Professional CMake:

A Practical Guide

Learn to use CMake effectively with practical advice from a CMake co-maintainer. You can also have the author work directly with your team!

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Professional CMake: A Practical Guide 21st Edition

Release Date: 20th May 2025

This is part of the change history for the book Professional CMake: A Practical Guide. The 21st Edition has been updated for the CMake 4.0 release. A few new usability features were added to CMake, but the most significant change was the removal of all OLD policy behaviours up to CMP0065 (i.e. all policies from CMake 3.4 and earlier). The Policies chapter of the book has been updated to give increased visibility to the policy life cycle, now that OLD behaviours have been completely removed for the first time.

The other major update in this edition is a new Debugging Executables chapter. This contains previous material covering Windows only, but has now been expanded to cover corresponding features for Xcode and some IDE-independent improvements from CMake 4.0. The new chapter is structured to allow focusing on specific problems encountered when running and debugging executables in IDE tools.

In addition to the usual updates, the effort to review existing material, improve clarity, and add more examples continues in this edition. Chapters 19 to 21 have been reviewed and updated, as noted in the details below.

Basic Testing And Deployment chapter:

  • Corrected a Ninja Multi-Config packaging example which previously used --config instead of -C to specify the configuration to package (Release).
  • Added a paragraph to highlight the inconsistency between cmake, ctest, and cpack where they use different options to specify the configuration (--config or -C) .

Policies chapter:

  • Added a new Policy Removal section which covers CMake’s formal policy removal timeline. CMake 4.0 was the first release to completely remove a set of OLD policies and to formally document expectations around future removals.
  • Broke up the Policy Control section into subsections for improved navigation.
  • Moved and expanded content to a new Overriding Policy Defaults And Warnings section. CMake 4.0 added a new CMAKE_POLICY_VERSION_MINIMUM variable to assist with the migration of older projects that still have not been updated to NEW policy settings where the OLD behavior is no longer available.

Debugging And Diagnostics chapter:

  • Added a note at the beginning of the chapter directing attention to the new Debugging Executables chapter for debugging code rather than CMake scripts.

Compiler And Linker Essentials chapter:

  • CMake 4.0 added support for a new ARCHIVER: prefix, which can be used with the STATIC_LIBRARY_OPTIONS target property. CMake 4.0 also extended support for the LINKER: prefix to the LINK_LIBRARIES and INTERFACE_LINK_LIBRARIES target properties. The Linker Flags and De-duplicating Options sections were updated accordingly.
  • CMake 4.0 added a new LINK_WARNING_AS_ERROR target property, an associated CMAKE_LINK_WARNING_AS_ERROR variable, and a --link-no-warning-as-error command line option. These are now covered in the Warnings As Errors section.
  • A new Runtime Checks Selection subsection was added to the Compiler Option Abstractions section. This discusses a new feature in CMake 4.0 which abstracts the /RTC... set of compiler flags when using the Visual Studio compilers.
  • Fixed an error in the example within the Debug Information Format Selection section. The PROPERTIES keyword was missing from the set_target_properties() call in earlier editions.

Language Requirements chapter:

  • This chapter was reviewed and wording improved in various places. Most changes were relatively minor grammatical improvements, with a few paragraphs being merged or reworked more substantially.
  • A new example was added to the Requirements For C++20 Modules section, showing how to set source file properties to disable scanning specific files for C++20 modules.

Advanced Linking chapter:

  • This chapter was reviewed, but no significant changes were made.

Target Types chapter:

  • This chapter was reviewed, and some minor improvements were made to readability. A few paragraphs in the Imported Libraries section were moved to the end of that section for improved logical flow.

Custom Tasks chapter:

  • A new INSTALL_JOB_SERVER_AWARE keyword was added to ExternalProject_Add() in CMake 4.0, and this is now mentioned very briefly with the JOB_SERVER_AWARE keyword in the Custom Targets section.
  • CMake 4.0 added a new CMAKE_EXECUTE_PROCESS_COMMAND_ERROR_IS_FATAL variable, which affects the default behavior of execute_process() when a command fails.

Package Generators chapter:

  • CMake 4.0 added support for a TAR package format with no compression.

Project Structure chapter:

  • Updated a paragraph in the Target Output Locations section to mention PROJECT_BINARY_DIR as another alternative to CMAKE_CURRENT_BINARY_DIR as preferred relative base directories over CMAKE_BINARY_DIR.
  • Move the Windows-specific Issues section content out to the new Debugging Executables chapter. The associated comments in the Recommended Practices section were also moved to that chapter.

Debugging Executables chapter:

  • This is a new chapter focused on the task of running executables in IDEs. Some of the content is moved from the Windows-specific Issues section of the Project Structure chapter. That content has been expanded to also cover equivalent features for Xcode.
  • The new DEBUGGER_WORKING_DIRECTORY target property added in CMake 4.0 is discussed prominently, including its relationship to the existing VS_DEBUGGER_WORKING_DIRECTORY and XCODE_SCHEME_WORKING_DIRECTORY target properties.