CMake 3.27 Release Notes
************************

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Changes made since CMake 3.26 include the following.

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

Debugger
--------

* :manual:`cmake(1)` now supports interactive debugging of the CMake language.
  See the :option:`--debugger <cmake --debugger>` option.

Presets
-------

* :manual:`cmake-presets(7)` files now support schema version ``7``.

* :manual:`cmake-presets(7)` now supports ``$penv{}`` macro expansion
  in ``include`` fields.

Generators
----------

* The :ref:`Makefile <Makefile Generators>` and :ref:`Ninja <Ninja Generators>`
  generators now support using the ``--dependency-file`` linker flag,
  added by GNU Binutils 2.35 and LLVM's LLD 12.0.0, so that files read by the
  linker will cause a relink if they change (typically modified timestamps).
  See the :variable:`CMAKE_LINK_DEPENDS_USE_LINKER` variable.

* The :ref:`Visual Studio Generators` for VS 2015 and above learned to
  select the Windows SDK version explicitly using a ``version=`` field
  in the :variable:`CMAKE_GENERATOR_PLATFORM` variable.
  See :ref:`Visual Studio Platform Selection`.

Languages
---------

* The ``CXX`` language now treats source file extensions
  ``.ccm``, ``.cxxm``, and ``.c++m`` as C++.

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

* The :manual:`cmake-file-api(7)` "codemodel" version 2 ``version`` field has
  been updated to 2.6.

* The :manual:`cmake-file-api(7)` "codemodel" version 2 "target" object gained
  a new "frameworks" field in the "compileGroups" objects.

Platforms
---------

* Apple text-based stubs (i.e. ``.tbd`` files) may now be created for shared
  libraries on macOS.  See the :prop_tgt:`ENABLE_EXPORTS` property.

Commands
--------

* The :command:`add_custom_command` command gained a new
  ``DEPENDS_EXPLICIT_ONLY`` option to tell the :ref:`Ninja Generators`
  not to add any dependencies implied by the target to which it is
  attached.  The :variable:`CMAKE_ADD_CUSTOM_COMMAND_DEPENDS_EXPLICIT_ONLY`
  variable was added to enable ``DEPENDS_EXPLICIT_ONLY`` on all calls to
  :command:`add_custom_command` command.

* The :command:`cmake_file_api` command was added for projects to add
  :manual:`CMake file API <cmake-file-api(7)>` queries for the current
  CMake run.

* The :command:`find_package` command now searches prefixes specified by
  upper-case :variable:`<PACKAGENAME>_ROOT` CMake variables and upper-case
  :envvar:`<PACKAGENAME>_ROOT` environment variables.
  See policy :policy:`CMP0144`.

* The :command:`install(CODE)` and :command:`install(SCRIPT)` commands
  now support the :genex:`$<INSTALL_PREFIX>` generator expression.

Variables
---------

* The :variable:`CMAKE_DLL_NAME_WITH_SOVERSION` variable and associated
  :prop_tgt:`DLL_NAME_WITH_SOVERSION` target property were added to
  optionally append the :prop_tgt:`SOVERSION` to the filename of the
  ``.dll`` part of a shared library on Windows.

* Variables :variable:`CMAKE_VS_DEBUGGER_COMMAND`,
  :variable:`CMAKE_VS_DEBUGGER_COMMAND_ARGUMENTS`,
  :variable:`CMAKE_VS_DEBUGGER_ENVIRONMENT`, and
  :variable:`CMAKE_VS_DEBUGGER_WORKING_DIRECTORY` were added to initialize
  corresponding target properties.

* The :variable:`CMAKE_VS_WINDOWS_TARGET_PLATFORM_MIN_VERSION` variable
  was added to initialize the :prop_tgt:`VS_WINDOWS_TARGET_PLATFORM_MIN_VERSION`
  target property on all targets when they are created.

Properties
----------

* A :prop_tgt:`CUDA_CUBIN_COMPILATION` target property was added to
  :ref:`Object Libraries` to support compiling to ``.cubin`` files
  instead of host object files. Currently only supported with NVIDIA.

* A :prop_tgt:`CUDA_FATBIN_COMPILATION` target property was added to
  :ref:`Object Libraries` to support compiling to ``.fatbin`` files
  instead of host object files. Currently only supported with NVIDIA.

* A :prop_tgt:`CUDA_OPTIX_COMPILATION` target property was added to
  :ref:`Object Libraries` to support compiling to ``.optixir`` files
  instead of host object files. Currently only supported with NVIDIA.

* The :prop_tgt:`<LANG>_CLANG_TIDY`, :prop_tgt:`<LANG>_CPPCHECK`,
  :prop_tgt:`<LANG>_CPPLINT`, and :prop_tgt:`<LANG>_INCLUDE_WHAT_YOU_USE`,
  target properties now support
  :manual:`generator expressions <cmake-generator-expressions(7)>`.

* The :prop_tgt:`<LANG>_LINKER_LAUNCHER` target property now supports
  :manual:`generator expressions <cmake-generator-expressions(7)>`.

* The :prop_sf:`SKIP_LINTING` source file property was added to suppress
  target-wide code checks on specific sources.

Modules
-------

* The :module:`FindCUDAToolkit` module now provides an imported target for
  ``cudla``, and imported targets for CUPTI's ``nvperf`` and ``pcsampling``
  components.

* The :module:`FindDoxygen` module's :command:`doxygen_add_docs` command gained
  a ``CONFIG_FILE`` option to specify a custom doxygen configuration file.

* The :module:`FindOpenGL` module gained support for components
  ``GLES2`` and ``GLES3``.

* The :module:`FindwxWidgets` module now provides an imported target.

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

* The :genex:`COMPILE_ONLY` generator expression was added to specify
  compilation usage requirements without any linking requirements.

* ``$<LIST:...>`` generator expressions were added for
  :ref:`query <GenEx List Queries>`,
  :ref:`transformation <GenEx List Transformations>`, and
  :ref:`ordering <GenEx List Ordering>` operations on
  :ref:`lists <CMake Language Lists>`.

* ``$<PATH:...>`` generator expressions for
  :ref:`decomposition <GenEx Path Decomposition>` and
  :ref:`transformation <GenEx Path Transformations>` operations learned
  to process :ref:`lists <CMake Language Lists>` of paths element-wise.

* The :genex:`TARGET_IMPORT_FILE`, :genex:`TARGET_IMPORT_FILE_BASE_NAME`,
  :genex:`TARGET_IMPORT_FILE_PREFIX`, :genex:`TARGET_IMPORT_FILE_SUFFIX`,
  :genex:`TARGET_IMPORT_FILE_NAME`, and :genex:`TARGET_IMPORT_FILE_DIR`
  generator expressions were added.  These expand to details about the
  linker import file for a target.

* The :genex:`TARGET_RUNTIME_DLL_DIRS` generator expression was added.
  It expands to a list of the directories containing DLLs in
  :genex:`TARGET_RUNTIME_DLLS`.

Autogen
-------

* The :variable:`CMAKE_AUTOMOC_EXECUTABLE`,
  :variable:`CMAKE_AUTORCC_EXECUTABLE`, and
  :variable:`CMAKE_AUTOUIC_EXECUTABLE` variables were added to initialize the
  corresponding target properties as targets are created.

* The :prop_tgt:`AUTOGEN_USE_SYSTEM_INCLUDE` target property and
  corresponding :variable:`CMAKE_AUTOGEN_USE_SYSTEM_INCLUDE` variable were
  added to explicitly control whether autogen headers are
  considered system headers.

* The :prop_tgt:`INTERFACE_AUTOMOC_MACRO_NAMES` target property was added to
  specify macro names for ``moc`` as a transitive usage requirement.

CTest
-----

* The :prop_test:`TIMEOUT_SIGNAL_NAME` and
  :prop_test:`TIMEOUT_SIGNAL_GRACE_PERIOD` test properties were added
  to specify a POSIX signal to send to a test process when its timeout
  is reached.

CPack
-----

* The :cpack_gen:`CPack Inno Setup Generator` was added to package using
  Inno Setup.

Deprecated and Removed Features
===============================

* Compatibility with versions of CMake older than 3.5 is now deprecated
  and will be removed from a future version.  Calls to
  :command:`cmake_minimum_required` or :command:`cmake_policy` that set
  the policy version to an older value now issue a deprecation diagnostic.

* The :ref:`Extra Generators` have been deprecated.  IDEs may use the
  :manual:`cmake-file-api(7)` to view CMake-generated project build trees.

* The :module:`FindCUDA` module, which has been deprecated since CMake 3.10,
  has been removed by policy :policy:`CMP0146`.  Port projects to CMake's
  first-class ``CUDA`` language support.

* The :module:`FindPythonInterp` and :module:`FindPythonLibs` modules,
  which have been deprecated since CMake 3.12, have been removed by
  policy :policy:`CMP0148`.  Port projects to :module:`FindPython3`,
  :module:`FindPython2`, or :module:`FindPython`.

* The :module:`Dart` and :module:`FindDart` modules have been deprecated via
  policy :policy:`CMP0145`.  Port projects to the :module:`CTest` module.

* The :generator:`Visual Studio 9 2008` generator is now deprecated
  and will be removed in a future version of CMake.

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

* ``cmake --build $dir --verbose`` will now print the working directory and
  command line used to perform the build.

* The :module:`ExternalProject` and :module:`FetchContent` modules
  now resolve relative ``GIT_REPOSITORY`` paths as relative to the
  parent project's remote, not as a relative local file system path.
  See :policy:`CMP0150`.

* The :module:`ExternalProject` ``configure`` step no longer re-runs on
  every build when the ``UPDATE_DISCONNECTED`` option is enabled.
  It will only re-run if details of the ``download``, ``update``,
  or ``patch`` step change.

* The :module:`ExternalProject` ``update`` and ``patch`` steps now always
  re-run if any of their details change, even if the ``UPDATE_DISCONNECTED``
  option is enabled.  If using the ``GIT`` download method, and the ``GIT_TAG``
  is changed to a commit that is not already known locally, an error is now
  issued instead of silently using the previous ``GIT_TAG``.

* The :module:`FindPython`, :module:`FindPython2` and :module:`FindPython3`
  modules now support the Windows ARM64 platform.

* The :command:`file(GET_RUNTIME_DEPENDENCIES)` command now case-preserves
  DLL names reported on Windows.  They are still converted to lowercase
  for filter matching.

* The :prop_tgt:`SYSTEM` target property is now honored for Apple Frameworks.

* :ref:`Visual Studio Generators`, for VS 15.8 (2017) and newer, now
  build custom commands in parallel.  See policy :policy:`CMP0147`.

Updates
=======

Changes made since CMake 3.27.0 include the following.

3.27.1
------

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