CMake 3.4 Release Notes
***********************

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Changes made since CMake 3.3 include the following.

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

Generators
----------

* The :generator:`Visual Studio 14 2015` generator learned to select
  a Windows 10 SDK based on the value of the :variable:`CMAKE_SYSTEM_VERSION`
  variable and the SDKs available on the host.

* CMake learned rudimentary support for the Apple Swift language.  When using
  the :generator:`Xcode` generator with Xcode 6.1 or higher, one may enable
  the ``Swift`` language with the :command:`enable_language` command or the
  :command:`project` command (this is an error with other generators or when
  Xcode is too old).  Then one may list ``.swift`` source files in targets
  for compilation.

Commands
--------

* The :command:`find_program` command learned a ``NAMES_PER_DIR``
  option to consider all given ``NAMES`` in each directory before
  moving on to the next directory.

* The :command:`get_filename_component` command learned a new ``BASE_DIR``
  subcommand.  This is used to specify a base directory when calculating an
  absolute path from a relative path.

* The :command:`if` command learned a new ``TEST`` operator that evaluates
  to true if a given test name has been defined by the :command:`add_test`
  command.  See policy :policy:`CMP0064`.

* The :command:`install(DIRECTORY)` command ``DESTINATION`` option learned to
  support :manual:`generator expressions <cmake-generator-expressions(7)>`.

* The :command:`install(FILES)` command ``DESTINATION`` option learned to
  support :manual:`generator expressions <cmake-generator-expressions(7)>`.

* The :command:`string` command learned a new ``APPEND`` subcommand.

Variables
---------

* The :ref:`Makefile Generators` and the :generator:`Ninja` generator
  learned to add compiler launcher tools like distcc and ccache along
  with the compiler for ``C`` and ``CXX`` languages.  See the
  :variable:`CMAKE_<LANG>_COMPILER_LAUNCHER` variable and
  :prop_tgt:`<LANG>_COMPILER_LAUNCHER` target property for details.

* New :variable:`CMAKE_LINK_SEARCH_START_STATIC` and
  :variable:`CMAKE_LINK_SEARCH_END_STATIC` variables were
  introduced to initialize the
  :prop_tgt:`LINK_SEARCH_START_STATIC` and
  :prop_tgt:`LINK_SEARCH_END_STATIC` target properties,
  respectively.

Properties
----------

* :ref:`Visual Studio Generators` learned to support additional
  target properties to customize projects for NVIDIA Nsight
  Tegra Visual Studio Edition:

  * :prop_tgt:`ANDROID_ANT_ADDITIONAL_OPTIONS`
  * :prop_tgt:`ANDROID_ARCH`
  * :prop_tgt:`ANDROID_ASSETS_DIRECTORIES`
  * :prop_tgt:`ANDROID_JAR_DEPENDENCIES`
  * :prop_tgt:`ANDROID_JAR_DIRECTORIES`
  * :prop_tgt:`ANDROID_JAVA_SOURCE_DIR`
  * :prop_tgt:`ANDROID_NATIVE_LIB_DEPENDENCIES`
  * :prop_tgt:`ANDROID_NATIVE_LIB_DIRECTORIES`
  * :prop_tgt:`ANDROID_PROCESS_MAX`
  * :prop_tgt:`ANDROID_PROGUARD`
  * :prop_tgt:`ANDROID_PROGUARD_CONFIG_PATH`
  * :prop_tgt:`ANDROID_SECURE_PROPS_PATH`
  * :prop_tgt:`ANDROID_SKIP_ANT_STEP`
  * :prop_tgt:`ANDROID_STL_TYPE`

* The :prop_tgt:`ARCHIVE_OUTPUT_DIRECTORY`,
  :prop_tgt:`LIBRARY_OUTPUT_DIRECTORY`, and
  :prop_tgt:`RUNTIME_OUTPUT_DIRECTORY` target properties learned to
  support :manual:`generator expressions <cmake-generator-expressions(7)>`.

* The :prop_tgt:`SOURCE_DIR` and :prop_tgt:`BINARY_DIR` target properties
  were introduced to allow project code to query where a target is defined.

* The :prop_tgt:`OUTPUT_NAME` target property and its variants learned to
  support :manual:`generator expressions <cmake-generator-expressions(7)>`.

* A :prop_gbl:`TARGET_MESSAGES` global property was added to tell the
  :ref:`Makefile Generators` whether to generate commands to print output
  after each target is completed.

* On Windows with MS-compatible tools, CMake learned to optionally
  generate a module definition (``.def``) file for ``SHARED`` libraries.
  See the :prop_tgt:`WINDOWS_EXPORT_ALL_SYMBOLS` target property.

Modules
-------

* The :module:`ExternalProject` module :command:`ExternalProject_Add`
  function ``GIT_SUBMODULES`` option now also limits the set of
  submodules that are initialized in addition to the prior behavior
  of limiting the set of submodules that are updated.

* The :module:`ExternalProject` module learned new ``USES_TERMINAL``
  arguments for giving steps exclusive terminal access.  This is
  useful with the :generator:`Ninja` generator to monitor CMake
  superbuild progress and prevent CPU oversubscription.

* The :module:`FindBISON` module ``BISON_TARGET`` macro learned a
  new ``DEFINES_FILE`` option to specify a custom output header
  to be generated.

* The :module:`FindHDF5` module learend a new ``HDF5_PREFER_PARALLEL``
  option allowing users to specify that a parallel HDF5 tool is
  preferred if both are available.

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

* The :module:`FindJava` module learned to optionally find
  the ``idlj`` and ``jarsigner`` tools.

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

* The :module:`FindOpenSSL` module learned a new ``OPENSSL_USE_STATIC_LIBS``
  option to search only for static libraries.

* The :module:`FindPkgConfig` learned a new :command:`pkg_get_variable`
  command which may be used to query for arbitrary variables from a package
  (such as for related tools or data and plugin install paths).

* The :module:`FindProtobuf` module gained a new
  :command:`protobuf_generate_python` function to generate python
  sources from ``.proto`` files.

* The :module:`FindTIFF` module learned to search separately for
  debug and release variants.

* The :module:`FindwxWidgets` module learned to support version requests.

* The :module:`FindXercesC` module learned to search separately for
  debug and release variants.

* The :module:`FindZLIB` module learned to search separately for
  debug and release variants.

* The :module:`GNUInstallDirs` module learned special default values
  for certain installation prefixes according to the `GNU Coding
  Standards`_ and the `Filesystem Hierarchy Standard`_.

* The :module:`UseJava` module ``add_jar`` function learned
  to support response files (e.g. ``@srcs.txt``) for source
  specification.

* The :module:`UseJava` module ``install_jar`` function learned
  new ``DESTINATION`` and ``COMPONENT`` options to specify
  the corresponding :command:`install` command options.

* The :module:`UseJava` module gained a new ``create_javah``
  function to create C headers from Java classes.

.. _`GNU Coding Standards`: https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
.. _`Filesystem Hierarchy Standard`: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/index.html

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

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

CTest
-----

* CTest learned to optionally measure the CPU load during parallel
  testing and avoid starting tests that may cause the load to exceed
  a given threshold.  See the :manual:`ctest(1)` command ``--test-load``
  option, the ``TestLoad`` setting of the :ref:`CTest Test Step`,
  the :variable:`CTEST_TEST_LOAD` variable, and the ``TEST_LOAD``
  option of the :command:`ctest_test` command.

* :manual:`ctest(1)` learned options
  ``--test-output-size-passed`` and ``--test-output-size-failed``
  to customize the limit on test output size submitted when
  running as a :ref:`Dashboard Client`.

CPack
-----

* The :cpack_gen:`CPack DEB Generator` learned to set package dependencies
  per component.  See variables:

  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_BREAKS`
  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_CONFLICTS`
  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_ENHANCES`
  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_PREDEPENDS`
  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_PROVIDES`
  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_RECOMMENDS`
  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_REPLACES`
  * :variable:`CPACK_DEBIAN_<COMPONENT>_PACKAGE_SUGGESTS`

* The :module:`CPack` module learned to package empty directories.

* The :module:`CPack` module gained a new setting, ``CPACK_VERBATIM_VARIABLES``,
  which can be used to ensure the cpack program receives the settings' values
  exactly as they were set, even if they contain CMake-special characters.
  For compatibility, it's off by default.

Other
-----

* The :manual:`Compile Features <cmake-compile-features(7)>` functionality
  is now aware of features supported by GNU C compilers on Windows.

* CMake learned to honor ``*.manifest`` source files with MSVC tools.
  Manifest files named as sources of ``.exe`` and ``.dll`` targets
  will be merged with linker-generated manifests and embedded in the
  binary.

* The Concurrent Fortran 77 compiler is now supported.
  Its :variable:`compiler id <CMAKE_<LANG>_COMPILER_ID>` is ``CCur``.

* :manual:`cmake(1)` gained a new ``--trace-expand`` command line option
  that is like ``--trace`` but expands variable references in the output.

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

* The :module:`CMakeExpandImportedTargets` module is now documented
  as deprecated.  See module documentation for an explanation.

* The :variable:`CMAKE_USE_RELATIVE_PATHS` variable no longer has any
  effect.  Previously it was partially implemented and unreliable.

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

* The :module:`CheckFunctionExists`, :module:`CheckLibraryExists`,
  :module:`CheckSymbolExists`, and :module:`FindThreads` modules learned to
  work in environments where only CXX is enabled.

* The :cpack_gen:`CPack DEB Generator` now correctly excludes symlinks
  during package checksum calculation.

* The :cpack_gen:`CPack DEB Generator` no longer uses fakeroot and
  system tar program for packaging.

* The :module:`CPack` module no longer mangles settings with CMake-special
  characters when they're used as defaults for other settings. The macro
  ``cpack_set_if_not_set``, which was responsible for this, is now deprecated.

* CMake no longer links executables with flags to export symbols
  unless the :prop_tgt:`ENABLE_EXPORTS` target property is set.
  See policy :policy:`CMP0065`.

* The ``SONAME`` field is no longer set for ``MODULE`` libraries
  created with the :command:`add_library` command.  ``MODULE``
  libraries are meant for explicit dynamic loading at runtime.
  They cannot be linked so ``SONAME`` is not useful.

* The internal :variable:`CMAKE_<LANG>_COMPILE_OBJECT` rule variable now
  substitutes compiler include flags in a separate ``<INCLUDES>`` placeholder
  instead of the main ``<FLAGS>`` placeholder.