[PyKDE] Fwd: Re: [Issue N6078] allowed distribution methods

Phil Thompson phil at river-bank.demon.co.uk
Thu Sep 19 19:29:01 BST 2002

On Thursday 19 September 2002 5:41 pm, Greg Fortune wrote:
> In reference to the discussion going on right now about licensing...  Yes,
> the qt dll can be distributed.  Thus, PyQt can be distrubuted allowing that
> you are not using the new commercial version of PyQt.  The end user, of
> course, would not be allowed to use qt in a development fashion such as
> fixing bugs in your application.  I think this means that if you develop an
> PyQt application that is meant to be run on windows, you can *not* license
> it under the GPL because the GPL requires that modification to the source
> is allowed, at least in my understanding.  That kinda sucks in a big way...
>  GPL apps for windows cannot be developed with Qt.  And yes, Trolltech's
> license is in the way here, but Phil's license is not helping things out...
> From the GPL, "You may modify your copy or copies of the Program or any
> portion of it, thus forming a work based on the Program, and copy and
> distribute such modifications or work under the terms of Section 1 above,
> provided that you also meet all of these conditions: "
> Anyone want to make me really happy and point out where I'm wrong?
> btw, trolltech, I would certainly like to hear the official stance on
> developing GPL applications in Qt in Windows.  It appears that even though
> I've paid a chunk of money so I can develop commercial Windows/Linux
> applications with Qt, I cannot license anything under the GPL if I use
> Python/PyQt in any fashion (because it's crossplatform itself and would be
> expected to run on Windows) and cannot develop *any* Qt application for
> Windows that would be licensed under the GPL.

This is from memory, but it's the GPL that prevents you from developing GPL 
applications with Qt on Windows. A GPL application cannot be linked against 
closed source libraries that don't come with the machine. This excludes 
commercial Qt on Windows but includes commercial Qt on the Zaurus.

> Does this mean that PyQt previous to the new license Phil implemented was
> violating the Qt license agreement.  Of course, this is a little silly, but
> all the implications are in place...  

The previous PyQt license was based on the X11 license which doesn't impose 
the restrictions that the GPL does.

> Has trolltech considered developing
> wrappers for languages other than C++ so we don't have to play these games.
> I suggest you take a look at Smoke, a recent addition to KDE.  Maybe
> something similar could be developed by Trolltech in house.

I haven't looked at SMOKE but from what I've read I don't see how it can 
produce good quality bindings - at least for Python, maybe Perl doesn't have 
the same issues. As I understand it SMOKE means you can use the original C++ 
header files rather than having to maintain separate .sip-like files. The 
problem is that there is extra information that you need to specify somewhere 
(at least for Python bindings) to handle (for example) object ownership and 


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