path: root/Help/release/3.15.rst

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

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Changes made since CMake 3.14 include the following.

* 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.

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

* Directory property :prop_dir:`ADDITIONAL_MAKE_CLEAN_FILES` was marked
  deprecated.  The new directory property :prop_dir:`ADDITIONAL_CLEAN_FILES`
  should be used instead.

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

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

* AppleClang compiler have learned how to compile C++20.

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

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

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

* The :manual:`cmake(1)` ``--build`` tool ``--target`` parameter gained support for
  multiple targets, e.g. ``cmake --build . --target Library1 Library2``.

* The :manual:`cmake(1)` ``-E tar`` tool now continues adding files to an
  archive, even if some of the files aren't readable. This behavior is more
  consistent with the classic ``tar`` tool.

* The :manual:`cmake(1)` ``-E tar`` tool now parses all flags, and if an
  invalid flag was provided, a warning is issued.
* The :manual:`cmake(1)` ``-E tar`` tool now displays an error if no action
  flag was specified, along with a list of possible actions: ``t`` (list),
  ``c`` (create) or ``x`` (extract).

* The :manual:`cmake(1)` ``-E tar`` tool allow for extract (``-x``) or list
  (``-t``) only specific files or directories.  To select pathnames append
  a space-separated list of file names or directories.
  When extracting selected files or directories, you must provide their exact
  pathname, as printed by list (``-t``)

* The :manual:`cmake(1)` ``-E tar`` tool now support Zstandard compression
  algorithm with ``--zstd`` option. Zstandard was designed to give
  a compression ratio comparable to that of the DEFLATE (zip) algorithm,
  but faster, especially for decompression.

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

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

* 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 :manual:`cmake(1)` ``--target`` parameter gained shorter
  version ``-t``, e.g. ``cmake --build . -t Library1 Library2`` is
  equivalant to ``cmake --build . --target Library1 Library2``.

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

* 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.

* The ``$<CUDA_COMPILER_ID:...>`` and ``$<CUDA_COMPILER_VERSION:...>``
  :manual:`generator expressions <cmake-generator-expressions(7)>` were added.

* 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.

* 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.

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

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

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

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

* 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.

* 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 internal logic for determining the value for
    ``Boost_FOUND``, for version and component checks, and
    for reporting the result to the user was replaced with
    the :module:`FindPackageHandleStandardArgs` module. (This
    fixed a bug that sometimes printed wrong status
    messages in config mode.)

  * The ``QUIET`` argument passed to :command:`find_package` is no
    longer ignored in config mode.

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

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

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

* Modules :module:`FindPython3`, :module:`FindPython2` and :module:`FindPython`
  have changed default strategy for lookup. See policy :policy:`CMP0094`.

* Modules :module:`FindPython3`, :module:`FindPython2` and :module:`FindPython`
  gain a new variable to control frameworks lookup on macOS.

* Modules :module:`FindPython3`, :module:`FindPython2` and :module:`FindPython`
  gain a new way to control lookup strategy.

* 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 :manual:`generator expressions <cmake-generator-expressions(7)>`
  ``C_COMPILER_ID``, ``CXX_COMPILER_ID``, ``CUDA_COMPILER_ID``,
  ``Fortran_COMPILER_ID``, ``COMPILE_LANGUAGE``, ``COMPILE_LANG_AND_ID``, and
  ``PLATFORM_ID`` learned to support matching one value from a comma-separated
  list.

* A new ``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 new ``$<FILTER:list,INCLUDE|EXCLUDE,regex>``
  :manual:`generator expression <cmake-generator-expressions(7)>`
  has been added.

* New ``$<TARGET_FILE_BASE_NAME:...>``, ``$<TARGET_LINKER_FILE_BASE_NAME:...>``
  and ``$<TARGET_PDB_FILE_BASE_NAME:...>``
  :manual:`generator expressions <cmake-generator-expressions(7)>` have been
  added to retrieve the base name of various artifacts.

* New ``$<TARGET_FILE_PREFIX:...>``, ``$<TARGET_LINKER_FILE_PREFIX:...>``,
  ``$<TARGET_FILE_SUFFIX:...>`` and ``$<TARGET_LINKER_FILE_SUFFIX:...>``
  :manual:`generator expressions <cmake-generator-expressions(7)>` have been
  added to retrieve the prefix and suffix of various artifacts.

* The :generator:`Green Hills MULTI` generator now supports
  :command:`add_custom_command` and :command:`add_custom_target`

* The :generator:`Green Hills MULTI` generator is now available on Linux.

* Support was added for the IAR compiler architectures Renesas RX,
  RL78, RH850 and Texas Instruments MSP430.
* The IAR compilers built for Linux (IAR BuildLx) now work as well.

* ``INTERFACE`` library can now have :prop_tgt:`PUBLIC_HEADER` and
  :prop_tgt:`PRIVATE_HEADER` properties set. 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.

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

* 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`.

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

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

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

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

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

* A variable :variable:`CMAKE_PROJECT_INCLUDE_BEFORE` was added to allow
  injection of custom code before the :command:`project` call.

* A variable :variable:`CMAKE_PROJECT_INCLUDE` was added to allow injection
  of custom code into the project without knowing the project name a priori.

* The ``TARGET_OBJECTS`` :manual:`generator expression <cmake-generator-expressions(7)>`
  is now supported on ``SHARED``, ``STATIC``, ``MODULE`` libraries and executables.

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

* A new ``$<REMOVE_DUPLICATES:list>``
  :manual:`generator expression <cmake-generator-expressions(7)>`
  has been added.

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

* 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 ``$<SHELL_PATH:...>`` :manual:`generator expression
  <cmake-generator-expressions(7)>` gained support for a list of paths.

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

* SunPro compiler have learned how to compile C++14.

* Preliminary support for the Swift language with the :generator:`Ninja`
  generator was added.  Use the :envvar:`SWIFTC` environment variable to
  specify a compiler.

* Support to emit an output file map was added to enable Swift compilation.

* A target property :prop_tgt:`Swift_DEPENDENCIES_FILE` was added to targets to
  indicate where to save the target swift dependencies file.  If one is not
  specified, it will default to `<TARGET>.swiftdeps`.

* A target property :prop_tgt:`Swift_MODULE_NAME` was added to targets to
  indicate the Swift module name.  If it is not specified, it will default to
  the name of the target.

* A source property :prop_sf:`Swift_DEPENDENCIES_FILE` was added to sources to
  indicate where to save the target swift dependencies file.  If one is not
  specified, it will default to `<OBJECT>.swiftdeps`.

* A source property :prop_sf:`Swift_DIAGNOSTICS_FILE` was added to sources to
  indicate where to write the serialised Swift diagnostics.

* 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.

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

* For the :ref:`Visual Studio Generators`,
  :ref:`Makefile Generators`, and the :generator:`Ninja` generators
  the Just My Code feature of the Visual Studio Debugger can be
  leveraged by turning on the :prop_tgt:`VS_JUST_MY_CODE_DEBUGGING` target
  property. Its default value is provided by the variable
  :variable:`CMAKE_VS_JUST_MY_CODE_DEBUGGING`.

* The :prop_tgt:`VS_PROJECT_IMPORT` target property was added which allows
  to import external .props files in managed Visual Studio targets.

* A :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.

* 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.

* IBM AIX XL compiler have learned how to compile C++14.