1. Carl Meyer
  2. cpython-robust-site


cpython-robust-site / README

This is Python version 3.0 release candidate 3

For notes specific to this release, see RELNOTES in this directory.
Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
Python Software Foundation.
All rights reserved.

Python 3000 (a.k.a. "Py3k", and released as Python 3.0) is a new
version of the language, which is incompatible with the 2.x line of
releases.  The language is mostly the same, but many details,
especially how built-in objects like dictionaries and strings work,
have changed considerably, and a lot of deprecated features have
finally been removed.

This is an ongoing project; the cleanup isn't expected to be complete
until some time in 2008.  In particular there are plans to reorganize
the standard library namespace.

Release Schedule

The release plan is to have a series of alpha releases in 2007 and 2008,
beta releases in 2008, and a final release in October 2008.  The alpha
releases are primarily aimed at developers who want a sneak peek at the
new langauge, especially those folks who plan to port their code to
Python 3000.  The hope is that by the time of the final release, many
3rd party packages will already be available in a 3.0-compatible form.

See PEP 361 for release details: http://www.python.org/dev/peps/pep-0361/


Documentation for Python 3000 is online, updated twice a day:


All documentation is also available online at the Python web site
(http://docs.python.org/, see below).  It is available online for
occasional reference, or can be downloaded in many formats for faster
access.  The documentation is downloadable in HTML, PostScript, PDF,
LaTeX (through 2.5), and reStructuredText (2.6+) formats; the LaTeX and
reStructuredText versions are primarily for documentation authors,
translators, and people with special formatting requirements.

This is a work in progress; please help improve it!

The design documents for Python 3000 are also online.  While the
reference documentation is being updated, the PEPs are often the best
source of information about new features.  Start by reading PEP 3000:


What's New

For an overview of what's new in Python 3000, see Guido van Rossum's
blog at artima.com:


We try to eventually have a comprehensive overview of the changes in
the "What's New in Python 3.0" document, found at


Please help write it!

For a more detailed change log, read Misc/NEWS (though this file, too,
is incomplete, and also doesn't list anything merged in from the 2.6
release under development).

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

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 inital 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

Converting From Python 2.x to 3.0

Python 2.6 (to be released concurrent with Python 3.0) will contain features
to help locating code that needs to be changed, such as optional warnings when
deprecated features are used, and backported versions of certain key Python
3000 features.

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 versio.  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/python 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 2.5, 2.6 and 3.0 with 2.6 being
the primary version, you would execute "make install" in your 2.6 build
directory and "make altinstall" in the others.

Configuration options and variables

A source-to-source translation tool, "2to3", can take care of the
mundane task of converting large amounts of source code.  It is not a
complete solution but is complemented by the deprecation warnings in
2.6.  This tool is currently available via the Subversion sandbox:


Issue Tracker and Mailing List

We're soliciting bug reports about all aspects of the language.  Fixes
are also welcome, preferable in unified diff format.  Please use the
issue tracker:


If you're not sure whether you're dealing with a bug or a feature, use
the mailing list:


To subscribe to the list, use the mailman form:


Build Instructions

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

    make test
    sudo make install    # or "make altinstall"

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

On Mac OS X, 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

On Windows, see 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 test

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

Copyright and License Information

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

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