|
|
|
.. cmake-manual-description: CMake Generator Expressions
|
|
|
|
|
|
|
|
cmake-generator-expressions(7)
|
|
|
|
******************************
|
|
|
|
|
|
|
|
.. only:: html
|
|
|
|
|
|
|
|
.. contents::
|
|
|
|
|
|
|
|
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 properties,
|
|
|
|
such as :prop_tgt:`LINK_LIBRARIES`, :prop_tgt:`INCLUDE_DIRECTORIES`,
|
|
|
|
:prop_tgt:`COMPILE_DEFINITIONS` and others. They may also be used when using
|
|
|
|
commands to populate those properties, such as :command:`target_link_libraries`,
|
|
|
|
:command:`target_include_directories`, :command:`target_compile_definitions`
|
|
|
|
and others.
|
|
|
|
|
|
|
|
This means that they enable conditional linking, conditional
|
|
|
|
definitions used when compiling, and conditional include directories and
|
|
|
|
more. The conditions may be based on the build configuration, target
|
|
|
|
properties, platform information or any other queryable information.
|
|
|
|
|
|
|
|
Logical Expressions
|
|
|
|
===================
|
|
|
|
|
|
|
|
Logical expressions are used to create conditional output. The basic
|
|
|
|
expressions are the ``0`` and ``1`` expressions. Because other logical
|
|
|
|
expressions evaluate to either ``0`` or ``1``, they can be composed to
|
|
|
|
create conditional output::
|
|
|
|
|
|
|
|
$<$<CONFIG:Debug>:DEBUG_MODE>
|
|
|
|
|
|
|
|
expands to ``DEBUG_MODE`` when the ``Debug`` configuration is used, and
|
|
|
|
otherwise expands to nothing.
|
|
|
|
|
|
|
|
Available logical expressions are:
|
|
|
|
|
|
|
|
``$<BOOL:...>``
|
|
|
|
``1`` if the ``...`` is true, else ``0``
|
|
|
|
``$<AND:?[,?]...>``
|
|
|
|
``1`` if all ``?`` are ``1``, else ``0``
|
|
|
|
|
|
|
|
The ``?`` must always be either ``0`` or ``1`` in boolean expressions.
|
|
|
|
|
|
|
|
``$<OR:?[,?]...>``
|
|
|
|
``0`` if all ``?`` are ``0``, else ``1``
|
|
|
|
``$<NOT:?>``
|
|
|
|
``0`` if ``?`` is ``1``, else ``1``
|
|
|
|
``$<STREQUAL:a,b>``
|
|
|
|
``1`` if ``a`` is STREQUAL ``b``, else ``0``
|
|
|
|
``$<EQUAL:a,b>``
|
|
|
|
``1`` if ``a`` is EQUAL ``b`` in a numeric comparison, else ``0``
|
|
|
|
``$<CONFIG:cfg>``
|
|
|
|
``1`` if config is ``cfg``, else ``0``. This is a case-insensitive comparison.
|
|
|
|
The mapping in :prop_tgt:`MAP_IMPORTED_CONFIG_<CONFIG>` is also considered by
|
|
|
|
this expression when it is evaluated on a property on an :prop_tgt:`IMPORTED`
|
|
|
|
target.
|
|
|
|
``$<PLATFORM_ID:comp>``
|
|
|
|
``1`` if the CMake-id of the platform matches ``comp``, otherwise ``0``.
|
|
|
|
``$<C_COMPILER_ID:comp>``
|
|
|
|
``1`` if the CMake-id of the C compiler matches ``comp``, otherwise ``0``.
|
|
|
|
``$<CXX_COMPILER_ID:comp>``
|
|
|
|
``1`` if the CMake-id of the CXX compiler matches ``comp``, otherwise ``0``.
|
|
|
|
``$<VERSION_GREATER:v1,v2>``
|
|
|
|
``1`` if ``v1`` is a version greater than ``v2``, else ``0``.
|
|
|
|
``$<VERSION_LESS:v1,v2>``
|
|
|
|
``1`` if ``v1`` is a version less than ``v2``, else ``0``.
|
|
|
|
``$<VERSION_EQUAL:v1,v2>``
|
|
|
|
``1`` if ``v1`` is the same version as ``v2``, else ``0``.
|
|
|
|
``$<C_COMPILER_VERSION:ver>``
|
|
|
|
``1`` if the version of the C compiler matches ``ver``, otherwise ``0``.
|
|
|
|
``$<CXX_COMPILER_VERSION:ver>``
|
|
|
|
``1`` if the version of the CXX compiler matches ``ver``, otherwise ``0``.
|
|
|
|
``$<TARGET_POLICY:pol>``
|
|
|
|
``1`` if the policy ``pol`` 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.
|
|
|
|
``$<COMPILE_FEATURES:feature[,feature]...>``
|
|
|
|
``1`` if all of the ``feature`` features are available for the 'head'
|
|
|
|
target, and ``0`` otherwise. If this expression is used while evaluating
|
|
|
|
the link implementation of a target and if any dependency transitively
|
|
|
|
increases the required :prop_tgt:`C_STANDARD` or :prop_tgt:`CXX_STANDARD`
|
|
|
|
for the 'head' target, an error is reported. See the
|
|
|
|
:manual:`cmake-compile-features(7)` manual for information on
|
|
|
|
compile features and a list of supported compilers.
|
|
|
|
``$<COMPILE_LANGUAGE:lang>``
|
|
|
|
``1`` when the language used for compilation unit matches ``lang``,
|
|
|
|
otherwise ``0``. This expression used to specify compile options for
|
|
|
|
source files of a particular language in a target. For example, to specify
|
|
|
|
the use of the ``-fno-exceptions`` compile option (compiler id checks
|
|
|
|
elided):
|
|
|
|
|
|
|
|
.. code-block:: cmake
|
|
|
|
|
|
|
|
add_executable(myapp main.cpp foo.c bar.cpp)
|
|
|
|
target_compile_options(myapp
|
|
|
|
PRIVATE $<$<COMPILE_LANGUAGE:CXX>:-fno-exceptions>
|
|
|
|
)
|
|
|
|
|
|
|
|
This generator expression has limited use because it is not possible to
|
|
|
|
use it with the Visual Studio generators. Portable buildsystems would
|
|
|
|
not use this expression, and would create separate libraries for each
|
|
|
|
source file language instead:
|
|
|
|
|
|
|
|
.. code-block:: cmake
|
|
|
|
|
|
|
|
add_library(myapp_c foo.c)
|
|
|
|
add_library(myapp_cxx foo.c)
|
|
|
|
target_compile_options(myapp_cxx PUBLIC -fno-exceptions)
|
|
|
|
add_executable(myapp main.cpp)
|
|
|
|
target_link_libraries(myapp myapp_c myapp_cxx)
|
|
|
|
|
|
|
|
The ``Makefile`` and ``Ninja`` based generators can also use this
|
|
|
|
expression to specify compile-language specific compile definitions
|
|
|
|
and include directories:
|
|
|
|
|
|
|
|
.. code-block:: cmake
|
|
|
|
|
|
|
|
add_executable(myapp main.cpp foo.c bar.cpp)
|
|
|
|
target_compile_definitions(myapp
|
|
|
|
PRIVATE $<$<COMPILE_LANGUAGE:CXX>:COMPILING_CXX>
|
|
|
|
)
|
|
|
|
target_include_directories(myapp
|
|
|
|
PRIVATE $<$<COMPILE_LANGUAGE:CXX>:/opt/foo/cxx_headers>
|
|
|
|
)
|
|
|
|
|
|
|
|
Informational Expressions
|
|
|
|
=========================
|
|
|
|
|
|
|
|
These expressions expand to some information. The information may be used
|
|
|
|
directly, eg::
|
|
|
|
|
|
|
|
include_directories(/usr/include/$<CXX_COMPILER_ID>/)
|
|
|
|
|
|
|
|
expands to ``/usr/include/GNU/`` or ``/usr/include/Clang/`` etc, depending on
|
|
|
|
the Id of the compiler.
|
|
|
|
|
|
|
|
These expressions may also may be combined with logical expressions::
|
|
|
|
|
|
|
|
$<$<VERSION_LESS:$<CXX_COMPILER_VERSION>,4.2.0>:OLD_COMPILER>
|
|
|
|
|
|
|
|
expands to ``OLD_COMPILER`` if the
|
|
|
|
:variable:`CMAKE_CXX_COMPILER_VERSION <CMAKE_<LANG>_COMPILER_VERSION>` is less
|
|
|
|
than 4.2.0.
|
|
|
|
|
|
|
|
Available informational expressions are:
|
|
|
|
|
|
|
|
``$<CONFIGURATION>``
|
|
|
|
Configuration name. Deprecated. Use ``CONFIG`` instead.
|
|
|
|
``$<CONFIG>``
|
|
|
|
Configuration name
|
|
|
|
``$<PLATFORM_ID>``
|
|
|
|
The CMake-id of the platform.
|
|
|
|
See also the :variable:`CMAKE_SYSTEM_NAME` variable.
|
|
|
|
``$<C_COMPILER_ID>``
|
|
|
|
The CMake-id of the C compiler used.
|
|
|
|
See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
|
|
|
|
``$<CXX_COMPILER_ID>``
|
|
|
|
The CMake-id of the CXX compiler used.
|
|
|
|
See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
|
|
|
|
``$<C_COMPILER_VERSION>``
|
|
|
|
The version of the C compiler used.
|
|
|
|
See also the :variable:`CMAKE_<LANG>_COMPILER_VERSION` variable.
|
|
|
|
``$<CXX_COMPILER_VERSION>``
|
|
|
|
The version of the CXX compiler used.
|
|
|
|
See also the :variable:`CMAKE_<LANG>_COMPILER_VERSION` variable.
|
|
|
|
``$<TARGET_FILE:tgt>``
|
|
|
|
Full path to main file (.exe, .so.1.2, .a) where ``tgt`` is the name of a target.
|
|
|
|
``$<TARGET_FILE_NAME:tgt>``
|
|
|
|
Name of main file (.exe, .so.1.2, .a).
|
|
|
|
``$<TARGET_FILE_DIR:tgt>``
|
|
|
|
Directory of main file (.exe, .so.1.2, .a).
|
|
|
|
``$<TARGET_LINKER_FILE:tgt>``
|
|
|
|
File used to link (.a, .lib, .so) where ``tgt`` is the name of a target.
|
|
|
|
``$<TARGET_LINKER_FILE_NAME:tgt>``
|
|
|
|
Name of file used to link (.a, .lib, .so).
|
|
|
|
``$<TARGET_LINKER_FILE_DIR:tgt>``
|
|
|
|
Directory of file used to link (.a, .lib, .so).
|
|
|
|
``$<TARGET_SONAME_FILE:tgt>``
|
|
|
|
File with soname (.so.3) where ``tgt`` is the name of a target.
|
|
|
|
``$<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 :prop_tgt:`PDB_NAME` and :prop_tgt:`PDB_OUTPUT_DIRECTORY`
|
|
|
|
target properties and their configuration specific variants
|
|
|
|
:prop_tgt:`PDB_NAME_<CONFIG>` and :prop_tgt:`PDB_OUTPUT_DIRECTORY_<CONFIG>`.
|
|
|
|
``$<TARGET_PDB_FILE_NAME:tgt>``
|
|
|
|
Name of the linker generated program database file (.pdb).
|
|
|
|
``$<TARGET_PDB_FILE_DIR:tgt>``
|
|
|
|
Directory of the linker generated program database file (.pdb).
|
|
|
|
``$<TARGET_PROPERTY:tgt,prop>``
|
|
|
|
Value of the property ``prop`` on the target ``tgt``.
|
|
|
|
|
|
|
|
Note that ``tgt`` is not added as a dependency of the target this
|
|
|
|
expression is evaluated on.
|
|
|
|
``$<TARGET_PROPERTY:prop>``
|
|
|
|
Value of the property ``prop`` on the target on which the generator
|
|
|
|
expression is evaluated.
|
|
|
|
``$<INSTALL_PREFIX>``
|
|
|
|
Content of the install prefix when the target is exported via
|
|
|
|
:command:`install(EXPORT)` and empty otherwise.
|
|
|
|
``$<COMPILE_LANGUAGE>``
|
|
|
|
The compile language of source files when evaluating compile options. See
|
|
|
|
the unary version for notes about portability of this generator
|
|
|
|
expression.
|
|
|
|
|
|
|
|
Output Expressions
|
|
|
|
==================
|
|
|
|
|
|
|
|
These expressions generate output, in some cases depending on an input. These
|
|
|
|
expressions may be combined with other expressions for information or logical
|
|
|
|
comparison::
|
|
|
|
|
|
|
|
-I$<JOIN:$<TARGET_PROPERTY:INCLUDE_DIRECTORIES>, -I>
|
|
|
|
|
|
|
|
generates a string of the entries in the :prop_tgt:`INCLUDE_DIRECTORIES` target
|
|
|
|
property with each entry preceeded by ``-I``. Note that a more-complete use
|
|
|
|
in this situation would require first checking if the INCLUDE_DIRECTORIES
|
|
|
|
property is non-empty::
|
|
|
|
|
|
|
|
$<$<BOOL:${prop}>:-I$<JOIN:${prop}, -I>>
|
|
|
|
|
|
|
|
where ``${prop}`` refers to a helper variable::
|
|
|
|
|
|
|
|
set(prop "$<TARGET_PROPERTY:INCLUDE_DIRECTORIES>")
|
|
|
|
|
|
|
|
Available output expressions are:
|
|
|
|
|
|
|
|
``$<0:...>``
|
|
|
|
Empty string (ignores ``...``)
|
|
|
|
``$<1:...>``
|
|
|
|
Content of ``...``
|
|
|
|
``$<JOIN:list,...>``
|
|
|
|
Joins the list with the content of ``...``
|
|
|
|
``$<ANGLE-R>``
|
|
|
|
A literal ``>``. Used to compare strings which contain a ``>`` for example.
|
|
|
|
``$<COMMA>``
|
|
|
|
A literal ``,``. Used to compare strings which contain a ``,`` for example.
|
|
|
|
``$<SEMICOLON>``
|
|
|
|
A literal ``;``. Used to prevent list expansion on an argument with ``;``.
|
|
|
|
``$<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.
|
|
|
|
``$<LINK_ONLY:...>``
|
|
|
|
Content of ``...`` except when evaluated in a link interface while
|
|
|
|
propagating :ref:`Target Usage Requirements`, in which case it is the
|
|
|
|
empty string.
|
|
|
|
Intended for use only in an :prop_tgt:`INTERFACE_LINK_LIBRARIES` target
|
|
|
|
property, perhaps via the :command:`target_link_libraries` command,
|
|
|
|
to specify private link dependencies without other usage requirements.
|
|
|
|
``$<INSTALL_INTERFACE:...>``
|
|
|
|
Content of ``...`` when the property is exported using :command:`install(EXPORT)`,
|
|
|
|
and empty otherwise.
|
|
|
|
``$<BUILD_INTERFACE:...>``
|
|
|
|
Content of ``...`` when the property is exported using :command:`export`, or
|
|
|
|
when the target is used by another target in the same buildsystem. Expands to
|
|
|
|
the empty string otherwise.
|
|
|
|
``$<LOWER_CASE:...>``
|
|
|
|
Content of ``...`` converted to lower case.
|
|
|
|
``$<UPPER_CASE:...>``
|
|
|
|
Content of ``...`` converted to upper case.
|
|
|
|
``$<MAKE_C_IDENTIFIER:...>``
|
|
|
|
Content of ``...`` converted to a C identifier.
|
|
|
|
``$<TARGET_OBJECTS:objLib>``
|
|
|
|
List of objects resulting from build of ``objLib``. ``objLib`` must be an
|
|
|
|
object of type ``OBJECT_LIBRARY``. This expression may only be used in
|
|
|
|
the sources of :command:`add_library` and :command:`add_executable`
|
|
|
|
commands.
|