FindPython¶
New in version 3.12.
Find Python interpreter, compiler and development environment (include directories and libraries).
When a version is requested, it can be specified as a simple value or as a
range. For a detailed description of version range usage and capabilities,
refer to the find_package() command.
The following components are supported:
Interpreter: search for Python interpreter.Compiler: search for Python compiler. Only offered by IronPython.Development: search for development artifacts (include directories and libraries). This component includes two sub-components which can be specified independently:Development.Module: search for artifacts for Python module developments.Development.Embed: search for artifacts for Python embedding developments.
NumPy: search for NumPy include directories.
If no COMPONENTS are specified, Interpreter is assumed.
If component Development is specified, it implies sub-components
Development.Module and Development.Embed.
To ensure consistent versions between components Interpreter, Compiler,
Development (or one of its sub-components) and NumPy, specify all
components at the same time:
find_package (Python COMPONENTS Interpreter Development)
This module looks preferably for version 3 of Python. If not found, version 2
is searched.
To manage concurrent versions 3 and 2 of Python, use FindPython3 and
FindPython2 modules rather than this one.
Note
If components Interpreter and Development (or one of its
sub-components) are both specified, this module search only for interpreter
with same platform architecture as the one defined by CMake
configuration. This constraint does not apply if only Interpreter
component is specified.
Imported Targets¶
This module defines the following Imported Targets
(when CMAKE_ROLE is PROJECT):
Python::InterpreterPython interpreter. Target defined if component
Interpreteris found.Python::CompilerPython compiler. Target defined if component
Compileris found.Python::ModulePython library for Python module. Target defined if component
Development.Moduleis found.Python::PythonPython library for Python embedding. Target defined if component
Development.Embedis found.Python::NumPyNumPy Python library. Target defined if component
NumPyis found.
Result Variables¶
This module will set the following variables in your project (see Standard Variable Names):
Python_FOUNDSystem has the Python requested components.
Python_Interpreter_FOUNDSystem has the Python interpreter.
Python_EXECUTABLEPath to the Python interpreter.
Python_INTERPRETER_ID- A short string unique to the interpreter. Possible values include:
Python
ActivePython
Anaconda
Canopy
IronPython
PyPy
Python_STDLIBStandard platform independent installation directory.
Information returned by
distutils.sysconfig.get_python_lib(plat_specific=False,standard_lib=True)or elsesysconfig.get_path('stdlib').Python_STDARCHStandard platform dependent installation directory.
Information returned by
distutils.sysconfig.get_python_lib(plat_specific=True,standard_lib=True)or elsesysconfig.get_path('platstdlib').Python_SITELIBThird-party platform independent installation directory.
Information returned by
distutils.sysconfig.get_python_lib(plat_specific=False,standard_lib=False)or elsesysconfig.get_path('purelib').Python_SITEARCHThird-party platform dependent installation directory.
Information returned by
distutils.sysconfig.get_python_lib(plat_specific=True,standard_lib=False)or elsesysconfig.get_path('platlib').Python_SOABIExtension suffix for modules.
Information returned by
distutils.sysconfig.get_config_var('SOABI')or computed fromdistutils.sysconfig.get_config_var('EXT_SUFFIX')orpython-config --extension-suffix. If packagedistutils.sysconfigis not available,sysconfig.get_config_var('SOABI')orsysconfig.get_config_var('EXT_SUFFIX')are used.Python_Compiler_FOUNDSystem has the Python compiler.
Python_COMPILERPath to the Python compiler. Only offered by IronPython.
Python_COMPILER_ID- A short string unique to the compiler. Possible values include:
IronPython
Python_DOTNET_LAUNCHERThe
.Netinterpreter. Only used byIronPythonimplementation.Python_Development_FOUNDSystem has the Python development artifacts.
Python_Development.Module_FOUNDSystem has the Python development artifacts for Python module.
Python_Development.Embed_FOUNDSystem has the Python development artifacts for Python embedding.
Python_INCLUDE_DIRSThe Python include directories.
Python_LINK_OPTIONSThe Python link options. Some configurations require specific link options for a correct build and execution.
Python_LIBRARIESThe Python libraries.
Python_LIBRARY_DIRSThe Python library directories.
Python_RUNTIME_LIBRARY_DIRSThe Python runtime library directories.
Python_VERSIONPython version.
Python_VERSION_MAJORPython major version.
Python_VERSION_MINORPython minor version.
Python_VERSION_PATCHPython patch version.
Python_PyPy_VERSIONPython PyPy version.
Python_NumPy_FOUNDSystem has the NumPy.
Python_NumPy_INCLUDE_DIRSThe NumPy include directories.
Python_NumPy_VERSIONThe NumPy version.
Hints¶
Python_ROOT_DIRDefine the root directory of a Python installation.
Python_USE_STATIC_LIBSIf not defined, search for shared libraries and static libraries in that order.
If set to TRUE, search only for static libraries.
If set to FALSE, search only for shared libraries.
Python_FIND_ABIThis variable defines which ABIs, as defined in PEP 3149, should be searched.
Note
This hint will be honored only when searched for
Pythonversion 3.Note
If
Python_FIND_ABIis not defined, any ABI will be searched.The
Python_FIND_ABIvariable is a 3-tuple specifying, in that order,pydebug(d),pymalloc(m) andunicode(u) flags. Each element can be set to one of the following:ON: Corresponding flag is selected.OFF: Corresponding flag is not selected.ANY: The two possibilities (ONandOFF) will be searched.
From this 3-tuple, various ABIs will be searched starting from the most specialized to the most general. Moreover,
debugversions will be searched afternon-debugones.For example, if we have:
set (Python_FIND_ABI "ON" "ANY" "ANY")
The following flags combinations will be appended, in that order, to the artifact names:
dmu,dm,du, andd.And to search any possible ABIs:
set (Python_FIND_ABI "ANY" "ANY" "ANY")
The following combinations, in that order, will be used:
mu,m,u,<empty>,dmu,dm,duandd.Note
This hint is useful only on
POSIXsystems. So, onWindowssystems, whenPython_FIND_ABIis defined,Pythondistributions from python.org will be found only if value for each flag isOFForANY.Python_FIND_STRATEGYThis variable defines how lookup will be done. The
Python_FIND_STRATEGYvariable can be set to one of the following:Python_FIND_REGISTRYOn Windows the
Python_FIND_REGISTRYvariable determine the order of preference between registry and environment variables. thePython_FIND_REGISTRYvariable can be set to one of the following:FIRST: Try to use registry before environment variables. This is the default.LAST: Try to use registry after environment variables.NEVER: Never try to use registry.
Python_FIND_FRAMEWORKOn macOS the
Python_FIND_FRAMEWORKvariable determine the order of preference between Apple-style and unix-style package components. This variable can take same values asCMAKE_FIND_FRAMEWORKvariable.Note
Value
ONLYis not supported soFIRSTwill be used instead.If
Python_FIND_FRAMEWORKis not defined,CMAKE_FIND_FRAMEWORKvariable will be used, if any.Python_FIND_VIRTUALENVThis variable defines the handling of virtual environments managed by
virtualenvorconda. It is meaningful only when a virtual environment is active (i.e. theactivatescript has been evaluated). In this case, it takes precedence overPython_FIND_REGISTRYandCMAKE_FIND_FRAMEWORKvariables. ThePython_FIND_VIRTUALENVvariable can be set to one of the following:FIRST: The virtual environment is used before any other standard paths to look-up for the interpreter. This is the default.ONLY: Only the virtual environment is used to look-up for the interpreter.STANDARD: The virtual environment is not used to look-up for the interpreter but environment variablePATHis always considered. In this case, variablePython_FIND_REGISTRY(Windows) orCMAKE_FIND_FRAMEWORK(macOS) can be set with valueLASTorNEVERto select preferably the interpreter from the virtual environment.
Note
If the component
Developmentis requested, it is strongly recommended to also include the componentInterpreterto get expected result.Python_FIND_IMPLEMENTATIONSThis variable defines, in an ordered list, the different implementations which will be searched. The
Python_FIND_IMPLEMENTATIONSvariable can hold the following values:CPython: this is the standard implementation. Various products, likeAnacondaorActivePython, rely on this implementation.IronPython: This implementation use theCSharplanguage for.NET Frameworkon top of the Dynamic Language Runtime (DLR). See IronPython.PyPy: This implementation useRPythonlanguage andRPython translation toolchainto produce the python interpreter. See PyPy.
The default value is:
Windows platform:
CPython,IronPythonOther platforms:
CPython
Note
This hint has the lowest priority of all hints, so even if, for example, you specify
IronPythonfirst andCPythonin second, a python product based onCPythoncan be selected because, for example withPython_FIND_STRATEGY=LOCATION, each location will be search first forIronPythonand second forCPython.Note
When
IronPythonis specified, on platforms other thanWindows, the.Netinterpreter (i.e.monocommand) is expected to be available through thePATHvariable.
Artifacts Specification¶
To solve special cases, it is possible to specify directly the artifacts by setting the following variables:
Python_EXECUTABLEThe path to the interpreter.
Python_COMPILERThe path to the compiler.
Python_DOTNET_LAUNCHERThe
.Netinterpreter. Only used byIronPythonimplementation.Python_LIBRARYThe path to the library. It will be used to compute the variables
Python_LIBRARIES,Python_LIBRARY_DIRSandPython_RUNTIME_LIBRARY_DIRS.Python_INCLUDE_DIRThe path to the directory of the
Pythonheaders. It will be used to compute the variablePython_INCLUDE_DIRS.Python_NumPy_INCLUDE_DIRThe path to the directory of the
NumPyheaders. It will be used to compute the variablePython_NumPy_INCLUDE_DIRS.
Note
All paths must be absolute. Any artifact specified with a relative path will be ignored.
Note
When an artifact is specified, all HINTS will be ignored and no search
will be performed for this artifact.
If more than one artifact is specified, it is the user’s responsibility to ensure the consistency of the various artifacts.
By default, this module supports multiple calls in different directories of a
project with different version/component requirements while providing correct
and consistent results for each call. To support this behavior, CMake cache
is not used in the traditional way which can be problematic for interactive
specification. So, to enable also interactive specification, module behavior
can be controlled with the following variable:
Python_ARTIFACTS_INTERACTIVESelects the behavior of the module. This is a boolean variable:
If set to
TRUE: Create CMake cache entries for the above artifact specification variables so that users can edit them interactively. This disables support for multiple version/component requirements.If set to
FALSEor undefined: Enable multiple version/component requirements.
Commands¶
This module defines the command Python_add_library (when
CMAKE_ROLE is PROJECT), which has the same semantics as
add_library() and adds a dependency to target Python::Python or,
when library type is MODULE, to target Python::Module and takes care of
Python module naming rules:
Python_add_library (<name> [STATIC | SHARED | MODULE [WITH_SOABI]]
<source1> [<source2> ...])
If the library type is not specified, MODULE is assumed.
For MODULE library type, if option WITH_SOABI is specified, the
module suffix will include the Python_SOABI value, if any.