[Python-Dev] Licensing question

Guido van Rossum guido@python.org
Tue, 19 Nov 2002 11:12:58 -0500

> Recently we've been trying to shore up copyrights in Bost code; some
> of our source files have no copyright notice at all. Boost.Python
> includes a modified version of Python.h to work around some C++
> interoperability bugs in Python 2.2.1's header. Lawyers in companies
> that use Boost would feel a lot more comfortable if the file included
> a copyright notice. My usual practice is to write:
>   // Copyright David Abrahams 2002. Permission to copy, use,
>   // modify, sell and distribute this software is granted provided this
>   // copyright notice appears in all copies. This software is provided
>   // "as is" without express or implied warranty, and with no claim as
>   // to its suitability for any purpose.
> At the top of every C++ source file. Is there any reason not to do
> that with our modified Python.h? If so, what should I put there?

As a derived work, it is indeed your copyright, but the original is
licensed to you under the conditions of the PSF license:

Relevant are in particular:

    2. Subject to the terms and conditions of this License Agreement, PSF
    hereby grants Licensee a nonexclusive, royalty-free, world-wide
    license to reproduce, analyze, test, perform and/or display publicly,
    prepare derivative works, distribute, and otherwise use Python 2.2.2
    alone or in any derivative version, provided, however, that PSF's
    License Agreement and PSF's notice of copyright, i.e., "Copyright (c)
    2001, 2002 Python Software Foundation; All Rights Reserved" are
    retained in Python 2.2.2 alone or in any derivative version prepared
    by Licensee.

    3. In the event Licensee prepares a derivative work that is based on
    or incorporates Python 2.2.2 or any part thereof, and wants to make
    the derivative work available to others as provided herein, then
    Licensee hereby agrees to include in any such work a brief summary of
    the changes made to Python 2.2.2.

I'd say you need to include at least the PSF copyright notice quoted
there and a comment explaining how your Python.h differs from the

--Guido van Rossum (home page: http://www.python.org/~guido/)