CMake 3.18 Release Notes

Contents

• CMake 3.18 Release Notes

  • New Features

    • Languages

    • Command-Line

    • Commands

    • Variables

    • Properties

    • Modules

    • Generator Expressions

    • CTest

    • CPack

    • Other

  • Deprecated and Removed Features

  • Other Changes

  • Updates

    • 3.18.1

    • 3.18.2

    • 3.18.3

Changes made since CMake 3.17 include the following.

New Features

Languages

• The CUDA language can now be compiled using Clang on non-Windows platforms. Separable compilation is not yet supported on any platform.

Command-Line

• cmake(1) gained support for profiling of CMake scripts through the parameters --profiling-output and --profiling-format.

• cmake(1) gained a cat command line option that can be used to concatenate files and print them on standard output.

Commands

• The add_library() and add_executable() commands learned to create Alias Targets referencing non-GLOBAL Imported Targets.

• The cmake_language() command was added for meta-operations on scripted or built-in commands, starting with a mode to CALL other commands, and EVAL CODE to inplace evaluate a CMake script.

• The execute_process() command gained the ECHO_OUTPUT_VARIABLE and ECHO_ERROR_VARIABLE options.

• The export() command now raise an error if used multiple times with same FILE without APPEND. See policy CMP0103.

• The file() command gained the ARCHIVE_CREATE and ARCHIVE_EXTRACT subcommands to expose the cmake(1) -E tar functionality to CMake scripting code.

• The file(CONFIGURE) subcommand was created in order to replicate the configure_file() functionality without resorting to a pre-existing file on disk as input. The content is instead passed as a string.

• The file(UPLOAD) command gained TLS_VERIFY and TLS_CAINFO options to control server certificate verification.

• The find_program(), find_library(), find_path() and find_file() commands gained a new REQUIRED option that will stop processing with an error message if nothing is found.

• The get_property() command with SOURCE scope gained the DIRECTORY and TARGET_DIRECTORY options to get a property from the provided directory scope.

• The get_source_file_property() command gained the DIRECTORY and TARGET_DIRECTORY options to get a property from the provided directory scope.

• The list() operation SORT gained the NATURAL sort option to sort using natural order (see strverscmp(3) manual).

• The set_property() command with the SOURCE scope gained the DIRECTORY and TARGET_DIRECTORY options to set properties in the provided directory scopes.

• The set_source_files_properties() command gained the DIRECTORY and TARGET_DIRECTORY options to set properties in the provided directory scopes.

• The string() command learned a new HEX sub-command, which converts strings into their hexadecimal representation.

Variables

• A CMAKE_CUDA_ARCHITECTURES variable was added to specify CUDA output architectures. Users are encouraged to use this instead of specifying options manually, as this approach is compiler-agnostic. The variable is initialized automatically when CMAKE_CUDA_COMPILER_ID is NVIDIA. The variable is used to initialize the new CUDA_ARCHITECTURES target property. See policy CMP0104.

• The CMAKE_PCH_WARN_INVALID variable was added to initialize the PCH_WARN_INVALID target property to allow the removal of the precompiled header invalid warning.

Properties

• The CUDA_ARCHITECTURES target property was added to specify CUDA output architectures. Users are encouraged to use this instead of specifying options manually, as this approach is compiler-agnostic. The property is initialized by the new CMAKE_CUDA_ARCHITECTURES variable. See policy CMP0104.

• The Fortran_PREPROCESS target property and Fortran_PREPROCESS source-file property were added to control preprocessing of Fortran source files.

• The FRAMEWORK_MULTI_CONFIG_POSTFIX_<CONFIG> target property and associated CMAKE_FRAMEWORK_MULTI_CONFIG_POSTFIX_<CONFIG> variable were created to allow adding a postfix to the name of a framework file name when using a multi-config generator.

• The OBJECT_OUTPUTS source file property now supports generator expressions.

• The PCH_WARN_INVALID target property was added to allow the removal of the precompiled header invalid warning.

• The UNITY_BUILD_MODE target property was added to tell generators which algorithm to use for grouping included source files.

• The VS_SOURCE_SETTINGS_<tool> target property was added to tell Visual Studio Generators for VS 2010 and above to add metadata to non-built source files using <tool>.

• The VS_SETTINGS source file property was added to tell Visual Studio Generators for VS 2010 and above to add metadata to a non-built source file.

• The VS_PLATFORM_TOOLSET target property was added to tell Visual Studio Generators for VS 2010 and above to override the platform toolset.

• The VS_SOLUTION_DEPLOY target property was added to tell Visual Studio Generators for VS 2010 and above to mark a target for deployment even when not building for Windows Phone/Store/CE.

Modules

• The CheckLinkerFlag module has been added to provide a facility to check validity of link flags.

• The ExternalProject module ExternalProject_Add() command gained a new GIT_REMOTE_UPDATE_STRATEGY keyword. This can be used to specify how failed rebase operations during a git update should be handled. The CMAKE_EP_GIT_REMOTE_UPDATE_STRATEGY variable was also added as a global default and is honored by both the ExternalProject and FetchContent modules.

• The FetchContent module FetchContent_Declare() command now supports a SOURCE_SUBDIR option. It can be used to direct FetchContent_MakeAvailable() to look in a different location for the CMakeLists.txt file.

• The FindBLAS module now provides an imported target.

• The FindCUDAToolkit module:

  • gained the variable CUDAToolkit_LIBRARY_ROOT, which is the directory containing the nvvm directory and version.txt.

  • uses toolkit and library root found during CUDA compiler detection.

• The FindLAPACK module now provides an imported target.

• The FindPython3, FindPython2 and FindPython modules:

  • gained the possibility to create per-artifact cache variables for interactive editing in cmake-gui(1) and ccmake(1).

  • gained sub-components Development.Module and Development.Embed under the Development component.

  • gained the capability to specify which Python implementations to find, including IronPython and PyPy.

• The FindRuby module input and output variables were all renamed from RUBY_ to Ruby_ for consistency with other find modules. Input variables of the old case will be honored if provided, and output variables of the old case are always provided.

• The FindSWIG module now accepts target languages as COMPONENTS and OPTIONAL_COMPONENTS arguments to find_package.

• The GoogleTest module gtest_discover_tests() command:

  • gained a new DISCOVERY_MODE option to control when the test discovery step is run. It offers a new PRE_TEST setting to run the discovery at test time instead of build time. A new CMAKE_GTEST_DISCOVER_TESTS_DISCOVERY_MODE variable can be used to change the default globally.

  • gained a new optional parameter XML_OUTPUT_DIR. When set the JUnit XML test results are stored in that directory.

• The FindLibXslt module now provides imported targets.

• The UseSWIG module now supports Fortran as a target language if the SWIG_EXECUTABLE is SWIG-Fortran.

Generator Expressions

• The $<DEVICE_LINK:...> and $<HOST_LINK:...> generator expressions were added to manage device and host link steps.

• The $<LINK_LANGUAGE:...> and $<LINK_LANG_AND_ID:...> generator expressions were added.

CTest

• ctest(1) gained a new CTEST_RESOURCE_SPEC_FILE variable, which can be used to specify a resource specification file.

• ctest(1) gained a --stop-on-failure option, which can be used to stop running the tests once one has failed.

• The ctest_test() command gained a STOP_ON_FAILURE option which can be used to stop running the tests once one has failed.

• The CTestCoverageCollectGCOV module ctest_coverage_collect_gcov() command gained a TARBALL_COMPRESSION option to control compression of the tarball of collected results.

CPack

• The CPack Archive Generator’s TXZ format learned the CPACK_ARCHIVE_THREADS variable to enable parallel compression. Requires support in the liblzma used by CMake.

• The CPack NSIS Generator gained a new variable CPACK_NSIS_MANIFEST_DPI_AWARE to declare that the installer is DPI-aware.

• The CPack RPM Generator gained CPACK_RPM_PRE_TRANS_SCRIPT_FILE and CPACK_RPM_POST_TRANS_SCRIPT_FILE variables to specify pre- and post-transaction scripts.

Other

• cmake-gui(1) now populates its generator selection widget default value from the CMAKE_GENERATOR environment variable. Additionally, environment variables CMAKE_GENERATOR_PLATFORM and CMAKE_GENERATOR_TOOLSET are used to populate their respective widget defaults.

• ccmake(1) learned to read a CCMAKE_COLORS environment variable to customize colors.

• The Compile Features functionality is now aware of the availability of C11 features in MSVC 19.27 and 19.28, including support for the c_restrict, c_static_assert features and the -std:c11 flag.

Deprecated and Removed Features

• The Documentation module has been deprecated via CMP0106. This module was essentially VTK code that CMake should not be shipping anymore.

• An explicit deprecation diagnostic was added for policy CMP0070 and policy CMP0071 (CMP0069 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.

Other Changes

• On Windows, the Ninja and Ninja Multi-Config generators, when a compiler is not explicitly specified, now select the first compiler (of any name) found in directories listed by the PATH environment variable.

• The LINK_OPTIONS and INTERFACE_LINK_OPTIONS target properties are now used for the device link step. See policy CMP0105.

• Creation of an ALIAS target overwriting an existing target now raises an error. See policy CMP0107.

• Linking a target to itself through an alias now raises an error. See policy CMP0108.

• The FindPackageHandleStandardArgs module option REQUIRED_VARS is now optional if HANDLE_COMPONENTS is specified.

• The source_group() command now also recognizes forward slashes as subgroup delimiters, not just backslashes.

• ctest(1) now logs environment variables that it sets for each test, either due to the ENVIRONMENT property or the resource allocation feature, and submits this log to CDash. It does not log environment variables that were set outside of CTest.

• When building CMake itself from source and not using a system-provided libcurl, HTTP/2 support is now enabled for commands supporting network communication via http(s), such as file(DOWNLOAD), file(UPLOAD), and ctest_submit(). The precompiled binaries provided on cmake.org now support HTTP/2.

• The cmake-file-api(7) “codemodel” version 2 version field has been updated to 2.1.

• The cmake-file-api(7) “codemodel” version 2 “target” object gained a new precompileHeaders field in the compileGroups objects.

Updates

Changes made since CMake 3.18.0 include the following.

3.18.1

• The Xcode generator, when CMAKE_OSX_ARCHITECTURES is not defined, now selects $(NATIVE_ARCH_ACTUAL) as the default architecture (the Xcode ARCHS setting). This is needed for Xcode 12 to select the host’s architecture, which older versions of Xcode did by default.

• In CMake 3.18.0 the add_test() command learned to support special characters in test names. This was accidentally left out of its release notes. Unfortunately the fix breaks existing projects that were using manual quoting or escaping to work around the prior limitation. This fix has been reverted in 3.18.1, but may be re-introduced in future versions of CMake with a policy for compatibility.

3.18.2

• The default value of CMAKE_AUTOMOC_PATH_PREFIX was changed to OFF because this feature can break existing projects that have identically named header files in different include directories. This restores compatibility with behavior of CMake 3.15 and below. The default was also changed to OFF in 3.16.9 and 3.17.5.

• The Compile Features functionality was updated for MSVC 19.27 as mentioned above (c_restrict).

3.18.3

• The Compile Features functionality was updated for MSVC 19.28 as mentioned above (c_static_assert).