Qt and the GPL

[Lou Grinzo]

This latest exchange points out one of the most troubling aspects of
software licensing--even many of the people who care about such 
issues and closely read the licenses can't always agree on exactly what
is and isn't allowed.

In this case, I think it would help everyone a great deal if the FSF added 
a page to their web site that simply enumerated all the combinations of
ways to statically and dynamically link free and non-free software to
create free and non-free software, and then indicate whether the GPL
and LGPL allow or forbid it.  (A sentence or two of explanation might 
also be a good idea, for some cases.)



Lou


-----Original Message-----
From: David Johnson [mailto:david at usermode.org]
Sent: Tuesday, September 05, 2000 2:35 AM
To: kmself at ix.netcom.com; License-Discuss
Subject: Re: Qt and the GPL

On Mon, 04 Sep 2000, kmself at ix.netcom.com wrote:

> > The reason it would have been impossible is that it would cause a huge
> > number of Qt based applications, including major portions of KDE, be
> > become illegal. With a GPL/Proprietary dual-license one has to either
> > write a GPL application or pay for a license. This would leave all of
> > the BSD, MIT, Artistic and even LGPL authors out in the cold.
>
> No.  BSD, MIT, Artistic, and LGPL are all convertible to GPL.  You'd
> leave out those people who were using these licenses to interoperate
> with software licensed under non-GPL terms as a single work.

Hmmm, this isn't how I understand it. One can link from a GPL
application to a BSD library, but not from a BSD application to a GPL
library. This is because the application is a derivative of the
library according to the GPL, and all derivatives of GPL code have to
be GPL as well.

In any case, it would also leave out the MPL and QPL users, of which
there is a significant number of the latter.

--
David Johnson
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