Modern CMake for C++: Discover a better approach to building, testing and packaging your software

460 Pages·2022·10.502 MB·English

by  Rafal Swidzinski

Modern CMake
for C++
Discover a better approach to building, testing,
and packaging your software
Rafał Świdziński
BIRMINGHAM—MUMBAI
Modern CMake for C++
Copyright © 2022 Packt Publishing
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First published: February 2022
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To my family: my parents, Bożena and Bogdan, my sisters, Ewelina and
Justyna, and my wife, Katarzyna, for their ongoing support and advice.
– Rafał Świdziński
Contributors
About the author
Rafał Świdziński works as a staff engineer at Google. With over 10 years of professional
experience as a full stack developer, he has been able to experiment with a vast multitude
of programming languages and technologies. During this time, he has been building
software under his own company and for corporations including Cisco Meraki, Amazon,
and Ericsson.
Originally from Łódź, Poland, he now lives in London, UK, from where he runs
a YouTube channel, "Smok," discussing topics related to software development. He tackles
technical problems, including real-life and work-related challenges encountered by many
people in the field. Throughout his work, he explains the technical concepts in detail and
demystifies the art and science behind the role of software engineer. His primary focus is
on high-quality code and the craftsmanship of programming.
About the reviewers
Sergio Guidi Tabosa Pessoa is a software engineer with more than 30 years of experience
in software development and maintenance, from complex enterprise software projects to
modern mobile applications. In the early days, he worked primarily with the Microsoft
stack, but soon discovered the power of the UNIX and Linux operating systems. Even
though he has worked with many languages over the years, C and C++ remain his favorite
languages for their power and speed.
He has a bachelor's degree in computer science and an MBA in IT management and is
always hungry to learn new technologies, break code, and learn from his mistakes. He
currently lives in Brazil with his wife, two Yorkshire Terriers, and two cockatiels.
First and foremost, I would like to thank all the people involved in this
project, including the author for crafting such a great piece of work, and
Packt Publishing for giving me this opportunity. I also would like to thank
my beautiful wife, Lucia, as well as Touché and Lion, for their patience and
for allowing me the time needed to help with this book.
Holding an engineering degree from ENSEEIHT and a Ph.D. in computer science from
UVSQ in France, Eric Noulard has been writing and compiling source code in a variety of
languages for 20 years. A user of CMake since 2006, he has also been an active contributor
to the project for several years. During his career, Eric has worked for private companies
and government agencies. He is now employed by Antidot, a software vendor responsible
for developing and marketing high-end information retrieval technology and solutions.
Mohammed Alqumairi is a software engineer at Cisco Meraki with experience in
developing critical and performant backend services using a variety of languages and
frameworks, with a particular focus on modern C++, CMake, and the Poco libraries.
Mohammed graduated with honors from City, University of London, with a B.Sc. in
Computer Science.

Table of Contents
Preface
Section 1: Introducing CMake
1
First Steps with CMake
Technical requirements   4 The source tree   30
Understanding the basics   5 The build tree   30
Listfiles   31
What is CMake?   5
CMakeLists.txt   32
How does it work?   7
CMakeCache.txt   33
Installing CMake on different The Config-files for packages   34
platforms    10 The cmake_install.cmake,
Docker   11 CTestTestfile.cmake, and CPackConfig.
cmake files   35
Windows   12
CMakePresets.json and
Linux   13
CMakeUserPresets.json   35
macOS   13
Ignoring files in Git   39
Building from the source   14
Discovering scripts and modules   40
Mastering the command line   14
Scripts   40
CMake   15
Utility modules   41
CTest   26
Find-modules   41
CPack   27
The CMake GUI   28 Summary   42
CCMake   29
Further reading   42
Navigating the project files   30
viii Table of Contents
2
The CMake Language
Technical requirements   44 Understanding control
The basics of the CMake structures in CMake    63
Language syntax   45 Conditional blocks   63
Comments   45 Loops   68
Command invocations   47 Command definitions   70
Command arguments   49
Useful commands   76
Working with variables    53 The message() command   76
Variable references   54 The include() command   78
Using the environment variables   55 The include_guard() command   79
Using the cache variables   57 The file() command   79
How to correctly use the variable The execute_process() command   79
scope in CMake   59
Summary   80
Using lists   61 Further reading   81
3
Setting Up Your First CMake Project
Technical requirements   84 Cross-compilation – what are host and
target systems?   100
Basic directives and commands   85
Abbreviated variables   100
Specifying the minimum CMake
Host system information   101
version – cmake_minimum_required()   85
Does the platform have 32-bit or 64-bit
Defining languages and metadata –
architecture?   102
project()   86
What is the endianness of the system?   103
Partitioning your project   87
Configuring the toolchain   103
Scoped subdirectories   90
Setting the C++ standard   103
Nested projects   92
Insisting on standard support   104
External projects   92
Vendor-specific extensions   105
Thinking about the project Interprocedural optimization   105
structure   93 Checking for supported compiler
Scoping the environment   99 features   106
Compiling a test file   106
Discovering the operating system   99
Table of Contents ix
Disabling in-source builds   108 Further reading   111
Summary   110
Section 2: Building With CMake
4
Working with Targets
Technical requirements   116 Using a custom command as a
generator   132
The concept of a target   116
Using a custom command as a target
Dependency graph   118
hook   134
Visualizing dependencies   121
Target properties   122 Understanding generator
What are transitive usage expressions   135
requirements?   123 General syntax   136
Dealing with conflicting propagated Types of evaluation   137
properties   126
Examples to try out   144
Meet the pseudo targets   128
Build targets   130 Summary   148
Further reading   148
Writing custom commands   131
5
Compiling C++ Sources with CMake
Technical requirements   152 General level   165
The basics of compilation   152 Function inlining   167
Loop unrolling   168
How compilation works   153
Loop vectorization   170
Initial configuration   155
Managing sources for targets   156 Managing the process of
compilation   171
Preprocessor configuration   158
Reducing compilation time   171
Providing paths to included files   158
Finding mistakes   176
Preprocessor definitions   159
Configuring the headers   162 Summary   182
Configuring the optimizer   164 Further reading   183