On Wednesday 31 Dec 2008, Ravindra Jaju wrote:
[snip] I guess I should be rephrasing that example. I did not mean "modified" QT code but independent code linking to QT. This new code's copyright is with the person creating this "work" - and it is upto this person to not release the source-code if he does not wish to.
If you distribute binaries based on code that links with a GPL library (which Qt is), you MUST make the source code of those binaries available too. That's what the GPL says.
Of course, I may be wrong here. But I did not see anything in the GPL in this regard, forcing one to release code which "can be reasonably considered independent". Of course, I'm treading on some shaky ground here - and this is where the need for LGPL arose too. Because it's not impossible (although, can be a PITA) to work around GPL's viral restrictions by really separating code and making them communicate over some sort of IPC to escape v2's clauses.
People have done that (gotten around the GPL library issue by using an intermediary vehicle) but it's (a) considered using the letter of the law to screw the community and (b) just not possible with something like Qt, which is supposed to do GUI work and would crawl to a halt and die if you started making library calls through some IPC. You might not even be able to do it hypothetically, depending on how closely Qt is bound to the X server.
In any case, library code under GPL is a sort of special case -- if you link your code with that library and distribute binaries you must release your code under the same terms as the GPL too.
BTW, Qt is quite unambiguously licensed under the GPL. From /usr/share/doc/libqt4-core/copyright:
License:
This package is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 or version 3 as published by the Free Software Foundation.
Perhaps we can stop discussing that particular issue (what is the Qt licence) now?
Regards,
-- Raju