I wrote the FSF today about propriatory GTK+ programs using KDE/Qt dialogs (through a patch to the GTK trunk). Below is what they said:
From: Dave Turner via RT
Reply-To: licensing@fsf.org
To: Taj Morton
Subject: [gnu.org #206030] Licensing Question on GTK and Qt
Date: Thu. 23 Jul 2004 19:29:00 -0400 (16:29 PDT)
> [EMAIL REMOVED - Mon Jul 12 10:13:06 2004]:
>
> Hello,
> I have (what I think) is a simple question about licensing of Qt and
> GTK. If I make a patch the the GTK source that makes (GPL compatible)
> GTK apps use KDE dialogs, that’s totally legal (right?). However, if a
> commercial app (read: non GPL-compatible) shows a KDE dialog, would
> someone need to pay a license for Qt?
A proprietary application which links against your modified version of
GTK (licensed under the GPL) could not be distributed at all. It would
violate the license of the code taken from QT, and the license of GTK
(GPL, since you converted it via LGPL’s clause 3 in order to link in the
QT code).
–
-Dave “Novalis” Turner
GPL Compliance Engineer
Free Software Foundation
could have two different versions of Gtk…one patched, one not. Or, I could just patch each app individually.