README.rst - platform/external/python/cpython3 - Gitiles

 This is Python version 3.8.0 alpha 0
 ====================================

 .. image:: https://travis-ci.org/python/cpython.svg?branch=master
    :alt: CPython build status on Travis CI
    :target: https://travis-ci.org/python/cpython

 .. image:: https://ci.appveyor.com/api/projects/status/4mew1a93xdkbf5ua/branch/master?svg=true
    :alt: CPython build status on Appveyor
    :target: https://ci.appveyor.com/project/python/cpython/branch/master

 .. image:: https://codecov.io/gh/python/cpython/branch/master/graph/badge.svg
    :alt: CPython code coverage on Codecov
    :target: https://codecov.io/gh/python/cpython

 Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,
 2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software Foundation.  All rights
 reserved.

 See the end of this file for further copyright and license information.

 .. contents::

 General Information
 -------------------

 - Website: https://www.python.org
 - Source code: https://github.com/python/cpython
 - Issue tracker: https://bugs.python.org
 - Documentation: https://docs.python.org
 - Developer's Guide: https://devguide.python.org/

 Contributing to CPython
 -----------------------

 For more complete instructions on contributing to CPython development,
 see the `Developer Guide`_.

 .. _Developer Guide: https://devguide.python.org/

 Using Python
 ------------

 Installable Python kits, and information about using Python, are available at
 `python.org`_.

 .. _python.org: https://www.python.org/

 Build Instructions
 ------------------

 On Unix, Linux, BSD, macOS, and Cygwin::

     ./configure
     make
     make test
     sudo make install

 This will install Python as python3.

 You can pass many options to the configure script; run ``./configure --help``
 to find out more.  On macOS and Cygwin, the executable is called ``python.exe``;
 elsewhere it's just ``python``.

 On macOS, if you have configured Python with ``--enable-framework``, you
 should use ``make frameworkinstall`` to do the installation.  Note that this
 installs the Python executable in a place that is not normally on your PATH,
 you may want to set up a symlink in ``/usr/local/bin``.

 On Windows, see `PCbuild/readme.txt
 <https://github.com/python/cpython/blob/master/PCbuild/readme.txt>`_.

 If you wish, you can create a subdirectory and invoke configure from there.
 For example::

     mkdir debug
     cd debug
     ../configure --with-pydebug
     make
     make test

 (This will fail if you *also* built at the top-level directory.  You should do
 a ``make clean`` at the toplevel first.)

 To get an optimized build of Python, ``configure --enable-optimizations``
 before you run ``make``.  This sets the default make targets up to enable
 Profile Guided Optimization (PGO) and may be used to auto-enable Link Time
 Optimization (LTO) on some platforms.  For more details, see the sections
 below.


 Profile Guided Optimization
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^

 PGO takes advantage of recent versions of the GCC or Clang compilers.  If ran,
 ``make profile-opt`` will do several steps.

 First, the entire Python directory is cleaned of temporary files that may have
 resulted in a previous compilation.

 Then, an instrumented version of the interpreter is built, using suitable
 compiler flags for each flavour. Note that this is just an intermediary step
 and the binary resulted after this step is not good for real life workloads, as
 it has profiling instructions embedded inside.

 After this instrumented version of the interpreter is built, the Makefile will
 automatically run a training workload. This is necessary in order to profile
 the interpreter execution. Note also that any output, both stdout and stderr,
 that may appear at this step is suppressed.

 Finally, the last step is to rebuild the interpreter, using the information
 collected in the previous one. The end result will be a Python binary that is
 optimized and suitable for distribution or production installation.


 Link Time Optimization
 ^^^^^^^^^^^^^^^^^^^^^^

 Enabled via configure's ``--with-lto`` flag.  LTO takes advantage of the
 ability of recent compiler toolchains to optimize across the otherwise
 arbitrary ``.o`` file boundary when building final executables or shared
 libraries for additional performance gains.


 What's New
 ----------

 We have a comprehensive overview of the changes in the `What's New in Python
 3.8 <https://docs.python.org/3.8/whatsnew/3.8.html>`_ document.  For a more
 detailed change log, read `Misc/NEWS
 <https://github.com/python/cpython/blob/master/Misc/NEWS.d>`_, but a full
 accounting of changes can only be gleaned from the `commit history
 <https://github.com/python/cpython/commits/master>`_.

 If you want to install multiple versions of Python see the section below
 entitled "Installing multiple versions".


 Documentation
 -------------

 `Documentation for Python 3.8 <https://docs.python.org/3.8/>`_ is online,
 updated daily.

 It can also be downloaded in many formats for faster access.  The documentation
 is downloadable in HTML, PDF, and reStructuredText formats; the latter version
 is primarily for documentation authors, translators, and people with special
 formatting requirements.

 For information about building Python's documentation, refer to `Doc/README.rst
 <https://github.com/python/cpython/blob/master/Doc/README.rst>`_.


 Converting From Python 2.x to 3.x
 ---------------------------------

 Significant backward incompatible changes were made for the release of Python
 3.0, which may cause programs written for Python 2 to fail when run with Python
 3.  For more information about porting your code from Python 2 to Python 3, see
 the `Porting HOWTO <https://docs.python.org/3/howto/pyporting.html>`_.


 Testing
 -------

 To test the interpreter, type ``make test`` in the top-level directory.  The
 test set produces some output.  You can generally ignore the messages about
 skipped tests due to optional features which can't be imported.  If a message
 is printed about a failed test or a traceback or core dump is produced,
 something is wrong.

 By default, tests are prevented from overusing resources like disk space and
 memory.  To enable these tests, run ``make testall``.

 If any tests fail, you can re-run the failing test(s) in verbose mode::

     make test TESTOPTS="-v test_that_failed"

 If the failure persists and appears to be a problem with Python rather than
 your environment, you can `file a bug report <https://bugs.python.org>`_ and
 include relevant output from that command to show the issue.


 Installing multiple versions
 ----------------------------

 On Unix and Mac systems if you intend to install multiple versions of Python
 using the same installation prefix (``--prefix`` argument to the configure
 script) you must take care that your primary python executable is not
 overwritten by the installation of a different version.  All files and
 directories installed using ``make altinstall`` contain the major and minor
 version and can thus live side-by-side.  ``make install`` also creates
 ``${prefix}/bin/python3`` which refers to ``${prefix}/bin/pythonX.Y``.  If you
 intend to install multiple versions using the same prefix you must decide which
 version (if any) is your "primary" version.  Install that version using ``make
 install``.  Install all other versions using ``make altinstall``.

 For example, if you want to install Python 2.7, 3.6, and 3.8 with 3.8 being the
 primary version, you would execute ``make install`` in your 3.8 build directory
 and ``make altinstall`` in the others.


 Issue Tracker and Mailing List
 ------------------------------

 Bug reports are welcome!  You can use the `issue tracker
 <https://bugs.python.org>`_ to report bugs, and/or submit pull requests `on
 GitHub <https://github.com/python/cpython>`_.

 You can also follow development discussion on the `python-dev mailing list
 <https://mail.python.org/mailman/listinfo/python-dev/>`_.


 Proposals for enhancement
 -------------------------

 If you have a proposal to change Python, you may want to send an email to the
 comp.lang.python or `python-ideas`_ mailing lists for initial feedback.  A
 Python Enhancement Proposal (PEP) may be submitted if your idea gains ground.
 All current PEPs, as well as guidelines for submitting a new PEP, are listed at
 `python.org/dev/peps/ <https://www.python.org/dev/peps/>`_.

 .. _python-ideas: https://mail.python.org/mailman/listinfo/python-ideas/


 Release Schedule
 ----------------

 See :pep:`569` for Python 3.8 release details.


 Copyright and License Information
 ---------------------------------

 Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,
 2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software Foundation.  All rights
 reserved.

 Copyright (c) 2000 BeOpen.com.  All rights reserved.

 Copyright (c) 1995-2001 Corporation for National Research Initiatives.  All
 rights reserved.

 Copyright (c) 1991-1995 Stichting Mathematisch Centrum.  All rights reserved.

 See the file "LICENSE" for information on the history of this software, terms &
 conditions for usage, and a DISCLAIMER OF ALL WARRANTIES.

 This Python distribution contains *no* GNU General Public License (GPL) code,
 so it may be used in proprietary projects.  There are interfaces to some GNU
 code but these are entirely optional.

 All trademarks referenced herein are property of their respective holders.
	This is Python version 3.8.0 alpha 0
	====================================

	.. image:: https://travis-ci.org/python/cpython.svg?branch=master
	:alt: CPython build status on Travis CI
	:target: https://travis-ci.org/python/cpython

	.. image:: https://ci.appveyor.com/api/projects/status/4mew1a93xdkbf5ua/branch/master?svg=true
	:alt: CPython build status on Appveyor
	:target: https://ci.appveyor.com/project/python/cpython/branch/master

	.. image:: https://codecov.io/gh/python/cpython/branch/master/graph/badge.svg
	:alt: CPython code coverage on Codecov
	:target: https://codecov.io/gh/python/cpython

	Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,
	2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software Foundation. All rights
	reserved.

	See the end of this file for further copyright and license information.

	.. contents::

	General Information
	-------------------

	- Website: https://www.python.org
	- Source code: https://github.com/python/cpython
	- Issue tracker: https://bugs.python.org
	- Documentation: https://docs.python.org
	- Developer's Guide: https://devguide.python.org/

	Contributing to CPython
	-----------------------

	For more complete instructions on contributing to CPython development,
	see the `Developer Guide`_.

	.. _Developer Guide: https://devguide.python.org/

	Using Python
	------------

	Installable Python kits, and information about using Python, are available at
	`python.org`_.

	.. _python.org: https://www.python.org/

	Build Instructions
	------------------

	On Unix, Linux, BSD, macOS, and Cygwin::

	./configure
	make
	make test
	sudo make install

	This will install Python as python3.

	You can pass many options to the configure script; run ``./configure --help``
	to find out more. On macOS and Cygwin, the executable is called ``python.exe``;
	elsewhere it's just ``python``.

	On macOS, if you have configured Python with ``--enable-framework``, you
	should use ``make frameworkinstall`` to do the installation. Note that this
	installs the Python executable in a place that is not normally on your PATH,
	you may want to set up a symlink in ``/usr/local/bin``.

	On Windows, see `PCbuild/readme.txt
	<https://github.com/python/cpython/blob/master/PCbuild/readme.txt>`_.

	If you wish, you can create a subdirectory and invoke configure from there.
	For example::

	mkdir debug
	cd debug
	../configure --with-pydebug
	make
	make test

	(This will fail if you also built at the top-level directory. You should do
	a ``make clean`` at the toplevel first.)

	To get an optimized build of Python, ``configure --enable-optimizations``
	before you run ``make``. This sets the default make targets up to enable
	Profile Guided Optimization (PGO) and may be used to auto-enable Link Time
	Optimization (LTO) on some platforms. For more details, see the sections
	below.


	Profile Guided Optimization
	^^^^^^^^^^^^^^^^^^^^^^^^^^^

	PGO takes advantage of recent versions of the GCC or Clang compilers. If ran,
	``make profile-opt`` will do several steps.

	First, the entire Python directory is cleaned of temporary files that may have
	resulted in a previous compilation.

	Then, an instrumented version of the interpreter is built, using suitable
	compiler flags for each flavour. Note that this is just an intermediary step
	and the binary resulted after this step is not good for real life workloads, as
	it has profiling instructions embedded inside.

	After this instrumented version of the interpreter is built, the Makefile will
	automatically run a training workload. This is necessary in order to profile
	the interpreter execution. Note also that any output, both stdout and stderr,
	that may appear at this step is suppressed.

	Finally, the last step is to rebuild the interpreter, using the information
	collected in the previous one. The end result will be a Python binary that is
	optimized and suitable for distribution or production installation.


	Link Time Optimization
	^^^^^^^^^^^^^^^^^^^^^^

	Enabled via configure's ``--with-lto`` flag. LTO takes advantage of the
	ability of recent compiler toolchains to optimize across the otherwise
	arbitrary ``.o`` file boundary when building final executables or shared
	libraries for additional performance gains.


	What's New
	----------

	We have a comprehensive overview of the changes in the `What's New in Python
	3.8 <https://docs.python.org/3.8/whatsnew/3.8.html>`_ document. For a more
	detailed change log, read `Misc/NEWS
	<https://github.com/python/cpython/blob/master/Misc/NEWS.d>`_, but a full
	accounting of changes can only be gleaned from the `commit history
	<https://github.com/python/cpython/commits/master>`_.

	If you want to install multiple versions of Python see the section below
	entitled "Installing multiple versions".


	Documentation
	-------------

	`Documentation for Python 3.8 <https://docs.python.org/3.8/>`_ is online,
	updated daily.

	It can also be downloaded in many formats for faster access. The documentation
	is downloadable in HTML, PDF, and reStructuredText formats; the latter version
	is primarily for documentation authors, translators, and people with special
	formatting requirements.

	For information about building Python's documentation, refer to `Doc/README.rst
	<https://github.com/python/cpython/blob/master/Doc/README.rst>`_.


	Converting From Python 2.x to 3.x
	---------------------------------

	Significant backward incompatible changes were made for the release of Python
	3.0, which may cause programs written for Python 2 to fail when run with Python
	3. For more information about porting your code from Python 2 to Python 3, see
	the `Porting HOWTO <https://docs.python.org/3/howto/pyporting.html>`_.


	Testing
	-------

	To test the interpreter, type ``make test`` in the top-level directory. The
	test set produces some output. You can generally ignore the messages about
	skipped tests due to optional features which can't be imported. If a message
	is printed about a failed test or a traceback or core dump is produced,
	something is wrong.

	By default, tests are prevented from overusing resources like disk space and
	memory. To enable these tests, run ``make testall``.

	If any tests fail, you can re-run the failing test(s) in verbose mode::

	make test TESTOPTS="-v test_that_failed"

	If the failure persists and appears to be a problem with Python rather than
	your environment, you can `file a bug report <https://bugs.python.org>`_ and
	include relevant output from that command to show the issue.


	Installing multiple versions
	----------------------------

	On Unix and Mac systems if you intend to install multiple versions of Python
	using the same installation prefix (``--prefix`` argument to the configure
	script) you must take care that your primary python executable is not
	overwritten by the installation of a different version. All files and
	directories installed using ``make altinstall`` contain the major and minor
	version and can thus live side-by-side. ``make install`` also creates
	``${prefix}/bin/python3`` which refers to ``${prefix}/bin/pythonX.Y``. If you
	intend to install multiple versions using the same prefix you must decide which
	version (if any) is your "primary" version. Install that version using ``make
	install``. Install all other versions using ``make altinstall``.

	For example, if you want to install Python 2.7, 3.6, and 3.8 with 3.8 being the
	primary version, you would execute ``make install`` in your 3.8 build directory
	and ``make altinstall`` in the others.


	Issue Tracker and Mailing List
	------------------------------

	Bug reports are welcome! You can use the `issue tracker
	<https://bugs.python.org>`_ to report bugs, and/or submit pull requests `on
	GitHub <https://github.com/python/cpython>`_.

	You can also follow development discussion on the `python-dev mailing list
	<https://mail.python.org/mailman/listinfo/python-dev/>`_.


	Proposals for enhancement
	-------------------------

	If you have a proposal to change Python, you may want to send an email to the
	comp.lang.python or `python-ideas`_ mailing lists for initial feedback. A
	Python Enhancement Proposal (PEP) may be submitted if your idea gains ground.
	All current PEPs, as well as guidelines for submitting a new PEP, are listed at
	`python.org/dev/peps/ <https://www.python.org/dev/peps/>`_.

	.. _python-ideas: https://mail.python.org/mailman/listinfo/python-ideas/


	Release Schedule
	----------------

	See :pep:`569` for Python 3.8 release details.


	Copyright and License Information
	---------------------------------

	Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,
	2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software Foundation. All rights
	reserved.

	Copyright (c) 2000 BeOpen.com. All rights reserved.

	Copyright (c) 1995-2001 Corporation for National Research Initiatives. All
	rights reserved.

	Copyright (c) 1991-1995 Stichting Mathematisch Centrum. All rights reserved.

	See the file "LICENSE" for information on the history of this software, terms &
	conditions for usage, and a DISCLAIMER OF ALL WARRANTIES.

	This Python distribution contains no GNU General Public License (GPL) code,
	so it may be used in proprietary projects. There are interfaces to some GNU
	code but these are entirely optional.

	All trademarks referenced herein are property of their respective holders.