CMAKE-GENERATOR-EXPRESSIONS(7) CMake CMAKE-GENERATOR-EXPRESSIONS(7)
NAME
cmake-generator-expressions - CMake Generator Expressions
INTRODUCTION
Generator expressions are evaluated during build system generation to
produce information specific to each build configuration.
Generator expressions are allowed in the context of many target proper-
ties, such as LINK_LIBRARIES, INCLUDE_DIRECTORIES, COMPILE_DEFINITIONS
and others. They may also be used when using commands to populate
those properties, such as target_link_libraries(), target_include_di-
rectories(), target_compile_definitions() and others.
They enable conditional linking, conditional definitions used when com-
piling, conditional include directories, and more. The conditions may
be based on the build configuration, target properties, platform infor-
mation or any other queryable information.
Generator expressions have the form $<...>. To avoid confusion, this
page deviates from most of the CMake documentation in that it omits an-
gular brackets <...> around placeholders like condition, string, tar-
get, among others.
Generator expressions can be nested, as shown in most of the examples
below.
BOOLEAN GENERATOR EXPRESSIONS
Boolean expressions evaluate to either 0 or 1. They are typically used
to construct the condition in a conditional generator expression.
Available boolean expressions are:
Logical Operators
$<BOOL:string>
Converts string to 0 or 1. Evaluates to 0 if any of the follow-
ing is true:
• string is empty,
• string is a case-insensitive equal of 0, FALSE, OFF, N, NO,
IGNORE, or NOTFOUND, or
• string ends in the suffix -NOTFOUND (case-sensitive).
Otherwise evaluates to 1.
$<AND:conditions>
where conditions is a comma-separated list of boolean expres-
sions. Evaluates to 1 if all conditions are 1. Otherwise eval-
uates to 0.
$<OR:conditions>
where conditions is a comma-separated list of boolean expres-
sions. 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.
String Comparisons
$<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>
New in version 3.12.
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>
New in version 3.7.
1 if v1 is a version less than or equal to v2, else 0.
$<VERSION_GREATER_EQUAL:v1,v2>
New in version 3.7.
1 if v1 is a version greater than or equal to v2, else 0.
Variable Queries
$<TARGET_EXISTS:target>
New in version 3.12.
1 if target exists, else 0.
$<CONFIG:cfgs>
1 if config is any one of the entries in comma-separated list
cfgs, else 0. This is a case-insensitive comparison. The mapping
in MAP_IMPORTED_CONFIG_<CONFIG> is also considered by this ex-
pression when it is evaluated on a property on an IMPORTED tar-
get.
$<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, oth-
erwise 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>_COM-
PILER_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>_COM-
PILER_ID variable.
$<CUDA_COMPILER_ID:compiler_ids>
New in version 3.15.
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>_COM-
PILER_ID variable.
$<OBJC_COMPILER_ID:compiler_ids>
New in version 3.16.
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>
New in version 3.16.
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 en-
tries in compiler_ids, otherwise 0. See also the
CMAKE_<LANG>_COMPILER_ID variable.
$<HIP_COMPILER_ID:compiler_ids>
where compiler_ids is a comma-separated list. 1 if the CMake's
compiler id of the HIP compiler matches any one of the entries
in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COM-
PILER_ID variable.
$<ISPC_COMPILER_ID:compiler_ids>
New in version 3.19.
where compiler_ids is a comma-separated list. 1 if the CMake's
compiler id of the ISPC compiler matches any one of the entries
in compiler_ids, otherwise 0. See also the CMAKE_<LANG>_COM-
PILER_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>
New in version 3.15.
1 if the version of the CXX compiler matches version, otherwise
0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.
$<OBJC_COMPILER_VERSION:version>
New in version 3.16.
1 if the version of the OBJC compiler matches version, otherwise
0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.
$<OBJCXX_COMPILER_VERSION:version>
New in version 3.16.
1 if the version of the OBJCXX compiler matches version, other-
wise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.
$<Fortran_COMPILER_VERSION:version>
1 if the version of the Fortran compiler matches version, other-
wise 0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.
$<HIP_COMPILER_VERSION:version>
1 if the version of the HIP compiler matches version, otherwise
0. See also the CMAKE_<LANG>_COMPILER_VERSION variable.
$<ISPC_COMPILER_VERSION:version>
New in version 3.19.
1 if the version of the ISPC 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 pol-
icy will be emitted. This generator expression only works for a
subset of policies.
$<COMPILE_FEATURES:features>
New in version 3.1.
where features is a comma-spearated list. Evaluates to 1 if all
of the features are available for the 'head' target, and 0 oth-
erwise. If this expression is used while evaluating the link im-
plementation of a target and if any dependency transitively in-
creases 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 sup-
ported compilers.
$<COMPILE_LANG_AND_ID:language,compiler_ids>
New in version 3.15.
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:lan-
guage> and $<LANG_COMPILER_ID:compiler_ids>. This expression may
be used to specify compile options, compile definitions, and in-
clude 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>
New in version 3.3.
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 di-
rectories 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 direc-
tory for C++ only (compiler id checks elided). It also speci-
fies 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 di-
rectories 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, ex-
pressions for both C and C++ sources will be evaluated using CXX
if there are any C++ sources and otherwise using C. A work-
around is to create separate libraries for each source file lan-
guage 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>
New in version 3.18.
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 con-
straints about the usage of this generator expression.
$<LINK_LANGUAGE:languages>
New in version 3.18.
1 when the language used for link step matches any of the en-
tries 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:
To determine the link language of a target, it is required to
collect, transitively, all the targets which will be linked
to it. So, for link libraries properties, a double evaluation
will be done. During the first evaluation, $<LINK_LAN-
GUAGE:..> expressions will always return 0. The link lan-
guage computed after this first pass will be used to do the
second pass. To avoid inconsistency, it is required that the
second pass do not change the link language. Moreover, to
avoid unexpected side-effects, it is required to specify com-
plete entities as part of the $<LINK_LANGUAGE:..> expression.
For example:
add_library(lib STATIC file.cxx)
add_library(libother STATIC file.c)
# bad usage
add_executable(myapp1 main.c)
target_link_libraries(myapp1 PRIVATE lib$<$<LINK_LANGUAGE:C>:other>)
# correct usage
add_executable(myapp2 main.c)
target_link_libraries(myapp2 PRIVATE $<$<LINK_LANGUAGE:C>:libother>)
In this example, for myapp1, the first pass will, unexpect-
edly, determine that the link language is CXX because the
evaluation of the generator expression will be an empty
string so myapp1 will depends on target lib which is C++. On
the contrary, for myapp2, the first evaluation will give C as
link language, so the second pass will correctly add target
libother as link dependency.
$<DEVICE_LINK:list>
New in version 3.18.
Returns the list if it is the device link step, an empty list
otherwise. The device link step is controlled by CUDA_SEPARA-
BLE_COMPILATION and CUDA_RESOLVE_DEVICE_SYMBOLS properties and
policy CMP0105. This expression can only be used to specify link
options.
$<HOST_LINK:list>
New in version 3.18.
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 $<DEVICE_LINK:list> generator expres-
sion). This expression can only be used to specify link options.
STRING-VALUED GENERATOR EXPRESSIONS
These expressions expand to some string. For example,
include_directories(/usr/include/$<CXX_COMPILER_ID>/)
expands to /usr/include/GNU/ or /usr/include/Clang/ etc, depending on
the compiler identifier.
String-valued expressions may also be combined with other expressions.
Here an example for a string-valued expression within a boolean expres-
sions within a conditional expression:
$<$<VERSION_LESS:$<CXX_COMPILER_VERSION>,4.2.0>:OLD_COMPILER>
expands to OLD_COMPILER if the CMAKE_CXX_COMPILER_VERSION is less than
4.2.0.
And here two nested string-valued expressions:
-I$<JOIN:$<TARGET_PROPERTY:INCLUDE_DIRECTORIES>, -I>
generates a string of the entries in the INCLUDE_DIRECTORIES target
property with each entry preceded by -I.
Expanding on the previous example, if one first wants to check if the
INCLUDE_DIRECTORIES property is non-empty, then it is advisable to in-
troduce a helper variable to keep the code readable:
set(prop "$<TARGET_PROPERTY:INCLUDE_DIRECTORIES>") # helper variable
$<$<BOOL:${prop}>:-I$<JOIN:${prop}, -I>>
The following string-valued generator expressions are available:
Escaped Characters
String literals to escape the special meaning a character would other-
wise have:
$<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
;.
Conditional Expressions
Conditional generator expressions depend on a boolean condition that
must be 0 or 1.
$<condition:true_string>
Evaluates to true_string if condition is 1. Otherwise evaluates
to the empty string.
$<IF:condition,true_string,false_string>
New in version 3.8.
Evaluates to true_string if condition is 1. Otherwise evaluates
to false_string.
Typically, the condition is a boolean generator expression. For in-
stance,
$<$<CONFIG:Debug>:DEBUG_MODE>
expands to DEBUG_MODE when the Debug configuration is used, and other-
wise expands to the empty string.
String Transformations
$<JOIN:list,string>
Joins the list with the content of string.
$<REMOVE_DUPLICATES:list>
New in version 3.15.
Removes duplicated items in the given list.
$<FILTER:list,INCLUDE|EXCLUDE,regex>
New in version 3.15.
Includes or removes items from list that match the regular ex-
pression regex.
$<LOWER_CASE:string>
Content of string converted to lower case.
$<UPPER_CASE:string>
Content of string converted to upper case.
$<GENEX_EVAL:expr>
New in version 3.12.
Content of expr evaluated as a generator expression in the cur-
rent context. This enables consumption of generator expressions
whose evaluation results itself in generator expressions.
$<TARGET_GENEX_EVAL:tgt,expr>
New in version 3.12.
Content of expr evaluated as a generator expression in the con-
text 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 gen-
erator 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_EX-
TRA_THINGS>).
To have the expected result (i.e. FOO_EXTRA_THINGS if config is
Debug), it is required to evaluate the output of $<TARGET_PROP-
ERTY:foo,CUSTOM_KEYS>:
add_custom_target(printFooKeys
COMMAND ${CMAKE_COMMAND} -E
echo $<TARGET_GENEX_EVAL:foo,$<TARGET_PROPERTY:foo,CUSTOM_KEYS>>
)
Variable Queries
$<CONFIG>
Configuration name.
$<CONFIGURATION>
Configuration name. Deprecated since CMake 3.0. Use CONFIG in-
stead.
$<PLATFORM_ID>
The current system's CMake platform id. See also the CMAKE_SYS-
TEM_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>
New in version 3.16.
The CMake's compiler id of the OBJC compiler used. See also the
CMAKE_<LANG>_COMPILER_ID variable.
$<OBJCXX_COMPILER_ID>
New in version 3.16.
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.
$<HIP_COMPILER_ID>
The CMake's compiler id of the HIP compiler used. See also the
CMAKE_<LANG>_COMPILER_ID variable.
$<ISPC_COMPILER_ID>
New in version 3.19.
The CMake's compiler id of the ISPC 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>
New in version 3.16.
The version of the OBJC compiler used. See also the
CMAKE_<LANG>_COMPILER_VERSION variable.
$<OBJCXX_COMPILER_VERSION>
New in version 3.16.
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.
$<HIP_COMPILER_VERSION>
The version of the HIP compiler used. See also the
CMAKE_<LANG>_COMPILER_VERSION variable.
$<ISPC_COMPILER_VERSION>
New in version 3.19.
The version of the ISPC compiler used. See also the
CMAKE_<LANG>_COMPILER_VERSION variable.
$<COMPILE_LANGUAGE>
New in version 3.3.
The compile language of source files when evaluating compile op-
tions. See the related boolean expression $<COMPILE_LAN-
GUAGE:language> for notes about the portability of this genera-
tor expression.
$<LINK_LANGUAGE>
New in version 3.18.
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:
This generator expression is not supported by the link li-
braries properties to avoid side-effects due to the double
evaluation of these properties.
Target-Dependent Queries
These queries refer to a target tgt. This can be any runtime artifact,
namely:
• 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()
In the following, "the tgt filename" means the name of the tgt binary
file. This has to be distinguished from "the target name", which is
just the string tgt.
$<TARGET_NAME_IF_EXISTS:tgt>
New in version 3.12.
The target name tgt if the target exists, an empty string other-
wise.
Note that tgt is not added as a dependency of the target this
expression is evaluated on.
$<TARGET_FILE:tgt>
Full path to the tgt binary file.
$<TARGET_FILE_BASE_NAME:tgt>
New in version 3.15.
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_OUT-
PUT_NAME and RUNTIME_OUTPUT_NAME target properties and their
configuration specific variants OUTPUT_NAME_<CONFIG>, AR-
CHIVE_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>
New in version 3.15.
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>
New in version 3.15.
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.
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<TARGET_FILE_DIR:tgt>
Directory of the tgt binary file.
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<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 li-
brary associated with the DLL.
$<TARGET_LINKER_FILE_BASE_NAME:tgt>
New in version 3.15.
Base name of file used to link the target tgt, i.e. $<TAR-
GET_LINKER_FILE_NAME:tgt> without prefix and suffix. For exam-
ple, if target file name is libbase.a, the base name is base.
See also the OUTPUT_NAME, ARCHIVE_OUTPUT_NAME, and LIBRARY_OUT-
PUT_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>
New in version 3.15.
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>
New in version 3.15.
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.
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<TARGET_LINKER_FILE_DIR:tgt>
Directory of file used to link target tgt.
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<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).
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<TARGET_SONAME_FILE_DIR:tgt>
Directory of with soname (.so.3).
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<TARGET_PDB_FILE:tgt>
New in version 3.1.
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>
New in version 3.15.
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 ex-
ample, if target file name is base.pdb, the base name is base.
See also the PDB_NAME target property and its configuration spe-
cific 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>
New in version 3.1.
Name of the linker generated program database file (.pdb).
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<TARGET_PDB_FILE_DIR:tgt>
New in version 3.1.
Directory of the linker generated program database file (.pdb).
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<TARGET_BUNDLE_DIR:tgt>
New in version 3.9.
Full path to the bundle directory (my.app, my.framework, or
my.bundle) where tgt is the name of a target.
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<TARGET_BUNDLE_CONTENT_DIR:tgt>
New in version 3.9.
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.
Note that tgt is not added as a dependency of the target this
expression is evaluated on (see policy CMP0112).
$<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 expres-
sion is being evaluated. Note that for generator expressions in
Target Usage Requirements this is the consuming target rather
than the target specifying the requirement.
$<TARGET_RUNTIME_DLLS:tgt>
New in version 3.21.
List of DLLs that the target depends on at runtime. This is de-
termined by the locations of all the SHARED and MODULE targets
in the target's transitive dependencies. Using this generator
expression on targets other than executables, SHARED libraries,
and MODULE libraries is an error. On non-DLL platforms, it
evaluates to an empty string.
This generator expression can be used to copy all of the DLLs
that a target depends on into its output directory in a
POST_BUILD custom command. For example:
find_package(foo CONFIG REQUIRED) # package generated by install(EXPORT)
add_executable(exe main.c)
target_link_libraries(exe PRIVATE foo::foo foo::bar)
add_custom_command(TARGET exe POST_BUILD
COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_RUNTIME_DLLS:exe> $<TARGET_FILE_DIR:exe>
COMMAND_EXPAND_LISTS
)
NOTE:
Imported Targets are supported only if they know the location
of their .dll files. An imported SHARED or MODULE library
must have IMPORTED_LOCATION set to its .dll file. See the
add_library imported libraries section for details. Many
Find Modules produce imported targets with the UNKNOWN type
and therefore will be ignored.
$<INSTALL_PREFIX>
Content of the install prefix when the target is exported via
install(EXPORT), or when evaluated in the INSTALL_NAME_DIR prop-
erty or the INSTALL_NAME_DIR argument of install(RUNTIME_DEPEN-
DENCY_SET), and empty otherwise.
Output-Related Expressions
$<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:...>
New in version 3.1.
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_LI-
BRARIES target property, perhaps via the target_link_libraries()
command, to specify private link dependencies without other us-
age requirements.
$<INSTALL_INTERFACE:...>
Content of ... when the property is exported using install(EX-
PORT), 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 buildsys-
tem. Expands to the empty string otherwise.
$<MAKE_C_IDENTIFIER:...>
Content of ... converted to a C identifier. The conversion fol-
lows the same behavior as string(MAKE_C_IDENTIFIER).
$<TARGET_OBJECTS:objLib>
New in version 3.1.
List of objects resulting from build of objLib.
$<SHELL_PATH:...>
New in version 3.4.
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.
New in version 3.14: 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 con-
taining this genex in double quotes in CMake source code so that
; does not split arguments.
$<OUTPUT_CONFIG:...>
New in version 3.20.
Only valid in add_custom_command() and add_custom_target() as
the outer-most generator expression in an argument. With the
Ninja Multi-Config generator, generator expressions in ... are
evaluated using the custom command's "output config". With
other generators, the content of ... is evaluated normally.
$<COMMAND_CONFIG:...>
New in version 3.20.
Only valid in add_custom_command() and add_custom_target() as
the outer-most generator expression in an argument. With the
Ninja Multi-Config generator, generator expressions in ... are
evaluated using the custom command's "command config". With
other generators, the content of ... is evaluated normally.
DEBUGGING
Since generator expressions are evaluated during generation of the
buildsystem, and not during processing of CMakeLists.txt files, it is
not possible to inspect their result with the message() command.
One possible way to generate debug messages is to add a custom target,
add_custom_target(genexdebug COMMAND ${CMAKE_COMMAND} -E echo "$<...>")
The shell command make genexdebug (invoked after execution of cmake)
would then print the result of $<...>.
Another way is to write debug messages to a file:
file(GENERATE OUTPUT filename CONTENT "$<...>")
COPYRIGHT
2000-2024 Kitware, Inc. and Contributors
3.22.1 February 03, 2024CMAKE-GENERATOR-EXPRESSIONS(7)
Generated by dwww version 1.14 on Sun Dec 22 08:42:30 CET 2024.