[Ctk-developers] Qt licenses model

[Tarbox, Lawrence]

I think the reason that the Qt Software folks (now owned by Nokia) left the GPL option in is for the benefit of some of their partners who were writing GPL code (or dual-licensed GPL/Commercial code) back in the days when Qt Software was TrollTech.  Some of those partners have made additions/modifications to Qt, released them under GPL, and do not want to ever release them under LGPL.  While technically they could still release their additions/modifications under GPL even though Qt is LGPL (i.e., LGPL allows it), these partners prefer to keep their licensing straight forward, and just say the whole combined mess is GPL.  Qt Software is merely saying formally that Qt Software is OK with that model, basically reaffirming their partners' right to continue releasing modified versions of Qt under GPL.

At least that is the impression that I get.

I don't think that there is a problem with release our software under a modified BSD license, as long as we are only linking to Qt, and not modifying Qt code directly (i.e., one could switch to a Qt clone, if it existed, or to a modified version of Qt by simply rebuilding against a different link library).

If we do modify the Qt code itself, then those modifications would have to be released as LGPL.  Of course, if we modify Qt itself, I would vote for feeding those modifications back to the Qt community for potential incorporation into a future release of Qt.

Lawrence

-----Original Message-----
From: ctk-developers-bounces at commontk.org [mailto:ctk-developers-bounces at commontk.org] On Behalf Of Marco Viceconti
Sent: Thursday, November 12, 2009 3:44 AM
To: ctk-developers at commontk.org
Subject: [Ctk-developers] Qt licenses model

I would like to open another discussion thread, parallel to the one we
started on Qt core.  Currently Qt is available under two possible open
source licenses: Qt GNU LGPL v. 2.1 and Qt GNU GPL v. 3.0.
http://qt.nokia.com/products/licensing

If I understand correctly the code is the same, the access rules are
the same, so I am not sure why one would choose GPL which is more
restrictive than LGPL.  Can someone clarify this to me?

Secondly, having agreed that CTK will be BSD-like, can anyone confirm
me that by using a LGPL library to develop CTK we shall not break the
BSD-like license we plan to adopt?

Thanks

Marco



--------------------------------------------------
MARCO VICECONTI, PhD
(viceconti at tecno.ior.it)
Laboratorio di Tecnologia Medica              tel.   39-051-6366865
Istituto Ortopedico Rizzoli                            fax.
39-051-6366863
via di Barbiano 1/10, 40136 - Bologna, Italy

Tiger! Tiger! Burning bright in the forest of the night,
what immortal hand or eye could frame thy fearful symmetry?
--------------------------------------------------
Opinions expressed here do not necessarily reflect those of my employer



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