Subj : Re: Copyright and addons or comercial GUI for a GPL software
To   : comp.programming
From : Rob Thorpe
Date : Thu Aug 11 2005 06:45 am

aslanski2002@yahoo.com wrote:
> Giannis Papadopoulos yazdi:
> > aslanski2002@yahoo.com wrote:
> > > Jonathan Bartlett yazdi:
> > >
> > >>>Are there any restrictions in using GPL code in comercial applicatins?
> > >>
> > >>Yes.
> > >>
> > >>
> > >>>I have seen the Linux Kernel used on a lot of appliances.
> > >>
> > >>That's because the kernel is not linked to the program.
> > >>
> > >>
> > >>>My intention as I mentioned in an earlier  thread is to design a good
> > >>>interface for some GPL applications and to sell this interface.
> > >>
> > >>Selling is not against the GPL.  Selling under non-GPL licenses is.
> > >>
> > >>
> > >>>I will
> > >>>not charge for the application itself but I think it is fair to charge
> > >>>for the interface. The design requires a lot of work for design and
> > >>>implementation.
> > >>
> > >>The amount of work is irrelevant.  What is relevant is whether or not
> > >>your work is considered a derivative work.
> > >>
> > >>If you link to libraries, that is usually considered a derivative work.
> > >>  Static linking definitely is, dynamic linking using headers supplied
> > >>under the GPL also is.  I do not know of the rules for dynamic linking
> > >>without the GPL headers.  However, if you are not linking to the GPL
> > >>work, but merely using it as a separate application, there is no
> > >>problem.  In fact, I know Mathematica does this.  If you look on the CD
> > >>they distribute you will see a source file containing a GPL application
> > >>which they use as a separate, unlinked application but is distributed
> > >>with Mathematica.
> > >>
> > >>As for LGPL libraries, there are other rules.  With those, you are
> > >>allowed to freely dynamically link.  For static linking, there are more
> > >>rules, but basically you have to provide the unlinked versions of both
> > >>your code and the libraries, so the user can upgrade the library and
> > >>relink if he wishes.
> > >>
> > >
> > > I have questions here:
> > > I have an application *A* which uses a DLL *D1* with (L)GPL code in it
> > > and another *D2* which has no (L)GPL code. *A* still can work if you
> > > delete *D1* (though not fully functional). And *A* has no (L)GPL code
> > > in it.
> > > - Do I still have to provide sources for *A* ?
> > > - I don't think I have to provide the sources of *D2*, do I?
> > >
> > >
> > >>Jon
> > >>----
> > >>Learn to program using Linux assembly language
> > >>http://www.cafeshops.com/bartlettpublish.8640017
> > >
> > >
> >
> > If D1 is GPL, then yes you have to provide A sourcecode. If it is LGPL
> > you don't have.
> >
> What if I provide *A* and *D1* as proprietary and some knowledge of how
> to create a plug-in for *A*. And some user creates a plug-in for *A* (
> call it *D2*) using some GPL code, isn't this the case where I have to
> provide source of *A*? I can't stop a user doing it!

No, the user can't create a plugin with a GPL license and link it to a
proprietry application.  If the user want to apply the GPL to any part
of the whole he/she must provide source code for the whole, which they
can't do without the proprietry source code.

Read the GPL FAQ http://www.gnu.org/licenses/gpl-faq.html

I of course would prefer it if you just GPLed the whole thing; much
simpler and better for the users.

.