Help/release/3.0.rst - third_party/cmake - Git at Google

 CMake 3.0 Release Notes
 ***********************

 .. only:: html

   .. contents::

 Changes made since CMake 2.8.12 include the following.

 Documentation Changes
 =====================

 * The CMake documentation has been converted to reStructuredText and
   now transforms via Sphinx (`<http://sphinx-doc.org>`__) into man and
   html pages.  This allows the documentation to be properly indexed
   and to contain cross-references.

   Conversion from the old internal documentation format was done by
   an automatic process so some documents may still contain artifacts.
   They will be updated incrementally over time.

   A basic reStructuredText processor has been implemented to support
   ``cmake --help-command`` and similar command-line options.

 * New manuals were added:

   - :manual:`cmake-buildsystem(7)`
   - :manual:`cmake-commands(7)`, replacing ``cmakecommands(1)``
     and ``cmakecompat(1)``
   - :manual:`cmake-developer(7)`
   - :manual:`cmake-generator-expressions(7)`
   - :manual:`cmake-generators(7)`
   - :manual:`cmake-language(7)`
   - :manual:`cmake-modules(7)`, replacing ``cmakemodules(1)``
   - :manual:`cmake-packages(7)`
   - :manual:`cmake-policies(7)`, replacing ``cmakepolicies(1)``
   - :manual:`cmake-properties(7)`, replacing ``cmakeprops(1)``
   - :manual:`cmake-qt(7)`
   - :manual:`cmake-toolchains(7)`
   - :manual:`cmake-variables(7)`, replacing ``cmakevars(1)``

 * Release notes for CMake 3.0.0 and above will now be included with
   the html documentation.

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

 Syntax
 ------

 * The CMake language has been extended with
   :ref:`Bracket Argument` and  :ref:`Bracket Comment`
   syntax inspired by Lua long brackets::

     set(x [===[bracket argument]===] #[[bracket comment]])

   Content between equal-length open- and close-brackets is taken
   literally with no variable replacements.

   .. warning::
     This syntax change could not be made in a fully compatible
     way.  No policy is possible because syntax parsing occurs before
     any chance to set a policy.  Existing code using an unquoted
     argument that starts with an open bracket will be interpreted
     differently without any diagnostic.  Fortunately the syntax is
     obscure enough that this problem is unlikely in practice.

 Generators
 ----------

 * A new :generator:`CodeLite` extra generator is available
   for use with the Makefile or Ninja generators.

 * A new :generator:`Kate` extra generator is available
   for use with the Makefile or Ninja generators.

 * The :generator:`Ninja` generator learned to use ``ninja`` job pools
   when specified by a new :prop_gbl:`JOB_POOLS` global property.

 Commands
 --------

 * The :command:`add_library` command learned a new ``INTERFACE``
   library type.  Interface libraries have no build rules but may
   have properties defining
   :manual:`usage requirements <cmake-buildsystem(7)>`
   and may be installed, exported, and imported.  This is useful to
   create header-only libraries that have concrete link dependencies
   on other libraries.

 * The :command:`export()` command learned a new ``EXPORT`` mode that
   retrieves the list of targets to export from an export set configured
   by the :command:`install(TARGETS)` command ``EXPORT`` option.  This
   makes it easy to export from the build tree the same targets that
   are exported from the install tree.

 * The :command:`export` command learned to work with multiple dependent
   export sets, thus allowing multiple packages to be built and exported
   from a single tree.  The feature requires CMake to wait until the
   generation step to write the output file.  This means one should not
   :command:`include` the generated targets file later during project
   configuration because it will not be available.
   Use :ref:`Alias Targets` instead.  See policy :policy:`CMP0024`.

 * The :command:`install(FILES)` command learned to support
   :manual:`generator expressions <cmake-generator-expressions(7)>`
   in the list of files.

 * The :command:`project` command learned to set some version variables
   to values specified by the new ``VERSION`` option or to empty strings.
   See policy :policy:`CMP0048`.

 * The :command:`string` command learned a new ``CONCAT`` mode.
   It is particularly useful in combination with the new
   :ref:`Bracket Argument` syntax.

 * The :command:`unset` command learned a ``PARENT_SCOPE`` option
   matching that of the :command:`set` command.

 * The :command:`include_external_msproject` command learned
   to handle non-C++ projects like ``.vbproj`` or ``.csproj``.

 * The :command:`ctest_update` command learned to update work trees
   managed by the Perforce (p4) version control tool.

 * The :command:`message` command learned a ``DEPRECATION`` mode. Such
   messages are not issued by default, but may be issued as a warning if
   :variable:`CMAKE_WARN_DEPRECATED` is enabled, or as an error if
   :variable:`CMAKE_ERROR_DEPRECATED` is enabled.

 * The :command:`target_link_libraries` command now allows repeated use of
   the ``LINK_PUBLIC`` and ``LINK_PRIVATE`` keywords.

 Variables
 ---------

 * Variable :variable:`CMAKE_FIND_NO_INSTALL_PREFIX` has been
   introduced to tell CMake not to add the value of
   :variable:`CMAKE_INSTALL_PREFIX` to the
   :variable:`CMAKE_SYSTEM_PREFIX_PATH` variable by default.
   This is useful when building a project that installs some
   of its own dependencies to avoid finding files it is about
   to replace.

 * Variable :variable:`CMAKE_STAGING_PREFIX` was introduced for use
   when cross-compiling to specify an installation prefix on the
   host system that differs from a :variable:`CMAKE_INSTALL_PREFIX`
   value meant for the target system.

 * Variable :variable:`CMAKE_SYSROOT` was introduced to specify the
   toolchain SDK installation prefix, typically for cross-compiling.
   This is used to pass a ``--sysroot`` option to the compiler and
   as a prefix searched by ``find_*`` commands.

 * Variable :variable:`CMAKE_<LANG>_COMPILER_TARGET` was introduced
   for use when cross-compiling to specify the target platform in the
   :ref:`toolchain file <Cross Compiling Toolchain>` specified by the
   :variable:`CMAKE_TOOLCHAIN_FILE` variable.
   This is used to pass an option such as ``--target=<triple>`` to some
   cross-compiling compiler drivers.

 * Variable :variable:`CMAKE_MAP_IMPORTED_CONFIG_<CONFIG>` has been
   introduced to optionally initialize the
   :prop_tgt:`MAP_IMPORTED_CONFIG_<CONFIG>` target property.

 Properties
 ----------

 * The :prop_dir:`ADDITIONAL_MAKE_CLEAN_FILES` directory property
   learned to support
   :manual:`generator expressions <cmake-generator-expressions(7)>`.

 * A new directory property :prop_dir:`CMAKE_CONFIGURE_DEPENDS`
   was introduced to allow projects to specify additional
   files on which the configuration process depends.  CMake will
   re-run at build time when one of these files is modified.
   Previously this was only possible to achieve by specifying
   such files as the input to a :command:`configure_file` command.

 * A new :ref:`Qt AUTORCC` feature replaces the need to
   invoke ``qt4_add_resources()`` by allowing ``.qrc`` files to
   be listed as target sources.

 * A new :ref:`Qt AUTOUIC` feature replaces the need to
   invoke ``qt4_wrap_ui()``.

 * Test properties learned to support
   :manual:`generator expressions <cmake-generator-expressions(7)>`.
   This is useful to specify per-configuration values for test
   properties like :prop_test:`REQUIRED_FILES` and
   :prop_test:`WORKING_DIRECTORY`.

 * A new :prop_test:`SKIP_RETURN_CODE` test property was introduced
   to tell :manual:`ctest(1)` to treat a particular test return code as
   if the test were not run.  This is useful for test drivers to report
   that certain test requirements were not available.

 * New types of :ref:`Compatible Interface Properties` were introduced,
   namely the :prop_tgt:`COMPATIBLE_INTERFACE_NUMBER_MAX` and
   :prop_tgt:`COMPATIBLE_INTERFACE_NUMBER_MIN` for calculating numeric
   maximum and minimum values respectively.

 Modules
 -------

 * The :module:`CheckTypeSize` module ``check_type_size`` macro and
   the :module:`CheckStructHasMember` module ``check_struct_has_member``
   macro learned a new ``LANGUAGE`` option to optionally check C++ types.

 * The :module:`ExternalData` module learned to work with no
   URL templates if a local store is available.

 * The :module:`ExternalProject` function ``ExternalProject_Add``
   learned a new ``GIT_SUBMODULES`` option to specify a subset
   of available submodules to checkout.

 * A new :module:`FindBacktrace` module has been added to support
   :command:`find_package(Backtrace)` calls.

 * A new :module:`FindLua` module has been added to support
   :command:`find_package(Lua)` calls.

 * The :module:`FindBoost` module learned a new ``Boost_NAMESPACE``
   option to change the ``boost`` prefix on library names.

 * The :module:`FindBoost` module learned to control search
   for libraries with the ``g`` tag (for MS debug runtime) with
   a new ``Boost_USE_DEBUG_RUNTIME`` option.  It is ``ON`` by
   default to preserve existing behavior.

 * The :module:`FindJava` and :module:`FindJNI` modules learned
   to use a ``JAVA_HOME`` CMake variable or environment variable,
   and then try ``/usr/libexec/java_home`` on OS X.

 * The :module:`UseJava` module ``add_jar`` function learned a new
   ``MANIFEST`` option to pass the ``-m`` option to ``jar``.

 * A new :module:`CMakeFindDependencyMacro` module was introduced with
   a ``find_dependency`` macro to find transitive dependencies in
   a :manual:`package configuration file <cmake-packages(7)>`.  Such
   dependencies are omitted by the listing of the :module:`FeatureSummary`
   module.

 * The :module:`FindQt4` module learned to create :ref:`Imported Targets`
   for Qt executables.  This helps disambiguate when using multiple
   :manual:`Qt versions <cmake-qt(7)>` in the same buildsystem.

 * The :module:`FindRuby` module learned to search for Ruby 2.0 and 2.1.

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

 * New ``$<PLATFORM_ID>`` and ``$<PLATFORM_ID:...>``
   :manual:`generator expressions <cmake-generator-expressions(7)>`
   have been added.

 * The ``$<CONFIG>``
   :manual:`generator expression <cmake-generator-expressions(7)>` now has
   a variant which takes no argument.  This is equivalent to the
   ``$<CONFIGURATION>`` expression.

 * New ``$<UPPER_CASE:...>`` and ``$<LOWER_CASE:...>``
   :manual:`generator expressions <cmake-generator-expressions(7)>`
   generator expressions have been added.

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

 Other
 -----

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

 * The :manual:`ccmake(1)` dialog learned to honor the
   :prop_cache:`STRINGS` cache entry property to cycle through
   the enumerated list of possible values.

 * The :manual:`cmake-gui(1)` dialog learned to remember window
   settings between sessions.

 * The :manual:`cmake-gui(1)` dialog learned to remember the type
   of a cache entry for completion in the ``Add Entry`` dialog.

 New Diagnostics
 ===============

 * Directories named in the :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES`
   target property of imported targets linked conditionally by a
   :manual:`generator expression <cmake-generator-expressions(7)>`
   were not checked for existence.  Now they are checked.
   See policy :policy:`CMP0027`.

 * Build target names must now match a validity pattern and may no longer
   conflict with CMake-defined targets.  See policy :policy:`CMP0037`.

 * Build targets that specify themselves as a link dependency were
   silently accepted but are now diagnosed.  See :policy:`CMP0038`.

 * The :command:`target_link_libraries` command used to silently ignore
   calls specifying as their first argument build targets created by
   :command:`add_custom_target` but now diagnoses this mistake.
   See policy :policy:`CMP0039`.

 * The :command:`add_custom_command` command used to silently ignore
   calls specifying the ``TARGET`` option with a non-existent target
   but now diagnoses this mistake.  See policy :policy:`CMP0040`.

 * Relative paths in the :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES`
   target property used to be silently accepted if they contained a
   :manual:`generator expression <cmake-generator-expressions(7)>`
   but are now rejected.  See policy :policy:`CMP0041`.

 * The :command:`get_target_property` command learned to reject calls
   specifying a non-existent target.  See policy :policy:`CMP0045`.

 * The :command:`add_dependencies` command learned to reject calls
   specifying a dependency on a non-existent target.
   See policy :policy:`CMP0046`.

 * Link dependency analysis learned to assume names containing ``::``
   refer to :ref:`Alias Targets` or :ref:`Imported Targets`.  It will
   now produce an error if such a linked target is missing.  Previously
   in this case CMake generated a link line that failed at build time.
   See policy :policy:`CMP0028`.

 * When the :command:`project` or :command:`enable_language` commands
   initialize support for a language, it is now an error if the full
   path to the compiler cannot be found and stored in the corresponding
   :variable:`CMAKE_<LANG>_COMPILER` variable.  This produces nicer error
   messages up front and stops processing when no working compiler
   is known to be available.

 * Target sources specified with the :command:`add_library` or
   :command:`add_executable` command learned to reject items which
   require an undocumented extra layer of variable expansion.
   See policy :policy:`CMP0049`.

 * Use of :command:`add_custom_command` undocumented ``SOURCE``
   signatures now results in an error.  See policy :policy:`CMP0050`.

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

 * Compatibility options supporting code written for CMake versions
   prior to 2.4 have been removed.

 * Several long-outdated commands that should no longer be called
   have been disallowed in new code by policies:

   - Policy :policy:`CMP0029` disallows :command:`subdir_depends`
   - Policy :policy:`CMP0030` disallows :command:`use_mangled_mesa`
   - Policy :policy:`CMP0031` disallows :command:`load_command`
   - Policy :policy:`CMP0032` disallows :command:`output_required_files`
   - Policy :policy:`CMP0033` disallows :command:`export_library_dependencies`
   - Policy :policy:`CMP0034` disallows :command:`utility_source`
   - Policy :policy:`CMP0035` disallows :command:`variable_requires`
   - Policy :policy:`CMP0036` disallows :command:`build_name`

 * The :manual:`cmake(1)` ``-i`` wizard mode has been removed.
   Instead use an interactive dialog such as :manual:`ccmake(1)`
   or use the ``-D`` option to set cache values from the command line.

 * The builtin documentation formatters that supported command-line
   options such as ``--help-man`` and ``--help-html`` have been removed
   in favor of the above-mentioned new documentation system.  These and
   other command-line options that used to generate man- and html-
   formatted pages no longer work.  The :manual:`cmake(1)`
   ``--help-custom-modules`` option now produces a warning at runtime
   and generates a minimal document that reports the limitation.

 * The :prop_dir:`COMPILE_DEFINITIONS_<CONFIG>` directory properties and the
   :prop_tgt:`COMPILE_DEFINITIONS_<CONFIG>` target properties have been
   deprecated.  Instead set the corresponding :prop_dir:`COMPILE_DEFINITIONS`
   directory property or :prop_tgt:`COMPILE_DEFINITIONS` target property and
   use :manual:`generator expressions <cmake-generator-expressions(7)>` like
   ``$<CONFIG:...>`` to specify per-configuration definitions.
   See policy :policy:`CMP0043`.

 * The :prop_tgt:`LOCATION` target property should no longer be read from
   non-IMPORTED targets.  It does not make sense in multi-configuration
   generators since the build configuration is not known while configuring
   the project.  It has been superseded by the ``$<TARGET_FILE>`` generator
   expression.  See policy :policy:`CMP0026`.

 * The :prop_tgt:`COMPILE_FLAGS` target property is now documented
   as deprecated, though no warning is issued.  Use the
   :prop_tgt:`COMPILE_OPTIONS` target property or the
   :command:`target_compile_options` command instead.

 * The :module:`GenerateExportHeader` module ``add_compiler_export_flags``
   function is now deprecated.  It has been superseded by the
   :prop_tgt:`<LANG>_VISIBILITY_PRESET` and
   :prop_tgt:`VISIBILITY_INLINES_HIDDEN` target properties.

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

 * The version scheme was changed to use only two components for
   the feature level instead of three.  The third component will
   now be used for bug-fix releases or the date of development versions.
   See the :variable:`CMAKE_VERSION` variable documentation for details.

 * The default install locations of CMake itself on Windows and
   OS X no longer contain the CMake version number.  This allows
   for easy replacement without re-generating local build trees
   manually.

 * Generators for Visual Studio 10 (2010) and later were renamed to
   include the product year like generators for older VS versions:

   - ``Visual Studio 10`` -> :generator:`Visual Studio 10 2010`
   - ``Visual Studio 11`` -> :generator:`Visual Studio 11 2012`
   - ``Visual Studio 12`` -> :generator:`Visual Studio 12 2013`

   This clarifies which generator goes with each Visual Studio
   version.  The old names are recognized for compatibility.

 * The :variable:`CMAKE_<LANG>_COMPILER_ID` value for Apple-provided
   Clang is now ``AppleClang``.  It must be distinct from upstream
   Clang because the version numbers differ.
   See policy :policy:`CMP0025`.

 * The :variable:`CMAKE_<LANG>_COMPILER_ID` value for ``qcc`` on QNX
   is now ``QCC``.  It must be distinct from ``GNU`` because the
   command-line options differ.  See policy :policy:`CMP0047`.

 * On 64-bit OS X the :variable:`CMAKE_HOST_SYSTEM_PROCESSOR` value
   is now correctly detected as ``x86_64`` instead of ``i386``.

 * On OS X, CMake learned to enable behavior specified by the
   :prop_tgt:`MACOSX_RPATH` target property by default.  This activates
   use of ``@rpath`` for runtime shared library searches.
   See policy :policy:`CMP0042`.

 * The :command:`build_command` command now returns a :manual:`cmake(1)`
   ``--build`` command line instead of a direct invocation of the native
   build tool.  When using ``Visual Studio`` generators, CMake and CTest
   no longer require :variable:`CMAKE_MAKE_PROGRAM` to be located up front.
   Selection of the proper msbuild or devenv tool is now performed as
   late as possible when the solution (``.sln``) file is available so
   it can depend on project content.

 * The :manual:`cmake(1)` ``--build`` command now shares its own stdout
   and stderr pipes with the native build tool by default.
   The ``--use-stderr`` option that once activated this is now ignored.

 * The ``$<C_COMPILER_ID:...>`` and ``$<CXX_COMPILER_ID:...>``
   :manual:`generator expressions <cmake-generator-expressions(7)>`
   used to perform case-insensitive comparison but have now been
   corrected to perform case-sensitive comparison.
   See policy :policy:`CMP0044`.

 * The builtin ``edit_cache`` target will no longer select
   :manual:`ccmake(1)` by default when no interactive terminal will
   be available (e.g. with :generator:`Ninja` or an IDE generator).
   Instead :manual:`cmake-gui(1)` will be preferred if available.

 * The :module:`ExternalProject` download step learned to
   re-attempt download in certain cases to be more robust to
   temporary network failure.

 * The :module:`FeatureSummary` no longer lists transitive
   dependencies since they were not directly requested by the
   current project.

 * The ``cmake-mode.el`` major Emacs editing mode has been cleaned
   up and enhanced in several ways.

 * Include directories specified in the
   :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` of :ref:`Imported Targets`
   are treated as ``SYSTEM`` includes by default when handled as
   :ref:`usage requirements <Include Directories and Usage Requirements>`.
	CMake 3.0 Release Notes
	***********************

	.. only:: html

	.. contents::

	Changes made since CMake 2.8.12 include the following.

	Documentation Changes
	=====================

	* The CMake documentation has been converted to reStructuredText and
	now transforms via Sphinx (`<http://sphinx-doc.org>`__) into man and
	html pages. This allows the documentation to be properly indexed
	and to contain cross-references.

	Conversion from the old internal documentation format was done by
	an automatic process so some documents may still contain artifacts.
	They will be updated incrementally over time.

	A basic reStructuredText processor has been implemented to support
	``cmake --help-command`` and similar command-line options.

	* New manuals were added:

	- :manual:`cmake-buildsystem(7)`
	- :manual:`cmake-commands(7)`, replacing ``cmakecommands(1)``
	and ``cmakecompat(1)``
	- :manual:`cmake-developer(7)`
	- :manual:`cmake-generator-expressions(7)`
	- :manual:`cmake-generators(7)`
	- :manual:`cmake-language(7)`
	- :manual:`cmake-modules(7)`, replacing ``cmakemodules(1)``
	- :manual:`cmake-packages(7)`
	- :manual:`cmake-policies(7)`, replacing ``cmakepolicies(1)``
	- :manual:`cmake-properties(7)`, replacing ``cmakeprops(1)``
	- :manual:`cmake-qt(7)`
	- :manual:`cmake-toolchains(7)`
	- :manual:`cmake-variables(7)`, replacing ``cmakevars(1)``

	* Release notes for CMake 3.0.0 and above will now be included with
	the html documentation.

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

	Syntax
	------

	* The CMake language has been extended with
	:ref:`Bracket Argument` and :ref:`Bracket Comment`
	syntax inspired by Lua long brackets::

	set(x [===[bracket argument]===] #[[bracket comment]])

	Content between equal-length open- and close-brackets is taken
	literally with no variable replacements.

	.. warning::
	This syntax change could not be made in a fully compatible
	way. No policy is possible because syntax parsing occurs before
	any chance to set a policy. Existing code using an unquoted
	argument that starts with an open bracket will be interpreted
	differently without any diagnostic. Fortunately the syntax is
	obscure enough that this problem is unlikely in practice.

	Generators
	----------

	* A new :generator:`CodeLite` extra generator is available
	for use with the Makefile or Ninja generators.

	* A new :generator:`Kate` extra generator is available
	for use with the Makefile or Ninja generators.

	* The :generator:`Ninja` generator learned to use ``ninja`` job pools
	when specified by a new :prop_gbl:`JOB_POOLS` global property.

	Commands
	--------

	* The :command:`add_library` command learned a new ``INTERFACE``
	library type. Interface libraries have no build rules but may
	have properties defining
	:manual:`usage requirements <cmake-buildsystem(7)>`
	and may be installed, exported, and imported. This is useful to
	create header-only libraries that have concrete link dependencies
	on other libraries.

	* The :command:`export()` command learned a new ``EXPORT`` mode that
	retrieves the list of targets to export from an export set configured
	by the :command:`install(TARGETS)` command ``EXPORT`` option. This
	makes it easy to export from the build tree the same targets that
	are exported from the install tree.

	* The :command:`export` command learned to work with multiple dependent
	export sets, thus allowing multiple packages to be built and exported
	from a single tree. The feature requires CMake to wait until the
	generation step to write the output file. This means one should not
	:command:`include` the generated targets file later during project
	configuration because it will not be available.
	Use :ref:`Alias Targets` instead. See policy :policy:`CMP0024`.

	* The :command:`install(FILES)` command learned to support
	:manual:`generator expressions <cmake-generator-expressions(7)>`
	in the list of files.

	* The :command:`project` command learned to set some version variables
	to values specified by the new ``VERSION`` option or to empty strings.
	See policy :policy:`CMP0048`.

	* The :command:`string` command learned a new ``CONCAT`` mode.
	It is particularly useful in combination with the new
	:ref:`Bracket Argument` syntax.

	* The :command:`unset` command learned a ``PARENT_SCOPE`` option
	matching that of the :command:`set` command.

	* The :command:`include_external_msproject` command learned
	to handle non-C++ projects like ``.vbproj`` or ``.csproj``.

	* The :command:`ctest_update` command learned to update work trees
	managed by the Perforce (p4) version control tool.

	* The :command:`message` command learned a ``DEPRECATION`` mode. Such
	messages are not issued by default, but may be issued as a warning if
	:variable:`CMAKE_WARN_DEPRECATED` is enabled, or as an error if
	:variable:`CMAKE_ERROR_DEPRECATED` is enabled.

	* The :command:`target_link_libraries` command now allows repeated use of
	the ``LINK_PUBLIC`` and ``LINK_PRIVATE`` keywords.

	Variables
	---------

	* Variable :variable:`CMAKE_FIND_NO_INSTALL_PREFIX` has been
	introduced to tell CMake not to add the value of
	:variable:`CMAKE_INSTALL_PREFIX` to the
	:variable:`CMAKE_SYSTEM_PREFIX_PATH` variable by default.
	This is useful when building a project that installs some
	of its own dependencies to avoid finding files it is about
	to replace.

	* Variable :variable:`CMAKE_STAGING_PREFIX` was introduced for use
	when cross-compiling to specify an installation prefix on the
	host system that differs from a :variable:`CMAKE_INSTALL_PREFIX`
	value meant for the target system.

	* Variable :variable:`CMAKE_SYSROOT` was introduced to specify the
	toolchain SDK installation prefix, typically for cross-compiling.
	This is used to pass a ``--sysroot`` option to the compiler and
	as a prefix searched by ``find_*`` commands.

	* Variable :variable:`CMAKE_<LANG>_COMPILER_TARGET` was introduced
	for use when cross-compiling to specify the target platform in the
	:ref:`toolchain file <Cross Compiling Toolchain>` specified by the
	:variable:`CMAKE_TOOLCHAIN_FILE` variable.
	This is used to pass an option such as ``--target=<triple>`` to some
	cross-compiling compiler drivers.

	* Variable :variable:`CMAKE_MAP_IMPORTED_CONFIG_<CONFIG>` has been
	introduced to optionally initialize the
	:prop_tgt:`MAP_IMPORTED_CONFIG_<CONFIG>` target property.

	Properties
	----------

	* The :prop_dir:`ADDITIONAL_MAKE_CLEAN_FILES` directory property
	learned to support
	:manual:`generator expressions <cmake-generator-expressions(7)>`.

	* A new directory property :prop_dir:`CMAKE_CONFIGURE_DEPENDS`
	was introduced to allow projects to specify additional
	files on which the configuration process depends. CMake will
	re-run at build time when one of these files is modified.
	Previously this was only possible to achieve by specifying
	such files as the input to a :command:`configure_file` command.

	* A new :ref:`Qt AUTORCC` feature replaces the need to
	invoke ``qt4_add_resources()`` by allowing ``.qrc`` files to
	be listed as target sources.

	* A new :ref:`Qt AUTOUIC` feature replaces the need to
	invoke ``qt4_wrap_ui()``.

	* Test properties learned to support
	:manual:`generator expressions <cmake-generator-expressions(7)>`.
	This is useful to specify per-configuration values for test
	properties like :prop_test:`REQUIRED_FILES` and
	:prop_test:`WORKING_DIRECTORY`.

	* A new :prop_test:`SKIP_RETURN_CODE` test property was introduced
	to tell :manual:`ctest(1)` to treat a particular test return code as
	if the test were not run. This is useful for test drivers to report
	that certain test requirements were not available.

	* New types of :ref:`Compatible Interface Properties` were introduced,
	namely the :prop_tgt:`COMPATIBLE_INTERFACE_NUMBER_MAX` and
	:prop_tgt:`COMPATIBLE_INTERFACE_NUMBER_MIN` for calculating numeric
	maximum and minimum values respectively.

	Modules
	-------

	* The :module:`CheckTypeSize` module ``check_type_size`` macro and
	the :module:`CheckStructHasMember` module ``check_struct_has_member``
	macro learned a new ``LANGUAGE`` option to optionally check C++ types.

	* The :module:`ExternalData` module learned to work with no
	URL templates if a local store is available.

	* The :module:`ExternalProject` function ``ExternalProject_Add``
	learned a new ``GIT_SUBMODULES`` option to specify a subset
	of available submodules to checkout.

	* A new :module:`FindBacktrace` module has been added to support
	:command:`find_package(Backtrace)` calls.

	* A new :module:`FindLua` module has been added to support
	:command:`find_package(Lua)` calls.

	* The :module:`FindBoost` module learned a new ``Boost_NAMESPACE``
	option to change the ``boost`` prefix on library names.

	* The :module:`FindBoost` module learned to control search
	for libraries with the ``g`` tag (for MS debug runtime) with
	a new ``Boost_USE_DEBUG_RUNTIME`` option. It is ``ON`` by
	default to preserve existing behavior.

	* The :module:`FindJava` and :module:`FindJNI` modules learned
	to use a ``JAVA_HOME`` CMake variable or environment variable,
	and then try ``/usr/libexec/java_home`` on OS X.

	* The :module:`UseJava` module ``add_jar`` function learned a new
	``MANIFEST`` option to pass the ``-m`` option to ``jar``.

	* A new :module:`CMakeFindDependencyMacro` module was introduced with
	a ``find_dependency`` macro to find transitive dependencies in
	a :manual:`package configuration file <cmake-packages(7)>`. Such
	dependencies are omitted by the listing of the :module:`FeatureSummary`
	module.

	* The :module:`FindQt4` module learned to create :ref:`Imported Targets`
	for Qt executables. This helps disambiguate when using multiple
	:manual:`Qt versions <cmake-qt(7)>` in the same buildsystem.

	* The :module:`FindRuby` module learned to search for Ruby 2.0 and 2.1.

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

	* New ``$<PLATFORM_ID>`` and ``$<PLATFORM_ID:...>``
	:manual:`generator expressions <cmake-generator-expressions(7)>`
	have been added.

	* The ``$<CONFIG>``
	:manual:`generator expression <cmake-generator-expressions(7)>` now has
	a variant which takes no argument. This is equivalent to the
	``$<CONFIGURATION>`` expression.

	* New ``$<UPPER_CASE:...>`` and ``$<LOWER_CASE:...>``
	:manual:`generator expressions <cmake-generator-expressions(7)>`
	generator expressions have been added.

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

	Other
	-----

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

	* The :manual:`ccmake(1)` dialog learned to honor the
	:prop_cache:`STRINGS` cache entry property to cycle through
	the enumerated list of possible values.

	* The :manual:`cmake-gui(1)` dialog learned to remember window
	settings between sessions.

	* The :manual:`cmake-gui(1)` dialog learned to remember the type
	of a cache entry for completion in the ``Add Entry`` dialog.

	New Diagnostics
	===============

	* Directories named in the :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES`
	target property of imported targets linked conditionally by a
	:manual:`generator expression <cmake-generator-expressions(7)>`
	were not checked for existence. Now they are checked.
	See policy :policy:`CMP0027`.

	* Build target names must now match a validity pattern and may no longer
	conflict with CMake-defined targets. See policy :policy:`CMP0037`.

	* Build targets that specify themselves as a link dependency were
	silently accepted but are now diagnosed. See :policy:`CMP0038`.

	* The :command:`target_link_libraries` command used to silently ignore
	calls specifying as their first argument build targets created by
	:command:`add_custom_target` but now diagnoses this mistake.
	See policy :policy:`CMP0039`.

	* The :command:`add_custom_command` command used to silently ignore
	calls specifying the ``TARGET`` option with a non-existent target
	but now diagnoses this mistake. See policy :policy:`CMP0040`.

	* Relative paths in the :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES`
	target property used to be silently accepted if they contained a
	:manual:`generator expression <cmake-generator-expressions(7)>`
	but are now rejected. See policy :policy:`CMP0041`.

	* The :command:`get_target_property` command learned to reject calls
	specifying a non-existent target. See policy :policy:`CMP0045`.

	* The :command:`add_dependencies` command learned to reject calls
	specifying a dependency on a non-existent target.
	See policy :policy:`CMP0046`.

	* Link dependency analysis learned to assume names containing ``::``
	refer to :ref:`Alias Targets` or :ref:`Imported Targets`. It will
	now produce an error if such a linked target is missing. Previously
	in this case CMake generated a link line that failed at build time.
	See policy :policy:`CMP0028`.

	* When the :command:`project` or :command:`enable_language` commands
	initialize support for a language, it is now an error if the full
	path to the compiler cannot be found and stored in the corresponding
	:variable:`CMAKE_<LANG>_COMPILER` variable. This produces nicer error
	messages up front and stops processing when no working compiler
	is known to be available.

	* Target sources specified with the :command:`add_library` or
	:command:`add_executable` command learned to reject items which
	require an undocumented extra layer of variable expansion.
	See policy :policy:`CMP0049`.

	* Use of :command:`add_custom_command` undocumented ``SOURCE``
	signatures now results in an error. See policy :policy:`CMP0050`.

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

	* Compatibility options supporting code written for CMake versions
	prior to 2.4 have been removed.

	* Several long-outdated commands that should no longer be called
	have been disallowed in new code by policies:

	- Policy :policy:`CMP0029` disallows :command:`subdir_depends`
	- Policy :policy:`CMP0030` disallows :command:`use_mangled_mesa`
	- Policy :policy:`CMP0031` disallows :command:`load_command`
	- Policy :policy:`CMP0032` disallows :command:`output_required_files`
	- Policy :policy:`CMP0033` disallows :command:`export_library_dependencies`
	- Policy :policy:`CMP0034` disallows :command:`utility_source`
	- Policy :policy:`CMP0035` disallows :command:`variable_requires`
	- Policy :policy:`CMP0036` disallows :command:`build_name`

	* The :manual:`cmake(1)` ``-i`` wizard mode has been removed.
	Instead use an interactive dialog such as :manual:`ccmake(1)`
	or use the ``-D`` option to set cache values from the command line.

	* The builtin documentation formatters that supported command-line
	options such as ``--help-man`` and ``--help-html`` have been removed
	in favor of the above-mentioned new documentation system. These and
	other command-line options that used to generate man- and html-
	formatted pages no longer work. The :manual:`cmake(1)`
	``--help-custom-modules`` option now produces a warning at runtime
	and generates a minimal document that reports the limitation.

	* The :prop_dir:`COMPILE_DEFINITIONS_<CONFIG>` directory properties and the
	:prop_tgt:`COMPILE_DEFINITIONS_<CONFIG>` target properties have been
	deprecated. Instead set the corresponding :prop_dir:`COMPILE_DEFINITIONS`
	directory property or :prop_tgt:`COMPILE_DEFINITIONS` target property and
	use :manual:`generator expressions <cmake-generator-expressions(7)>` like
	``$<CONFIG:...>`` to specify per-configuration definitions.
	See policy :policy:`CMP0043`.

	* The :prop_tgt:`LOCATION` target property should no longer be read from
	non-IMPORTED targets. It does not make sense in multi-configuration
	generators since the build configuration is not known while configuring
	the project. It has been superseded by the ``$<TARGET_FILE>`` generator
	expression. See policy :policy:`CMP0026`.

	* The :prop_tgt:`COMPILE_FLAGS` target property is now documented
	as deprecated, though no warning is issued. Use the
	:prop_tgt:`COMPILE_OPTIONS` target property or the
	:command:`target_compile_options` command instead.

	* The :module:`GenerateExportHeader` module ``add_compiler_export_flags``
	function is now deprecated. It has been superseded by the
	:prop_tgt:`<LANG>_VISIBILITY_PRESET` and
	:prop_tgt:`VISIBILITY_INLINES_HIDDEN` target properties.

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

	* The version scheme was changed to use only two components for
	the feature level instead of three. The third component will
	now be used for bug-fix releases or the date of development versions.
	See the :variable:`CMAKE_VERSION` variable documentation for details.

	* The default install locations of CMake itself on Windows and
	OS X no longer contain the CMake version number. This allows
	for easy replacement without re-generating local build trees
	manually.

	* Generators for Visual Studio 10 (2010) and later were renamed to
	include the product year like generators for older VS versions:

	- ``Visual Studio 10`` -> :generator:`Visual Studio 10 2010`
	- ``Visual Studio 11`` -> :generator:`Visual Studio 11 2012`
	- ``Visual Studio 12`` -> :generator:`Visual Studio 12 2013`

	This clarifies which generator goes with each Visual Studio
	version. The old names are recognized for compatibility.

	* The :variable:`CMAKE_<LANG>_COMPILER_ID` value for Apple-provided
	Clang is now ``AppleClang``. It must be distinct from upstream
	Clang because the version numbers differ.
	See policy :policy:`CMP0025`.

	* The :variable:`CMAKE_<LANG>_COMPILER_ID` value for ``qcc`` on QNX
	is now ``QCC``. It must be distinct from ``GNU`` because the
	command-line options differ. See policy :policy:`CMP0047`.

	* On 64-bit OS X the :variable:`CMAKE_HOST_SYSTEM_PROCESSOR` value
	is now correctly detected as ``x86_64`` instead of ``i386``.

	* On OS X, CMake learned to enable behavior specified by the
	:prop_tgt:`MACOSX_RPATH` target property by default. This activates
	use of ``@rpath`` for runtime shared library searches.
	See policy :policy:`CMP0042`.

	* The :command:`build_command` command now returns a :manual:`cmake(1)`
	``--build`` command line instead of a direct invocation of the native
	build tool. When using ``Visual Studio`` generators, CMake and CTest
	no longer require :variable:`CMAKE_MAKE_PROGRAM` to be located up front.
	Selection of the proper msbuild or devenv tool is now performed as
	late as possible when the solution (``.sln``) file is available so
	it can depend on project content.

	* The :manual:`cmake(1)` ``--build`` command now shares its own stdout
	and stderr pipes with the native build tool by default.
	The ``--use-stderr`` option that once activated this is now ignored.

	* The ``$<C_COMPILER_ID:...>`` and ``$<CXX_COMPILER_ID:...>``
	:manual:`generator expressions <cmake-generator-expressions(7)>`
	used to perform case-insensitive comparison but have now been
	corrected to perform case-sensitive comparison.
	See policy :policy:`CMP0044`.

	* The builtin ``edit_cache`` target will no longer select
	:manual:`ccmake(1)` by default when no interactive terminal will
	be available (e.g. with :generator:`Ninja` or an IDE generator).
	Instead :manual:`cmake-gui(1)` will be preferred if available.

	* The :module:`ExternalProject` download step learned to
	re-attempt download in certain cases to be more robust to
	temporary network failure.

	* The :module:`FeatureSummary` no longer lists transitive
	dependencies since they were not directly requested by the
	current project.

	* The ``cmake-mode.el`` major Emacs editing mode has been cleaned
	up and enhanced in several ways.

	* Include directories specified in the
	:prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` of :ref:`Imported Targets`
	are treated as ``SYSTEM`` includes by default when handled as
	:ref:`usage requirements <Include Directories and Usage Requirements>`.