CMake/Modules/FindPython.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
FindPython
----------

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

Three 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).

If no ``COMPONENTS`` is specified, ``Interpreter`` is assumed.

To ensure consistent versions between components ``Interpreter``, ``Compiler``
and ``Development``, 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 :module:`FindPython3` and
:module:`FindPython2` modules rather than this one.

Imported Targets
^^^^^^^^^^^^^^^^

This module defines the following :ref:`Imported Targets <Imported Targets>`:

``Python::Interpreter``
  Python interpreter. Target defined if component ``Interpreter`` is found.
``Python::Compiler``
  Python compiler. Target defined if component ``Compiler`` is found.
``Python::Python``
  Python library. Target defined if component ``Development`` is found.

Result Variables
^^^^^^^^^^^^^^^^

This module will set the following variables in your project
(see :ref:`Standard Variable Names <CMake Developer 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_INTERPRETER_ID``
  A short string unique to the interpreter. Possible values include:
    * Python
    * ActivePython
    * Anaconda
    * Canopy
    * IronPython
``Python_STDLIB``
  Standard platform independent installation directory.

  Information returned by
  ``distutils.sysconfig.get_python_lib(plat_specific=False,standard_lib=True)``.
``Python_STDARCH``
  Standard platform dependent installation directory.

  Information returned by
  ``distutils.sysconfig.get_python_lib(plat_specific=True,standard_lib=True)``.
``Python_SITELIB``
  Third-party platform independent installation directory.

  Information returned by
  ``distutils.sysconfig.get_python_lib(plat_specific=False,standard_lib=False)``.
``Python_SITEARCH``
  Third-party platform dependent installation directory.

  Information returned by
  ``distutils.sysconfig.get_python_lib(plat_specific=True,standard_lib=False)``.
``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_Development_FOUND``
  System has the Python development artifacts.
``Python_INCLUDE_DIRS``
  The Python include directories.
``Python_LIBRARIES``
  The Python libraries.
``Python_LIBRARY_DIRS``
  The Python library directories.
``Python_RUNTIME_LIBRARY_DIRS``
  The Python runtime library directories.
``Python_VERSION``
  Python version.
``Python_VERSION_MAJOR``
  Python major version.
``Python_VERSION_MINOR``
  Python minor version.
``Python_VERSION_PATCH``
  Python patch 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.

Commands
^^^^^^^^

This module defines the command ``Python_add_library`` which have the same
semantic as :command:`add_library` but take care of Python module naming rules
(only applied if library is of type ``MODULE``) and add dependency to target
``Python::Python``::

  Python_add_library (my_module MODULE src1.cpp)

If library type is not specified, ``MODULE`` is assumed.
#]=======================================================================]


set (_PYTHON_PREFIX Python)

if (DEFINED Python_FIND_VERSION)
  set (_Python_REQUIRED_VERSION_MAJOR ${Python_FIND_VERSION_MAJOR})

  include (${CMAKE_CURRENT_LIST_DIR}/FindPython/Support.cmake)
else()
  # iterate over versions in quiet and NOT required modes to avoid multiple
  # "Found" messages and prematurally failure.
  set (_Python_QUIETLY ${Python_FIND_QUIETLY})
  set (_Python_REQUIRED ${Python_FIND_REQUIRED})
  set (Python_FIND_QUIETLY TRUE)
  set (Python_FIND_REQUIRED FALSE)

  foreach (_Python_REQUIRED_VERSION_MAJOR IN ITEMS 3 2)
    set (Python_FIND_VERSION ${_Python_REQUIRED_VERSION_MAJOR})
    include (${CMAKE_CURRENT_LIST_DIR}/FindPython/Support.cmake)
    if (Python_FOUND)
      break()
    endif()
    # clean-up some CACHE variables to ensure look-up restart from scratch
    foreach (_Python_ITEM IN ITEMS EXECUTABLE COMPILER
                                   LIBRARY_RELEASE RUNTIME_LIBRARY_RELEASE
                                   LIBRARY_DEBUG RUNTIME_LIBRARY_DEBUG
                                   INCLUDE_DIR)
      unset (Python_${_Python_ITEM} CACHE)
    endforeach()
  endforeach()

  unset (Python_FIND_VERSION)

  set (Python_FIND_QUIETLY ${_Python_QUIETLY})
  set (Python_FIND_REQUIRED ${_Python_REQUIRED})
  if (Python_FIND_REQUIRED OR NOT Python_FIND_QUIETLY)
    # call again validation command to get "Found" or error message
    find_package_handle_standard_args (Python HANDLE_COMPONENTS
                                              REQUIRED_VARS ${_Python_REQUIRED_VARS}
                                              VERSION_VAR Python_VERSION)
  endif()
endif()

if (COMMAND __Python_add_library)
  macro (Python_add_library)
    __Python_add_library (Python ${ARGV})
  endmacro()
endif()

unset (_PYTHON_PREFIX)