hypothetical(?) GPL problem

[Marc Eberhard]

Hi Lutz!

On Tue, Jun 19, 2001 at 09:28:30PM +0200, Lutz Horn wrote:
> 1. Software vendor V produces a proprietary program P. This program has
> some function which can be implemented by using an existing and
> excellent library L. Since this library is covered by the GNU GPL, V can
> not use L with his proprietary program P and distribute the whole unless
> he places the whole under the GPL as well.

As far as I remember, a library should be put under the LGPL and not the
GPL. Because putting the lib under the GPL would restrict the freedom to use
it, as you point out. Thus the LGPL was designed to allow such a use. Anyone
knows more details? Anyone knows the statistics? How many libraries are
under the LGPL compared to the GPL?

> 2. Since the function which could be implemented using L is really
> needed, V programs a replacement R for L which he is free to distribute
> under any license he wishes.

I would write a wrapper and place that one under the LGPL. Should be easier.
Since the wrapper does not contain any valuable code, the company can
release it under the LGPL without a thread to their business. Then it can
link their own product against their LPGL'd wrapper lib. Would that work
legally? The GPL'd lib is only accessed from the LGPL'd and not from the
program itself.

> 3. Customer C gets P from V. He is unsatisfied by the quality of the
> replacement R and asks V if he can change P so that it uses the superior
> free library L. V walks over to C's place and changes P to use L instead
> of R. He does not change the proprietary license under which he provided
> P to C in the first place.

No need for this step with my proposal.

> Is V violating the terms of the GPL in step 3? Is it possible to say
> that he is _not redistributing_ a work including both code form L
> covered by the GPL and his own proprietary code and that he is _not
> violating_ the GPL since 2.b) of the GPL only aplies to distributing or
> publishing? Can V claim that he is only providing a service in altering
> P after he distributed it and that altering can not be called
> distribution?

Well, he distributes the alteration. Which is in reality distributing a
modified version of his program and thus the GPL should hold and disallow
it. I think, there is no difference, if the program is modified at the
creating company or from employees of the creating company at some customers
place.

But I'm not a lawyer...

> It is my strong believe that answering the above questions with 'yes' is
> at least against the spirit of the GPL. But is it against it's words,
> too?

Well, I would say, that it is already against the spirit of free software to
publish a library under the GPL and not the LGPL. I think so, because you
limit the freedom of usage of the library quite significantly. I would favor
to publish it under the LGPL and kindly ask the commercial software house to
mention the library as being part of their software. Like some startup
notice: This software uses the xyz library from uvw, which is free software.

Bye,
Marc
_______________________________________________________________________________

email: marc at greenie.net
email: m.a.eberhard at aston.ac.uk, web: http://www.aston.ac.uk/~eberhama/