| This is Python version 3.8.0 alpha 0 |
| ==================================== |
| |
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| |
| Copyright (c) 2001-2018 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``. |
| |
| If you are running on macOS with the latest updates installed, make sure to install |
| openSSL or some other SSL software along with Homebrew or another package manager. |
| If issues persist, see https://devguide.python.org/setup/#macos-and-os-x for more |
| information. |
| |
| 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 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. |
| |
| |
| 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. 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 <https://bugs.python.org>`_ and |
| include relevant output from that command to show the issue. |
| |
| See `Running & Writing Tests <https://devguide.python.org/runtests/>`_ |
| for more on running tests. |
| |
| 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) 2001-2018 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. |