qt-copy and Qt 4.3

[Clarence Dang]

On Friday 23 March 2007 16:48, Thiago Macieira wrote:
> Clarence Dang wrote:
> >My understanding is that if people develop kdelibs with a GPL Qt/Windows
> > and then commit changes to kdelibs, those changes must be under the
> > GPL, which would be problematic.
>
> No. Your code is licensed using the license *you* choose. Neither
> Trolltech nor anyone else can impose a license on the code you're about
> to write.

Because dynamically linking against a library results in a derived work, a 
condition of using that library might be that you license your code under a 
particular licence or else, don't use the library at all.

I thought linking against a GPL-only library requires licensing anything you 
developed, while linked to the library, as GPL.  IANAL but I think this is 
2.b) in GPLv2: "b) You must cause any work that you distribute or publish, 
that in whole or in part contains or is derived from the Program or any part 
thereof, to be licensed as a whole at no charge to all third parties under 
the terms of this License."

> What happens is that Trolltech doesn't let you use their own code unless
> your code is GPL compatible. And "GPL compatible" doesn't mean GPL: it
> has to be as restrictive as GPL or less. So, LGPL qualifies. Therefore,
> the kdelibs licensing policy applies and all licenses there are valid to
> link to Qt in any edition.

As far as I understand, QPL versions of Qt allow you to license your code 
under most opensource licenses as you describe, including LGPL.  However, I'm 
reading that the free Windows version of Qt is GPL-only, with no QPL option 
(please correct me if I'm wrong).

Thanks,
Clarence