FindPython3¶
Added in version 3.12.
Find Python 3 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 3 interpreterCompiler: search for Python 3 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 3 module developments.Development.Embed: search for artifacts for Python 3 embedding developments.
Added 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.
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 (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::InterpreterDebugAdded 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::InterpreterMultiConfigAdded 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::ModuleAdded in version 3.15.
Python 3 library for Python module. Target defined if component
Development.Moduleis found.Python3::SABIModuleAdded 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::NumPyAdded 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_DEBUGAdded in version 3.30.
Path to the debug Python 3 interpreter. It is only defined on
Windowsplatform.Python3_INTERPRETERAdded 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_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.Python3_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.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_LAUNCHERAdded in version 3.18.
The
.Netinterpreter. Only used byIronPythonimplementation.
Python3_Development_FOUND
System has the Python 3 development artifacts.
Python3_Development.Module_FOUNDAdded in version 3.18.
System has the Python 3 development artifacts for Python module.
Python3_Development.SABIModule_FOUNDAdded in version 3.26.
System has the Python 3 development artifacts for Python module using the Stable Application Binary Interface.
Python3_Development.Embed_FOUNDAdded in version 3.18.
System has the Python 3 development artifacts for Python embedding.
Python3_INCLUDE_DIRS
The Python 3 include directories.
Python3_DEFINITIONSAdded in version 3.30.3.
The Python 3 preprocessor definitions.
Python3_DEBUG_POSTFIXAdded in version 3.30.
Postfix of debug python module. This variable can be used to define the
DEBUG_POSTFIXtarget property.Python3_LINK_OPTIONSAdded 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_LIBRARIESAdded in version 3.26.
The Python 3 libraries for the Stable Application Binary Interface.
Python3_SABI_LIBRARY_DIRSAdded in version 3.26.
The Python 3
SABIlibrary directories.Python3_RUNTIME_SABI_LIBRARY_DIRSAdded 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_VERSIONAdded in version 3.18.
Python 3 PyPy version.
Python3_NumPy_FOUNDAdded in version 3.14.
System has the NumPy.
Python3_NumPy_INCLUDE_DIRSAdded in version 3.14.
The NumPy include directories.
Python3_NumPy_VERSIONAdded 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_ABIAdded 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.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
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_STRATEGYAdded 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_REGISTRYAdded 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_FRAMEWORKAdded 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_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 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.
Added in version 3.17: Added support for
condaenvironments.Note
If the component
Developmentis requested (or one of its sub-components) and is not found or the wrong artifacts are returned, including also the componentInterpretermay be helpful.Python3_FIND_IMPLEMENTATIONSAdded 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_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,
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¶
Added 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_LAUNCHERAdded 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_LIBRARYAdded 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 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:
Python3_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.
Python3_ARTIFACTS_PREFIXAdded in version 4.0.
Define a custom prefix which will be used for the definition of all the result variables, targets, and commands. By using this variable, this module supports multiple calls in the same directory with different version/component requirements. For example, in case of cross-compilation, development components are needed but the native python interpreter can also be required:
find_package(Python3 COMPONENTS Development) set(Python3_ARTIFACTS_PREFIX "_HOST") find_package(Python3 COMPONENTS Interpreter) # Here Python3_HOST_EXECUTABLE and Python3_HOST::Interpreter artifacts are defined
Note
For consistency with standard behavior of modules, the various standard
_FOUNDvariables (i.e. without the custom prefix) are also defined by each call to thefind_package()command.
Commands¶
This module defines the command Python3_add_library (when
CMAKE_ROLE is PROJECT), which has the same semantics as
add_library() and adds a dependency to target Python3::Python or,
when library type is MODULE, to target Python3::Module or
Python3::SABIModule (when USE_SABI option 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, MODULE is assumed.
Added in version 3.17: For MODULE library type, if option WITH_SOABI is specified, the
module suffix will include the Python3_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 Python3_SOSABI value, if any.
Added in version 3.30: For MODULE type, the DEBUG_POSTFIX target property is
initialized with the value of Python3_DEBUG_POSTFIX variable if defined.