FindPython¶
New in version 3.12.
Find Python interpreter, compiler and development environment (include directories and libraries).
New 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).New 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.
New 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.
New 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::InterpreterDebugNew 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::InterpreterMultiConfigNew 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::ModuleNew in version 3.15.
Python library for Python module. Target defined if component
Development.Moduleis found.Python::SABIModuleNew 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::NumPyNew 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_DEBUGNew in version 3.30.
Path to the debug Python interpreter. It is only defined on the
Windowsplatform.Python_INTERPRETERNew 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_SOABINew 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_SOSABINew 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_LAUNCHERNew in version 3.18.
The
.Netinterpreter. Only used byIronPythonimplementation.Python_Development_FOUNDSystem has the Python development artifacts.
Python_Development.Module_FOUNDNew in version 3.18.
System has the Python development artifacts for Python module.
Python_Development.SABIModule_FOUNDNew in version 3.26.
System has the Python development artifacts for Python module using the Stable Application Binary Interface.
Python_Development.Embed_FOUNDNew in version 3.18.
System has the Python development artifacts for Python embedding.
Python_INCLUDE_DIRS
The Python include directories.
Python_DEFINITIONSNew in version 3.30.3.
The Python preprocessor definitions.
Python_DEBUG_POSTFIXPostfix of debug python module. This variable can be used to define the
DEBUG_POSTFIXtarget property.Python_LINK_OPTIONSNew 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_LIBRARIESNew in version 3.26.
The Python libraries for the Stable Application Binary Interface.
Python_SABI_LIBRARY_DIRSNew in version 3.26.
The Python
SABIlibrary directories.Python_RUNTIME_SABI_LIBRARY_DIRSNew 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_VERSIONNew in version 3.18.
Python PyPy version.
Python_NumPy_FOUNDNew in version 3.14.
System has the NumPy.
Python_NumPy_INCLUDE_DIRSNew in version 3.14.
The NumPy include directories.
Python_NumPy_VERSIONNew 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_ABINew 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.New 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
Python3_FIND_ABIis not defined, any ABI, excluding thegil_disabledflag, 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_STRATEGYNew 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_REGISTRYNew 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_FRAMEWORKNew 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_VIRTUALENVNew 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.
New 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_IMPLEMENTATIONSNew 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_NAMESNew 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¶
New 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_LAUNCHERNew 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_LIBRARYNew 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
HINTSwill 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_INTERACTIVENew 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(whenCMAKE_ROLEisPROJECT), which has the same semantics asadd_library()and adds a dependency to targetPython::Pythonor, when library type isMODULE, to targetPython::ModuleorPython::SABIModule(whenUSE_SABIoption 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,
MODULEis assumed.New in version 3.17: For
MODULElibrary type, if optionWITH_SOABIis specified, the module suffix will include thePython_SOABIvalue, if any.New in version 3.26: For
MODULEtype, if the optionUSE_SABIis specified, the preprocessor definitionPy_LIMITED_APIwill be specified, asPRIVATE, for the target<name>with the value computed from<version>argument. The expected format for<version>ismajor[.minor], where each component is a numeric value. Ifminorcomponent is specified, the version should be, at least,3.2which is the version where the Stable Application Binary Interface was introduced. Specifying only major version3is equivalent to3.2.When option
WITH_SOABIis also specified, the module suffix will include thePython_SOSABIvalue, if any.New in version 3.30: For
MODULEtype, theDEBUG_POSTFIXtarget property is initialized with the value ofPython_DEBUG_POSTFIXvariable if defined.