.. _extending-index:

##################################################
  Extending and Embedding the Python Interpreter
##################################################

This document describes how to write modules in C or C++ to extend the Python
interpreter with new modules.  Those modules can not only define new functions
but also new object types and their methods.  The document also describes how
to embed the Python interpreter in another application, for use as an extension
language.  Finally, it shows how to compile and link extension modules so that
they can be loaded dynamically (at run time) into the interpreter, if the
underlying operating system supports this feature.

This document assumes basic knowledge about Python.  For an informal
introduction to the language, see :ref:`tutorial-index`.  :ref:`reference-index`
gives a more formal definition of the language.  :ref:`library-index` documents
the existing object types, functions and modules (both built-in and written in
Python) that give the language its wide application range.

For a detailed description of the whole Python/C API, see the separate
:ref:`c-api-index`.


Recommended third party tools
=============================

This guide only covers the basic tools for creating extensions provided
as part of this version of CPython. Third party tools like
`Cython <https://cython.org/>`_, `cffi <https://cffi.readthedocs.io>`_,
`SWIG <https://www.swig.org>`_ and `Numba <https://numba.pydata.org/>`_
offer both simpler and more sophisticated approaches to creating C and C++
extensions for Python.

.. seealso::

   `Python Packaging User Guide: Binary Extensions <https://packaging.python.org/guides/packaging-binary-extensions/>`_
      The Python Packaging User Guide not only covers several available
      tools that simplify the creation of binary extensions, but also
      discusses the various reasons why creating an extension module may be
      desirable in the first place.


Creating extensions without third party tools
=============================================

This section of the guide covers creating C and C++ extensions without
assistance from third party tools. It is intended primarily for creators
of those tools, rather than being a recommended way to create your own
C extensions.

.. toctree::
   :maxdepth: 2
   :numbered:

   extending.rst
   newtypes_tutorial.rst
   newtypes.rst
   building.rst
   windows.rst

Embedding the CPython runtime in a larger application
=====================================================

Sometimes, rather than creating an extension that runs inside the Python
interpreter as the main application, it is desirable to instead embed
the CPython runtime inside a larger application. This section covers
some of the details involved in doing that successfully.

.. toctree::
   :maxdepth: 2
   :numbered:

   embedding.rst