CMake 3.16.0-rc4 is ready for testing

Announcements
1

I am proud to announce the fourth CMake 3.16 release candidate.
https://cmake.org/download/

Documentation is available at:
https://cmake.org/cmake/help/v3.16

Release notes appear below and are also published at
https://cmake.org/cmake/help/v3.16/release/3.16.html

Some of the more significant changes in CMake 3.16 are:

  • CMake learned to support the Objective C (“OBJC”) and Objective
    C++ (“OBJCXX”) languages. They may be enabled via the “project()”
    and “enable_language()” commands. When “OBJC” or “OBJCXX” is
    enabled, source files with the “.m” or “.mm”, respectively, will be
    compiled as Objective C or C++. Otherwise they will be treated as
    plain C++ sources as they were before.

  • The “target_precompile_headers()” command was added to specify a
    list of headers to precompile for faster compilation times.

  • The “UNITY_BUILD” target property was added to tell generators to
    batch include source files for faster compilation times.

  • The “find_file()”, “find_library()”, “find_path()”,
    “find_package()”, and “find_program()” commands have learned to
    check the following variables to control searching

    • “CMAKE_FIND_USE_CMAKE_ENVIRONMENT_PATH” - Controls the searching
      the cmake-specific environment variables.

    • “CMAKE_FIND_USE_CMAKE_PATH” - Controls the searching the cmake-
      specific cache variables.

    • “CMAKE_FIND_USE_CMAKE_SYSTEM_PATH” - Controls the searching
      cmake platform specific variables.

    • “CMAKE_FIND_USE_PACKAGE_ROOT_PATH” - Controls the searching of
      “_ROOT” variables.

    • “CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH” - Controls the
      searching the standard system environment variables.

  • The “file()” command learned a new sub-command,
    “GET_RUNTIME_DEPENDENCIES”, which allows you to recursively get the
    list of libraries linked by an executable or library. This sub-
    command is intended as a replacement for “GetPrerequisites”.

  • “ctest(1)” now has the ability to serialize tests based on
    resource requirements for each test. See Resource Allocation for
    details.

  • On AIX, executables using the “ENABLE_EXPORTS” target property now
    produce a linker import file with a “.imp” extension in addition to
    the executable file. Plugins (created via “add_library()” with the
    “MODULE” option) that use “target_link_libraries()” to link to the
    executable for its symbols are now linked using the import file. The
    “install(TARGETS)” command now installs the import file as an
    “ARCHIVE” artifact.

  • On AIX, runtime linking is no longer enabled by default. CMake
    provides the linker enough information to resolve all symbols up
    front. One may manually enable runtime linking for shared libraries
    and/or loadable modules by adding “-Wl,-G” to their link flags (e.g.
    in the “CMAKE_SHARED_LINKER_FLAGS” or “CMAKE_MODULE_LINKER_FLAGS”
    variable). One may manually enable runtime linking for executables
    by adding “-Wl,-brtl” to their link flags (e.g. in the
    “CMAKE_EXE_LINKER_FLAGS” variable).

  • “cmake(1)” “-E” now supports “true” and “false” commands, which do
    nothing while returning exit codes of 0 and 1, respectively.

  • “cmake(1)” gained a “–trace-redirect=” command line option
    that can be used to redirect “–trace” output to a file instead of
    “stderr”.

  • The “cmake(1)” “–loglevel” command line option has been renamed
    to “–log-level” to make it consistent with the naming of other
    command line options. The “–loglevel” option is still supported to
    preserve backward compatibility.

  • The “CMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY” variable has been
    deprecated. Use the “CMAKE_FIND_USE_PACKAGE_REGISTRY” variable
    instead.

  • The “GetPrerequisites” module has been deprecated, as it has been
    superceded by “file(GET_RUNTIME_DEPENDENCIES)”.

CMake 3.16 Release Notes

Changes made since CMake 3.15 include the following.

New Features

Languages

  • CMake learned to support the Objective C (“OBJC”) and Objective
    C++ (“OBJCXX”) languages. They may be enabled via the “project()”
    and “enable_language()” commands. When “OBJC” or “OBJCXX” is
    enabled, source files with the “.m” or “.mm”, respectively, will be
    compiled as Objective C or C++. Otherwise they will be treated as
    plain C++ sources as they were before.

Compilers

  • The “Clang” compiler is now supported on “Solaris”.

Platforms

  • On AIX, executables using the “ENABLE_EXPORTS” target property now
    produce a linker import file with a “.imp” extension in addition to
    the executable file. Plugins (created via “add_library()” with the
    “MODULE” option) that use “target_link_libraries()” to link to the
    executable for its symbols are now linked using the import file. The
    “install(TARGETS)” command now installs the import file as an
    “ARCHIVE” artifact.

  • On AIX, runtime linking is no longer enabled by default. CMake
    provides the linker enough information to resolve all symbols up
    front. One may manually enable runtime linking for shared libraries
    and/or loadable modules by adding “-Wl,-G” to their link flags (e.g.
    in the “CMAKE_SHARED_LINKER_FLAGS” or “CMAKE_MODULE_LINKER_FLAGS”
    variable). One may manually enable runtime linking for executables
    by adding “-Wl,-brtl” to their link flags (e.g. in the
    “CMAKE_EXE_LINKER_FLAGS” variable).

Command-Line

  • “cmake(1)” “-E” now supports “true” and “false” commands, which do
    nothing while returning exit codes of 0 and 1, respectively.

  • “cmake(1)” gained a “–trace-redirect=” command line option
    that can be used to redirect “–trace” output to a file instead of
    “stderr”.

  • The “cmake(1)” “–loglevel” command line option has been renamed
    to “–log-level” to make it consistent with the naming of other
    command line options. The “–loglevel” option is still supported to
    preserve backward compatibility.

Commands

  • The “add_test()” command learned the option “COMMAND_EXPAND_LISTS”
    which causes lists in the “COMMAND” argument to be expanded,
    including lists created by generator expressions.

  • The “file()” command learned a new sub-command,
    “GET_RUNTIME_DEPENDENCIES”, which allows you to recursively get the
    list of libraries linked by an executable or library. This sub-
    command is intended as a replacement for “GetPrerequisites”.

  • The “find_file()”, “find_library()”, “find_path()”,
    “find_package()”, and “find_program()” commands have learned to
    check the following variables to control searching

    • “CMAKE_FIND_USE_CMAKE_ENVIRONMENT_PATH” - Controls the searching
      the cmake-specific environment variables.

    • “CMAKE_FIND_USE_CMAKE_PATH” - Controls the searching the cmake-
      specific cache variables.

    • “CMAKE_FIND_USE_CMAKE_SYSTEM_PATH” - Controls the searching
      cmake platform specific variables.

    • “CMAKE_FIND_USE_PACKAGE_ROOT_PATH” - Controls the searching of
      “_ROOT” variables.

    • “CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH” - Controls the
      searching the standard system environment variables.

  • The “find_package()” command has learned to check the following
    variables to control searching

    • “CMAKE_FIND_USE_PACKAGE_REGISTRY” - Controls the searching the
      cmake user registry.

  • The “message()” command learned indentation control with the new
    “CMAKE_MESSAGE_INDENT” variable.

  • The “target_precompile_headers()” command was added to specify a
    list of headers to precompile for faster compilation times.

Variables

  • The “CMAKE_CUDA_RESOLVE_DEVICE_SYMBOLS” variable has been
    introduced to optionally initialize the
    “CUDA_RESOLVE_DEVICE_SYMBOLS” target property.

  • The “CMAKE_ECLIPSE_RESOURCE_ENCODING” variable was added to
    specify the resource encoding for the the “Eclipse CDT4” extra
    generator.

Properties

  • The “BUILD_RPATH” and “INSTALL_RPATH” target properties now
    support “generator expressions”.

  • The “INSTALL_REMOVE_ENVIRONMENT_RPATH” target property was added
    to remove compiler-defined “RPATH” entries from a target. This
    property is initialized by the
    “CMAKE_INSTALL_REMOVE_ENVIRONMENT_RPATH” variable.

  • The “PRECOMPILE_HEADERS” target property was added to specify a
    list of headers to precompile for faster compilation times. Set it
    using the “target_precompile_headers()” command.

  • The “UNITY_BUILD” target property was added to tell generators to
    batch include source files for faster compilation times.

  • The “VS_CONFIGURATION_TYPE” target property now supports
    “generator expressions”.

  • The “VS_DPI_AWARE” target property was added to tell Visual Studio
    Generators to set the “EnableDpiAwareness” property in “.vcxproj”
    files.

  • The “XCODE_SCHEME_DEBUG_DOCUMENT_VERSIONING” target property was
    added to tell the “Xcode” generator to set the value of the “Allow
    debugging when using document Versions Browser” schema option.

Modules

  • The “FindDoxygen” module “doxygen_add_docs()” command gained a new
    “USE_STAMP_FILE” option. When this option present, the custom
    target created by the command will only re-run Doxygen if any of the
    source files have changed since the last successful run.

  • The “FindGnuTLS” module now provides an imported target.

  • The “FindPackageHandleStandardArgs” module
    “find_package_handle_standard_args()” command gained a new
    “REASON_FAILURE_MESSAGE” option to specify a message giving the
    reason for the failure.

  • The “FindPkgConfig” module “pkg_search_module()” macro now defines
    a “_MODULE_NAME” result variable containing the first
    matching module name.

  • The “FindPython3” and “FindPython” modules gained options to
    control which “ABIs” will be searched.

  • The “FindPython3”, “FindPython2”, and “FindPython” modules now
    support direct specification of artifacts via cache entries.

Autogen

  • When using “AUTOMOC”, CMake now generates the “-p” path prefix
    option for “moc”. This ensures that “moc” output files are
    identical on different build setups (given, that the headers
    compiled by “moc” are in an “include directory”). Also it ensures
    that “moc” output files will compile correctly when the source
    and/or build directory is a symbolic link.

    The “moc” path prefix generation behavior can be configured by
    setting the new “CMAKE_AUTOMOC_PATH_PREFIX” variable and/or
    “AUTOMOC_PATH_PREFIX” target property.

CTest

  • “ctest(1)” now has the ability to serialize tests based on
    resource requirements for each test. See Resource Allocation for
    details.

  • A new test property, “SKIP_REGULAR_EXPRESSION”, has been added.
    This property is similar to “FAIL_REGULAR_EXPRESSION” and
    “PASS_REGULAR_EXPRESSION”, but with the same meaning as
    “SKIP_RETURN_CODE”. This is useful, for example, in cases where the
    user has no control over the return code of the test. For example,
    in Catch2, the return value is the number of assertion failed,
    therefore it is impossible to use it for “SKIP_RETURN_CODE”.

CPack

  • CPack variable “CPACK_INSTALL_CMAKE_CONFIGURATIONS” was added to
    control what configurations are to be packaged for multi-
    configuration CMake generators.

  • The “CPack DEB Generator” is now able to format generic text
    (usually used as the description for multiple CPack generators)
    according to the Debian Policy Manual. See the
    “CPACK_PACKAGE_DESCRIPTION_FILE” and
    “CPACK_DEBIAN__DESCRIPTION” variables.

  • The “CPack Archive Generator” learned to generate “.tar.zst”
    packages with Zstandard compression.

Deprecated and Removed Features

  • An explicit deprecation diagnostic was added for policy “CMP0067”
    (“CMP0066” and below were already deprecated). The “cmake-
    policies(7)” manual explains that the OLD behaviors of all policies
    are deprecated and that projects should port to the NEW behaviors.

  • The “CMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY” variable has been
    deprecated. Use the “CMAKE_FIND_USE_PACKAGE_REGISTRY” variable
    instead.

  • The “GetPrerequisites” module has been deprecated, as it has been
    superceded by “file(GET_RUNTIME_DEPENDENCIES)”.

  • The “CPACK_INSTALL_SCRIPT” variable has been deprecated in favor
    of the new, more accurately named “CPACK_INSTALL_SCRIPTS” variable.

Other Changes

  • The “cmake(1)” "-C " option now evaluates the
    initial cache script with “CMAKE_SOURCE_DIR” and “CMAKE_BINARY_DIR”
    set to the top-level source and build trees.

  • The “cmake(1)” “-E remove_directory” command-line tool, when given
    the path to a symlink to a directory, now removes just the symlink.
    It no longer removes content of the linked directory.

  • The “ctest(1)” “–build-makeprogram” command-line option now
    specifies the make program used when configuring a project with the
    “Ninja” generator or the Makefile Generators.

  • The “ExternalProject” module “ExternalProject_Add()” command has
    been updated so that “GIT_SUBMODULES “”” initializes no submodules.
    See policy “CMP0097”.

  • The “FindGTest” module has been updated to recognize MSVC build
    trees generated by GTest 1.8.1.

  • The “project()” command no longer strips leading zeros in version
    components. See policy “CMP0096”.

  • The Qt Compressed Help file is now named “CMake.qch”, which no
    longer contains the release version in the file name. When CMake is
    upgraded in-place, the name and location of this file will remain
    constant. Tools such as IDEs, help viewers, etc. should now be able
    to refer to this file at a fixed location that remains valid across
    CMake upgrades.

  • “RPATH” entries are properly escaped in the generated CMake
    scripts used for installation. See policy “CMP0095”.

  • When using “CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS” on Windows the auto-
    generated exports are now updated only when the object files
    providing the symbols are updated.

Changes made since CMake 3.16.0-rc3:

Alex Turbov (1):
CPack: Remove CPACK_INSTALL_CMAKE_CONFIGURATIONS

Arkadiusz Drabczyk (1):
Tutorial: replace Unicode EN DASH with ASCII dash

Ben Boeckel (3):
Help: drop confusing reference to if() from $<BOOL:>
FindPostgreSQL: support version encoding used in pre-10 releases
FindPostgreSQL: also search for libraries in the MacPorts suffix

Brad King (20):
CTest: Rename PROCESSES test property to RESOURCE_GROUPS
CTest: Rename “Processes” lexer to “ResourceGroups”
Help/dev: Update maintainer guide for Discourse transition
cmGlobalXCodeGenerator: Mark known source locations
Xcode: Fix generated references to CMakeLists.txt files
CMakeCPack: Update Debian package contact email
Help: Replace links to mailing lists with links to our Discourse Forum
README: Update links to cmake.org pages
README: Replace link to mailing list the CMake Discourse Forum
CMakeSystemSpecificInformation: Replace mailing list with Discourse Forum
FindBinUtils: Revert “Use the compiler to get the path to compiler tools”
Help: Document target_precompile_headers genex with angle brackets
CTestCoverageCollectGCOV: Fix typo in ctest_coverage_collect_gcov docs
expat: Update script to get Expat 2.2.9
expat: Update CMake build for 2.2.9
Tests: Fix ExportImport PCH expectation on Cray Classic compiler
Tests: Add RunCMake.CPackCommandLine case for multi-config package
Tests: Organize Objective C/C++ test directories
CPack: Restore support for custom package configuration templates
CMake 3.16.0-rc4

Charles Barto (1):
Help: Clarify load_cache documentation of first parameter

Craig Scott (14):
ForceToRelativePath: Fix spurious assertion when local path is root dir
Help: list(REMOVE_ITEM) removes all instances, not just the first found
Help: Typo and grammar fixes for file(GET_RUNTIME_DEPENDENCIES)
Tutorial: clean up typos, grammar and formatting
RPATH: Remove stray indent in generated file(RPATH_CHANGE) command
Help: Fix inaccuracies in INSTALL_REMOVE_ENVIRONMENT_RPATH docs
CTest: Rename hardware -> resources for CMake variables, command options
cmCTestMultiProcessHandler: Rename resource locking functions
CTest: Rename hardware -> resources for source code
CTest: Rename hardware -> resources for RunCMake tests
Help: Improve readability and fix inaccuracies in unity build docs
Help: Reorganise target_precompile_headers() docs for readability
Help: Provide guidance on INTERFACE for target_precompile_headers()
Help: Clarify compile features handling for OBJC and OBJCXX

Craig Sturdy (1):
FindwxWidgets: Add support for wxQt

Cristian Adam (13):
PCH: Add support for OBJC/OBJCXX languages
CMakeVersion.rc: Fix build with llvm-rc
ObjC: Mark explicitly the language for compilation
Unity build: Include GENERATED files into unity build
ObjC: Set same settings for all languages supported on Darwin
ObjC: Add try_compile support
PCH: No repeated path for internal generated PCH files
Unity: Don’t include sources with HEADER_FILE_ONLY property set
ObjC: Document ObjC/ObjCXX standard properties / variables
ObjC: Add OBJC/OBJCXX flags to Xcode projects
ObjC: Initialize ObjC/XX standard properties from C/C++ counterparts
ObjC: Proper initialization of ObjC/XX standard properties
PCH: Do not issue an error on duplicate target_precompile_headers call

Daniel Eiband (2):
cmFileAPI: Resolve full path in PCH source comparison
UnityBuild: Resolve full paths of unity source includes

Deniz Bahadir (1):
FindBoost: Prevent warning due to new meta-component “ALL” of Boost 1.73

Expat Upstream (1):
expat 2019-09-25 (a7bc26b6)

Grant Kim (1):
FindwxWidgets: Add link dependencies for MinGW

Kyle Edwards (2):
Help: Fix error in resource allocation example
Tests: Fix reliance on undefined behavior of cm::optional

Marc Aldorasi (2):
Help: Reference IMPORTED_IMPLIB from the IMPORTED_LOCATION documentation
Help: Both add_custom_command signatures support COMMAND_EXPAND_LISTS

Mateusz Janek (1):
source_group: ensure that passed file is not a directory

Robert Maynard (3):
Help: Remove out of date bounds on compile feature supported versions
find_package: Add support for CMAKE_FIND_USE_SYSTEM_PACKAGE_REGISTRY
Help: Clarify what ‘aware’ means as it relates to C++ standards

Saleem Abdulrasool (3):
Swift: Allow build and installed RPATHs to differ
Swift: support INSTALL_NAME_DIR on Darwin
Swift: support -rpath on Darwin

Tomasz Słodkowicz (1):
FindwxWidgets: Add support for 3.1.3 VS binaries

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