FindPython3

Find Python 3 interpreter, compiler and development environment (include directories and libraries).

Three 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)

  • NumPy: search for NumPy include directories.

If no COMPONENTS is specified, Interpreter is assumed.

To ensure consistent versions between components Interpreter, Compiler, Development 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 are both specified, this module search only for interpreter with same platform architecture as the one defined by CMake configuration. This contraint does not apply if only Interpreter component is specified.

Imported Targets

This module defines the following Imported Targets (when CMAKE_ROLE is PROJECT):

Python3::Interpreter

Python 3 interpreter. Target defined if component Interpreter is found.

Python3::Compiler

Python 3 compiler. Target defined if component Compiler is found.

Python3::Python

Python 3 library for Python embedding. Target defined if component Development is found.

Python3::Module

Python 3 library for Python module. Target defined if component Development is found.

Python3::NumPy

NumPy library for Python 3. Target defined if component NumPy is 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_INTERPRETER_ID
A short string unique to the interpreter. Possible values include:

  • Python

  • ActivePython

  • Anaconda

  • Canopy

  • IronPython

Python3_STDLIB

Standard platform independent installation directory.

Information returned by distutils.sysconfig.get_python_lib(plat_specific=False,standard_lib=True).

Python3_STDARCH

Standard platform dependent installation directory.

Information returned by distutils.sysconfig.get_python_lib(plat_specific=True,standard_lib=True).

Python3_SITELIB

Third-party platform independent installation directory.

Information returned by distutils.sysconfig.get_python_lib(plat_specific=False,standard_lib=False).

Python3_SITEARCH

Third-party platform dependent installation directory.

Information returned by distutils.sysconfig.get_python_lib(plat_specific=True,standard_lib=False).

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_Development_FOUND

System has the Python 3 development artifacts.

Python3_INCLUDE_DIRS

The Python 3 include directories.

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_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_NumPy_FOUND

System has the NumPy.

Python3_NumPy_INCLUDE_DIRS

The NumPy include directries.

Python3_NumPy_VERSION

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.

Python3_FIND_STRATEGY

This variable defines how lookup will be done. The Python3_FIND_STRATEGY variable can be set to empty or one of the following:

  • VERSION: Try to find the most recent version in all specified locations. This is the default if policy CMP0094 is undefined or set to OLD.

  • LOCATION: Stops lookup as soon as a version satisfying version constraints is founded. This is the default if policy CMP0094 is set to NEW.

Python3_FIND_REGISTRY

On Windows the Python3_FIND_REGISTRY variable determine the order of preference between registry and environment variables. The Python3_FIND_REGISTRY variable can be set to empty or 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

On macOS the Python3_FIND_FRAMEWORK variable determine the order of preference between Apple-style and unix-style package components. This variable can be set to empty or take same values as CMAKE_FIND_FRAMEWORK variable.

Note

Value ONLY is not supported so FIRST will be used instead.

If Python3_FIND_FRAMEWORK is not defined, CMAKE_FIND_FRAMEWORK variable will be used, if any.

Python3_FIND_VIRTUALENV

This variable defines the handling of virtual environments. It is meaningfull only when a virtual environment is active (i.e. the activate script has been evaluated). In this case, it takes precedence over Python3_FIND_REGISTRY and CMAKE_FIND_FRAMEWORK variables. The Python3_FIND_VIRTUALENV variable can be set to empty or 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. In this case, variable Python3_FIND_REGISTRY (Windows) or CMAKE_FIND_FRAMEWORK (macOS) can be set with value LAST or NEVER to select preferably the interpreter from the virtual environment.

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 Python3::Python or, when library type is MODULE, to target Python3::Module and takes care of Python module naming rules:

Python3_add_library (my_module MODULE src1.cpp)

If library type is not specified, MODULE is assumed.