CMake 4.2.0-rc4 is ready for testing

Announcements
1

I am proud to announce the fourth CMake 4.2 release candidate.
https://cmake.org/download/

Documentation is available at:
https://cmake.org/cmake/help/v4.2

Release notes appear below and are also published at
https://cmake.org/cmake/help/v4.2/release/4.2.html

Release milestone is available at:
release milestone

Some of the most significant changes in CMake 4.2 are:

  • The “Visual Studio 18 2026” generator was added.

  • The “FASTBuild” generator was added.

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

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

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

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

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.

  • 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”.

Changes made since CMake 4.2.0-rc3:

Brad King (19):

  • Tests: Update expected Zstandard magic number for libarchive 3.8.2
  • execute_process: Restore termination of processes on timeout
  • cmDocumentationFormatter: Implement PrintFormatted privately
  • Tests/FindJNI/Minimal: Fix test for Java 24 and above
  • FindJNI: Add Debian/Ubuntu specific paths for more recent JDK versions
  • FindImageMagick: Fix detection of version 7 from headers
  • FindPostgreSQL: Add support for version 17
  • ci: Update debian12-ninja job to use Swift 6.2.1
  • ci: Update to TIClang 4.0.4
  • ci: Update base images to Debian 13
  • ci: use Debian 13 images and environments
  • IWYU: Update for Debian 13 CI job
  • VS: Add CUDA flag table entry for nvcc --keep flag
  • Help: Update 4.2 release note for Visual Studio 18.0 release
  • autogen: Remove unnecessary nullptr check
  • VS: Fix SLNX with multiple solution-to-project configuration mappings
  • VS: Add SLNX default startup project
  • ci: update macOS jobs to use Xcode 26.1
  • CMake 4.2.0-rc4

Craig Scott (1):

  • Help: Fix typos and formatting for 4.2 release

Eduard Voronkin (3):

  • FASTBuild: rename test target to RUN_TESTS
  • FASTBuild: remove non-existent autogen byproducts
  • FASTBuild: fix multi-language PCHs