path: root/Help/release/3.1.0.rst

CMake 3.1.0 Release Notes
*************************

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Changes made since CMake 3.0.0 include the following.

* The :module:`CheckFortranSourceCompiles` module was added to
  provide a ``CHECK_Fortran_SOURCE_COMPILES`` macro.

* The :command:`add_custom_command` command learned to interpret
  :manual:`cmake-generator-expressions(7)` in arguments to ``DEPENDS``.

* The :module:`FindOpenCL` module was introduced.

* The :manual:`cmake(1)` ``-E tar`` command learned to support
  lzma-compressed files.

* :ref:`Object Libraries` may now have extra sources that do not
  compile to object files so long as they would not affect linking
  of a normal library (e.g. ``.dat`` is okay but not ``.def``).

* The :module:`CMakeDetermineVSServicePack` module now warns that
  it is deprecated and should not longer be used.  Use the
  :variable:`CMAKE_<LANG>_COMPILER_VERSION` variable instead.

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

* The :manual:`cmake-gui(1)` learned to capture output from child
  processes started by the :command:`execute_process` command
  and display it in the output window.

* The :module:`CMakePackageConfigHelpers` module
  :command:`configure_package_config_file` command learned a new
  ``INSTALL_PREFIX`` option to generate package configuration files
  meant for a prefix other than :variable:`CMAKE_INSTALL_PREFIX`.

* Policy :policy:`CMP0052` introduced to control directories in the
  :prop_tgt:`INTERFACE_INCLUDE_DIRECTORIES` of exported targets.

* The :manual:`cmake-language(7)` syntax for :ref:`Variable References` and
  :ref:`Escape Sequences` was simplified in order to allow a much faster
  implementation.  See policy :policy:`CMP0053`.

* New :prop_tgt:`CXX_STANDARD` and :prop_tgt:`CXX_EXTENSIONS` target
  properties may specify values which CMake uses to compute required
  compile options such as ``-std=c++11`` or ``-std=gnu++11``. The
  :variable:`CMAKE_CXX_STANDARD` and :variable:`CMAKE_CXX_EXTENSIONS`
  variables may be set to initialize the target properties.

* New :prop_tgt:`C_STANDARD` and :prop_tgt:`C_EXTENSIONS` target
  properties may specify values which CMake uses to compute required
  compile options such as ``-std=c11`` or ``-std=gnu11``. The
  :variable:`CMAKE_C_STANDARD` and :variable:`CMAKE_C_EXTENSIONS`
  variables may be set to initialize the target properties.

* New :prop_tgt:`COMPILE_FEATURES` target property may contain a list
  of features required to compile a target.  CMake uses this
  information to ensure that the compiler in use is capable of building
  the target, and to add any necessary compile flags to support language
  features.

* New :command:`target_compile_features` command allows populating the
  :prop_tgt:`COMPILE_FEATURES` target property, just like any other
  build variable.

* New ``COMPILE_FEATURES``
  :manual:`generator expression <cmake-generator-expressions(7)>` allows
  setting build properties based on available compiler features.

* :manual:`cpack(1)` gained ``7Z`` and ``TXZ`` generators supporting
  lzma-compressed archives.

* The :module:`CPackDeb` module learned a new
  :variable:`CPACK_DEBIAN_COMPRESSION_TYPE` variable to set the
  tarball compression type.

* :manual:`cpack(1)` gained an ``IFW`` generator to package using
  Qt Framework Installer tools.  See the :module:`CPackIFW` module.

* The :command:`ctest_coverage` command learned to read variable
  ``CTEST_COVERAGE_EXTRA_FLAGS`` to set ``CoverageExtraFlags``.

* The :command:`ctest_coverage` command learned to support
  Intel coverage files with the ``codecov`` tool.

* The :command:`ctest_memcheck` command learned to support sanitizer
  modes, including ``AddressSanitizer``, ``MemorySanitizer``,
  ``ThreadSanitizer``, and ``UndefinedBehaviorSanitizer``.
  Options may be set using the new
  :variable:`CTEST_MEMORYCHECK_SANITIZER_OPTIONS` variable.

* Add a `CMAKE_NINJA_DEPTYPE_<LANG>` variable so that compilers may set the
  deptype for use in Ninja other than those CMake itself knows about.

* The :variable:`CMAKE_GENERATOR_TOOLSET` variable may now be
  initialized in a toolchain file specified by the
  :variable:`CMAKE_TOOLCHAIN_FILE` variable.  This is useful
  when cross-compiling with the Xcode or Visual Studio
  generators.

* The :module:`GenerateExportHeader` module ``generate_export_header``
  function learned to allow use with :ref:`Object Libraries`.

* The :module:`ExternalData` module learned to tolerate a ``DATA{}``
  reference to a missing source file with a warning instead of
  rejecting it with an error.  This helps developers write new
  ``DATA{}`` references to test reference outputs that have not
  yet been created.

* The :module:`ExternalProject` module learned to support lzma-compressed
  source tarballs with ``.7z``, ``.tar.xz``, and ``.txz`` extensions.

* The :module:`ExternalProject` module ``ExternalProject_Add`` command
  learned a new ``BUILD_ALWAYS`` option to cause the external project
  build step to run every time the host project is built.

* The :module:`ExternalProject` module ``ExternalProject_Add`` command
  learned a new ``EXCLUDE_FROM_ALL`` option to cause the external
  project target to have the :prop_tgt:`EXCLUDE_FROM_ALL` target
  property set.

* The :module:`ExternalProject` module ``ExternalProject_Add_Step`` command
  learned a new ``EXCLUDE_FROM_MAIN`` option to cause the step to not be
  a direct dependency of the main external project target.

* The :module:`ExternalProject` module ``ExternalProject_Add`` command
  learned a new ``DOWNLOAD_NO_PROGRESS`` option to disable progress
  output while downloading the source tarball.

* The :manual:`cmake-language(7)` internal implementation of generator
  expression and list expansion parsers have been optimized and shows
  non-trivial speedup on large projects.

* The :module:`FeatureSummary` module ``feature_summary`` API
  learned to accept multiple values for the ``WHAT`` option and
  combine them appropriately.

* The :command:`file(STRINGS)` command gained a new ``ENCODING``
  option to enable extraction of ``UTF-8`` strings.

* The :module:`FindCUDA` module learned to support ``fatbin`` and ``cubin``
  modules.

* The :module:`FindGTest` module ``gtest_add_tests`` macro learned
  a new ``AUTO`` option to automatically read the :prop_tgt:`SOURCES`
  target property of the test executable and scan the source files
  for tests to be added.

* The :module:`FindHg` module gained a new ``Hg_WC_INFO`` macro to
  help run ``hg`` to extract information about a Mercurial work copy.

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

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

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

* The :module:`FindOpenGL` module now provides imported targets
  ``OpenGL::GL`` and ``OpenGL::GLU`` when the libraries are found.

* The :module:`FindOpenMP` module learned to support Fortran.

* The :module:`FindPkgConfig` module learned to use the ``PKG_CONFIG``
  environment variable value as the ``pkg-config`` executable, if set.

* The :module:`FindVTK` module dropped support for finding VTK 4.0.
  It is now a thin-wrapper around ``find_package(VTK ... NO_MODULE)``.
  This produces much clearer error messages when VTK is not found.

* The :module:`BundleUtilities` module learned to resolve and replace
  ``@rpath`` placeholders on OS X to correctly bundle applications
  using them.

* The :prop_tgt:`INTERFACE_LINK_LIBRARIES` target property now supports
  a ``$<LINK_ONLY:...>``
  :manual:`generator expression <cmake-generator-expressions(7)>`.

* The :command:`if` command no longer automatically dereferences
  variables named in quoted or bracket arguments.  See policy
  :policy:`CMP0054`.

* The :command:`install` command learned a ``MESSAGE_NEVER`` option
  to avoid output during installation.

* The :variable:`CMAKE_INSTALL_MESSAGE` variable was introduced to
  optionally reduce output installation.

* The :module:`InstallRequiredSystemLibraries` module gained a new
  ``CMAKE_INSTALL_OPENMP_LIBRARIES`` option to install MSVC OpenMP
  runtime libraries.

* The Makefile generators learned to use response files with GNU tools
  on Windows to pass library directories and names to the linker.

* When generating linker command-lines, CMake now avoids repeating
  items corresponding to SHARED library targets.

* The :module:`WriteCompilerDetectionHeader` module was added to allow
  creation of a portable header file for compiler optional feature detection.

* New :prop_tgt:`COMPILE_PDB_NAME` and
  :prop_tgt:`COMPILE_PDB_OUTPUT_DIRECTORY` target properties
  were introduced to specify the MSVC compiler program database
  file location (``cl /Fd``).  This complements the existing
  :prop_tgt:`PDB_NAME` and :prop_tgt:`PDB_OUTPUT_DIRECTORY`
  target properties that specify the linker program database
  file location (``link /pdb``).

* In CMake 3.0 the :command:`target_link_libraries` command
  accidentally began allowing unquoted arguments to use
  :manual:`generator expressions <cmake-generator-expressions(7)>`
  containing a (``;`` separated) list within them.  For example::

    set(libs B C)
    target_link_libraries(A PUBLIC $<BUILD_INTERFACE:${libs}>)

  This is equivalent to writing::

    target_link_libraries(A PUBLIC $<BUILD_INTERFACE:B C>)

  and was never intended to work.  It did not work in CMake 2.8.12.
  Such generator expressions should be in quoted arguments::

    set(libs B C)
    target_link_libraries(A PUBLIC "$<BUILD_INTERFACE:${libs}>")

  CMake 3.1 again requires the quotes for this to work correctly.

* Support for the Open Watcom compiler has been overhauled.
  The :variable:`CMAKE_<LANG>_COMPILER_ID` is now ``OpenWatcom``,
  and the :variable:`CMAKE_<LANG>_COMPILER_VERSION` now uses
  the Open Watcom external version numbering.  The external
  version numbers are lower than the internal version number
  by 11.

* The :command:`export(PACKAGE)` command learned to check the
  :variable:`CMAKE_EXPORT_NO_PACKAGE_REGISTRY` variable to skip
  exporting the package.

* The :command:`find_package` command learned to check the
  :variable:`CMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY` and
  :variable:`CMAKE_FIND_PACKAGE_NO_SYSTEM_PACKAGE_REGISTRY`
  variables to skip searching the package registries.

* The :command:`string` command learned a new ``GENEX_STRIP`` subcommand
  which removes
  :manual:`generator expression <cmake-generator-expressions(7)>`.

* The :command:`string` command learned a new ``UUID`` subcommand
  to generate a univerally unique identifier.

* A new :prop_tgt:`INTERFACE_SOURCES` target property was introduced. This is
  consumed by dependent targets, which compile and link the listed sources.

* The :command:`target_sources` command was added to add to the
  :prop_tgt:`SOURCES` target property.

* The :prop_tgt:`SOURCES` target property now contains
  :manual:`generator expression <cmake-generator-expressions(7)>`
  such as ``TARGET_OBJECTS`` when read at configure time, if
  policy :policy:`CMP0051` is ``NEW``.

* The :prop_tgt:`SOURCES` target property now generally supports
  :manual:`generator expression <cmake-generator-expressions(7)>`.  The
  generator expressions may be used in the :command:`add_library` and
  :command:`add_executable` commands.

* It is now possible to write and append to the :prop_tgt:`SOURCES` target
  property.  The :variable:`CMAKE_DEBUG_TARGET_PROPERTIES` variable may be
  used to trace the origin of sources.

* The :module:`UseSWIG` module learned to detect the module name
  from ``.i`` source files if possible to avoid the need to set
  the ``SWIG_MODULE_NAME`` source file property explicitly.

* Callbacks established by the :command:`variable_watch` command will no
  longer receive the ``ALLOWED_UNKNOWN_READ_ACCESS`` access type when
  the undocumented ``CMAKE_ALLOW_UNKNOWN_VARIABLE_READ_ACCESS`` variable is
  set.  Uninitialized variable accesses will always be reported as
  ``UNKNOWN_READ_ACCESS``.

* A :generator:`Visual Studio 14` generator was added.

* The Visual Studio generators for versions 8 (2005) and above
  learned to read the target platform name from a new
  :variable:`CMAKE_GENERATOR_PLATFORM` variable when it is
  not specified as part of the generator name.  The platform
  name may be specified on the :manual:`cmake(1)` command line
  with the ``-A`` option, e.g. ``-G "Visual Studio 12 2013" -A x64``.

* Visual Studio generators for VS 8 and later learned to support
  the ``ASM_MASM`` language.

* Generators for Visual Studio 10 (2010) and above learned to generate
  projects for NVIDIA Nsight Tegra Visual Studio Edition.  One may set
  the :variable:`CMAKE_SYSTEM_NAME` variable to ``Android`` on the
  :manual:`cmake(1)` command-line or in a :variable:`CMAKE_TOOLCHAIN_FILE`
  to activate this platform.

* A :prop_sf:`VS_DEPLOYMENT_CONTENT` source file property was added
  to tell the Visual Studio generators to mark content for deployment
  in Windows Phone and Windows Store projects.

* The Visual Studio generators learned to treat ``.hlsl`` source
  files as High Level Shading Language sources (using ``FXCompile``
  in ``.vcxproj`` files).  A :prop_sf:`VS_SHADER_TYPE` source file
  property was added to specify the Shader Type.

* The :prop_tgt:`VS_WINRT_COMPONENT` target property was created to
  tell Visual Studio generators to compile a shared library as a
  Windows Runtime (WinRT) component.

* Generators for Visual Studio 11 (2012) and above learned to generate
  projects for Windows Phone and Windows Store.  One may set the
  :variable:`CMAKE_SYSTEM_NAME` variable to ``WindowsPhone``
  or ``WindowsStore`` on the :manual:`cmake(1)` command-line
  or in a :variable:`CMAKE_TOOLCHAIN_FILE` to activate these platforms.
  Also set :variable:`CMAKE_SYSTEM_VERSION` to ``8.0`` or ``8.1`` to
  specify the version of Windows to be targeted.

* The :manual:`cpack(1)` ``WiX`` generator learned to support
  a :prop_inst:`CPACK_WIX_ACL` installed file property to
  specify an Access Control List.

* The :generator:`Xcode` generator learned to check source
  file properties  :prop_sf:`XCODE_EXPLICIT_FILE_TYPE` and
  :prop_sf:`XCODE_LAST_KNOWN_FILE_TYPE` for a custom Xcode
  file reference type.