Help/release/4.2.rst - third_party/github.com/Kitware/CMake - Git at Google

 CMake 4.2 Release Notes
 ***********************

 .. only:: html

   .. contents::

 Changes made since CMake 4.1 include the following.

 New Features
 ============

 File-Based API
 --------------

 * The :manual:`cmake-file-api(7)` "codemodel" version 2 ``version`` field has
   been updated to 2.9.

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

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

 Generators
 ----------

 * The :generator:`Visual Studio 18 2026` generator was added.

 * The :generator:`FASTBuild` generator was added.

 Platforms
 ---------

 * CMake now supports :ref:`Cross Compiling for Emscripten` with simple
   toolchain files.

 Command-Line
 ------------

 * The :manual:`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 :command:`cmake_language(TRACE)` command was added to enable or
   disable tracing during script execution.

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

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

 Variables
 ---------

 * The :variable:`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 :variable:`CMAKE_INTERMEDIATE_DIR_STRATEGY` variable and corresponding
   :envvar:`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 :variable:`CMAKE_AUTOGEN_INTERMEDIATE_DIR_STRATEGY` variable and
   corresponding :envvar:`CMAKE_AUTOGEN_INTERMEDIATE_DIR_STRATEGY` environment
   variable were added to change the strategy used to name intermediate
   directories used for :manual:`Qt Autogen <cmake-qt(7)>` files.

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

 Properties
 ----------

 * The :prop_sf:`INSTALL_OBJECT_NAME` source file property was added to
   control names of installed object files for specific compiled sources.

 * The :prop_tgt:`INSTALL_OBJECT_NAME_STRATEGY` target property was added
   to control the naming strategy for installed object files.

 * The :prop_tgt:`INSTALL_OBJECT_ONLY_USE_DESTINATION` target property was
   added to more precisely control the installation path for object files.

 * The :prop_sf:`JOB_POOL_COMPILE` source file property was added
   to assign individual source compilations to :prop_gbl:`JOB_POOLS`.

 * The :prop_sf:`OBJECT_NAME` source file property was added to control
   object names of compiled source files.

 * The :prop_tgt:`UNITY_BUILD_FILENAME_PREFIX` target property was added
   to control names of source files generated by :prop_tgt:`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 :module:`CheckTypeSize` module's :command:`check_type_size` command
   gained a new ``RESULT_VARIABLE`` keyword to customize the result variable
   name instead of the default ``HAVE_<size-var>``.

 * The :module:`ExternalProject` module's :command:`ExternalProject_Add`
   and :command:`ExternalProject_Add_Step` commands now provide options to set
   environment variables on the configure, build, install, and test steps.

 * The :module:`FindPython3`, :module:`FindPython2`, and :module:`FindPython`
   modules no longer make ``NumPy`` depend on ``Development.Module``.
   See policy :policy:`CMP0201`.

 * The :module:`GoogleTest` module's :command:`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 :module:`UseSWIG` module's :command:`swig_add_library` command gained a
   ``DEBUG_POSTFIX`` option to control the :prop_tgt:`DEBUG_POSTFIX` target
   property.

 Generator Expressions
 ---------------------

 * The :genex:`<LANG>_COMPILER_LINKER_ID <C_COMPILER_LINKER_ID>` and
   :genex:`<LANG>_COMPILER_LINKER_FRONTEND_VARIANT <C_COMPILER_LINKER_FRONTEND_VARIANT>`
   families of generator expressions were added to access the value of the
   associated :variable:`CMAKE_<LANG>_COMPILER_LINKER_ID` and
   :variable:`CMAKE_<LANG>_COMPILER_LINKER_FRONTEND_VARIANT` variables.

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

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

 CPack
 -----

 * The :cpack_gen:`CPack AppImage Generator` was added.

 * The :variable:`CPACK_PACKAGE_CHECKSUM` variable now supports multiple values.

 * The :cpack_gen:`CPack NSIS Generator` gained a
   :variable:`CPACK_NSIS_CRC_CHECK` variable for setting the ``CRCCheck``
   attribute.

 * The :cpack_gen:`CPack WIX Generator` gained a
   :variable:`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 :module:`FindwxWidgets` module's result variable
   ``wxWidgets_USE_FILE`` is now deprecated in favor of including the
   :module:`UsewxWidgets` module directly.

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

 Other Changes
 =============

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

 * Selection of configuration and location of imported targets is now more
   consistent.  See policy :policy:`CMP0200`.

 * The :variable:`CMAKE_PARENT_LIST_FILE` variable is no longer defined when
   processing a ``CMakeLists.txt`` file.  See policy :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 :policy:`CMP0204`.

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

 * The :ref:`Visual Studio Generators` now suppress Visual Studio's default
   flags ``-fp:precise``, ``-Gd``, and ``-GS`` if they are not specified by
   the project or user.  This makes builds more consistent with other
   generators, and with what projects and users actually specify.

 Updates
 =======

 Changes made since CMake 4.2.0 include the following.

 4.2.1
 -----

 * This version made no changes to documented features or interfaces.
   Some implementation updates were made to support ecosystem changes
   and/or fix regressions.
	CMake 4.2 Release Notes
	***********************

	.. only:: html

	.. contents::

	Changes made since CMake 4.1 include the following.

	New Features
	============

	File-Based API
	--------------

	* The :manual:`cmake-file-api(7)` "codemodel" version 2 ``version`` field has
	been updated to 2.9.

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

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

	Generators
	----------

	* The :generator:`Visual Studio 18 2026` generator was added.

	* The :generator:`FASTBuild` generator was added.

	Platforms
	---------

	* CMake now supports :ref:`Cross Compiling for Emscripten` with simple
	toolchain files.

	Command-Line
	------------

	* The :manual:`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 :command:`cmake_language(TRACE)` command was added to enable or
	disable tracing during script execution.

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

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

	Variables
	---------

	* The :variable:`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 :variable:`CMAKE_INTERMEDIATE_DIR_STRATEGY` variable and corresponding
	:envvar:`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 :variable:`CMAKE_AUTOGEN_INTERMEDIATE_DIR_STRATEGY` variable and
	corresponding :envvar:`CMAKE_AUTOGEN_INTERMEDIATE_DIR_STRATEGY` environment
	variable were added to change the strategy used to name intermediate
	directories used for :manual:`Qt Autogen <cmake-qt(7)>` files.

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

	Properties
	----------

	* The :prop_sf:`INSTALL_OBJECT_NAME` source file property was added to
	control names of installed object files for specific compiled sources.

	* The :prop_tgt:`INSTALL_OBJECT_NAME_STRATEGY` target property was added
	to control the naming strategy for installed object files.

	* The :prop_tgt:`INSTALL_OBJECT_ONLY_USE_DESTINATION` target property was
	added to more precisely control the installation path for object files.

	* The :prop_sf:`JOB_POOL_COMPILE` source file property was added
	to assign individual source compilations to :prop_gbl:`JOB_POOLS`.

	* The :prop_sf:`OBJECT_NAME` source file property was added to control
	object names of compiled source files.

	* The :prop_tgt:`UNITY_BUILD_FILENAME_PREFIX` target property was added
	to control names of source files generated by :prop_tgt:`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 :module:`CheckTypeSize` module's :command:`check_type_size` command
	gained a new ``RESULT_VARIABLE`` keyword to customize the result variable
	name instead of the default ``HAVE_<size-var>``.

	* The :module:`ExternalProject` module's :command:`ExternalProject_Add`
	and :command:`ExternalProject_Add_Step` commands now provide options to set
	environment variables on the configure, build, install, and test steps.

	* The :module:`FindPython3`, :module:`FindPython2`, and :module:`FindPython`
	modules no longer make ``NumPy`` depend on ``Development.Module``.
	See policy :policy:`CMP0201`.

	* The :module:`GoogleTest` module's :command:`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 :module:`UseSWIG` module's :command:`swig_add_library` command gained a
	``DEBUG_POSTFIX`` option to control the :prop_tgt:`DEBUG_POSTFIX` target
	property.

	Generator Expressions
	---------------------

	* The :genex:`<LANG>_COMPILER_LINKER_ID <C_COMPILER_LINKER_ID>` and
	:genex:`<LANG>_COMPILER_LINKER_FRONTEND_VARIANT <C_COMPILER_LINKER_FRONTEND_VARIANT>`
	families of generator expressions were added to access the value of the
	associated :variable:`CMAKE_<LANG>_COMPILER_LINKER_ID` and
	:variable:`CMAKE_<LANG>_COMPILER_LINKER_FRONTEND_VARIANT` variables.

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

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

	CPack
	-----

	* The :cpack_gen:`CPack AppImage Generator` was added.

	* The :variable:`CPACK_PACKAGE_CHECKSUM` variable now supports multiple values.

	* The :cpack_gen:`CPack NSIS Generator` gained a
	:variable:`CPACK_NSIS_CRC_CHECK` variable for setting the ``CRCCheck``
	attribute.

	* The :cpack_gen:`CPack WIX Generator` gained a
	:variable:`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 :module:`FindwxWidgets` module's result variable
	``wxWidgets_USE_FILE`` is now deprecated in favor of including the
	:module:`UsewxWidgets` module directly.

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

	Other Changes
	=============

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

	* Selection of configuration and location of imported targets is now more
	consistent. See policy :policy:`CMP0200`.

	* The :variable:`CMAKE_PARENT_LIST_FILE` variable is no longer defined when
	processing a ``CMakeLists.txt`` file. See policy :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 :policy:`CMP0204`.

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

	* The :ref:`Visual Studio Generators` now suppress Visual Studio's default
	flags ``-fp:precise``, ``-Gd``, and ``-GS`` if they are not specified by
	the project or user. This makes builds more consistent with other
	generators, and with what projects and users actually specify.

	Updates
	=======

	Changes made since CMake 4.2.0 include the following.

	4.2.1
	-----

	* This version made no changes to documented features or interfaces.
	Some implementation updates were made to support ecosystem changes
	and/or fix regressions.