github cpython_cpython: https://github.com/python/cpython

This is Python version 3.8.0 alpha 0

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.

For more complete instructions on contributing to CPython development,

see the Developer Guide.

Installable Python kits, and information about using Python, are available at

python.org.

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.

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.

PGO takes advantage of recent versions of the GCC or Clang compilers. If used,

either via configure --enable-optimizations or by manually running

make profile-opt regardless of configure flags, the optimized build

process will perform the following steps:

The entire Python directory is cleaned of temporary files that may have

resulted from a previous compilation.

An instrumented version of the interpreter is built, using suitable compiler

flags for each flavour. Note that this is just an intermediary step. The

binary resulting from this step is not good for real life workloads as it has

profiling instructions embedded inside.

After the instrumented interpreter is built, the Makefile will 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.

The final step is to build the actual interpreter, using the information

collected from the instrumented one. The end result will be a Python binary

that is optimized; suitable for distribution or production installation.

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.

We have a comprehensive overview of the changes in the What's New in Python

3.8 document. For a more

detailed change log, read Misc/NEWS, but a full

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

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

entitled "Installing multiple versions".

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.

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.

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. For

example, if test_os and test_gdb failed, you can run:

make test TESTOPTS="-v test_os test_gdb"

If the failure persists and appears to be a problem with Python rather than

your environment, you can file a bug report and

include relevant output from that command to show the issue.

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.

Bug reports are welcome! You can use the issue tracker to report bugs, and/or submit pull requests on

GitHub.

You can also follow development discussion on the python-dev mailing list.

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/.

See PEP 569 for Python 3.8 release details.

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.