This is Python version 3.6.3

============================

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   :target: https://travis-ci.org/python/cpython

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Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,

2012, 2013, 2014, 2015, 2016, 2017 Python Software Foundation.  All rights

reserved.

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

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/3.6/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

3.6 <https://docs.python.org/3.6/whatsnew/3.6.html>`_ document.  For a more

detailed change log, read `Misc/NEWS

<https://github.com/python/cpython/blob/3.6/Misc/NEWS.d>`_, but a full

accounting of changes can only be gleaned from the `commit history

<https://github.com/python/cpython/commits/3.6>`_.

If you want to install multiple versions of Python see the section below

entitled "Installing multiple versions".

Documentation

-------------

`Documentation for Python 3.6 <https://docs.python.org/3.6/>`_ 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/3.6/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, 3.5, and 3.6 with 3.6 being the

primary version, you would execute ``make install`` in your 3.6 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:`494` for Python 3.6 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 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.