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List:       kde-devel
Subject:    Re: GPL + non-GPL library question
From:       Gary Cramblitt <garycramblitt () comcast ! net>
Date:       2005-04-24 11:33:02
Message-ID: 200504241133.02757.garycramblitt () comcast ! net
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On Wednesday 20 April 2005 03:37 am, Thiago Macieira wrote:
> Gary Cramblitt wrote:
> >The problem is that the Swift library is proprietary and licensed under
> > the Cepstral license.  My read of the GPL says I cannot release my
> > plugin code under the GPL unless I can get Cepstral to agree to adding
> > the exception clause mentioned here
>
> It's the other way around: you must add that exception to KTTS.
>
> >Do I have this interpretation correct?  If so, would inclusion of such
> > GPL code with exception violate KDE license requirements?
>
> I don't know.
>
> > I don't
> > understand the last sentence of the exception, since it seems to say
> > that derivatives of my work can remove the exception, but still link
> > against the Swift library?
>
> It means that, if someone modifies the KTTS library, they can choose to
> remove the exception from the file, meaning it has now copyrighted code
> that doesn't have the exception. That means you cannot merge back code
> from that version into the mainstream KTTS.
>
> > Also, the exception clause says that
> > Cepstral must grant permission to distribute my plugin code and the
> > Swift library.
>
> Not sure, but it might be interpreted that way.
>
> > I doubt that Cepstral would grant the right to
> > distribute their library.  Can an exception clause like the following
> > be added instead?
> >
> >--
> >In addition, as a special exception, Cepstral, LLC gives permission to
>
> No. "In addition, as a special exception, the KTTS copyright holders give
> permission to"
>
> > link the code of this program with the Swift library (or with modified
> > versions of Swift that use the same license as Swift)  You must obey
> > the GNU General Public License in all respects for all of the code used
> > other than Swift.
>
> Makes sense for me.
>
> Now:
> 1) I'm not sure if this is acceptable by KDE, even though that exception
> was originally conceived for KDE to be able to link to Qt when it wasn't
> GPL yet.
>
> 2) I am not sure either if the exception must be present in all code using
> KTTS, not just KTTS itself.

Thanks to Thiago, Dirk, and Kevin for responding.  Indeed, at what point does 
the "viral" nature of the GPL stop.  Since applications interface to KTTS via 
DCOP, I feel confident they do not need the exception.  Furthermore, I 
received an opinion from Matthias Kalle Dalheimer (KDE e.v. President, but 
not a lawyer) that loading a plugin at runtime does not taint the plugin.  
This is similar to the Linux kernel which loads proprietary drivers at 
runtime.  By this interpretation, the rest of KTTS does not need the 
exception either.  On the other hand, all parts of KTTS, including plugins,  
link against a convenience library, and by a strict interpretation of the 
GPL, then all must be licensed the same.

One way I can avoid this issue is to write an interactive command-line program 
to interface with Swift.  KTTS would then invoke this command-line program as 
a separate executable and communicate with it via StdIn/StdOut.  The 
command-line program would be BSD licensed while the rest of KTTS would be 
normal GPL.  According to the KDE Licensing Policy page, this should be 
acceptable, but if anyone sees a problem with this, please let me know.

Thanks for listening.

-- 
Gary Cramblitt (aka PhantomsDad)
KDE Text-to-Speech Maintainer
http://accessibility.kde.org/developer/kttsd/index.php
 
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