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 interpreter
- Compiler: 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 version- 3.2and 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::Interpreter
- Python 3 interpreter. This target is defined only if the - Interpretercomponent is found.
- Python3::InterpreterDebug
- New in version 3.30. - Python 3 debug interpreter. This target is defined only if the - Interpretercomponent is found and the- Python3_EXECUTABLE_DEBUGvariable is defined. The target is only defined on the- Windowsplatform.
- Python3::InterpreterMultiConfig
- New 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 found
- Python3::Compiler
- Python 3 compiler. This target is defined only if the - Compilercomponent is found.
- Python3::Module
- New in version 3.15. - Python 3 library for Python module. Target defined if component - Development.Moduleis found.
- Python3::SABIModule
- New in version 3.26. - Python 3 library for Python module using the Stable Application Binary Interface. Target defined if component - Development.SABIModuleis found.
- Python3::Python
- Python 3 library for Python embedding. Target defined if component - Development.Embedis found.
- Python3::NumPy
- New 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_FOUND
- System has the Python 3 requested components. 
- Python3_Interpreter_FOUND
- System has the Python 3 interpreter. 
- Python3_EXECUTABLE
- Path to the Python 3 interpreter. 
- Python3_EXECUTABLE_DEBUG
- New in version 3.30. - Path to the debug Python 3 interpreter. It is only defined on - Windowsplatform.
- Python3_INTERPRETER
- New in version 3.30. - Path to the Python 3 interpreter, defined as a - generator expressionselecting the- Python3_EXECUTABLEor- Python3_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_STDLIB
- Standard platform independent installation directory. - Information returned by - sysconfig.get_path('stdlib').
- Python3_STDARCH
- Standard platform dependent installation directory. - Information returned by - sysconfig.get_path('platstdlib').
- Python3_SITELIB
- Third-party platform independent installation directory. - Information returned by - sysconfig.get_path('purelib').
- Python3_SITEARCH
- Third-party platform dependent installation directory. - Information returned by - sysconfig.get_path('platlib').
- Python3_SOABI
- New in version 3.17. - Extension suffix for modules. - Information computed from - sysconfig.get_config_var('EXT_SUFFIX')or- sysconfig.get_config_var('SOABI')or- python3-config --extension-suffix.
- Python3_SOSABI
- New in version 3.26. - Extension suffix for modules using the Stable Application Binary Interface. - Information computed from - importlib.machinery.EXTENSION_SUFFIXESif the COMPONENT- Interpreterwas specified. Otherwise, the extension is- abi3except for- Windows,- MSYSand- CYGWINfor which this is an empty string.
- Python3_Compiler_FOUND
- System has the Python 3 compiler. 
- Python3_COMPILER
- Path 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_LAUNCHER
- New in version 3.18. - The - .Netinterpreter. Only used by- IronPythonimplementation.
Python3_Development_FOUND
System has the Python 3 development artifacts.
- Python3_Development.Module_FOUND
- New in version 3.18. - System has the Python 3 development artifacts for Python module. 
- Python3_Development.SABIModule_FOUND
- New in version 3.26. - System has the Python 3 development artifacts for Python module using the Stable Application Binary Interface. 
- Python3_Development.Embed_FOUND
- New in version 3.18. - System has the Python 3 development artifacts for Python embedding. 
Python3_INCLUDE_DIRS
The Python 3 include directories.
- Python3_DEFINITIONS
- New in version 3.30.3. - The Python 3 preprocessor definitions. 
- Python3_DEBUG_POSTFIX
- Postfix of debug python module. This variable can be used to define the - DEBUG_POSTFIXtarget property.
- Python3_LINK_OPTIONS
- New in version 3.19. - The Python 3 link options. Some configurations require specific link options for a correct build and execution. 
- Python3_LIBRARIES
- The Python 3 libraries. 
- Python3_LIBRARY_DIRS
- The Python 3 library directories. 
- Python3_RUNTIME_LIBRARY_DIRS
- The Python 3 runtime library directories. 
- Python3_SABI_LIBRARIES
- New in version 3.26. - The Python 3 libraries for the Stable Application Binary Interface. 
- Python3_SABI_LIBRARY_DIRS
- New in version 3.26. - The Python 3 - SABIlibrary directories.
- Python3_RUNTIME_SABI_LIBRARY_DIRS
- New in version 3.26. - The Python 3 runtime - SABIlibrary directories.
- Python3_VERSION
- Python 3 version. 
- Python3_VERSION_MAJOR
- Python 3 major version. 
- Python3_VERSION_MINOR
- Python 3 minor version. 
- Python3_VERSION_PATCH
- Python 3 patch version. 
- Python3_PyPy_VERSION
- New in version 3.18. - Python 3 PyPy version. 
- Python3_NumPy_FOUND
- New in version 3.14. - System has the NumPy. 
- Python3_NumPy_INCLUDE_DIRS
- New in version 3.14. - The NumPy include directories. 
- Python3_NumPy_VERSION
- New in version 3.14. - The NumPy version. 
Hints¶
- Python3_ROOT_DIR
- Define the root directory of a Python 3 installation. 
- Python3_USE_STATIC_LIBS
- If 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_ABI
- New 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) and- gil_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 is- OFF.- 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 (- ONand- OFF) will be searched.
 - Note - If - Python3_FIND_ABIis not defined, any ABI, excluding the- gil_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 for- pydebugand- gil_disabled,- debugand- free threadedversions will be searched after- non-debugand- non-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, and- td.- 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, and- td.- Note - This hint is useful only on - POSIXsystems except for the- gil_disabledflag. So, on- Windowssystems, when- Python_FIND_ABIis defined,- Pythondistributions from python.org will be found only if the value for each flag is- OFFor- ANYexcept for the fourth one (- gil_disabled).
- Python3_FIND_STRATEGY
- New 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 policy- CMP0094is undefined or set to- OLD.
- LOCATION: Stops lookup as soon as a version satisfying version constraints is founded. This is the default if policy- CMP0094is set to- NEW.
 - See also - Python3_FIND_UNVERSIONED_NAMES.
- Python3_FIND_REGISTRY
- New in version 3.13. - On Windows the - Python3_FIND_REGISTRYvariable determine the order of preference between registry and environment variables. The- Python3_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_FRAMEWORK
- New 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 as- CMAKE_FIND_FRAMEWORKvariable.- Note - Value - ONLYis not supported so- FIRSTwill be used instead.- If - Python3_FIND_FRAMEWORKis not defined,- CMAKE_FIND_FRAMEWORKvariable will be used, if any.
- Python3_FIND_VIRTUALENV
- New in version 3.15. - This variable defines the handling of virtual environments managed by - virtualenvor- conda. It is meaningful only when a virtual environment is active (i.e. the- activatescript has been evaluated). In this case, it takes precedence over- Python3_FIND_REGISTRYand- CMAKE_FIND_FRAMEWORKvariables. The- Python3_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 variable- PATHis always considered. In this case, variable- Python3_FIND_REGISTRY(Windows) or- CMAKE_FIND_FRAMEWORK(macOS) can be set with value- LASTor- NEVERto 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 component- Interpreterto get expected result.
- Python3_FIND_IMPLEMENTATIONS
- New 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, like- Anacondaor- ActivePython, rely on this implementation.
- IronPython: This implementation use the- CSharplanguage for- .NET Frameworkon top of the Dynamic Language Runtime (- DLR). See IronPython.
- PyPy: This implementation use- RPythonlanguage and- RPython translation toolchainto produce the python interpreter. See PyPy.
 - The default value is: - Windows platform: - CPython,- IronPython
- Other platforms: - CPython
 - Note - This hint has the lowest priority of all hints, so even if, for example, you specify - IronPythonfirst and- CPythonin second, a python product based on- CPythoncan be selected because, for example with- Python3_FIND_STRATEGY=LOCATION, each location will be search first for- IronPythonand second for- CPython.- Note - When - IronPythonis specified, on platforms other than- Windows, the- .Netinterpreter (i.e.- monocommand) is expected to be available through the- PATHvariable.
- Python3_FIND_UNVERSIONED_NAMES
- New 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, - python3and- python. The- Python3_FIND_UNVERSIONED_NAMESvariable can be set to one of the following values:- FIRST: The generic names are searched before the more specialized ones (such as- python3.5for 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_EXECUTABLE
- The path to the interpreter. 
- Python3_COMPILER
- The path to the compiler. 
- Python3_DOTNET_LAUNCHER
- New in version 3.18. - The - .Netinterpreter. Only used by- IronPythonimplementation.
- Python3_LIBRARY
- The path to the library. It will be used to compute the variables - Python3_LIBRARIES,- Python3_LIBRARY_DIRSand- Python3_RUNTIME_LIBRARY_DIRS.
- Python3_SABI_LIBRARY
- New 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_DIRSand- Python3_RUNTIME_SABI_LIBRARY_DIRS.
- Python3_INCLUDE_DIR
- The path to the directory of the - Pythonheaders. It will be used to compute the variable- Python3_INCLUDE_DIRS.
- Python3_NumPy_INCLUDE_DIR
- The path to the directory of the - NumPyheaders. It will be used to compute the variable- Python3_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_INTERACTIVE
- New 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 (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.
New 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.
New 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.
New in version 3.30: For MODULE type, the DEBUG_POSTFIX target property is
initialized with the value of Python3_DEBUG_POSTFIX variable if defined.
