Re: Re (2): testing before a release

[Stuart Ballard]

"Etienne M. Gagnon" wrote:
> 
> Mark Wielaard wrote:
> 
> > - Even if I accept the GPL then I can still make (private) modifications
> >   since the GPL gives me explicit permission to run the program without
> >   restrictions.
> 
> This depends whether linking is a modification or not.  According to a private
> message RMS sent me a while ago, linking is a modification (or so he thought 
> at
> that time).

I think I disagree, even if linking *is* a modification. Note that this
is all based on my interpretation of US copyright law, and Canada's
might be different, although I would have expected to have heard
rumblings about any such drastic difference between the two.

The GPL gives you permission to modify any GPL'd program as much as you
like, so long as you don't distribute the result. (Technically I'm not
sure whether it is the GPL or copyright law that gives this permission,
but you have it).

So it's perfectly permissible to take, say, libreadline (a GPL'd
library) and a proprietary shell that you have the source code to, and
modify your *own* copy of that shell to use readline. It's perfectly
permissible to run the resulting program, linked against readline. But
you can't *distribute* the resulting linked executable.

I think the intent is that you can't even distribute the source code to
your modified proprietary shell, although I think that considering your
modified shell a derived work of readline is a bit iffy.

It's possible to modify a GPL'd app to use a proprietary library, and
run that, too, so long as you don't distribute the result (the fact that
the modified app is a derived work is clearer in this case, too).

The GPL only kicks in for distribution. Period. If that's not the case,
then I've been very much misled in every licensing discussion I've ever
had, and by the GPL FAQ and other FSF documents on the GPL. And if
that's true then someone ought to really raise a stink, because I doubt
I'm the only one.

Stuart.