FindPython¶
Added in version 3.12.
Find Python interpreter, compiler and development environment (include directories and libraries).
Added in version 3.19: 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).Added in version 3.18: 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.
Added in version 3.26:
Development.SABIModule: search for artifacts for Python module developments using the Stable Application Binary Interface. This component is available only for version3.2and upper.
NumPy: search for NumPy include directories.
Added in version 3.14: Added the NumPy component.
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:
Changed in version 3.14: Imported Targets are only created when
CMAKE_ROLE is PROJECT.
Python::InterpreterPython interpreter. This target is defined only if the
Interpretercomponent is found.Python::InterpreterDebugAdded in version 3.30.
Python debug interpreter. This target is defined only if the
Interpretercomponent is found and thePython_EXECUTABLE_DEBUGvariable is defined. The target is only defined on theWindowsplatform.Python::InterpreterMultiConfigAdded in version 3.30.
Python interpreter. The release or debug version of the interpreter will be used, based on the context (platform, configuration). This target is defined only if the
Interpretercomponent is foundPython::CompilerPython compiler. This target is defined only if the
Compilercomponent is found.Python::ModuleAdded in version 3.15.
Python library for Python module. Target defined if component
Development.Moduleis found.Python::SABIModuleAdded in version 3.26.
Python library for Python module using the Stable Application Binary Interface. Target defined if component
Development.SABIModuleis found.Python::PythonPython library for Python embedding. Target defined if component
Development.Embedis found.Python::NumPyAdded in version 3.14.
NumPy 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_EXECUTABLE_DEBUGAdded in version 3.30.
Path to the debug Python interpreter. It is only defined on the
Windowsplatform.Python_INTERPRETERAdded in version 3.30.
Path to the Python interpreter, defined as a
generator expressionselecting thePython_EXECUTABLEorPython_EXECUTABLE_DEBUGvariable based on the context (platform, configuration).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
sysconfig.get_path('stdlib').Python_STDARCHStandard platform dependent installation directory.
Information returned by
sysconfig.get_path('platstdlib').Python_SITELIBThird-party platform independent installation directory.
Information returned by
sysconfig.get_path('purelib').Python_SITEARCHThird-party platform dependent installation directory.
Information returned by
sysconfig.get_path('platlib').Python_SOABIAdded in version 3.17.
Extension suffix for modules.
Information computed from
sysconfig.get_config_var('EXT_SUFFIX')orsysconfig.get_config_var('SOABI')orpython3-config --extension-suffix.Python_SOSABIAdded in version 3.26.
Extension suffix for modules using the Stable Application Binary Interface.
Information computed from
importlib.machinery.EXTENSION_SUFFIXESif the COMPONENTInterpreterwas specified. Otherwise, the extension isabi3except forWindows,MSYSandCYGWINfor which this is an empty string.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_LAUNCHERAdded in version 3.18.
The
.Netinterpreter. Only used byIronPythonimplementation.Python_Development_FOUNDSystem has the Python development artifacts.
Python_Development.Module_FOUNDAdded in version 3.18.
System has the Python development artifacts for Python module.
Python_Development.SABIModule_FOUNDAdded in version 3.26.
System has the Python development artifacts for Python module using the Stable Application Binary Interface.
Python_Development.Embed_FOUNDAdded in version 3.18.
System has the Python development artifacts for Python embedding.
Python_INCLUDE_DIRS
The Python include directories.
Python_DEBUG_POSTFIXPostfix of debug python module. This variable can be used to define the
DEBUG_POSTFIXtarget property.Python_LINK_OPTIONSAdded in version 3.19.
The 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_SABI_LIBRARIESAdded in version 3.26.
The Python libraries for the Stable Application Binary Interface.
Python_SABI_LIBRARY_DIRSAdded in version 3.26.
The Python
SABIlibrary directories.Python_RUNTIME_SABI_LIBRARY_DIRSAdded in version 3.26.
The Python runtime
SABIlibrary directories.Python_VERSIONPython version.
Python_VERSION_MAJORPython major version.
Python_VERSION_MINORPython minor version.
Python_VERSION_PATCHPython patch version.
Python_PyPy_VERSIONAdded in version 3.18.
Python PyPy version.
Python_NumPy_FOUNDAdded in version 3.14.
System has the NumPy.
Python_NumPy_INCLUDE_DIRSAdded in version 3.14.
The NumPy include directories.
Python_NumPy_VERSIONAdded in version 3.14.
The 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.
Note
This hint will be ignored on
Windowsbecause static libraries are not available on this platform.Python_FIND_ABIAdded in version 3.16.
This variable defines which ABIs, as defined in PEP 3149, should be searched.
Note
This hint will be honored only when searched for
Pythonversion 3.The
Python_FIND_ABIvariable is a 4-tuple specifying, in that order,pydebug(d),pymalloc(m),unicode(u) andgil_disabled(t) flags.Added in version 3.30: A fourth element, specifying the
gil_disabledflag (i.e. free threaded python), is added and is optional. If not specified, the value isOFF.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.
Note
If
Python_FIND_ABIis not defined, any ABI will be searched.From this 4-tuple, various ABIs will be searched starting from the most specialized to the most general. Moreover, when
ANYis specified forpydebugandgil_disabled,debugandfree threadedversions will be searched afternon-debugandnon-gil-disabledones.For example, if we have:
set (Python_FIND_ABI "ON" "ANY" "ANY" "ON")
The following flags combinations will be appended, in that order, to the artifact names:
tdmu,tdm,tdu, andtd.And to search any possible ABIs:
set (Python_FIND_ABI "ANY" "ANY" "ANY" "ANY")
The following combinations, in that order, will be used:
mu,m,u,<empty>,dmu,dm,du,d,tmu,tm,tu,t,tdmu,tdm,tdu, andtd.Note
This hint is useful only on
POSIXsystems except for thegil_disabledflag. So, onWindowssystems, whenPython_FIND_ABIis defined,Pythondistributions from python.org will be found only if the value for each flag isOFForANYexcept for the fourth one (gil_disabled).Python_FIND_STRATEGYAdded in version 3.15.
This variable defines how lookup will be done. The
Python_FIND_STRATEGYvariable can be set to one of the following:VERSION: Try to find the most recent version in all specified locations. This is the default if policyCMP0094is undefined or set toOLD.LOCATION: Stops lookup as soon as a version satisfying version constraints is founded. This is the default if policyCMP0094is set toNEW.
See also
Python_FIND_UNVERSIONED_NAMES.Python_FIND_REGISTRYAdded in version 3.13.
On 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_FRAMEWORKAdded in version 3.15.
On 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_VIRTUALENVAdded in version 3.15.
This 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.
Added in version 3.17: Added support for
condaenvironments.Note
If the component
Developmentis requested, it is strongly recommended to also include the componentInterpreterto get expected result.Python_FIND_IMPLEMENTATIONSAdded in version 3.18.
This 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.Python_FIND_UNVERSIONED_NAMESAdded in version 3.20.
This variable defines how the generic names will be searched. Currently, it only applies to the generic names of the interpreter, namely,
python3orpython2andpython. ThePython_FIND_UNVERSIONED_NAMESvariable can be set to one of the following values:FIRST: The generic names are searched before the more specialized ones (such aspython2.5for example).LAST: The generic names are searched after the more specialized ones. This is the default.NEVER: The generic name are not searched at all.
See also
Python_FIND_STRATEGY.
Artifacts Specification¶
Added in version 3.16.
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_LAUNCHERAdded in version 3.18.
The
.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_SABI_LIBRARYAdded in version 3.26.
The path to the library for Stable Application Binary Interface. It will be used to compute the variables
Python_SABI_LIBRARIES,Python_SABI_LIBRARY_DIRSandPython_RUNTIME_SABI_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_INTERACTIVEAdded in version 3.18.
Selects 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 or
Python::SABIModule (when USE_SABI option is specified) and takes care
of Python module naming rules:
Python_add_library (<name> [STATIC | SHARED | MODULE [USE_SABI <version>] [WITH_SOABI]]
<source1> [<source2> ...])
If the library type is not specified, MODULE is assumed.
Added in version 3.17: For MODULE library type, if option WITH_SOABI is specified, the
module suffix will include the Python_SOABI value, if any.
Added in version 3.26: For MODULE type, if the option USE_SABI is specified, the
preprocessor definition Py_LIMITED_API will be specified, as PRIVATE,
for the target <name> with the value computed from <version> argument.
The expected format for <version> is major[.minor], where each
component is a numeric value. If minor component is specified, the
version should be, at least, 3.2 which is the version where the
Stable Application Binary Interface
was introduced. Specifying only major version 3 is equivalent to 3.2.
When option WITH_SOABI is also specified, the module suffix will include
the Python_SOSABI value, if any.
Added in version 3.30: For MODULE type, the DEBUG_POSTFIX target property is
initialized with the value of Python_DEBUG_POSTFIX variable if defined.