CMake 4.2 Release Notes

Changes made since CMake 4.1 include the following.

New Features

File-Based API

• The cmake-file-api(7) "codemodel" version 2 version field has been updated to 2.9.

• The cmake-file-api(7) "codemodel" version 2 "target" and "directory" objects gained a new codemodelVersion field.

• The cmake-file-api(7) "codemodel" version 2 now includes imported targets and all interface library targets in its replies. Previously, imported targets were omitted, and only those interface targets that participated in the build system were included. The following changes support these new additions:

  • The "target" object gained imported, local, and abstract fields.

  • The "target" object's type field can now also hold the value UNKNOWN_LIBRARY.

  • The "codemodel" object's configurations entries gained a new abstractTargets array.

  • Entries in the directories and projects arrays of the "codemodel" object's configurations entries gained a new abstractTargetIndexes array.

• The cmake-file-api(7) "codemodel" version 2 "target" object gained new linkLibraries, interfaceLinkLibraries, compileDependencies, interfaceCompileDependencies, objectDependencies, and orderDependencies fields.

Generators

• The Visual Studio 18 2026 generator was added. This is experimental and based on "Visual Studio 2026 Insiders" because this version of VS has not been released.

• The FASTBuild generator was added.

Platforms

• CMake now supports Cross Compiling for Emscripten with simple toolchain files.

Command-Line

• The cmake(1) command-line tool now supports cmake -E copy_if_newer and cmake -E copy_directory_if_newer subcommands to copy files based on timestamp comparison instead of content comparison. These commands copy files only if the source is newer than the destination, providing better performance for build systems compared to copy_if_different which compares file contents.

Commands

• The cmake_language(TRACE) command was added to enable or disable tracing during script execution.

• The set(CACHE{<variable>}) and unset(CACHE{<variable>}) commands were added to explicitly set and unset cache entries.

• The string(REGEX QUOTE) command was added to generate a regular expression exactly matching a string.

Variables

• The CMAKE_CXX_STDLIB_MODULES_JSON variable was added to set the path to the import std metadata file for the standard library rather than using the compiler to discover its location.

• The CMAKE_INTERMEDIATE_DIR_STRATEGY variable and corresponding CMAKE_INTERMEDIATE_DIR_STRATEGY environment variable were added to change the strategy used to name intermediate directories used for object files and other associated target metadata.

• The CMAKE_AUTOGEN_INTERMEDIATE_DIR_STRATEGY variable and corresponding CMAKE_AUTOGEN_INTERMEDIATE_DIR_STRATEGY environment variable were added to change the strategy used to name intermediate directories used for Qt Autogen files.

• The CMAKE_SKIP_LINTING variable and corresponding SKIP_LINTING target property were added to tell the Command-Line Build Tool Generators to skip linting all sources in a target.

Properties

• The INSTALL_OBJECT_NAME source file property was added to control names of installed object files for specific compiled sources.

• The INSTALL_OBJECT_NAME_STRATEGY target property was added to control the naming strategy for installed object files.

• The INSTALL_OBJECT_ONLY_USE_DESTINATION target property was added to more precisely control the installation path for object files.

• The JOB_POOL_COMPILE source file property was added to assign individual source compilations to JOB_POOLS.

• The OBJECT_NAME source file property was added to control object names of compiled source files.

• The UNITY_BUILD_FILENAME_PREFIX target property was added to control names of source files generated by UNITY_BUILD.

Modules

• Nearly all find modules now provide a <PackageName>_VERSION result variable matching the casing of its module name. Existing variants such as <PackageName>_VERSION_STRING and uppercased <PACKAGENAME>_VERSION are deprecated. See documentation of each find module for details.

• The CheckTypeSize module's check_type_size() command gained a new RESULT_VARIABLE keyword to customize the result variable name instead of the default HAVE_<size-var>.

• The ExternalProject module's ExternalProject_Add() and ExternalProject_Add_Step() commands now provide options to set environment variables on the configure, build, install, and test steps.

• The FindPython3, FindPython2, and FindPython modules no longer make NumPy depend on Development.Module. See policy CMP0201.

• The GoogleTest module's gtest_discover_tests() command now sets the DEF_SOURCE_LINE test property for each discovered test if gtest supports the --gtest_output=json option. This test property is used by some IDEs to locate the source for each test.

• The UseSWIG module's swig_add_library() command gained a DEBUG_POSTFIX option to control the DEBUG_POSTFIX target property.

Generator Expressions

• The <LANG>_COMPILER_LINKER_ID and <LANG>_COMPILER_LINKER_FRONTEND_VARIANT families of generator expressions were added to access the value of the associated CMAKE_<LANG>_COMPILER_LINKER_ID and CMAKE_<LANG>_COMPILER_LINKER_FRONTEND_VARIANT variables.

• The TARGET_FILE_BASE_NAME, TARGET_IMPORT_FILE_BASE_NAME, TARGET_LINKER_FILE_BASE_NAME, TARGET_LINKER_LIBRARY_FILE_BASE_NAME, TARGET_LINKER_IMPORT_FILE_BASE_NAME, and TARGET_PDB_FILE_BASE_NAME generator expressions gained a POSTFIX option to control the inclusion of the <CONFIG>_POSTFIX target property as part of the base names of the corresponding files.

• The TARGET_INTERMEDIATE_DIR generator expression was added to refer to a target's intermediate files directory in the build tree.

CPack

• The CPACK_PACKAGE_CHECKSUM variable now supports multiple values.

• The CPack NSIS Generator gained a CPACK_NSIS_CRC_CHECK variable for setting the CRCCheck attribute.

• The CPack WIX Generator gained a CPACK_WIX_CAB_PER_COMPONENT variable to enable one .cab per component.

Deprecated and Removed Features

• All find modules now provide a <PackageName>_FOUND result variable matching the casing of its module name. Existing variants, such as the uppercased <PACKAGENAME>_FOUND, are deprecated where appropriate. See documentation of each find module for details.

• The FindwxWidgets module's result variable wxWidgets_USE_FILE is now deprecated in favor of including the UsewxWidgets module directly.

• The Visual Studio 14 2015 generator is now deprecated and will be removed in a future version of CMake.

Other Changes

• The $<CONFIG:cfgs> generator expression, when appearing on an imported target, has been fixed to only match the configuration actually being consumed. See policy CMP0199.

• Selection of configuration and location of imported targets is now more consistent. See policy CMP0200.

• The CMAKE_PARENT_LIST_FILE variable is no longer defined when processing a CMakeLists.txt file. See policy CMP0198.

• For builds targeting the MSVC ABI, all generators now add the _MBCS preprocessor definition when compiling sources unless _UNICODE or _SBCS is found. See policy CMP0204.

• For builds targeting the MSVC ABI, all generators now add the _WINDLL preprocessor definition when compiling sources in shared libraries. See policy CMP0203.