Re: About GPL and proprietary software - Mailing list pgsql-general

On Tue, 2003-09-02 at 08:52, Jonathan Bartlett wrote:
> I think the main issue in dynamic linking is whether or not you used the
> GPL headers.  If you did, then you are in fact combining your work with a
> GPL work.  If you did not, then how is one to know _which_ library you are
> linking against.   It could be the GPL library, but it could also be any
> other library which exports the same symbols.  If I link to Motif, I am
> not obliging myself to the GPL just because Lesstif exists.

Exactly.  If you use GPL headers, then you are tying (i.e. "linking"
in the grammatical sense) yourself to that GPL software, and *that*
would mean that you must GPL your own software.

> Jon
>
> On 1 Sep 2003, Doug Quale wrote:
>
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >
> > > The FSF would _like_ dynamic linking to pass the GPL to the
> > > closed-source binary, but that doesn't make it so --- I would like a lot
> > > of things but wanting it to happen isn't enough.
> > >
> > > Their FAQ says (http://www.gnu.org/licenses/gpl-faq.html):
> > >
> > >     What is the difference between "mere aggregation" and "combining two
> > >     modules into one program"?
> > >
> > >         Mere aggregation of two programs means putting them side by side on
> > >     the same CD-ROM or hard disk. We use this term in the case where they
> > >     are separate programs, not parts of a single program. In this case, if
> > >     one of the programs is covered by the GPL, it has no effect on the other
> > >     program.
> > >
> > >         Combining two modules means connecting them together so that they
> > >     form a single larger program. If either part is covered by the GPL, the
> > >     whole combination must also be released under the GPL--if you can't, or
> > >     won't, do that, you may not combine them.
> > >
> > >         What constitutes combining two parts into one program? This is a
> > >     legal question, which ultimately judges will decide. We believe that a
> > >
> > >     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > >     proper criterion depends both on the mechanism of communication (exec,
> > >     pipes, rpc, function calls within a shared address space, etc.) and the
> > >     semantics of the communication (what kinds of information are
> > >     interchanged).
> > >
> > > You can bet that RMS, control freak that he is, wouldn't have put that
> > > disclaimer in there if he felt he had much chance of making the GPL
> > > dynamic linking restriction enforceable.
> >
> > Name calling ("control freak") is childish.
> >
> > If you are not a lawyer and you want to bet that dynamic linking to a
> > GPL'ed library doesn't invoke the GPL then I think you're taking a
> > gamble.  Clearly you think you know more about the law than the FSF
> > General Counsel Eben Moglen (professor of law at Columbia).
> >
> > Combined works dynamically linked to GPL libraries involve untested
> > legal issues.  The legal issues are complex, and when law and
> > technology collide it can be hard to predict the outcome.  RMS
> > believes the GPL is enforcable in this case, but until someone is
> > willing to be sued by the FSF over this no one will know for sure.
> > (None of the GPL violators the FSF has pursued have been willing to
> > risk a trial so far.)


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