automatically handle the comparison, generate and output a report on the result, and continue running other tests even if one fails.


In the next lesson, we will introduce **Google Test**, a popular, feature-rich testing framework. We'll learn how to integrate it into our project using vcpkg and refactor our manual test driver to use Google Test's assertion macros and test fixtures.


</Preview>


</Pw>

Google Test Integration with vcpkg

CMake Presets Fundamentals

CTest Documentation

`enable_testing()` Command

`add_test()` Command

Regression testing

Test Driven Development

A step-by-step guide to automated testing with CMake and CTest. Learn why testing matters, how to set up a test executable, register it with add_test(), and run your tests using the ctest command and CMake Presets.

Automated Testing and CTest

Understanding the Basics

Practical Applications

Common Mistakes

Next Steps

Additional Resources

Assessment Preparation

Managing C++ Projects Using CMake