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 version- 3.2and 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::Interpreter
- Python interpreter. This target is defined only if the - Interpretercomponent is found.
- Python::InterpreterDebug
- Added in version 3.30. - Python debug interpreter. This target is defined only if the - Interpretercomponent is found and the- Python_EXECUTABLE_DEBUGvariable is defined. The target is only defined on the- Windowsplatform.
- Python::InterpreterMultiConfig
- Added 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 found
- Python::Compiler
- Python compiler. This target is defined only if the - Compilercomponent is found.
- Python::Module
- Added in version 3.15. - Python library for Python module. Target defined if component - Development.Moduleis found.
- Python::SABIModule
- Added in version 3.26. - Python library for Python module using the Stable Application Binary Interface. Target defined if component - Development.SABIModuleis found.
- Python::Python
- Python library for Python embedding. Target defined if component - Development.Embedis found.
- Python::NumPy
- Added 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_FOUND
- System has the Python requested components. 
- Python_Interpreter_FOUND
- System has the Python interpreter. 
- Python_EXECUTABLE
- Path to the Python interpreter. 
- Python_EXECUTABLE_DEBUG
- Added in version 3.30. - Path to the debug Python interpreter. It is only defined on the - Windowsplatform.
- Python_INTERPRETER
- Added in version 3.30. - Path to the Python interpreter, defined as a - generator expressionselecting the- Python_EXECUTABLEor- Python_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_STDLIB
- Standard platform independent installation directory. - Information returned by - sysconfig.get_path('stdlib').
- Python_STDARCH
- Standard platform dependent installation directory. - Information returned by - sysconfig.get_path('platstdlib').
- Python_SITELIB
- Third-party platform independent installation directory. - Information returned by - sysconfig.get_path('purelib').
- Python_SITEARCH
- Third-party platform dependent installation directory. - Information returned by - sysconfig.get_path('platlib').
- Python_SOABI
- Added 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.
- Python_SOSABI
- Added 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.
- Python_Compiler_FOUND
- System has the Python compiler. 
- Python_COMPILER
- Path to the Python compiler. Only offered by IronPython. 
- Python_COMPILER_ID
- A short string unique to the compiler. Possible values include:
- IronPython 
 
 
- Python_DOTNET_LAUNCHER
- Added in version 3.18. - The - .Netinterpreter. Only used by- IronPythonimplementation.
- Python_Development_FOUND
- System has the Python development artifacts. 
- Python_Development.Module_FOUND
- Added in version 3.18. - System has the Python development artifacts for Python module. 
- Python_Development.SABIModule_FOUND
- Added in version 3.26. - System has the Python development artifacts for Python module using the Stable Application Binary Interface. 
- Python_Development.Embed_FOUND
- Added in version 3.18. - System has the Python development artifacts for Python embedding. 
Python_INCLUDE_DIRS
The Python include directories.
- Python_DEFINITIONS
- Added in version 3.30.3. - The Python preprocessor definitions. 
- Python_DEBUG_POSTFIX
- Added in version 3.30. - Postfix of debug python module. This variable can be used to define the - DEBUG_POSTFIXtarget property.
- Python_LINK_OPTIONS
- Added in version 3.19. - The Python link options. Some configurations require specific link options for a correct build and execution. 
- Python_LIBRARIES
- The Python libraries. 
- Python_LIBRARY_DIRS
- The Python library directories. 
- Python_RUNTIME_LIBRARY_DIRS
- The Python runtime library directories. 
- Python_SABI_LIBRARIES
- Added in version 3.26. - The Python libraries for the Stable Application Binary Interface. 
- Python_SABI_LIBRARY_DIRS
- Added in version 3.26. - The Python - SABIlibrary directories.
- Python_RUNTIME_SABI_LIBRARY_DIRS
- Added in version 3.26. - The Python runtime - SABIlibrary directories.
- Python_VERSION
- Python version. 
- Python_VERSION_MAJOR
- Python major version. 
- Python_VERSION_MINOR
- Python minor version. 
- Python_VERSION_PATCH
- Python patch version. 
- Python_PyPy_VERSION
- Added in version 3.18. - Python PyPy version. 
- Python_NumPy_FOUND
- Added in version 3.14. - System has the NumPy. 
- Python_NumPy_INCLUDE_DIRS
- Added in version 3.14. - The NumPy include directories. 
- Python_NumPy_VERSION
- Added in version 3.14. - The NumPy version. 
Hints¶
- Python_ROOT_DIR
- Define the root directory of a Python installation. 
- Python_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.
- Python_FIND_ABI
- Added 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) and- gil_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 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 (Python_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 (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, 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).
- Python_FIND_STRATEGY
- Added 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 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 - Python_FIND_UNVERSIONED_NAMES.
- Python_FIND_REGISTRY
- Added in version 3.13. - On Windows the - Python_FIND_REGISTRYvariable determine the order of preference between registry and environment variables. the- Python_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_FRAMEWORK
- Added 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 as- CMAKE_FIND_FRAMEWORKvariable.- Note - Value - ONLYis not supported so- FIRSTwill be used instead.- If - Python_FIND_FRAMEWORKis not defined,- CMAKE_FIND_FRAMEWORKvariable will be used, if any.
- Python_FIND_VIRTUALENV
- Added 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- Python_FIND_REGISTRYand- CMAKE_FIND_FRAMEWORKvariables. The- Python_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- Python_FIND_REGISTRY(Windows) or- CMAKE_FIND_FRAMEWORK(macOS) can be set with value- LASTor- NEVERto 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 component- Interpretermay be helpful.
- Python_FIND_IMPLEMENTATIONS
- Added 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, 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- Python_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.
- Python_FIND_UNVERSIONED_NAMES
- Added 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, - python3or- python2and- python. The- Python_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- python2.5for 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_EXECUTABLE
- The path to the interpreter. 
- Python_COMPILER
- The path to the compiler. 
- Python_DOTNET_LAUNCHER
- Added in version 3.18. - The - .Netinterpreter. Only used by- IronPythonimplementation.
- Python_LIBRARY
- The path to the library. It will be used to compute the variables - Python_LIBRARIES,- Python_LIBRARY_DIRSand- Python_RUNTIME_LIBRARY_DIRS.
- Python_SABI_LIBRARY
- Added 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_DIRSand- Python_RUNTIME_SABI_LIBRARY_DIRS.
- Python_INCLUDE_DIR
- The path to the directory of the - Pythonheaders. It will be used to compute the variable- Python_INCLUDE_DIRS.
- Python_NumPy_INCLUDE_DIR
- The path to the directory of the - NumPyheaders. It will be used to compute the variable- Python_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_INTERACTIVE
- Added 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.
 
- Python_ARTIFACTS_PREFIX
- Added 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(Python COMPONENTS Development) set(Python_ARTIFACTS_PREFIX "_HOST") find_package(Python COMPONENTS Interpreter) # Here Python_HOST_EXECUTABLE and Python_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 the- find_package()command.
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.
