$<BOOL:string>

Converts string to 0 or 1. Evaluates to 0 if any of the following is true:

Otherwise evaluates to 1.

$<AND:conditions>

where conditions is a comma-separated list of boolean expressions. Evaluates to 1 if all conditions are 1. Otherwise evaluates to 0.

$<OR:conditions>

where conditions is a comma-separated list of boolean expressions. Evaluates to 1 if at least one of the conditions is 1. Otherwise evaluates to 0.

$<NOT:condition>

0 if condition is 1, else 1.

$<STREQUAL:string1,string2>

1 if string1 and string2 are equal, else 0. The comparison is case-sensitive. For a case-insensitive comparison, combine with a string transforming generator expression,

$<STREQUAL:$<UPPER_CASE:${foo}>,"BAR"> # "1" if ${foo} is any of "BAR", "Bar", "bar", ...

$<EQUAL:value1,value2>

1 if value1 and value2 are numerically equal, else 0.

$<IN_LIST:string,list>

1 if string is member of the semicolon-separated list, else 0. Uses case-sensitive comparisons.

$<VERSION_LESS:v1,v2>

1 if v1 is a version less than v2, else 0.

$<VERSION_GREATER:v1,v2>

1 if v1 is a version greater than v2, else 0.

$<VERSION_EQUAL:v1,v2>

1 if v1 is the same version as v2, else 0.

$<VERSION_LESS_EQUAL:v1,v2>

1 if v1 is a version less than or equal to v2, else 0.

$<VERSION_GREATER_EQUAL:v1,v2>

1 if v1 is a version greater than or equal to v2, else 0.

$<TARGET_EXISTS:target>

1 if target exists, else 0.

$<CONFIG:cfg>

1 if config is cfg, else 0. This is a case-insensitive comparison. The mapping in MAP_IMPORTED_CONFIG_<CONFIG> is also considered by this expression when it is evaluated on a property on an IMPORTED target.

$<PLATFORM_ID:platform_ids>

where platform_ids is a comma-separated list. 1 if the CMake’s platform id matches any one of the entries in platform_ids, otherwise 0. See also the CMAKE_SYSTEM_NAME variable.

$<C_COMPILER_ID:compiler_ids>

where compiler_ids is a comma-separated list. 1 if the CMake’s compiler id of the C compiler matches any one of the entries in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<CXX_COMPILER_ID:compiler_ids>

where compiler_ids is a comma-separated list. 1 if the CMake’s compiler id of the CXX compiler matches any one of the entries in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<CUDA_COMPILER_ID:compiler_ids>

where compiler_ids is a comma-separated list. 1 if the CMake’s compiler id of the CUDA compiler matches any one of the entries in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<OBJC_COMPILER_ID:compiler_ids>

where compiler_ids is a comma-separated list. 1 if the CMake’s compiler id of the Objective-C compiler matches any one of the entries in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<OBJCXX_COMPILER_ID:compiler_ids>

where compiler_ids is a comma-separated list. 1 if the CMake’s compiler id of the Objective-C++ compiler matches any one of the entries in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<Fortran_COMPILER_ID:compiler_ids>

where compiler_ids is a comma-separated list. 1 if the CMake’s compiler id of the Fortran compiler matches any one of the entries in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<C_COMPILER_VERSION:version>

1 if the version of the C compiler matches version, otherwise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<CXX_COMPILER_VERSION:version>

1 if the version of the CXX compiler matches version, otherwise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<CUDA_COMPILER_VERSION:version>

1 if the version of the CXX compiler matches version, otherwise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<OBJC_COMPILER_VERSION:version>

1 if the version of the OBJC compiler matches version, otherwise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<OBJCXX_COMPILER_VERSION:version>

1 if the version of the OBJCXX compiler matches version, otherwise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<Fortran_COMPILER_VERSION:version>

1 if the version of the Fortran compiler matches version, otherwise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<TARGET_POLICY:policy>

1 if the policy was NEW when the ‘head’ target was created, else 0. If the policy was not set, the warning message for the policy will be emitted. This generator expression only works for a subset of policies.

$<COMPILE_FEATURES:features>

where features is a comma-spearated list. Evaluates to 1 if all of the features are available for the ‘head’ target, and 0 otherwise. If this expression is used while evaluating the link implementation of a target and if any dependency transitively increases the required C_STANDARD or CXX_STANDARD for the ‘head’ target, an error is reported. See the cmake-compile-features(7) manual for information on compile features and a list of supported compilers.

$<COMPILE_LANG_AND_ID:language,compiler_ids>

1 when the language used for compilation unit matches language and the CMake’s compiler id of the language compiler matches any one of the entries in compiler_ids, otherwise 0. This expression is a short form for the combination of $<COMPILE_LANGUAGE:language> and $<LANG_COMPILER_ID:compiler_ids>. This expression may be used to specify compile options, compile definitions, and include directories for source files of a particular language and compiler combination in a target. For example:

add_executable(myapp main.cpp foo.c bar.cpp zot.cu)
target_compile_definitions(myapp


  PRIVATE $<$<COMPILE_LANG_AND_ID:CXX,AppleClang,Clang>:COMPILING_CXX_WITH_CLANG>


          $<$<COMPILE_LANG_AND_ID:CXX,Intel>:COMPILING_CXX_WITH_INTEL>


          $<$<COMPILE_LANG_AND_ID:C,Clang>:COMPILING_C_WITH_CLANG>
)

This specifies the use of different compile definitions based on both the compiler id and compilation language. This example will have a COMPILING_CXX_WITH_CLANG compile definition when Clang is the CXX compiler, and COMPILING_CXX_WITH_INTEL when Intel is the CXX compiler. Likewise when the C compiler is Clang it will only see the COMPILING_C_WITH_CLANG definition.

Without the COMPILE_LANG_AND_ID generator expression the same logic would be expressed as:

target_compile_definitions(myapp


  PRIVATE $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:AppleClang,Clang>>:COMPILING_CXX_WITH_CLANG>


          $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:Intel>>:COMPILING_CXX_WITH_INTEL>


          $<$<AND:$<COMPILE_LANGUAGE:C>,$<C_COMPILER_ID:Clang>>:COMPILING_C_WITH_CLANG>
)

$<COMPILE_LANGUAGE:languages>

1 when the language used for compilation unit matches any of the entries in languages, otherwise 0. This expression may be used to specify compile options, compile definitions, and include directories for source files of a particular language in a target. For example:

add_executable(myapp main.cpp foo.c bar.cpp zot.cu)
target_compile_options(myapp


  PRIVATE $<$<COMPILE_LANGUAGE:CXX>:-fno-exceptions>
)
target_compile_definitions(myapp


  PRIVATE $<$<COMPILE_LANGUAGE:CXX>:COMPILING_CXX>


          $<$<COMPILE_LANGUAGE:CUDA>:COMPILING_CUDA>
)
target_include_directories(myapp


  PRIVATE $<$<COMPILE_LANGUAGE:CXX,CUDA>:/opt/foo/headers>
)

This specifies the use of the -fno-exceptions compile option, COMPILING_CXX compile definition, and cxx_headers include directory for C++ only (compiler id checks elided). It also specifies a COMPILING_CUDA compile definition for CUDA.

Note that with Visual Studio Generators and Xcode there is no way to represent target-wide compile definitions or include directories separately for C and CXX languages. Also, with Visual Studio Generators there is no way to represent target-wide flags separately for C and CXX languages. Under these generators, expressions for both C and C++ sources will be evaluated using CXX if there are any C++ sources and otherwise using C. A workaround is to create separate libraries for each source file language instead:

add_library(myapp_c foo.c)
add_library(myapp_cxx bar.cpp)
target_compile_options(myapp_cxx PUBLIC -fno-exceptions)
add_executable(myapp main.cpp)
target_link_libraries(myapp myapp_c myapp_cxx)

$<LINK_LANG_AND_ID:language,compiler_ids>

1 when the language used for link step matches language and the CMake’s compiler id of the language linker matches any one of the entries in compiler_ids, otherwise 0. This expression is a short form for the combination of $<LINK_LANGUAGE:language> and $<LANG_COMPILER_ID:compiler_ids>. This expression may be used to specify link libraries, link options, link directories and link dependencies of a particular language and linker combination in a target. For example:

add_library(libC_Clang ...)
add_library(libCXX_Clang ...)
add_library(libC_Intel ...)
add_library(libCXX_Intel ...)
add_executable(myapp main.c)
if (CXX_CONFIG)


  target_sources(myapp PRIVATE file.cxx)
endif()
target_link_libraries(myapp


  PRIVATE $<$<LINK_LANG_AND_ID:CXX,Clang,AppleClang>:libCXX_Clang>


          $<$<LINK_LANG_AND_ID:C,Clang,AppleClang>:libC_Clang>


          $<$<LINK_LANG_AND_ID:CXX,Intel>:libCXX_Intel>


          $<$<LINK_LANG_AND_ID:C,Intel>:libC_Intel>)

This specifies the use of different link libraries based on both the compiler id and link language. This example will have target libCXX_Clang as link dependency when Clang or AppleClang is the CXX linker, and libCXX_Intel when Intel is the CXX linker. Likewise when the C linker is Clang or AppleClang, target libC_Clang will be added as link dependency and libC_Intel when Intel is the C linker.

See the note related to $<LINK_LANGUAGE:language> for constraints about the usage of this generator expression.

$<LINK_LANGUAGE:languages>

1 when the language used for link step matches any of the entries in languages, otherwise 0. This expression may be used to specify link libraries, link options, link directories and link dependencies of a particular language in a target. For example:

add_library(api_C ...)
add_library(api_CXX ...)
add_library(api INTERFACE)
target_link_options(api INTERFACE $<$<LINK_LANGUAGE:C>:-opt_c>


                                    $<$<LINK_LANGUAGE:CXX>:-opt_cxx>)
target_link_libraries(api INTERFACE $<$<LINK_LANGUAGE:C>:api_C>


                                    $<$<LINK_LANGUAGE:CXX>:api_CXX>)
add_executable(myapp1 main.c)
target_link_options(myapp1 PRIVATE api)
add_executable(myapp2 main.cpp)
target_link_options(myapp2 PRIVATE api)

This specifies to use the api target for linking targets myapp1 and myapp2. In practice, myapp1 will link with target api_C and option -opt_c because it will use C as link language. And myapp2 will link with api_CXX and option -opt_cxx because CXX will be the link language.

NOTE:

add_library(lib STATIC file.cxx)
add_library(libother STATIC file.c)
# bad usage
add_executable(myapp1 main.c)
target_link_libraries(myapp1 PRIVATE lib$<$<LINK_LANGUAGE:C>:other>)
# correct usage
add_executable(myapp2 main.c)
target_link_libraries(myapp2 PRIVATE $<$<LINK_LANGUAGE:C>:libother>)

$<DEVICE_LINK:list>

Returns the list if it is the device link step, an empty list otherwise. The device link step is controlled by CUDA_SEPARABLE_COMPILATION and CUDA_RESOLVE_DEVICE_SYMBOLS properties and policy CMP0105. This expression can only be used to specify link options.

$<HOST_LINK:list>

Returns the list if it is the normal link step, an empty list otherwise. This expression is mainly useful when a device link step is also involved (see $<DEVICE_LINK:list> generator expression). This expression can only be used to specify link options.

$<ANGLE-R>

A literal >. Used for example to compare strings that contain a >.

$<COMMA>

A literal ,. Used for example to compare strings which contain a ,.

$<SEMICOLON>

A literal ;. Used to prevent list expansion on an argument with ;.

$<condition:true_string>

Evaluates to true_string if condition is 1. Otherwise evaluates to the empty string.

$<IF:condition,true_string,false_string>

Evaluates to true_string if condition is 1. Otherwise evaluates to false_string.

$<JOIN:list,string>

Joins the list with the content of string.

$<REMOVE_DUPLICATES:list>

Removes duplicated items in the given list.

$<FILTER:list,INCLUDE|EXCLUDE,regex>

Includes or removes items from list that match the regular expression regex.

$<LOWER_CASE:string>

Content of string converted to lower case.

$<UPPER_CASE:string>

Content of string converted to upper case.

$<GENEX_EVAL:expr>

Content of expr evaluated as a generator expression in the current context. This enables consumption of generator expressions whose evaluation results itself in generator expressions.

$<TARGET_GENEX_EVAL:tgt,expr>

Content of expr evaluated as a generator expression in the context of tgt target. This enables consumption of custom target properties that themselves contain generator expressions.

Having the capability to evaluate generator expressions is very useful when you want to manage custom properties supporting generator expressions. For example:

add_library(foo ...)
set_property(TARGET foo PROPERTY


  CUSTOM_KEYS $<$<CONFIG:DEBUG>:FOO_EXTRA_THINGS>
)
add_custom_target(printFooKeys


  COMMAND ${CMAKE_COMMAND} -E echo $<TARGET_PROPERTY:foo,CUSTOM_KEYS>
)

This naive implementation of the printFooKeys custom command is wrong because CUSTOM_KEYS target property is not evaluated and the content is passed as is (i.e. $<$<CONFIG:DEBUG>:FOO_EXTRA_THINGS>).

To have the expected result (i.e. FOO_EXTRA_THINGS if config is Debug), it is required to evaluate the output of $<TARGET_PROPERTY:foo,CUSTOM_KEYS>:

add_custom_target(printFooKeys


  COMMAND ${CMAKE_COMMAND} -E


    echo $<TARGET_GENEX_EVAL:foo,$<TARGET_PROPERTY:foo,CUSTOM_KEYS>>
)

$<CONFIG>

Configuration name.

$<CONFIGURATION>

Configuration name. Deprecated since CMake 3.0. Use CONFIG instead.

$<PLATFORM_ID>

The current system’s CMake platform id. See also the CMAKE_SYSTEM_NAME variable.

$<C_COMPILER_ID>

The CMake’s compiler id of the C compiler used. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<CXX_COMPILER_ID>

The CMake’s compiler id of the CXX compiler used. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<CUDA_COMPILER_ID>

The CMake’s compiler id of the CUDA compiler used. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<OBJC_COMPILER_ID>

The CMake’s compiler id of the OBJC compiler used. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<OBJCXX_COMPILER_ID>

The CMake’s compiler id of the OBJCXX compiler used. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<Fortran_COMPILER_ID>

The CMake’s compiler id of the Fortran compiler used. See also the CMAKE_<LANG>_COMPILER_ID variable.

$<C_COMPILER_VERSION>

The version of the C compiler used. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<CXX_COMPILER_VERSION>

The version of the CXX compiler used. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<CUDA_COMPILER_VERSION>

The version of the CUDA compiler used. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<OBJC_COMPILER_VERSION>

The version of the OBJC compiler used. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<OBJCXX_COMPILER_VERSION>

The version of the OBJCXX compiler used. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<Fortran_COMPILER_VERSION>

The version of the Fortran compiler used. See also the CMAKE_<LANG>_COMPILER_VERSION variable.

$<COMPILE_LANGUAGE>

The compile language of source files when evaluating compile options. See the related boolean expression $<COMPILE_LANGUAGE:language> for notes about the portability of this generator expression.

$<LINK_LANGUAGE>

The link language of target when evaluating link options. See the related boolean expression $<LINK_LANGUAGE:language> for notes about the portability of this generator expression.

NOTE:

• an executable target created by add_executable()
• a shared library target (.so, .dll but not their .lib import library) created by add_library()
• a static library target created by add_library()

$<TARGET_NAME_IF_EXISTS:tgt>

The target name tgt if the target exists, an empty string otherwise.

$<TARGET_FILE:tgt>

Full path to the tgt binary file.

$<TARGET_FILE_BASE_NAME:tgt>

Base name of tgt, i.e. $<TARGET_FILE_NAME:tgt> without prefix and suffix. For example, if the tgt filename is libbase.so, the base name is base.

See also the OUTPUT_NAME, ARCHIVE_OUTPUT_NAME, LIBRARY_OUTPUT_NAME and RUNTIME_OUTPUT_NAME target properties and their configuration specific variants OUTPUT_NAME_<CONFIG>, ARCHIVE_OUTPUT_NAME_<CONFIG>, LIBRARY_OUTPUT_NAME_<CONFIG> and RUNTIME_OUTPUT_NAME_<CONFIG>.

The <CONFIG>_POSTFIX and DEBUG_POSTFIX target properties can also be considered.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_FILE_PREFIX:tgt>

Prefix of the tgt filename (such as lib).

See also the PREFIX target property.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_FILE_SUFFIX:tgt>

Suffix of the tgt filename (extension such as .so or .exe).

See also the SUFFIX target property.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_FILE_NAME:tgt>

The tgt filename.

$<TARGET_FILE_DIR:tgt>

Directory of the tgt binary file.

$<TARGET_LINKER_FILE:tgt>

File used when linking to the tgt target. This will usually be the library that tgt represents (.a, .lib, .so), but for a shared library on DLL platforms, it would be the .lib import library associated with the DLL.

$<TARGET_LINKER_FILE_BASE_NAME:tgt>

Base name of file used to link the target tgt, i.e. $<TARGET_LINKER_FILE_NAME:tgt> without prefix and suffix. For example, if target file name is libbase.a, the base name is base.

See also the OUTPUT_NAME, ARCHIVE_OUTPUT_NAME, and LIBRARY_OUTPUT_NAME target properties and their configuration specific variants OUTPUT_NAME_<CONFIG>, ARCHIVE_OUTPUT_NAME_<CONFIG> and LIBRARY_OUTPUT_NAME_<CONFIG>.

The <CONFIG>_POSTFIX and DEBUG_POSTFIX target properties can also be considered.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_LINKER_FILE_PREFIX:tgt>

Prefix of file used to link target tgt.

See also the PREFIX and IMPORT_PREFIX target properties.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_LINKER_FILE_SUFFIX:tgt>

Suffix of file used to link where tgt is the name of a target.

The suffix corresponds to the file extension (such as “.so” or “.lib”).

See also the SUFFIX and IMPORT_SUFFIX target properties.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_LINKER_FILE_NAME:tgt>

Name of file used to link target tgt.

$<TARGET_LINKER_FILE_DIR:tgt>

Directory of file used to link target tgt.

$<TARGET_SONAME_FILE:tgt>

File with soname (.so.3) where tgt is the name of a target.

$<TARGET_SONAME_FILE_NAME:tgt>

Name of file with soname (.so.3).

$<TARGET_SONAME_FILE_DIR:tgt>

Directory of with soname (.so.3).

$<TARGET_PDB_FILE:tgt>

Full path to the linker generated program database file (.pdb) where tgt is the name of a target.

See also the PDB_NAME and PDB_OUTPUT_DIRECTORY target properties and their configuration specific variants PDB_NAME_<CONFIG> and PDB_OUTPUT_DIRECTORY_<CONFIG>.

$<TARGET_PDB_FILE_BASE_NAME:tgt>

Base name of the linker generated program database file (.pdb) where tgt is the name of a target.

The base name corresponds to the target PDB file name (see $<TARGET_PDB_FILE_NAME:tgt>) without prefix and suffix. For example, if target file name is base.pdb, the base name is base.

See also the PDB_NAME target property and its configuration specific variant PDB_NAME_<CONFIG>.

The <CONFIG>_POSTFIX and DEBUG_POSTFIX target properties can also be considered.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_PDB_FILE_NAME:tgt>

Name of the linker generated program database file (.pdb).

$<TARGET_PDB_FILE_DIR:tgt>

Directory of the linker generated program database file (.pdb).

$<TARGET_BUNDLE_DIR:tgt>

Full path to the bundle directory (my.app, my.framework, or my.bundle) where tgt is the name of a target.

$<TARGET_BUNDLE_CONTENT_DIR:tgt>

Full path to the bundle content directory where tgt is the name of a target. For the macOS SDK it leads to my.app/Contents, my.framework, or my.bundle/Contents. For all other SDKs (e.g. iOS) it leads to my.app, my.framework, or my.bundle due to the flat bundle structure.

$<TARGET_PROPERTY:tgt,prop>

Value of the property prop on the target tgt.

Note that tgt is not added as a dependency of the target this expression is evaluated on.

$<TARGET_PROPERTY:prop>

Value of the property prop on the target for which the expression is being evaluated. Note that for generator expressions in Target Usage Requirements this is the consuming target rather than the target specifying the requirement.

$<INSTALL_PREFIX>

Content of the install prefix when the target is exported via install(EXPORT), or when evaluated in INSTALL_NAME_DIR, and empty otherwise.

$<TARGET_NAME:...>

Marks ... as being the name of a target. This is required if exporting targets to multiple dependent export sets. The ... must be a literal name of a target- it may not contain generator expressions.

$<LINK_ONLY:...>

Content of ... except when evaluated in a link interface while propagating Target Usage Requirements, in which case it is the empty string. Intended for use only in an INTERFACE_LINK_LIBRARIES target property, perhaps via the target_link_libraries() command, to specify private link dependencies without other usage requirements.

$<INSTALL_INTERFACE:...>

Content of ... when the property is exported using install(EXPORT), and empty otherwise.

$<BUILD_INTERFACE:...>

Content of ... when the property is exported using export(), or when the target is used by another target in the same buildsystem. Expands to the empty string otherwise.

$<MAKE_C_IDENTIFIER:...>

Content of ... converted to a C identifier. The conversion follows the same behavior as string(MAKE_C_IDENTIFIER).

$<TARGET_OBJECTS:objLib>

List of objects resulting from build of objLib.

$<SHELL_PATH:...>

Content of ... converted to shell path style. For example, slashes are converted to backslashes in Windows shells and drive letters are converted to posix paths in MSYS shells. The ... must be an absolute path. The ... may be a semicolon-separated list of paths, in which case each path is converted individually and a result list is generated using the shell path separator (: on POSIX and ; on Windows). Be sure to enclose the argument containing this genex in double quotes in CMake source code so that ; does not split arguments.