FindPython3¶
New in version 3.12.
Find Python 3 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 3 interpreterCompiler: search for Python 3 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 3 module developments.Development.Embed: search for artifacts for Python 3 embedding developments.
New in version 3.26:
Development.SABIModule: search for artifacts for Python 3 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 (Python3 COMPONENTS Interpreter Development)
This module looks only for version 3 of Python. This module can be used
concurrently with FindPython2 module to use both Python versions.
The FindPython module can be used if Python version does not matter
for you.
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.
Python3::InterpreterPython 3 interpreter. This target is defined only if the
Interpretercomponent is found.Python3::InterpreterDebugNew in version 3.30.
Python 3 debug interpreter. This target is defined only if the
Interpretercomponent is found and thePython3_EXECUTABLE_DEBUGvariable is defined. The target is only defined on theWindowsplatform.Python3::InterpreterMultiConfigNew in version 3.30.
Python 3 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 foundPython3::CompilerPython 3 compiler. This target is defined only if the
Compilercomponent is found.Python3::ModuleNew in version 3.15.
Python 3 library for Python module. Target defined if component
Development.Moduleis found.Python3::SABIModuleNew in version 3.26.
Python 3 library for Python module using the Stable Application Binary Interface. Target defined if component
Development.SABIModuleis found.Python3::PythonPython 3 library for Python embedding. Target defined if component
Development.Embedis found.Python3::NumPyNew in version 3.14.
NumPy library for Python 3. Target defined if component
NumPyis found.
Result Variables¶
This module will set the following variables in your project (see Standard Variable Names):
Python3_FOUNDSystem has the Python 3 requested components.
Python3_Interpreter_FOUNDSystem has the Python 3 interpreter.
Python3_EXECUTABLEPath to the Python 3 interpreter.
Python3_EXECUTABLE_DEBUGNew in version 3.30.
Path to the debug Python 3 interpreter. It is only defined on
Windowsplatform.Python3_INTERPRETERNew in version 3.30.
Path to the Python 3 interpreter, defined as a
generator expressionselecting thePython3_EXECUTABLEorPython3_EXECUTABLE_DEBUGvariable based on the context (platform, configuration).Python3_INTERPRETER_ID- A short string unique to the interpreter. Possible values include:
Python
ActivePython
Anaconda
Canopy
IronPython
PyPy
Python3_STDLIBStandard platform independent installation directory.
Information returned by
sysconfig.get_path('stdlib').Python3_STDARCHStandard platform dependent installation directory.
Information returned by
sysconfig.get_path('platstdlib').Python3_SITELIBThird-party platform independent installation directory.
Information returned by
sysconfig.get_path('purelib').Python3_SITEARCHThird-party platform dependent installation directory.
Information returned by
sysconfig.get_path('platlib').Python3_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.Python3_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.Python3_Compiler_FOUNDSystem has the Python 3 compiler.
Python3_COMPILERPath to the Python 3 compiler. Only offered by IronPython.
Python3_COMPILER_ID- A short string unique to the compiler. Possible values include:
IronPython
Python3_DOTNET_LAUNCHERNew in version 3.18.
The
.Netinterpreter. Only used byIronPythonimplementation.
Python3_Development_FOUND
System has the Python 3 development artifacts.
Python3_Development.Module_FOUNDNew in version 3.18.
System has the Python 3 development artifacts for Python module.
Python3_Development.SABIModule_FOUNDNew in version 3.26.
System has the Python 3 development artifacts for Python module using the Stable Application Binary Interface.
Python3_Development.Embed_FOUNDNew in version 3.18.
System has the Python 3 development artifacts for Python embedding.
Python3_INCLUDE_DIRS
The Python 3 include directories.
Python3_DEFINITIONSNew in version 3.30.3.
The Python 3 preprocessor definitions.
Python3_DEBUG_POSTFIXPostfix of debug python module. This variable can be used to define the
DEBUG_POSTFIXtarget property.Python3_LINK_OPTIONSNew in version 3.19.
The Python 3 link options. Some configurations require specific link options for a correct build and execution.
Python3_LIBRARIESThe Python 3 libraries.
Python3_LIBRARY_DIRSThe Python 3 library directories.
Python3_RUNTIME_LIBRARY_DIRSThe Python 3 runtime library directories.
Python3_SABI_LIBRARIESNew in version 3.26.
The Python 3 libraries for the Stable Application Binary Interface.
Python3_SABI_LIBRARY_DIRSNew in version 3.26.
The Python 3
SABIlibrary directories.Python3_RUNTIME_SABI_LIBRARY_DIRSNew in version 3.26.
The Python 3 runtime
SABIlibrary directories.Python3_VERSIONPython 3 version.
Python3_VERSION_MAJORPython 3 major version.
Python3_VERSION_MINORPython 3 minor version.
Python3_VERSION_PATCHPython 3 patch version.
Python3_PyPy_VERSIONNew in version 3.18.
Python 3 PyPy version.
Python3_NumPy_FOUNDNew in version 3.14.
System has the NumPy.
Python3_NumPy_INCLUDE_DIRSNew in version 3.14.
The NumPy include directories.
Python3_NumPy_VERSIONNew in version 3.14.
The NumPy version.
Hints¶
Python3_ROOT_DIRDefine the root directory of a Python 3 installation.
Python3_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.Python3_FIND_ABINew in version 3.16.
This variable defines which ABIs, as defined in PEP 3149, should be searched.
The
Python3_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 (Python3_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 (Python3_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).Python3_FIND_STRATEGYNew in version 3.15.
This variable defines how lookup will be done. The
Python3_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
Python3_FIND_UNVERSIONED_NAMES.Python3_FIND_REGISTRYNew in version 3.13.
On Windows the
Python3_FIND_REGISTRYvariable determine the order of preference between registry and environment variables. ThePython3_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.
Python3_FIND_FRAMEWORKNew in version 3.15.
On macOS the
Python3_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
Python3_FIND_FRAMEWORKis not defined,CMAKE_FIND_FRAMEWORKvariable will be used, if any.Python3_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 overPython3_FIND_REGISTRYandCMAKE_FIND_FRAMEWORKvariables. ThePython3_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, variablePython3_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.Python3_FIND_IMPLEMENTATIONSNew in version 3.18.
This variable defines, in an ordered list, the different implementations which will be searched. The
Python3_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 withPython3_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.Python3_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,
python3andpython. ThePython3_FIND_UNVERSIONED_NAMESvariable can be set to one of the following values:FIRST: The generic names are searched before the more specialized ones (such aspython3.5for 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
Python3_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:
Python3_EXECUTABLEThe path to the interpreter.
Python3_COMPILERThe path to the compiler.
Python3_DOTNET_LAUNCHERNew in version 3.18.
The
.Netinterpreter. Only used byIronPythonimplementation.Python3_LIBRARYThe path to the library. It will be used to compute the variables
Python3_LIBRARIES,Python3_LIBRARY_DIRSandPython3_RUNTIME_LIBRARY_DIRS.Python3_SABI_LIBRARYNew in version 3.26.
The path to the library for Stable Application Binary Interface. It will be used to compute the variables
Python3_SABI_LIBRARIES,Python3_SABI_LIBRARY_DIRSandPython3_RUNTIME_SABI_LIBRARY_DIRS.Python3_INCLUDE_DIRThe path to the directory of the
Pythonheaders. It will be used to compute the variablePython3_INCLUDE_DIRS.Python3_NumPy_INCLUDE_DIRThe path to the directory of the
NumPyheaders. It will be used to compute the variablePython3_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:
Python3_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
Python3_add_library(whenCMAKE_ROLEisPROJECT), which has the same semantics asadd_library()and adds a dependency to targetPython3::Pythonor, when library type isMODULE, to targetPython3::ModuleorPython3::SABIModule(whenUSE_SABIoption is specified) and takes care of Python module naming rules:Python3_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 thePython3_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 thePython3_SOSABIvalue, if any.New in version 3.30: For
MODULEtype, theDEBUG_POSTFIXtarget property is initialized with the value ofPython3_DEBUG_POSTFIXvariable if defined.