CMake 3.0 Release Notes¶
Contents
Changes made since CMake 2.8.12 include the following.
Documentation Changes¶
- The CMake documentation has been converted to reStructuredText and now transforms via Sphinx (http://sphinx-doc.org) into man and html pages. This allows the documentation to be properly indexed and to contain cross-references. - Conversion from the old internal documentation format was done by an automatic process so some documents may still contain artifacts. They will be updated incrementally over time. - A basic reStructuredText processor has been implemented to support - cmake --help-commandand similar command-line options.
- New manuals were added: - cmake-buildsystem(7)
- cmake-commands(7), replacing- cmakecommands(1)and- cmakecompat(1)
- cmake-developer(7)
- cmake-generator-expressions(7)
- cmake-generators(7)
- cmake-language(7)
- cmake-modules(7), replacing- cmakemodules(1)
- cmake-packages(7)
- cmake-policies(7), replacing- cmakepolicies(1)
- cmake-properties(7), replacing- cmakeprops(1)
- cmake-qt(7)
- cmake-toolchains(7)
- cmake-variables(7), replacing- cmakevars(1)
 
- Release notes for CMake 3.0.0 and above will now be included with the html documentation. 
New Features¶
Syntax¶
- The CMake language has been extended with Bracket Argument and Bracket Comment syntax inspired by Lua long brackets: - set(x [===[bracket argument]===] #[[bracket comment]]) - Content between equal-length open- and close-brackets is taken literally with no variable replacements. - Warning - This syntax change could not be made in a fully compatible way. No policy is possible because syntax parsing occurs before any chance to set a policy. Existing code using an unquoted argument that starts with an open bracket will be interpreted differently without any diagnostic. Fortunately the syntax is obscure enough that this problem is unlikely in practice. 
Commands¶
- The add_library()command learned a newINTERFACElibrary type. Interface libraries have no build rules but may have properties definingusage requirementsand may be installed, exported, and imported. This is useful to create header-only libraries that have concrete link dependencies on other libraries.
- The export()command learned a newEXPORTmode that retrieves the list of targets to export from an export set configured by theinstall(TARGETS)commandEXPORToption. This makes it easy to export from the build tree the same targets that are exported from the install tree.
- The export()command learned to work with multiple dependent export sets, thus allowing multiple packages to be built and exported from a single tree. The feature requires CMake to wait until the generation step to write the output file. This means one should notinclude()the generated targets file later during project configuration because it will not be available. Use Alias Targets instead. See policyCMP0024.
- The install(FILES)command learned to supportgenerator expressionsin the list of files.
- The project()command learned to set some version variables to values specified by the newVERSIONoption or to empty strings. See policyCMP0048.
- The string()command learned a newCONCATmode. It is particularly useful in combination with the new Bracket Argument syntax.
- The unset()command learned aPARENT_SCOPEoption matching that of theset()command.
- The include_external_msproject()command learned to handle non-C++ projects like.vbprojor.csproj.
- The ctest_update()command learned to update work trees managed by the Perforce (p4) version control tool.
- The message()command learned aDEPRECATIONmode. Such messages are not issued by default, but may be issued as a warning ifCMAKE_WARN_DEPRECATEDis enabled, or as an error ifCMAKE_ERROR_DEPRECATEDis enabled.
- The target_link_libraries()command now allows repeated use of theLINK_PUBLICandLINK_PRIVATEkeywords.
Variables¶
- Variable CMAKE_FIND_NO_INSTALL_PREFIXhas been introduced to tell CMake not to add the value ofCMAKE_INSTALL_PREFIXto theCMAKE_SYSTEM_PREFIX_PATHvariable by default. This is useful when building a project that installs some of its own dependencies to avoid finding files it is about to replace.
- Variable CMAKE_STAGING_PREFIXwas introduced for use when cross-compiling to specify an installation prefix on the host system that differs from aCMAKE_INSTALL_PREFIXvalue meant for the target system.
- Variable CMAKE_SYSROOTwas introduced to specify the toolchain SDK installation prefix, typically for cross-compiling. This is used to pass a--sysrootoption to the compiler and as a prefix searched byfind_*commands.
- Variable CMAKE_<LANG>_COMPILER_TARGETwas introduced for use when cross-compiling to specify the target platform in the toolchain file specified by theCMAKE_TOOLCHAIN_FILEvariable. This is used to pass an option such as--target=<triple>to some cross-compiling compiler drivers.
- Variable CMAKE_MAP_IMPORTED_CONFIG_<CONFIG>has been introduced to optionally initialize theMAP_IMPORTED_CONFIG_<CONFIG>target property.
Properties¶
- The ADDITIONAL_MAKE_CLEAN_FILESdirectory property learned to supportgenerator expressions.
- A new directory property CMAKE_CONFIGURE_DEPENDSwas introduced to allow projects to specify additional files on which the configuration process depends. CMake will re-run at build time when one of these files is modified. Previously this was only possible to achieve by specifying such files as the input to aconfigure_file()command.
- A new AUTORCC feature replaces the need to
invoke qt4_add_resources()by allowing.qrcfiles to be listed as target sources.
- A new AUTOUIC feature replaces the need to
invoke qt4_wrap_ui().
- Test properties learned to support
generator expressions. This is useful to specify per-configuration values for test properties likeREQUIRED_FILESandWORKING_DIRECTORY.
- A new SKIP_RETURN_CODEtest property was introduced to tellctest(1)to treat a particular test return code as if the test were not run. This is useful for test drivers to report that certain test requirements were not available.
- New types of Compatible Interface Properties were introduced,
namely the COMPATIBLE_INTERFACE_NUMBER_MAXandCOMPATIBLE_INTERFACE_NUMBER_MINfor calculating numeric maximum and minimum values respectively.
Modules¶
- The CheckTypeSizemodulecheck_type_sizemacro and theCheckStructHasMembermodulecheck_struct_has_membermacro learned a newLANGUAGEoption to optionally check C++ types.
- The ExternalDatamodule learned to work with no URL templates if a local store is available.
- The ExternalProjectfunctionExternalProject_Addlearned a newGIT_SUBMODULESoption to specify a subset of available submodules to checkout.
- A new FindBacktracemodule has been added to supportfind_package(Backtrace)calls.
- A new FindLuamodule has been added to supportfind_package(Lua)calls.
- The FindBoostmodule learned a newBoost_NAMESPACEoption to change theboostprefix on library names.
- The FindBoostmodule learned to control search for libraries with thegtag (for MS debug runtime) with a newBoost_USE_DEBUG_RUNTIMEoption. It isONby default to preserve existing behavior.
- The FindJavaandFindJNImodules learned to use aJAVA_HOMECMake variable or environment variable, and then try/usr/libexec/java_homeon OS X.
- The UseJavamoduleadd_jarfunction learned a newMANIFESToption to pass the-moption tojar.
- A new CMakeFindDependencyMacromodule was introduced with afind_dependencymacro to find transitive dependencies in apackage configuration file. Such dependencies are omitted by the listing of theFeatureSummarymodule.
- The FindQt4module learned to create Imported Targets for Qt executables. This helps disambiguate when using multipleQt versionsin the same buildsystem.
- The FindRubymodule learned to search for Ruby 2.0 and 2.1.
Generator Expressions¶
- New $<PLATFORM_ID>and$<PLATFORM_ID:...>generator expressionshave been added.
- The $<CONFIG>generator expressionnow has a variant which takes no argument. This is equivalent to the$<CONFIGURATION>expression.
- New $<UPPER_CASE:...>and$<LOWER_CASE:...>generator expressionsgenerator expressions have been added.
- A new $<MAKE_C_IDENTIFIER:...>generator expressionhas been added.
Other¶
- The cmake(1)-Eoption learned a newsleepcommand.
- The ccmake(1)dialog learned to honor theSTRINGScache entry property to cycle through the enumerated list of possible values.
- The cmake-gui(1)dialog learned to remember window settings between sessions.
- The cmake-gui(1)dialog learned to remember the type of a cache entry for completion in theAdd Entrydialog.
New Diagnostics¶
- Directories named in the INTERFACE_INCLUDE_DIRECTORIEStarget property of imported targets linked conditionally by agenerator expressionwere not checked for existence. Now they are checked. See policyCMP0027.
- Build target names must now match a validity pattern and may no longer
conflict with CMake-defined targets.  See policy CMP0037.
- Build targets that specify themselves as a link dependency were
silently accepted but are now diagnosed.  See CMP0038.
- The target_link_libraries()command used to silently ignore calls specifying as their first argument build targets created byadd_custom_target()but now diagnoses this mistake. See policyCMP0039.
- The add_custom_command()command used to silently ignore calls specifying theTARGEToption with a non-existent target but now diagnoses this mistake. See policyCMP0040.
- Relative paths in the INTERFACE_INCLUDE_DIRECTORIEStarget property used to be silently accepted if they contained agenerator expressionbut are now rejected. See policyCMP0041.
- The get_target_property()command learned to reject calls specifying a non-existent target. See policyCMP0045.
- The add_dependencies()command learned to reject calls specifying a dependency on a non-existent target. See policyCMP0046.
- Link dependency analysis learned to assume names containing ::refer to Alias Targets or Imported Targets. It will now produce an error if such a linked target is missing. Previously in this case CMake generated a link line that failed at build time. See policyCMP0028.
- When the project()orenable_language()commands initialize support for a language, it is now an error if the full path to the compiler cannot be found and stored in the correspondingCMAKE_<LANG>_COMPILERvariable. This produces nicer error messages up front and stops processing when no working compiler is known to be available.
- Target sources specified with the add_library()oradd_executable()command learned to reject items which require an undocumented extra layer of variable expansion. See policyCMP0049.
- Use of add_custom_command()undocumentedSOURCEsignatures now results in an error. See policyCMP0050.
Deprecated and Removed Features¶
- Compatibility options supporting code written for CMake versions prior to 2.4 have been removed.
- Several long-outdated commands that should no longer be called
have been disallowed in new code by policies:- Policy CMP0029disallowssubdir_depends()
- Policy CMP0030disallowsuse_mangled_mesa()
- Policy CMP0031disallowsload_command()
- Policy CMP0032disallowsoutput_required_files()
- Policy CMP0033disallowsexport_library_dependencies()
- Policy CMP0034disallowsutility_source()
- Policy CMP0035disallowsvariable_requires()
- Policy CMP0036disallowsbuild_name()
 
- Policy 
- The cmake(1)-iwizard mode has been removed. Instead use an interactive dialog such asccmake(1)or use the-Doption to set cache values from the command line.
- The builtin documentation formatters that supported command-line
options such as --help-manand--help-htmlhave been removed in favor of the above-mentioned new documentation system. These and other command-line options that used to generate man- and html- formatted pages no longer work. Thecmake(1)--help-custom-modulesoption now produces a warning at runtime and generates a minimal document that reports the limitation.
- The COMPILE_DEFINITIONS_<CONFIG>directory properties and theCOMPILE_DEFINITIONS_<CONFIG>target properties have been deprecated. Instead set the correspondingCOMPILE_DEFINITIONSdirectory property orCOMPILE_DEFINITIONStarget property and usegenerator expressionslike$<CONFIG:...>to specify per-configuration definitions. See policyCMP0043.
- The LOCATIONtarget property should no longer be read from non-IMPORTED targets. It does not make sense in multi-configuration generators since the build configuration is not known while configuring the project. It has been superseded by the$<TARGET_FILE>generator expression. See policyCMP0026.
- The COMPILE_FLAGStarget property is now documented as deprecated, though no warning is issued. Use theCOMPILE_OPTIONStarget property or thetarget_compile_options()command instead.
- The GenerateExportHeadermoduleadd_compiler_export_flagsfunction is now deprecated. It has been superseded by the<LANG>_VISIBILITY_PRESETandVISIBILITY_INLINES_HIDDENtarget properties.
Other Changes¶
- The version scheme was changed to use only two components for the feature level instead of three. The third component will now be used for bug-fix releases or the date of development versions. See the - CMAKE_VERSIONvariable documentation for details.
- The default install locations of CMake itself on Windows and OS X no longer contain the CMake version number. This allows for easy replacement without re-generating local build trees manually. 
- Generators for Visual Studio 10 (2010) and later were renamed to include the product year like generators for older VS versions: - Visual Studio 10->- Visual Studio 10 2010
- Visual Studio 11->- Visual Studio 11 2012
- Visual Studio 12->- Visual Studio 12 2013
 - This clarifies which generator goes with each Visual Studio version. The old names are recognized for compatibility. 
- The - CMAKE_<LANG>_COMPILER_IDvalue for Apple-provided Clang is now- AppleClang. It must be distinct from upstream Clang because the version numbers differ. See policy- CMP0025.
- The - CMAKE_<LANG>_COMPILER_IDvalue for- qccon QNX is now- QCC. It must be distinct from- GNUbecause the command-line options differ. See policy- CMP0047.
- On 64-bit OS X the - CMAKE_HOST_SYSTEM_PROCESSORvalue is now correctly detected as- x86_64instead of- i386.
- On OS X, CMake learned to enable behavior specified by the - MACOSX_RPATHtarget property by default. This activates use of- @rpathfor runtime shared library searches. See policy- CMP0042.
- The - build_command()command now returns a- cmake(1)- --buildcommand line instead of a direct invocation of the native build tool. When using- Visual Studiogenerators, CMake and CTest no longer require- CMAKE_MAKE_PROGRAMto be located up front. Selection of the proper msbuild or devenv tool is now performed as late as possible when the solution (- .sln) file is available so it can depend on project content.
- The - cmake(1)- --buildcommand now shares its own stdout and stderr pipes with the native build tool by default. The- --use-stderroption that once activated this is now ignored.
- The - $<C_COMPILER_ID:...>and- $<CXX_COMPILER_ID:...>- generator expressionsused to perform case-insensitive comparison but have now been corrected to perform case-sensitive comparison. See policy- CMP0044.
- The builtin - edit_cachetarget will no longer select- ccmake(1)by default when no interactive terminal will be available (e.g. with- Ninjaor an IDE generator). Instead- cmake-gui(1)will be preferred if available.
- The - ExternalProjectdownload step learned to re-attempt download in certain cases to be more robust to temporary network failure.
- The - FeatureSummaryno longer lists transitive dependencies since they were not directly requested by the current project.
- The - cmake-mode.elmajor Emacs editing mode has been cleaned up and enhanced in several ways.
- Include directories specified in the - INTERFACE_INCLUDE_DIRECTORIESof Imported Targets are treated as- SYSTEMincludes by default when handled as usage requirements.
