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 theCMAKE_XCODE_GENERATE_SCHEMEvariable andXCODE_GENERATE_SCHEMEtarget property.The
Green Hills MULTIgenerator has been updated:It now supports the
add_custom_command()andadd_custom_target()commands.It is now available on Linux.
Languages¶
Preliminary support for the
Swiftlanguage was added to theNinjagenerator:Use the
SWIFTCenvironment variable to specify a compiler.The
Swift_DEPENDENCIES_FILEtarget property andSwift_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 whencmake(1)is run without a-Goption. Additionally, environment variablesCMAKE_GENERATOR_PLATFORM,CMAKE_GENERATOR_TOOLSET, andCMAKE_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) orx(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()andadd_custom_target()commands gained a newJOB_POOLoption that works with theNinjagenerator to set the pool variable on the build statement.The
add_library()commandALIASoption learned to support import libraries of theUNKNOWNtype.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 aCOMMAND_ECHOoption and supportingCMAKE_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_FRONTandPOP_BACK.The
message()command learned new types:NOTICE,VERBOSE,DEBUGandTRACE.The
string()learned a new sub-commandREPEAT.
Variables¶
The
CMAKE_CROSSCOMPILING_EMULATORvariable and correspondingCROSSCOMPILING_EMULATORtarget property learned to support arguments to the emulator.The
CMAKE_FIND_PACKAGE_PREFER_CONFIGvariable was added to tellfind_package()calls to look for a package configuration file first even if a find module is available.The
CMAKE_FRAMEWORKvariable was added to initialize theFRAMEWORKproperty on all targets.The
CMAKE_VS_JUST_MY_CODE_DEBUGGINGvariable andVS_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 andMSVC_RUNTIME_LIBRARYtarget property were introduced to select the runtime library used by compilers targeting the MSVC ABI. See policyCMP0091.The
CMAKE_PROJECT_INCLUDEandCMAKE_PROJECT_INCLUDE_BEFOREvariables were added to allow injection of custom code at the sites ofproject()calls without knowing the project name a priori.
Properties¶
The
ADDITIONAL_CLEAN_FILEStarget property andADDITIONAL_CLEAN_FILESdirectory property were added. They allow to register additional files that should be removed during the clean stage.The
PUBLIC_HEADERandPRIVATE_HEADERproperties may now be set on Interface Libraries. The headers specified by those properties can be installed using theinstall(TARGETS)command by passing thePUBLIC_HEADERandPRIVATE_HEADERarguments respectively.The
VS_PACKAGE_REFERENCEStarget property was added to tell Visual Studio Generators to add references tonugetpackages.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 asBoost::boost).New output variables
Boost_VERSION_MACRO,Boost_VERSION_MAJOR,Boost_VERSION_MINOR,Boost_VERSION_PATCH, andBoost_VERSION_COUNTwere added.The
QUIETargument passed tofind_package()is no longer ignored in config mode. Note that the CMake package shipped with Boost1.70.0ignores theQUIETargument passed tofind_package(). This is fixed in the next Boost release.The input switch
Boost_DETAILED_FAILURE_MSGwas removed.Boost_VERSIONnow reports the version inx.y.zformat in module mode. See policyCMP0093.
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 populatesINTERFACE_LINK_OPTIONSproperty of imported targets with other (non-library) linker flags.The
FindPostgreSQLmodule learned to find debug and release variants separately.Modules
FindPython3,FindPython2andFindPythongained additional lookup strategies and controls, and a new default. See policyCMP0094.Modules
FindPython,FindPython2andFindPython3gain a new target (respectivelyPython::Module,Python2::ModuleandPython3::Module) which can be used to develop Python modules.Modules
FindPython3,FindPython2andFindPythongain capability to control how virtual environments are handled.The
UseSWIGmodule learned to manage alternate library names by passing-interface <library_name>forpythonlanguage or-dllimport <library_name>forCSharplanguage to theSWIGcompiler.
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 theCMAKE_<LANG>_COMPILER_IDandLANGUAGEof 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 onSHARED,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 newCPACK_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 thecmake-file-api(7)instead.The
ADDITIONAL_MAKE_CLEAN_FILESdirectory property is now deprecated. Use theADDITIONAL_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 viaCMAKE_EXPORT_PACKAGE_REGISTRY. See policyCMP0090.The
Xcodegenerator now requires at least Xcode 5.An explicit deprecation diagnostic was added for policy
CMP0066(CMP0065and below were already deprecated). Thecmake-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 policyCMP0092.IBM Clang-based XL compilers that define
__ibmxl__now use the compiler idXLClanginstead ofXL. See policyCMP0089.The
file(REMOVE)andfile(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 implementedCMAKE_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 thefind_package()command to fail on a missing package even without theREQUIREDoption. 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.