Help/release/3.15.rst - third_party/cmake - Git at Google

 CMake 3.15 Release Notes
 ************************

 .. only:: html

   .. contents::

 Changes made since CMake 3.14 include the following.

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

 Generators
 ----------

 * The :generator:`Xcode` generator now supports per-target schemes.
   See the :variable:`CMAKE_XCODE_GENERATE_SCHEME` variable and
   :prop_tgt:`XCODE_GENERATE_SCHEME` target property.

 * The :generator:`Green Hills MULTI` generator has been updated:

   * It now supports the :command:`add_custom_command` and
     :command:`add_custom_target` commands.

   * It is now available on Linux.

 Languages
 ---------

 * Preliminary support for the ``Swift`` language was added to the
   :generator:`Ninja` generator:

   * Use the :envvar:`SWIFTC` environment variable to specify a compiler.

   * The :prop_tgt:`Swift_DEPENDENCIES_FILE` target property and
     :prop_sf:`Swift_DEPENDENCIES_FILE` source file property were added
     to customize dependency files.

   * The :prop_tgt:`Swift_MODULE_NAME` target property was added to
     customize the Swift module name.

   * The :prop_sf:`Swift_DIAGNOSTICS_FILE` source property was added to
     indicate where to write the serialized Swift diagnostics.

   The Swift support is experimental, not considered stable, and may change
   in future releases of CMake.

 Compilers
 ---------

 * The ``Clang`` compiler variant on Windows that targets the MSVC ABI
   but has a GNU-like command line is now supported.

 * Support for the Clang-based ARM compiler was added with compiler id
   ``ARMClang``.

 * Support was added for the IAR compiler architectures Renesas RX,
   RL78, RH850 and Texas Instruments MSP430.

 * Support was added for the IAR compilers built for Linux (IAR BuildLx).

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

 * The :envvar:`CMAKE_GENERATOR` environment variable was added
   to specify a default generator to use when :manual:`cmake(1)` is
   run without a ``-G`` option.  Additionally, environment variables
   :envvar:`CMAKE_GENERATOR_PLATFORM`, :envvar:`CMAKE_GENERATOR_TOOLSET`,
   and :envvar:`CMAKE_GENERATOR_INSTANCE` were created to configure
   the generator.

 * The :manual:`cmake(1)` ``--build`` tool ``--target`` parameter gained support
   for multiple targets, e.g. ``cmake --build . --target Library1 Library2``.
   It now also has a short form ``-t`` alias, e.g.
   ``cmake --build . -t Library1 Library2``.

 * The :manual:`cmake(1)` command gained a new ``--install`` option.
   This may be used after building a project to run installation without
   using the generated build system or the native build tool.

 * The :manual:`cmake(1)` command learned a new CLI option ``--loglevel``.

 * The :manual:`cmake(1)` ``-E remove_directory`` command-line tool learned
   to support removing multiple directories.

 * The :manual:`cmake(1)` ``-E tar`` tool has been improved:

   * It now continues adding files to an archive even if some of the files
     are not readable.  This behavior is more consistent with the
     classic ``tar`` tool.

   * It now parses all flags, and if an invalid flag was provided, a
     warning is issued.

   * It now displays an error if no action flag was specified, along with a
     list of possible actions: ``t`` (list), ``c`` (create) or ``x`` (extract).

   * It now supports extracting (``-x``) or listing (``-t``) only specific
     files or directories.

   * It now supports Zstandard compression with a ``--zstd`` option.
     Zstandard was designed to give a compression ratio comparable to that
     of the DEFLATE (zip) algorithm, but faster, especially for decompression.

 Commands
 --------

 * The :command:`add_custom_command` and :command:`add_custom_target` commands
   gained a new ``JOB_POOL`` option that works with the :generator:`Ninja`
   generator to set the pool variable on the build statement.

 * The :command:`add_library` command ``ALIAS`` option learned to support
   import libraries of the ``UNKNOWN`` type.

 * The :command:`cmake_parse_arguments` command gained an additional
   ``<prefix>_KEYWORDS_MISSING_VALUES`` output variable to report
   keyword arguments that were given by the caller with no values.

 * The :command:`execute_process` command gained a ``COMMAND_ECHO`` option
   and supporting :variable:`CMAKE_EXECUTE_PROCESS_COMMAND_ECHO` variable
   to enable echoing of the command-line string before execution.

 * The :command:`file(INSTALL)` command learned a new argument,
   ``FOLLOW_SYMLINK_CHAIN``, which can be used to recursively resolve and
   install symlinks.

 * :command:`list` learned new sub-commands:
   ``PREPEND``, ``POP_FRONT`` and ``POP_BACK``.

 * The :command:`message` command learned new types:
   ``NOTICE``, ``VERBOSE``, ``DEBUG`` and ``TRACE``.

 * The :command:`string` learned a new sub-command ``REPEAT``.

 Variables
 ---------

 * The :variable:`CMAKE_CROSSCOMPILING_EMULATOR` variable and corresponding
   :prop_tgt:`CROSSCOMPILING_EMULATOR` target property learned to support
   arguments to the emulator.

 * The :variable:`CMAKE_FIND_PACKAGE_PREFER_CONFIG` variable was added to tell
   :command:`find_package` calls to look for a package configuration
   file first even if a find module is available.

 * The :variable:`CMAKE_FRAMEWORK` variable was added to initialize the
   :prop_tgt:`FRAMEWORK` property on all targets.

 * The :variable:`CMAKE_VS_JUST_MY_CODE_DEBUGGING` variable and
   :prop_tgt:`VS_JUST_MY_CODE_DEBUGGING` target property were added to
   enable the Just My Code feature of the Visual Studio Debugger when
   compiling with MSVC cl 19.05 and higher.

 * The :variable:`CMAKE_MSVC_RUNTIME_LIBRARY` variable and
   :prop_tgt:`MSVC_RUNTIME_LIBRARY` target property were introduced to
   select the runtime library used by compilers targeting the MSVC ABI.
   See policy :policy:`CMP0091`.

 * The :variable:`CMAKE_PROJECT_INCLUDE` and
   :variable:`CMAKE_PROJECT_INCLUDE_BEFORE` variables were added to allow
   injection of custom code at the sites of :command:`project` calls
   without knowing the project name a priori.

 Properties
 ----------

 * The :prop_tgt:`ADDITIONAL_CLEAN_FILES` target property and
   :prop_dir:`ADDITIONAL_CLEAN_FILES` directory property were added.
   They allow to register additional files that should be removed during
   the clean stage.

 * The :prop_tgt:`PUBLIC_HEADER` and :prop_tgt:`PRIVATE_HEADER` properties
   may now be set on :ref:`Interface Libraries`. The headers specified by those
   properties can be installed using the :command:`install(TARGETS)` command by
   passing the ``PUBLIC_HEADER`` and ``PRIVATE_HEADER`` arguments respectively.

 * The :prop_tgt:`VS_PACKAGE_REFERENCES` target property was added to
   tell :ref:`Visual Studio Generators` to add references to ``nuget``
   packages.

 * The :prop_tgt:`VS_PROJECT_IMPORT` target property was added to allow
   managed Visual Studio project files to import external ``.props`` files.

 * The :prop_tgt:`VS_NO_SOLUTION_DEPLOY` target property was added to
   tell :ref:`Visual Studio Generators` whether to deploy an artifact
   to the WinCE or Windows Phone target device.

 Modules
 -------

 * The :module:`FindBoost` module was reworked to expose a more consistent
   user experience between its "Config" and "Module" modes and with other
   find modules in general.

   * A new imported target ``Boost::headers`` is now defined (same
     as ``Boost::boost``).

   * New output variables ``Boost_VERSION_MACRO``,
     ``Boost_VERSION_MAJOR``, ``Boost_VERSION_MINOR``,
     ``Boost_VERSION_PATCH``, and ``Boost_VERSION_COUNT``
     were added.

   * The ``QUIET`` argument passed to :command:`find_package` is no
     longer ignored in config mode.  Note that the CMake package shipped with
     Boost ``1.70.0`` ignores the ``QUIET`` argument passed to
     :command:`find_package`.  This is fixed in the next Boost release.

   * The input switch ``Boost_DETAILED_FAILURE_MSG`` was removed.

   * ``Boost_VERSION`` now reports the version in ``x.y.z``
     format in module mode.  See policy :policy:`CMP0093`.

 * The :module:`FindCups` module now provides imported targets.

 * The :module:`FindEnvModules` module was added to use Lua- and TCL-based
   environment modules in :ref:`CTest Scripts <CTest Script>`.

 * The :module:`FindGLEW` module now provides an interface more consistent
   with what upstream GLEW provides in its own CMake package files.

 * The :module:`FindPkgConfig` now populates :prop_tgt:`INTERFACE_LINK_OPTIONS`
   property of imported targets with other (non-library) linker flags.

 * The :module:`FindPostgreSQL` module learned to find debug and release
   variants separately.

 * Modules :module:`FindPython3`, :module:`FindPython2` and :module:`FindPython`
   gained additional lookup strategies and controls, and a new default.
   See policy :policy:`CMP0094`.

 * Modules :module:`FindPython`, :module:`FindPython2` and :module:`FindPython3`
   gain a new target (respectively ``Python::Module``, ``Python2::Module``
   and ``Python3::Module``) which can be used to develop Python modules.

 * Modules :module:`FindPython3`, :module:`FindPython2` and :module:`FindPython`
   gain capability to control how virtual environments are handled.

 * The :module:`UseSWIG` module learned to manage alternate library names
   by passing ``-interface <library_name>`` for ``python`` language or
   ``-dllimport <library_name>`` for ``CSharp`` language to the ``SWIG``
   compiler.

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

 * The generator expressions :genex:`$<C_COMPILER_ID>`,
   :genex:`$<CXX_COMPILER_ID>`, :genex:`$<CUDA_COMPILER_ID>`,
   :genex:`$<Fortran_COMPILER_ID>`, :genex:`$<COMPILE_LANGUAGE>`,
   :genex:`$<COMPILE_LANG_AND_ID>`, and :genex:`$<PLATFORM_ID>` learned to
   support matching one value from a comma-separated list.

 * The :genex:`$<CUDA_COMPILER_ID:...>` and :genex:`$<CUDA_COMPILER_VERSION:...>`
   generator expressions were added.

 * The :genex:`$<COMPILE_LANG_AND_ID:...>` generator expression was introduced to
   allow specification of compile options for target files based on the
   :variable:`CMAKE_<LANG>_COMPILER_ID` and :prop_sf:`LANGUAGE` of
   each source file.

 * A :genex:`$<FILTER:list,INCLUDE|EXCLUDE,regex>` generator expression has
   been added.

 * A :genex:`$<REMOVE_DUPLICATES:list>` generator expression has been added.

 * The :genex:`$<SHELL_PATH:...>` generator expression gained support for a
   list of paths.

 * New ``$<TARGET_FILE*>`` :manual:`generator expressions
   <cmake-generator-expressions(7)>` were added to retrieve the prefix, base
   name, and suffix of the file names of various artifacts:

   * :genex:`$<TARGET_FILE_PREFIX:...>`
   * :genex:`$<TARGET_FILE_BASE_NAME:...>`
   * :genex:`$<TARGET_FILE_SUFFIX:...>`
   * :genex:`$<TARGET_LINKER_FILE_PREFIX:...>`
   * :genex:`$<TARGET_LINKER_FILE_BASE_NAME:...>`
   * :genex:`$<TARGET_LINKER_FILE_SUFFIX:...>`
   * :genex:`$<TARGET_PDB_FILE_BASE_NAME:...>`

 * The :genex:`$<TARGET_OBJECTS:...>` generator expression is now supported
   on ``SHARED``, ``STATIC``, ``MODULE`` libraries and executables.

 CTest
 -----

 * The :command:`ctest_submit` command learned a new option: ``BUILD_ID``.
   This can be used to store the ID assigned to this build by CDash to a
   variable.

 * The :command:`ctest_update` command learned to honor a new variable:
   :variable:`CTEST_UPDATE_VERSION_OVERRIDE`. This can be used to specify
   the current version of your source tree rather than using the update
   command to discover the current version that is checked out.

 CPack
 -----

 * The :cpack_gen:`CPack IFW Generator` gained a new
   :variable:`CPACK_IFW_PACKAGE_STYLE_SHEET` variable to customize the
   installer stylesheet.

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

 * The :manual:`cmake-server(7)` mode has been deprecated and will be
   removed from a future version of CMake.  Please port clients to use
   the :manual:`cmake-file-api(7)` instead.

 * The :prop_dir:`ADDITIONAL_MAKE_CLEAN_FILES` directory property is now
   deprecated.  Use the :prop_dir:`ADDITIONAL_CLEAN_FILES` directory property
   instead.

 * The variable :variable:`CMAKE_AUTOMOC_RELAXED_MODE` is considered
   deprecated.  Support still exists but will be removed in future versions.

 * The :command:`export(PACKAGE)` command now does nothing unless
   enabled via :variable:`CMAKE_EXPORT_PACKAGE_REGISTRY`.
   See policy :policy:`CMP0090`.

 * The :generator:`Xcode` generator now requires at least Xcode 5.

 * An explicit deprecation diagnostic was added for policy ``CMP0066``
   (``CMP0065`` and below were already deprecated).
   The :manual:`cmake-policies(7)` manual explains that the OLD behaviors
   of all policies are deprecated and that projects should port to the
   NEW behaviors.

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

 * If a feature specified by :command:`target_compile_features` is available
   in the compiler's default standard level, CMake 3.14 and below incorrectly
   added unnecessary ``-std=`` flags that could lower the standard level.
   This bug has been fixed in CMake 3.15.  This behavior change may expose
   bugs in existing projects that were relying on undocumented implementation
   details.  Specifying compile features only ensures that the compiler runs
   in a mode that has those features, not that any specific standard level is
   used or explicit ``-std=`` flag passed.

 * CMake learned how to compile C++14 with the IBM AIX XL compiler
   and the SunPro compiler and to compile C++20 with the AppleClang compiler.

 * With MSVC-like compilers the value of :variable:`CMAKE_<LANG>_FLAGS`
   no longer contains warning flags like ``/W3`` by default.
   See policy :policy:`CMP0092`.

 * IBM Clang-based XL compilers that define ``__ibmxl__`` now use the
   compiler id ``XLClang`` instead of ``XL``.  See policy :policy:`CMP0089`.

 * The :command:`file(REMOVE)` and :command:`file(REMOVE_RECURSE)` commands
   were changed to ignore empty arguments with a warning instead of treating
   them as a relative path and removing the contents of the current directory.

 Updates
 =======

 Changes made since CMake 3.15.0 include the following.

 3.15.1
 ------

 * In CMake 3.15.0 support for the GNU-like ``Clang`` compiler targeting the
   MSVC ABI implemented :variable:`CMAKE_CXX_STANDARD` values 98 and 11 using
   the corresponding ``-std=`` flags.  However, these modes do not work with
   the MSVC standard library.  Therefore CMake 3.15.1 passes C++14 standard
   flags even for C++98 and C++11.  This is consistent with MSVC itself which
   always runs in a mode aware of C++14.

 * Preliminary Swift support added in 3.15.0 has been updated.

 3.15.2
 ------

 * In CMake 3.15.0 and 3.15.1 the :variable:`CMAKE_FIND_PACKAGE_PREFER_CONFIG`
   variable caused the :command:`find_package` command to fail on a missing
   package even without the ``REQUIRED`` option.  This has been fixed.

 3.15.3
 ------

 * ``CrayPrgEnv`` compiler wrapper support has been updated for the 19.06
   release of the Cray Programming Environment for which the default linking
   mode on XC Cray systems is now dynamic instead of static.

 3.15.4
 ------

 * In CMake 3.15.0 through 3.15.3, the :prop_dir:`EXCLUDE_FROM_ALL`
   directory property was regressed from pre-3.14 behavior and caused
   targets within the directory to be excluded even from its own "all".
   This has been fixed.
   The bug also existed in 3.14.0 through 3.14.6 and is fixed in 3.14.7.
	CMake 3.15 Release Notes
	************************

	.. only:: html

	.. contents::

	Changes made since CMake 3.14 include the following.

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

	Generators
	----------

	* The :generator:`Xcode` generator now supports per-target schemes.
	See the :variable:`CMAKE_XCODE_GENERATE_SCHEME` variable and
	:prop_tgt:`XCODE_GENERATE_SCHEME` target property.

	* The :generator:`Green Hills MULTI` generator has been updated:

	* It now supports the :command:`add_custom_command` and
	:command:`add_custom_target` commands.

	* It is now available on Linux.

	Languages
	---------

	* Preliminary support for the ``Swift`` language was added to the
	:generator:`Ninja` generator:

	* Use the :envvar:`SWIFTC` environment variable to specify a compiler.

	* The :prop_tgt:`Swift_DEPENDENCIES_FILE` target property and
	:prop_sf:`Swift_DEPENDENCIES_FILE` source file property were added
	to customize dependency files.

	* The :prop_tgt:`Swift_MODULE_NAME` target property was added to
	customize the Swift module name.

	* The :prop_sf:`Swift_DIAGNOSTICS_FILE` source property was added to
	indicate where to write the serialized Swift diagnostics.

	The Swift support is experimental, not considered stable, and may change
	in future releases of CMake.

	Compilers
	---------

	* The ``Clang`` compiler variant on Windows that targets the MSVC ABI
	but has a GNU-like command line is now supported.

	* Support for the Clang-based ARM compiler was added with compiler id
	``ARMClang``.

	* Support was added for the IAR compiler architectures Renesas RX,
	RL78, RH850 and Texas Instruments MSP430.

	* Support was added for the IAR compilers built for Linux (IAR BuildLx).

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

	* The :envvar:`CMAKE_GENERATOR` environment variable was added
	to specify a default generator to use when :manual:`cmake(1)` is
	run without a ``-G`` option. Additionally, environment variables
	:envvar:`CMAKE_GENERATOR_PLATFORM`, :envvar:`CMAKE_GENERATOR_TOOLSET`,
	and :envvar:`CMAKE_GENERATOR_INSTANCE` were created to configure
	the generator.

	* The :manual:`cmake(1)` ``--build`` tool ``--target`` parameter gained support
	for multiple targets, e.g. ``cmake --build . --target Library1 Library2``.
	It now also has a short form ``-t`` alias, e.g.
	``cmake --build . -t Library1 Library2``.

	* The :manual:`cmake(1)` command gained a new ``--install`` option.
	This may be used after building a project to run installation without
	using the generated build system or the native build tool.

	* The :manual:`cmake(1)` command learned a new CLI option ``--loglevel``.

	* The :manual:`cmake(1)` ``-E remove_directory`` command-line tool learned
	to support removing multiple directories.

	* The :manual:`cmake(1)` ``-E tar`` tool has been improved:

	* It now continues adding files to an archive even if some of the files
	are not readable. This behavior is more consistent with the
	classic ``tar`` tool.

	* It now parses all flags, and if an invalid flag was provided, a
	warning is issued.

	* It now displays an error if no action flag was specified, along with a
	list of possible actions: ``t`` (list), ``c`` (create) or ``x`` (extract).

	* It now supports extracting (``-x``) or listing (``-t``) only specific
	files or directories.

	* It now supports Zstandard compression with a ``--zstd`` option.
	Zstandard was designed to give a compression ratio comparable to that
	of the DEFLATE (zip) algorithm, but faster, especially for decompression.

	Commands
	--------

	* The :command:`add_custom_command` and :command:`add_custom_target` commands
	gained a new ``JOB_POOL`` option that works with the :generator:`Ninja`
	generator to set the pool variable on the build statement.

	* The :command:`add_library` command ``ALIAS`` option learned to support
	import libraries of the ``UNKNOWN`` type.

	* The :command:`cmake_parse_arguments` command gained an additional
	``<prefix>_KEYWORDS_MISSING_VALUES`` output variable to report
	keyword arguments that were given by the caller with no values.

	* The :command:`execute_process` command gained a ``COMMAND_ECHO`` option
	and supporting :variable:`CMAKE_EXECUTE_PROCESS_COMMAND_ECHO` variable
	to enable echoing of the command-line string before execution.

	* The :command:`file(INSTALL)` command learned a new argument,
	``FOLLOW_SYMLINK_CHAIN``, which can be used to recursively resolve and
	install symlinks.

	* :command:`list` learned new sub-commands:
	``PREPEND``, ``POP_FRONT`` and ``POP_BACK``.

	* The :command:`message` command learned new types:
	``NOTICE``, ``VERBOSE``, ``DEBUG`` and ``TRACE``.

	* The :command:`string` learned a new sub-command ``REPEAT``.

	Variables
	---------

	* The :variable:`CMAKE_CROSSCOMPILING_EMULATOR` variable and corresponding
	:prop_tgt:`CROSSCOMPILING_EMULATOR` target property learned to support
	arguments to the emulator.

	* The :variable:`CMAKE_FIND_PACKAGE_PREFER_CONFIG` variable was added to tell
	:command:`find_package` calls to look for a package configuration
	file first even if a find module is available.

	* The :variable:`CMAKE_FRAMEWORK` variable was added to initialize the
	:prop_tgt:`FRAMEWORK` property on all targets.

	* The :variable:`CMAKE_VS_JUST_MY_CODE_DEBUGGING` variable and
	:prop_tgt:`VS_JUST_MY_CODE_DEBUGGING` target property were added to
	enable the Just My Code feature of the Visual Studio Debugger when
	compiling with MSVC cl 19.05 and higher.

	* The :variable:`CMAKE_MSVC_RUNTIME_LIBRARY` variable and
	:prop_tgt:`MSVC_RUNTIME_LIBRARY` target property were introduced to
	select the runtime library used by compilers targeting the MSVC ABI.
	See policy :policy:`CMP0091`.

	* The :variable:`CMAKE_PROJECT_INCLUDE` and
	:variable:`CMAKE_PROJECT_INCLUDE_BEFORE` variables were added to allow
	injection of custom code at the sites of :command:`project` calls
	without knowing the project name a priori.

	Properties
	----------

	* The :prop_tgt:`ADDITIONAL_CLEAN_FILES` target property and
	:prop_dir:`ADDITIONAL_CLEAN_FILES` directory property were added.
	They allow to register additional files that should be removed during
	the clean stage.

	* The :prop_tgt:`PUBLIC_HEADER` and :prop_tgt:`PRIVATE_HEADER` properties
	may now be set on :ref:`Interface Libraries`. The headers specified by those
	properties can be installed using the :command:`install(TARGETS)` command by
	passing the ``PUBLIC_HEADER`` and ``PRIVATE_HEADER`` arguments respectively.

	* The :prop_tgt:`VS_PACKAGE_REFERENCES` target property was added to
	tell :ref:`Visual Studio Generators` to add references to ``nuget``
	packages.

	* The :prop_tgt:`VS_PROJECT_IMPORT` target property was added to allow
	managed Visual Studio project files to import external ``.props`` files.

	* The :prop_tgt:`VS_NO_SOLUTION_DEPLOY` target property was added to
	tell :ref:`Visual Studio Generators` whether to deploy an artifact
	to the WinCE or Windows Phone target device.

	Modules
	-------

	* The :module:`FindBoost` module was reworked to expose a more consistent
	user experience between its "Config" and "Module" modes and with other
	find modules in general.

	* A new imported target ``Boost::headers`` is now defined (same
	as ``Boost::boost``).

	* New output variables ``Boost_VERSION_MACRO``,
	``Boost_VERSION_MAJOR``, ``Boost_VERSION_MINOR``,
	``Boost_VERSION_PATCH``, and ``Boost_VERSION_COUNT``
	were added.

	* The ``QUIET`` argument passed to :command:`find_package` is no
	longer ignored in config mode. Note that the CMake package shipped with
	Boost ``1.70.0`` ignores the ``QUIET`` argument passed to
	:command:`find_package`. This is fixed in the next Boost release.

	* The input switch ``Boost_DETAILED_FAILURE_MSG`` was removed.

	* ``Boost_VERSION`` now reports the version in ``x.y.z``
	format in module mode. See policy :policy:`CMP0093`.

	* The :module:`FindCups` module now provides imported targets.

	* The :module:`FindEnvModules` module was added to use Lua- and TCL-based
	environment modules in :ref:`CTest Scripts <CTest Script>`.

	* The :module:`FindGLEW` module now provides an interface more consistent
	with what upstream GLEW provides in its own CMake package files.

	* The :module:`FindPkgConfig` now populates :prop_tgt:`INTERFACE_LINK_OPTIONS`
	property of imported targets with other (non-library) linker flags.

	* The :module:`FindPostgreSQL` module learned to find debug and release
	variants separately.

	* Modules :module:`FindPython3`, :module:`FindPython2` and :module:`FindPython`
	gained additional lookup strategies and controls, and a new default.
	See policy :policy:`CMP0094`.

	* Modules :module:`FindPython`, :module:`FindPython2` and :module:`FindPython3`
	gain a new target (respectively ``Python::Module``, ``Python2::Module``
	and ``Python3::Module``) which can be used to develop Python modules.

	* Modules :module:`FindPython3`, :module:`FindPython2` and :module:`FindPython`
	gain capability to control how virtual environments are handled.

	* The :module:`UseSWIG` module learned to manage alternate library names
	by passing ``-interface <library_name>`` for ``python`` language or
	``-dllimport <library_name>`` for ``CSharp`` language to the ``SWIG``
	compiler.

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

	* The generator expressions :genex:`$<C_COMPILER_ID>`,
	:genex:`$<CXX_COMPILER_ID>`, :genex:`$<CUDA_COMPILER_ID>`,
	:genex:`$<Fortran_COMPILER_ID>`, :genex:`$<COMPILE_LANGUAGE>`,
	:genex:`$<COMPILE_LANG_AND_ID>`, and :genex:`$<PLATFORM_ID>` learned to
	support matching one value from a comma-separated list.

	* The :genex:`$<CUDA_COMPILER_ID:...>` and :genex:`$<CUDA_COMPILER_VERSION:...>`
	generator expressions were added.

	* The :genex:`$<COMPILE_LANG_AND_ID:...>` generator expression was introduced to
	allow specification of compile options for target files based on the
	:variable:`CMAKE_<LANG>_COMPILER_ID` and :prop_sf:`LANGUAGE` of
	each source file.

	* A :genex:`$<FILTER:list,INCLUDE\|EXCLUDE,regex>` generator expression has
	been added.

	* A :genex:`$<REMOVE_DUPLICATES:list>` generator expression has been added.

	* The :genex:`$<SHELL_PATH:...>` generator expression gained support for a
	list of paths.

	* New ``$<TARGET_FILE*>`` :manual:`generator expressions
	<cmake-generator-expressions(7)>` were added to retrieve the prefix, base
	name, and suffix of the file names of various artifacts:

	* :genex:`$<TARGET_FILE_PREFIX:...>`
	* :genex:`$<TARGET_FILE_BASE_NAME:...>`
	* :genex:`$<TARGET_FILE_SUFFIX:...>`
	* :genex:`$<TARGET_LINKER_FILE_PREFIX:...>`
	* :genex:`$<TARGET_LINKER_FILE_BASE_NAME:...>`
	* :genex:`$<TARGET_LINKER_FILE_SUFFIX:...>`
	* :genex:`$<TARGET_PDB_FILE_BASE_NAME:...>`

	* The :genex:`$<TARGET_OBJECTS:...>` generator expression is now supported
	on ``SHARED``, ``STATIC``, ``MODULE`` libraries and executables.

	CTest
	-----

	* The :command:`ctest_submit` command learned a new option: ``BUILD_ID``.
	This can be used to store the ID assigned to this build by CDash to a
	variable.

	* The :command:`ctest_update` command learned to honor a new variable:
	:variable:`CTEST_UPDATE_VERSION_OVERRIDE`. This can be used to specify
	the current version of your source tree rather than using the update
	command to discover the current version that is checked out.

	CPack
	-----

	* The :cpack_gen:`CPack IFW Generator` gained a new
	:variable:`CPACK_IFW_PACKAGE_STYLE_SHEET` variable to customize the
	installer stylesheet.

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

	* The :manual:`cmake-server(7)` mode has been deprecated and will be
	removed from a future version of CMake. Please port clients to use
	the :manual:`cmake-file-api(7)` instead.

	* The :prop_dir:`ADDITIONAL_MAKE_CLEAN_FILES` directory property is now
	deprecated. Use the :prop_dir:`ADDITIONAL_CLEAN_FILES` directory property
	instead.

	* The variable :variable:`CMAKE_AUTOMOC_RELAXED_MODE` is considered
	deprecated. Support still exists but will be removed in future versions.

	* The :command:`export(PACKAGE)` command now does nothing unless
	enabled via :variable:`CMAKE_EXPORT_PACKAGE_REGISTRY`.
	See policy :policy:`CMP0090`.

	* The :generator:`Xcode` generator now requires at least Xcode 5.

	* An explicit deprecation diagnostic was added for policy ``CMP0066``
	(``CMP0065`` and below were already deprecated).
	The :manual:`cmake-policies(7)` manual explains that the OLD behaviors
	of all policies are deprecated and that projects should port to the
	NEW behaviors.

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

	* If a feature specified by :command:`target_compile_features` is available
	in the compiler's default standard level, CMake 3.14 and below incorrectly
	added unnecessary ``-std=`` flags that could lower the standard level.
	This bug has been fixed in CMake 3.15. This behavior change may expose
	bugs in existing projects that were relying on undocumented implementation
	details. Specifying compile features only ensures that the compiler runs
	in a mode that has those features, not that any specific standard level is
	used or explicit ``-std=`` flag passed.

	* CMake learned how to compile C++14 with the IBM AIX XL compiler
	and the SunPro compiler and to compile C++20 with the AppleClang compiler.

	* With MSVC-like compilers the value of :variable:`CMAKE_<LANG>_FLAGS`
	no longer contains warning flags like ``/W3`` by default.
	See policy :policy:`CMP0092`.

	* IBM Clang-based XL compilers that define ``__ibmxl__`` now use the
	compiler id ``XLClang`` instead of ``XL``. See policy :policy:`CMP0089`.

	* The :command:`file(REMOVE)` and :command:`file(REMOVE_RECURSE)` commands
	were changed to ignore empty arguments with a warning instead of treating
	them as a relative path and removing the contents of the current directory.

	Updates
	=======

	Changes made since CMake 3.15.0 include the following.

	3.15.1
	------

	* In CMake 3.15.0 support for the GNU-like ``Clang`` compiler targeting the
	MSVC ABI implemented :variable:`CMAKE_CXX_STANDARD` values 98 and 11 using
	the corresponding ``-std=`` flags. However, these modes do not work with
	the MSVC standard library. Therefore CMake 3.15.1 passes C++14 standard
	flags even for C++98 and C++11. This is consistent with MSVC itself which
	always runs in a mode aware of C++14.

	* Preliminary Swift support added in 3.15.0 has been updated.

	3.15.2
	------

	* In CMake 3.15.0 and 3.15.1 the :variable:`CMAKE_FIND_PACKAGE_PREFER_CONFIG`
	variable caused the :command:`find_package` command to fail on a missing
	package even without the ``REQUIRED`` option. This has been fixed.

	3.15.3
	------

	* ``CrayPrgEnv`` compiler wrapper support has been updated for the 19.06
	release of the Cray Programming Environment for which the default linking
	mode on XC Cray systems is now dynamic instead of static.

	3.15.4
	------

	* In CMake 3.15.0 through 3.15.3, the :prop_dir:`EXCLUDE_FROM_ALL`
	directory property was regressed from pre-3.14 behavior and caused
	targets within the directory to be excluded even from its own "all".
	This has been fixed.
	The bug also existed in 3.14.0 through 3.14.6 and is fixed in 3.14.7.