CMake 3.15 Release Notes¶
Changes made since CMake 3.14 include the following.
New Features¶
Generators¶
- The - Xcodegenerator now supports per-target schemes. See the- CMAKE_XCODE_GENERATE_SCHEMEvariable and- XCODE_GENERATE_SCHEMEtarget property.
- The - Green Hills MULTIgenerator has been updated:- It now supports the - add_custom_command()and- add_custom_target()commands.
- It is now available on Linux. 
 
Languages¶
- Preliminary support for the - Swiftlanguage was added to the- Ninjagenerator:- Use the - SWIFTCenvironment variable to specify a compiler.
- The - Swift_DEPENDENCIES_FILEtarget property and- Swift_DEPENDENCIES_FILEsource file property were added to customize dependency files.
- The - Swift_MODULE_NAMEtarget property was added to customize the Swift module name.
- The - Swift_DIAGNOSTICS_FILEsource property was added to indicate where to write the serialized Swift diagnostics.
 - The Swift support is experimental, not considered stable, and may change in future releases of CMake. 
Compilers¶
- The - Clangcompiler variant on Windows that targets the MSVC ABI but has a GNU-like command line is now supported.
- Support for the Clang-based ARM compiler was added with compiler id - ARMClang.
- Support was added for the IAR compiler architectures Renesas RX, RL78, RH850 and Texas Instruments MSP430. 
- Support was added for the IAR compilers built for Linux (IAR BuildLx). 
Command-Line¶
- The - CMAKE_GENERATORenvironment variable was added to specify a default generator to use when- cmake(1)is run without a- -Goption. Additionally, environment variables- CMAKE_GENERATOR_PLATFORM,- CMAKE_GENERATOR_TOOLSET, and- CMAKE_GENERATOR_INSTANCEwere created to configure the generator.
- The - cmake(1)- --buildtool- --targetparameter gained support for multiple targets, e.g.- cmake --build . --target Library1 Library2. It now also has a short form- -talias, e.g.- cmake --build . -t Library1 Library2.
- The - cmake(1)command gained a new- --installoption. This may be used after building a project to run installation without using the generated build system or the native build tool.
- The - cmake(1)command learned a new CLI option- --loglevel.
- The - cmake(1)- -E remove_directorycommand-line tool learned to support removing multiple directories.
- The - cmake(1)- -E tartool has been improved:- It now continues adding files to an archive even if some of the files are not readable. This behavior is more consistent with the classic - tartool.
- It now parses all flags, and if an invalid flag was provided, a warning is issued. 
- It now displays an error if no action flag was specified, along with a list of possible actions: - t(list),- c(create) or- x(extract).
- It now supports extracting ( - -x) or listing (- -t) only specific files or directories.
- It now supports Zstandard compression with a - --zstdoption. Zstandard was designed to give a compression ratio comparable to that of the DEFLATE (zip) algorithm, but faster, especially for decompression.
 
Commands¶
- The - add_custom_command()and- add_custom_target()commands gained a new- JOB_POOLoption that works with the- Ninjagenerator to set the pool variable on the build statement.
- The - add_library()command- ALIASoption learned to support import libraries of the- UNKNOWNtype.
- The - cmake_parse_arguments()command gained an additional- <prefix>_KEYWORDS_MISSING_VALUESoutput variable to report keyword arguments that were given by the caller with no values.
- The - execute_process()command gained a- COMMAND_ECHOoption and supporting- CMAKE_EXECUTE_PROCESS_COMMAND_ECHOvariable to enable echoing of the command-line string before execution.
- The - file(INSTALL)command learned a new argument,- FOLLOW_SYMLINK_CHAIN, which can be used to recursively resolve and install symlinks.
- list()learned new sub-commands:- PREPEND,- POP_FRONTand- POP_BACK.
- The - message()command learned new types:- NOTICE,- VERBOSE,- DEBUGand- TRACE.
- The - string()learned a new sub-command- REPEAT.
Variables¶
- The - CMAKE_CROSSCOMPILING_EMULATORvariable and corresponding- CROSSCOMPILING_EMULATORtarget property learned to support arguments to the emulator.
- The - CMAKE_FIND_PACKAGE_PREFER_CONFIGvariable was added to tell- find_package()calls to look for a package configuration file first even if a find module is available.
- The - CMAKE_FRAMEWORKvariable was added to initialize the- FRAMEWORKproperty on all targets.
- The - CMAKE_VS_JUST_MY_CODE_DEBUGGINGvariable and- VS_JUST_MY_CODE_DEBUGGINGtarget property were added to enable the Just My Code feature of the Visual Studio Debugger when compiling with MSVC cl 19.05 and higher.
- The - CMAKE_MSVC_RUNTIME_LIBRARYvariable and- MSVC_RUNTIME_LIBRARYtarget property were introduced to select the runtime library used by compilers targeting the MSVC ABI. See policy- CMP0091.
- The - CMAKE_PROJECT_INCLUDEand- CMAKE_PROJECT_INCLUDE_BEFOREvariables were added to allow injection of custom code at the sites of- project()calls without knowing the project name a priori.
Properties¶
- The - ADDITIONAL_CLEAN_FILEStarget property and- ADDITIONAL_CLEAN_FILESdirectory property were added. They allow to register additional files that should be removed during the clean stage.
- The - PUBLIC_HEADERand- PRIVATE_HEADERproperties may now be set on Interface Libraries. The headers specified by those properties can be installed using the- install(TARGETS)command by passing the- PUBLIC_HEADERand- PRIVATE_HEADERarguments respectively.
- The - VS_PACKAGE_REFERENCEStarget property was added to tell Visual Studio Generators to add references to- nugetpackages.
- The - VS_PROJECT_IMPORTtarget property was added to allow managed Visual Studio project files to import external- .propsfiles.
- The - VS_NO_SOLUTION_DEPLOYtarget property was added to tell Visual Studio Generators whether to deploy an artifact to the WinCE or Windows Phone target device.
Modules¶
- The - FindBoostmodule was reworked to expose a more consistent user experience between its "Config" and "Module" modes and with other find modules in general.- A new imported target - Boost::headersis now defined (same as- Boost::boost).
- New output variables - Boost_VERSION_MACRO,- Boost_VERSION_MAJOR,- Boost_VERSION_MINOR,- Boost_VERSION_PATCH, and- Boost_VERSION_COUNTwere added.
- The - QUIETargument passed to- find_package()is no longer ignored in config mode. Note that the CMake package shipped with Boost- 1.70.0ignores the- QUIETargument passed to- find_package(). This is fixed in the next Boost release.
- The input switch - Boost_DETAILED_FAILURE_MSGwas removed.
- Boost_VERSIONnow reports the version in- x.y.zformat in module mode. See policy- CMP0093.
 
- The - FindCupsmodule now provides imported targets.
- The - FindEnvModulesmodule was added to use Lua- and TCL-based environment modules in CTest Scripts.
- The - FindGLEWmodule now provides an interface more consistent with what upstream GLEW provides in its own CMake package files.
- The - FindPkgConfignow populates- INTERFACE_LINK_OPTIONSproperty of imported targets with other (non-library) linker flags.
- The - FindPostgreSQLmodule learned to find debug and release variants separately.
- Modules - FindPython3,- FindPython2and- FindPythongained additional lookup strategies and controls, and a new default. See policy- CMP0094.
- Modules - FindPython,- FindPython2and- FindPython3gain a new target (respectively- Python::Module,- Python2::Moduleand- Python3::Module) which can be used to develop Python modules.
- Modules - FindPython3,- FindPython2and- FindPythongain capability to control how virtual environments are handled.
- The - UseSWIGmodule learned to manage alternate library names by passing- -interface <library_name>for- pythonlanguage or- -dllimport <library_name>for- CSharplanguage to the- SWIGcompiler.
Generator Expressions¶
- The generator expressions - $<C_COMPILER_ID>,- $<CXX_COMPILER_ID>,- $<CUDA_COMPILER_ID>,- $<Fortran_COMPILER_ID>,- $<COMPILE_LANGUAGE>,- $<COMPILE_LANG_AND_ID>, and- $<PLATFORM_ID>learned to support matching one value from a comma-separated list.
- The - $<CUDA_COMPILER_ID:...>and- $<CUDA_COMPILER_VERSION:...>generator expressions were added.
- The - $<COMPILE_LANG_AND_ID:...>generator expression was introduced to allow specification of compile options for target files based on the- CMAKE_<LANG>_COMPILER_IDand- LANGUAGEof each source file.
- A - $<FILTER:list,INCLUDE|EXCLUDE,regex>generator expression has been added.
- A - $<REMOVE_DUPLICATES:list>generator expression has been added.
- The - $<SHELL_PATH:...>generator expression gained support for a list of paths.
- New - $<TARGET_FILE*>- generator expressionswere added to retrieve the prefix, base name, and suffix of the file names of various artifacts:
- The - $<TARGET_OBJECTS:...>generator expression is now supported on- SHARED,- STATIC,- MODULElibraries and executables.
CTest¶
- The - ctest_submit()command learned a new option:- BUILD_ID. This can be used to store the ID assigned to this build by CDash to a variable.
- The - ctest_update()command learned to honor a new variable:- CTEST_UPDATE_VERSION_OVERRIDE. This can be used to specify the current version of your source tree rather than using the update command to discover the current version that is checked out.
CPack¶
- The - CPack IFW Generatorgained a new- CPACK_IFW_PACKAGE_STYLE_SHEETvariable to customize the installer stylesheet.
Deprecated and Removed Features¶
- The - cmake-server(7)mode has been deprecated and will be removed from a future version of CMake. Please port clients to use the- cmake-file-api(7)instead.
- The - ADDITIONAL_MAKE_CLEAN_FILESdirectory property is now deprecated. Use the- ADDITIONAL_CLEAN_FILESdirectory property instead.
- The variable - CMAKE_AUTOMOC_RELAXED_MODEis considered deprecated. Support still exists but will be removed in future versions.
- The - export(PACKAGE)command now does nothing unless enabled via- CMAKE_EXPORT_PACKAGE_REGISTRY. See policy- CMP0090.
- The - Xcodegenerator now requires at least Xcode 5.
- An explicit deprecation diagnostic was added for policy - CMP0066(- CMP0065and 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¶
- If a feature specified by - target_compile_features()is available in the compiler's default standard level, CMake 3.14 and below incorrectly added unnecessary- -std=flags that could lower the standard level. This bug has been fixed in CMake 3.15. This behavior change may expose bugs in existing projects that were relying on undocumented implementation details. Specifying compile features only ensures that the compiler runs in a mode that has those features, not that any specific standard level is used or explicit- -std=flag passed.
- CMake learned how to compile C++14 with the IBM AIX XL compiler and the SunPro compiler and to compile C++20 with the AppleClang compiler. 
- With MSVC-like compilers the value of - CMAKE_<LANG>_FLAGSno longer contains warning flags like- /W3by default. See policy- CMP0092.
- IBM Clang-based XL compilers that define - __ibmxl__now use the compiler id- XLClanginstead of- XL. See policy- CMP0089.
- The - file(REMOVE)and- file(REMOVE_RECURSE)commands were changed to ignore empty arguments with a warning instead of treating them as a relative path and removing the contents of the current directory.
Updates¶
Changes made since CMake 3.15.0 include the following.
3.15.1¶
- In CMake 3.15.0 support for the GNU-like - Clangcompiler targeting the MSVC ABI implemented- CMAKE_CXX_STANDARDvalues 98 and 11 using the corresponding- -std=flags. However, these modes do not work with the MSVC standard library. Therefore CMake 3.15.1 passes C++14 standard flags even for C++98 and C++11. This is consistent with MSVC itself which always runs in a mode aware of C++14.
- Preliminary Swift support added in 3.15.0 has been updated. 
3.15.2¶
- In CMake 3.15.0 and 3.15.1 the - CMAKE_FIND_PACKAGE_PREFER_CONFIGvariable caused the- find_package()command to fail on a missing package even without the- REQUIREDoption. This has been fixed.
3.15.3¶
- CrayPrgEnvcompiler wrapper support has been updated for the 19.06 release of the Cray Programming Environment for which the default linking mode on XC Cray systems is now dynamic instead of static.
3.15.4¶
- In CMake 3.15.0 through 3.15.3, the - EXCLUDE_FROM_ALLdirectory property was regressed from pre-3.14 behavior and caused targets within the directory to be excluded even from its own "all". This has been fixed. The bug also existed in 3.14.0 through 3.14.6 and is fixed in 3.14.7.
