Re: [Freeciv-Dev] qt-Freeciv client !

[Greg Wooledge <wooledge@xxxxxxxxxxx>]

Nicolas Brunel (brunel@xxxxxxxxxxxxxxxxxxxx) wrote:

> Knowing that freeciv is under GNU license version 2.

> Please note that the Qt Free Edition version 1 is itself not free
> software, in the usual meaning of the term. You are not allowed to make
> modifications to the Qt Free Edition
> itself.

These two facts are what lead to the fundamental incompatibility between
the two licenses.  Section 6 of the GPL says:

      6. Each time you redistribute the Program (or any work based on the
    Program), the recipient automatically receives a license from the
    original licensor to copy, distribute or modify the Program subject to
    these terms and conditions.  You may not impose any further
    restrictions on the recipients' exercise of the rights granted herein.

The restriction on distributing modified copies of the Qt library is,
from the point of view of the GPL, a "further restriction", and is thus
explicitly disallowed by the GPL.

(To get the full argument, you have to read other sections of the GPL
as well.  I recommend reading it in its entirety, for anyone who hasn't
done so, or who hasn't done so recently.  I won't try to go through the
whole "proof" here.)

(I'm not trying to fan the flames here, folks -- just pointing out some
licensing issues to clear up misunderstandings.  Believe me, the last
thing I want to see on this list is a full-blown Qt-vs-GPL flame war.
For that reason, I've strictly avoided adding my personal opinions about
either license in this message.)

-- 
Greg Wooledge                    | Distributed.NET http://www.distributed.net/
wooledge@xxxxxxxxxxx             | because a CPU is a terrible thing to waste.
http://www.kellnet.com/wooledge/ |