Subj : Re: GNU Public Licences Revisited (again)
To   : comp.programming
From : gswork
Date : Tue Aug 23 2005 10:13 am


Arthur J. O'Dwyer wrote:
> On Tue, 23 Aug 2005 gswork@mailcity.com wrote:
> [...]
> > hmm, well just drifting through my thoughts on what you said based
> > around a hypothetical commercial closed source app...
>
>    See my post in reply to Joe's. But here are the parts relevant to your
> thoughts:
>
> > I'd have thought that if you use a gpl library, for instance, and used
> > it unmodified you'd just say so, and maybe produce the code on request
> > (or just point to the project that produced it).
>
>    That's okay, as long as the project that produced it sticks around. If
> they go under, then it's your responsibility to distribute the source on
> request.

ok, unless this project goes under (presumably)

>
> >   If you used a
> > library and altered it then you would be obliged to make your
> > modifications open source too.
>
>    Yes.
>
> > I'm not sure if the entire application which calls the library needs to
> > be made open source, that's sounds unrealistic because it is the
> > library source that's been used and altered not the rest of the app.
>
>    Writing a bunch of extra code that calls the library /is/ altering the
> library, from the literal-minded CS point of view. You're taking one
> collection of source code and turning it into another, different
> collection that includes a lot of the original. That makes it a derivative
> work, copyrightically speaking. If the library was GPL'd, the resulting
> work must be GPL'd. If the library was LGPL'd, the resulting work doesn't
> need to be GPL'd, although it can be, of course.

that's interesting - is it a sliding scale of 'involvement' or an
absolute, for a silly extreme example let's imagine we have an open
source library

TinyOpen - one function called "int TheFunction(int i)"

the project checks it out and changes part of the function

the project - a great huge monolith of an app, but on line 33641 there
is this:

b=TheFunction(c);

that being the code which calls the library.  It does I suppose use the
code and link it into binaries - but is that all it takes to oblige the
entire project to bcome open source or am i just missing a point here?

In contrast had the project not altered the library then would they
stay out of the gpl for the whole app?

> > Imagine the consequence of using a tiny open source compression library
> > inside an enormous application just to compress some data and having to
> > turn over the whole app because of it, no one making a closed source
> > app would bother with it.
>
>    Exactly! Now you're seeing the light!  If it becomes so infeasible to
> create closed-source compressors that nobody does it, then the field of
> compression technology will suddenly have become completely free and open,
> thus benefiting everybody. Remember, locked is bad. Unlocked is good.

I'd imagine in these cases that it would encourage the careful
selection of LGLP or public domain code, commercial +/or closed
libraries or just a reinvention based on known algorithms

I'm not sure that GPL would automatically lead to ever more open source
by 'forcing' other projects to become so, or whether infact it would
just lead to seperateness - GPL gets used in GPL and other things get
used in closed source.

Perhaps it's too early to tell

> > now if you just took the entire source to Abiword, for instance, and
> > changed that around a bit to produce a variant then you would need to
> > release source for the whole, it being a derivative of abiword.
>
>    Assuming you released the derivative as a binary, yes. Of course, since
> AbiWord is free software, you can do whatever you want with it on your
> /own/ time. (Unlike Microsoft Word, where even /making/ a derivative is
> cause for a lawsuit. This is perhaps the coolest difference between GPL
> and closed-source licenses.)
>
> > Those are just some thoughts anyway - the actual terms of the license
> > are what matter.
> >
> > what i would add is that it must be nearly impossible to police,
> > especially in gray areas - let's say you produce a nice word processor
> > which borrowed heavily from Abiword but was actually significantly
> > different - it may fall under the gpl and you may be obliged to release
> > to whole or part of what you've done, but who is going to really know
> > or be able to tell except you?
>
>    The judge, when the maker of AbiWord decides to actually /enforce/ the
> GPL. ;-)

Are there any test cases setting the precedent?   It would be
interesting to see the GPL in legal action.  It's quite an undertaking
to go from 'hey that app looks like it uses gpl code' to investing the
time effort and lawyer fees to get it investigated, forcing the defence
to reveal code they are accused of stealing etc.

Much the same as when commercial vendors go at each other i suppose,
except they usually have the economic reserves and economic incentive
to undertake it.

.