Editing Python (programming language) (section)

===Reference implementation===
[[CPython]] is the [[reference implementation]] of Python. This implementation is written in C, meeting the [[C11 (C standard revision)|C11]] standard<ref>{{Cite web |title=PEP 7 – Style Guide for C Code {{!}} peps.python.org |url=https://peps.python.org/pep-0007/ |access-date=2022-04-28 |website=peps.python.org |archive-date=24 April 2022 |archive-url=https://web.archive.org/web/20220424202827/https://peps.python.org/pep-0007/ |url-status=live}}</ref> (since version 3.11, older versions use the [[C89 (C version)|C89]] standard with several select [[C99]] features), but third-party extensions are not limited to older C versions—e.g., they can be implemented using C11 or C++.<ref>{{Cite web|title=4. Building C and C++ Extensions – Python 3.9.2 documentation|url=https://docs.python.org/3/extending/building.html|access-date=2021-03-01|website=docs.python.org|archive-date=3 March 2021|archive-url=https://web.archive.org/web/20210303002519/https://docs.python.org/3/extending/building.html|url-status=live}}</ref><ref name="AutoNT-66"/> CPython [[compiler|compiles]] Python programs into an intermediate [[bytecode]],<ref name="AutoNT-67"/> which is then executed by a [[virtual machine]].<ref name="AutoNT-68"/> CPython is distributed with a large standard library written in a combination of C and native Python.

CPython is available for many platforms, including Windows and most modern [[Unix-like]] systems, including macOS (and [[Apple M1]] Macs, since Python&nbsp;3.9.1, using an experimental installer). <!-- "Windows Vista support dropped in Python 3.7" -->Starting with Python&nbsp;3.9, the Python installer intentionally fails to install on [[Windows 7]] and 8<!-- but not 8.1? -->;<ref>{{Cite web |title=Changelog – Python 3.9.0 documentation |url=https://docs.python.org/release/3.9.0/whatsnew/changelog.html#changelog |url-status=live |archive-url=https://web.archive.org/web/20210207001142/https://docs.python.org/release/3.9.0/whatsnew/changelog.html#changelog |archive-date=7 February 2021 |access-date=2021-02-08 |website=docs.python.org}}</ref><ref>{{Cite web |title=Download Python |url=https://www.python.org/downloads/release/python-391 |url-status=live |archive-url=https://web.archive.org/web/20201208045225/https://www.python.org/downloads/release/python-391/ |archive-date=8 December 2020 |access-date=2020-12-13 |website=Python.org |language=en}}</ref> [[Windows XP]] was supported until Python&nbsp;3.5<!--"Windows XP support dropped in Python 3.5"-->, with unofficial support for [[OpenVMS|VMS]].<!--"Put online a new version of Python 3.10.0a (IA64only)"--><ref>{{Cite web|title=history [vmspython]|url=https://www.vmspython.org/doku.php?id=history|access-date=2020-12-04|website=www.vmspython.org|archive-date=2 December 2020|archive-url=https://web.archive.org/web/20201202194743/https://www.vmspython.org/doku.php?id=history|url-status=live}}</ref> Platform portability was one of Python's earliest priorities.<ref name="AutoNT-69" /> During development of Python&nbsp;1 and 2, even [[OS/2]] and [[Solaris (operating system)|Solaris]] were supported;<!-- Also python-3.2.2 at http://unixpackages.com/packages/package-list --><ref>{{Cite web|title=Download Python for Other Platforms|url=https://www.python.org/download/other/|access-date=2020-12-04|website=Python.org|language=en|archive-date=27 November 2020|archive-url=https://web.archive.org/web/20201127015815/https://www.python.org/download/other/|url-status=live}}</ref> since that time, support has been dropped for many platforms.<!--

Starting with CPython 3.7.0, *nix platforms are expected to provide at least one of C.UTF-8 (full locale), C.utf8 (full locale) or UTF-8 (LC_CTYPE-only locale) as an alternative to the legacy C locale.
-->

All current Python versions (since 3.7) support only operating systems that feature multithreading<!-- (then in 3.7 removing support for [[IRIX]]; and before many other operating systems such as [[OS/2]] and [[VMS]]) -->, by now supporting not nearly as many operating systems (dropping many outdated) than in the past.