[DB-SIG] Re: [Psycopg] GPL or LGPL

M.-A. Lemburg mal@lemburg.com
Wed, 02 Oct 2002 12:07:43 +0200

Federico Di Gregorio wrote:
> a single answer and then i'll consider the argument closed.
> Il mer, 2002-10-02 alle 11:25, M.-A. Lemburg ha scritto:
>>Input and output of GPLed programs are not automatically
>>covered by the GPL, e.g. the GNU C compiler needs many
>>instructions to tell it what to do with the code, but that
>>doesn't make the code automatically fall under the GPL.
>>Please read clause 0. of the GPL and the FAQ for details.
>>	http://www.gnu.org/licenses/gpl.html
>>	http://www.gnu.org/licenses/gpl-faq.html
> the FAQ says that bytecode is data and GPL interpreters *can* execute
> non GPL code. why an external library simply adding functionality to the
> interpreter would invalid this is a mistery to me. there is confusion
> about bindings and the binded library (it seems that if the binded
> library is GPL then the bytecode should be GPL, but this is complete
> crap, IMO). why is an interpreter+library different from the interpreter
> alone? i can't answer (imo it should not.)

Frederico, the problem arises if someone builds an application
around Python and e.g. psycopg (which I understand is GPLed) and
wants to distribute that application to a different user.
In this case, the application needs both Python and psycopg,
so the the application forms a new work together with Python and
psycopg. This is where the GPL comes in. It forces you to
ship the complete work under the GPL.

The situation is different if the OS the application
runs on ships Python and psycopg as part of the OS. On
those platforms, the already mentioned OS clause in the
GPL lets you ship the application under a different
license -- but only on those platforms.

> M.-A., the problem is not as clear as you put it..

Oh, it is :-) The solution for an application developer
is just as simple: never use GPLed code in applications which
you want to deliver under non-GPL licenses. LGPL is fine,
but even there, the developer should carefully read the

> then, what will i do? simply nothing. if you have a *real* problem with
> psycopg licensing just write me and we'll arrange it. but don't write me
> on teoretical problems, we already had enough of them.

Oh, I don't have a problem with this :-) I just wanted to
clarify things a bit. It really all depends on which audience
you want reach with psycopg and what kind of distribution model
you have in mind (e.g. a business model, an FSF view of the
world or a charity view of things).

Marc-Andre Lemburg
CEO eGenix.com Software GmbH
eGenix.com -- Makers of the Python mx Extensions: mxDateTime,mxODBC,...
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