Dynamic linking, was: Re: Dispelling BSD License Misconceptions
Chuck Swiger
chuck at codefab.com
Fri Jan 19 03:32:02 UTC 2007
On Jan 18, 2007, at 3:39 PM, Matthew Flaschen wrote:
>> Notice the key phrases "...where your code depends on static or
>> dynamic
>> linking of a GPL'ed library..." & "...in order to operate".
>
> Sticking to the example of readline and Python, part of the code is
> still specifically written to depend on readline. I think under
> Eben's
> argument, this part would then be a derivative work. Thus, that
> part at
> least should be licensed under the GPL.
Well, Python's Modules/readline.c isn't under the GPL. Python's
README states:
> This Python distribution contains no GNU General Public Licensed
> (GPLed) code so it may be used in proprietary projects just like prior
> Python distributions. There are interfaces to some GNU code but these
> are entirely optional.
...and the LICENSE states:
> (1) GPL-compatible doesn't mean that we're distributing Python under
> the GPL. All Python licenses, unlike the GPL, let you distribute
> a modified version without making your changes open source. The
> GPL-compatible licenses make it possible to combine Python with
> other software that is released under the GPL; the others don't.
>
> (2) According to Richard Stallman, 1.6.1 is not GPL-compatible,
> because its license has a choice of law clause. According to
> CNRI, however, Stallman's lawyer has told CNRI's lawyer that 1.6.1
> is "not incompatible" with the GPL.
Feel free to report Python to gpl-violations.org, if you like.
[ ... ]
>> http://www.linuxdevices.com/files/misc/asay-paper.pdf
>>
>> ...where he's quoted as saying (with regard to whether a situation
>> would
>> create a derivative work, ppg 15-16):
>>
>> "A module written to be plugged into an API defined specifically to
>> support dynamic loading?
>> Moglen: No."
>
> This isn't quite the same thing. Readline wasn't written to an
> existing
> Python plugin API. Part of Python was written to interact
> specifically
> with readline.
Python is designed with a plugin API which can dynamically load
optional modules if present. It's entirely possible to add readline
support to a version of Python compiled without it; for examples see:
http://face.centosprime.com/macosxw/?p=171
http://cheeseshop.python.org/pypi/readline/2.4.2
> Also, Chuck, please don't CC list members to list mail, unless they
> ask you to.
Sigh. Different mailing lists have different conventions with regard
to that;
I will be happy to refrain from CC:ing you in the future, or at least
try not to do so....
--
-Chuck
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