Help/release/3.12.rst

CMake 3.12 Release Notes
************************

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Changes made since CMake 3.11 include the following.

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

Generators
----------

* The :ref:`Visual Studio Generators` for VS 2017 learned to support a
  ``version=14.##`` option in the :variable:`CMAKE_GENERATOR_TOOLSET`
  value (e.g. via the :manual:`cmake(1)` ``-T`` option) to specify a
  toolset version number.

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

* The :manual:`cmake(1)` :ref:`Build Tool Mode` (``cmake --build``) gained
  ``--parallel [<jobs>]`` and ``-j [<jobs>]`` options to specify a parallel
  build level.  They map to corresponding options of the native build tool.

Commands
--------

* The :command:`add_compile_definitions` command was added to set preprocessor
  definitions at directory level.  This supersedes :command:`add_definitions`.

* The :command:`cmake_minimum_required` and :command:`cmake_policy(VERSION)`
  commands now accept a version range using the form ``<min>[...<max>]``.
  The ``<min>`` version is required but policies are set based on the
  older of the running CMake version and the version specified by
  ``<max>``.  This allows projects to specify a range of versions
  for which they have been updated and avoid explicit policy settings.

* The :command:`file(GLOB)` and :command:`file(GLOB_RECURSE)` commands
  learned a new flag ``CONFIGURE_DEPENDS`` which enables expression of
  build system dependency on globbed directory's contents.

* The :command:`file(TOUCH)` and :command:`file(TOUCH_NOCREATE)` commands
  were added to expose ``TOUCH`` functionality without having to use
  CMake's command-line tool mode with :command:`execute_process`.

* The :command:`find_package` command now searches prefixes specified by
  the :variable:`<PackageName>_ROOT` CMake variable and the
  :envvar:`<PackageName>_ROOT` environment variable.  Package roots are
  maintained as a stack so nested calls to all ``find_*`` commands inside
  find modules also search the roots as prefixes.
  See policy :policy:`CMP0074`.

* The :command:`install` command learned an optional ``NAMELINK_COMPONENT``
  parameter, which allows you to change the component for a shared library's
  namelink. If none is specified, the value of ``COMPONENT`` is used by
  default.

* The :command:`list` command learned a ``JOIN`` sub-command
  to concatenate list's elements separated by a glue string.

* The :command:`list` command learned a ``SUBLIST`` sub-command
  to get a sublist of the list.

* The :command:`list` command learned a ``TRANSFORM`` sub-command
  to apply various string transformation to list's elements.

* The :command:`project` command learned an optional ``HOMEPAGE_URL``
  parameter which has the effect of setting variables like
  :variable:`PROJECT_HOMEPAGE_URL`, :variable:`<PROJECT-NAME>_HOMEPAGE_URL`
  and :variable:`CMAKE_PROJECT_HOMEPAGE_URL`.

* The :command:`string` command learned a ``JOIN`` sub-command
  to concatenate input strings separated by a glue string.

* :command:`target_compile_options` and :command:`add_compile_options`
  commands gained a ``SHELL:`` prefix to specify a group of related
  options using shell-like quoting.

* The :command:`target_link_libraries` command now supports
  :ref:`Object Libraries`.  Linking to an object library uses its object
  files in direct dependents and also propagates usage requirements.

Variables
---------

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

* The :variable:`CMAKE_DOTNET_TARGET_FRAMEWORK_VERSION` variable
  was defined to initialize all
  :prop_tgt:`DOTNET_TARGET_FRAMEWORK_VERSION` target properties.

* ``CMAKE_PROJECT_VERSION*`` variables have been introduced:

  - :variable:`CMAKE_PROJECT_VERSION`
  - :variable:`CMAKE_PROJECT_VERSION_MAJOR`
  - :variable:`CMAKE_PROJECT_VERSION_MINOR`
  - :variable:`CMAKE_PROJECT_VERSION_PATCH`
  - :variable:`CMAKE_PROJECT_VERSION_TWEAK`

* The :variable:`CMAKE_SUPPRESS_REGENERATION` variable was extended to
  support the :generator:`Ninja` and :ref:`Makefile Generators`.
  It is also now documented.

* ``CMAKE_VS_SDK_*_DIRECTORIES`` variables were defined to tell
  :ref:`Visual Studio Generators` for VS 2010 and above how to populate
  fields in ``.vcxproj`` files that specify SDK directories.  The
  variables are:

  - :variable:`CMAKE_VS_SDK_EXCLUDE_DIRECTORIES`
  - :variable:`CMAKE_VS_SDK_EXECUTABLE_DIRECTORIES`
  - :variable:`CMAKE_VS_SDK_INCLUDE_DIRECTORIES`
  - :variable:`CMAKE_VS_SDK_LIBRARY_DIRECTORIES`
  - :variable:`CMAKE_VS_SDK_LIBRARY_WINRT_DIRECTORIES`
  - :variable:`CMAKE_VS_SDK_REFERENCE_DIRECTORIES`
  - :variable:`CMAKE_VS_SDK_SOURCE_DIRECTORIES`

* A :variable:`MSVC_TOOLSET_VERSION` variable was added to provide the
  MSVC toolset version associated with the current MSVC compiler version
  in :variable:`MSVC_VERSION`.

Properties
----------

* The :prop_tgt:`COMMON_LANGUAGE_RUNTIME` target property was introduced
  to configure the use of managed C++ for :ref:`Visual Studio Generators`
  for VS 2010 and above.
  A corresponding :prop_tgt:`IMPORTED_COMMON_LANGUAGE_RUNTIME` target
  property was added to support ``C++/CLI`` for imported targets.

* The :prop_tgt:`DOTNET_TARGET_FRAMEWORK_VERSION` target property
  was introduced as replacement for
  :prop_tgt:`VS_DOTNET_TARGET_FRAMEWORK_VERSION`, which is considered
  deprecated now.

* An :prop_tgt:`EXPORT_PROPERTIES` target property was added to specify a
  custom list of target properties to include in targets exported by the
  :command:`install(EXPORT)` and :command:`export` commands.

* The :prop_tgt:`PDB_OUTPUT_DIRECTORY` property learned to support
  :manual:`generator expressions <cmake-generator-expressions(7)>`.

* A :prop_dir:`TESTS` directory property was added to hold the list of
  tests defined by the :command:`add_test` command.

* A :prop_tgt:`VS_DEBUGGER_COMMAND` target property was created to set the
  debugging command line with :ref:`Visual Studio Generators` for VS 2010
  and above.

* HLSL source file properties :prop_sf:`VS_SHADER_DISABLE_OPTIMIZATIONS`
  and :prop_sf:`VS_SHADER_ENABLE_DEBUG` gained support for generator
  expressions.

* HLSL source file property :prop_sf:`VS_SHADER_OBJECT_FILE_NAME` has been
  added to the :ref:`Visual Studio Generators` for VS 2010 and above.
  The property specifies the file name of the compiled shader object.

Modules
-------

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

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

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

* The :module:`FindLibXml2` module now provides imported targets.

* The :module:`FindMatlab` module now supports the Matlab Runtime
  Compiler (MCR) for compiling and linking matlab extensions.

* A :module:`FindODBC` module was added to find an Open Database Connectivity
  (ODBC) library.

* The :module:`FindPkgConfig` module has learned to export the found
  libraries with full path for direct consumption with the
  :command:`target_link_libraries` command.

* New :module:`FindPython3` and :module:`FindPython2` modules, as well as
  a new :module:`FindPython` module, have been added to provide a new way
  to locate python environments.

* The :module:`UseSWIG` module gained a whole refresh and is now more
  consistent with standard CMake commands to generate libraries and is
  fully configurable through properties.

* The :module:`UseSWIG` module learned to manage multiple behaviors through
  ``UseSWIG_MODULE_VERSION`` variable to ensure legacy support as well as more
  robust handling of ``SWIG`` advanced features (like ``%template``).

* The :module:`UseSWIG` module learned to support CSHARP variant
  wrapper files.

* The :module:`WriteCompilerDetectionHeader` module gained a ``BARE_FEATURES``
  option to add a compatibility define for the exact keyword of a new language
  feature.

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

* A new ``$<GENEX_EVAL:...>`` and ``$<TARGET_GENEX_EVAL:target,...>``
  :manual:`generator expression <cmake-generator-expressions(7)>`
  has been added to enable consumption of generator expressions whose
  evaluation results itself in generator expressions.

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

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

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

CTest
-----

* The :command:`ctest_start` command has been reworked so that you can simply
  call ``ctest_start(APPEND)`` and it will read all the needed information from
  the TAG file. The argument parsing has also been relaxed so that the order of
  the arguments is less significant.

* A :prop_test:`PROCESSOR_AFFINITY` test property was added to request
  that CTest run a test with CPU affinity for a set of processors
  disjoint from other concurrently running tests with the property set.

CPack
-----

* The :module:`CPack` module now uses variables
  :variable:`CMAKE_PROJECT_VERSION_MAJOR`,
  :variable:`CMAKE_PROJECT_VERSION_MINOR` and
  :variable:`CMAKE_PROJECT_VERSION_PATCH`
  to initialize corresponding CPack variables.

* A :cpack_gen:`CPack NuGet Generator` was was added with basic
  support for `NuGet`_.

.. _NuGet: https://docs.microsoft.com/en-us/nuget/what-is-nuget

Other
-----

* The :manual:`Compile Features <cmake-compile-features(7)>` functionality
  is now aware of C++ 20.  No specific features are yet enumerated besides
  the ``cxx_std_20`` meta-feature.

* The :manual:`Compile Features <cmake-compile-features(7)>` functionality
  is now aware of the availability of C features in MSVC since VS 2010.

* The :manual:`Compile Features <cmake-compile-features(7)>` functionality
  is now aware of C language standards supported by Texas Instruments C
  compilers.

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

* The :generator:`Visual Studio 8 2005` generator has been removed.

* CMake no longer produces ``<tgt>_LIB_DEPENDS`` cache entries
  for library targets.  See policy :policy:`CMP0073`.

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

* Include flags for directories marked as ``SYSTEM`` are now moved after
  non-system directories.  The ``-isystem`` flag does this automatically,
  so moving them explicitly to the end makes the behavior consistent on
  compilers that do not have any ``-isystem`` flag.

* Fortran dependency scanning now supports dependencies implied by
  `Fortran Submodules`_.

* The existence and functionality of the file
  ``${CMAKE_BINARY_DIR}/cmake_install.cmake`` has now been documented in the
  :command:`install` documentation so that external packaging software can take
  advantage of CPack-style component installs.

* The :module:`CheckIncludeFile` module ``check_include_file`` macro
  learned to honor the ``CMAKE_REQUIRED_LIBRARIES`` variable.
  See policy :policy:`CMP0075`.

* The :module:`CheckIncludeFileCXX` module ``check_include_file_cxx`` macro
  learned to honor the ``CMAKE_REQUIRED_LIBRARIES`` variable.
  See policy :policy:`CMP0075`.

* The :module:`CheckIncludeFiles` module ``check_include_files`` macro
  learned to honor the ``CMAKE_REQUIRED_LIBRARIES`` variable.
  See policy :policy:`CMP0075`.

* The :manual:`cmake(1)` ``-E copy_directory`` tool now fails when the
  source directory does not exist.  Previously it succeeded by creating
  an empty destination directory.

* The :module:`UseSWIG` module :command:`swig_add_library` command
  (and legacy ``swig_add_module`` command) now set the prefix of
  Java modules to ``""`` for MINGW, MSYS, and CYGWIN environments.

.. _`Fortran Submodules`: http://fortranwiki.org/fortran/show/Submodules