CMake hands-on workshop

CMake is a language-agnostic, cross-platform build tool and is nowadays the de facto standard, with large projects using it to reliably build, test, and deploy their codebases. You will learn how to:

Write a CMake build system for C, C++, and Fortran projects producing libraries and/or executables.
Run tests for your code with CTest.
Ensure your build system will work on different platforms.
Detect and use external dependencies in your project.
Safely and effectively build mixed-language projects (Python+C/C++, Python+Fortran, Fortran+C/C++)

Prerequisites

Before attending this workshop, please make sure that you have access to a computer with a compiler for your favorite language and a recent version of CMake. If you have access to a supercomputer (e.g. a SNIC system) with a compute allocation you can use that during the workshop. Any questions on how to use a particular HPC resource should be directed to the appropriate support desk. You can also use your own computer for this workshop, provided that it has the necessary tools installed. If you do not already have these installed, we recommend that you set up an isolated software environment using conda. For Windows computers we recommend to use the Windows Subsystem for Linux (WSL). Detailed instructions can be found on the Setting up your system page.

30 min	From sources to executables
40 min	CMake syntax
40 min	Creating and running tests with CTest
40 min	Probing compilation, linking, and execution
40 min	Target-based build systems with CMake
30 min	Finding and using dependencies
40 min	Automated dependency handling with FetchContent
35 min	Mixing Python and compiled languages
20 min	Using CMake: tips and tricks

Reference

Who is the course for?

This course is for students, researchers, engineers, and programmers that have heard of CMake and want to learn how to use it effectively with projects they are working on. This course assumes no previous experience with CMake. You will have to be familiar with the tools commonly used to build software in your compiled language of choice: C++, C, Fortran. Specifically, this lesson assumes that participants have some prior experience with or knowledge of the following topics (but no expertise is required):

Compiling and linking executables and libraries.
Differences between shared and static libraries.
Automated testing.

About the course

This lesson material is developed by the EuroCC National Competence Center Sweden (ENCCS) and taught in ENCCS workshops. It is aimed at researchers and developers who might have had some exposure to CMake and want to learn how to use it effectively. This lesson targets CMake >=3.18. Each lesson episode has clearly defined learning objectives and includes multiple exercises along with solutions, and is therefore also useful for self-learning. The lesson material is licensed under CC-BY-4.0 and can be reused in any form (with appropriate credit) in other courses and workshops. Instructors who wish to teach this lesson can refer to the Instructor’s guide for practical advice.

Graphical and text conventions

We adopt a few conventions which help organize the material.

Function signatures

These are shown in a text block marked with a wrench emoji:

cmake_minimum_required

cmake_minimum_required(VERSION <min>[...<max>] [FATAL_ERROR])

The signature can be hidden by clicking the toggle.

Command parameters

The description of the command parameters will appear in a separate text box. It will be marked with a laptop emoji:

Parameters

VERSION: Minimum and, optionally, maximum version of CMake to use.
FATAL_ERROR: Raise a fatal error if the version constraint is not satisfied. This option is ignored by CMake >=2.6

The description is hidden and will be shown by clicking the toggle.

Type-along

The text and code for these activities are in a separate text box, marked with a keyboard emoji:

Let’s look at an example

cmake_minimum_required(VERSION 3.16)

project(Hello LANGUAGES CXX)

The content can be hidden by clicking the toggle.

Exercises

Each exercise is presented in a separate text box, marked with a hand emoji. Each box introduces the exercise and describes the objectives:

Exercise 10

We will use CMake to build a Fortran library.

Credits

The lesson file structure and browsing layout is inspired by and derived from work by CodeRefinery licensed under the MIT license. We have copied and adapted most of their license text.

Instructional Material

All ENCCS instructional material is made available under the Creative Commons Attribution license (CC-BY-4.0). The following is a human-readable summary of (and not a substitute for) the full legal text of the CC-BY-4.0 license. You are free:

to share - copy and redistribute the material in any medium or format
to adapt - remix, transform, and build upon the material for any purpose, even commercially.

The licensor cannot revoke these freedoms as long as you follow these license terms:

Attribution - You must give appropriate credit (mentioning that your work is derived from work that is Copyright (c) ENCCS and, where practical, linking to https://enccs.se), provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
No additional restrictions - You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits. With the understanding that:
- You do not have to comply with the license for elements of the material in the public domain or where your use is permitted by an applicable exception or limitation.
- No warranties are given. The license may not give you all of the permissions necessary for your intended use. For example, other rights such as publicity, privacy, or moral rights may limit how you use the material.

Software

The code samples and exercises in this lesson were adapted from the GitHub repository for the CMake Cookbook.

Except where otherwise noted, the example programs and other software provided by ENCCS are made available under the OSI-approved MIT license.