Re: gEDA-user: firmware and the GPL license

[Peter Clifton <pcjc2@xxxxxxxxx>]

On Thu, 2007-11-15 at 17:07 -0800, Chris Albertson wrote:
> > If you link in GPL'd code, period. That includes dynamic linking, and
> > any attempts to "wrap" the proprietary code in a GPL'd wrapper.
> 
> It is easy to come up with counter examples...
> 
> So if I write a proprietary program the uses the Motif widget set
> and I license it with very restrictive terms and sell it to a user.
> Now lets say that user one day decides to install a GPL'd
> Motiff library (lesstiff) on his system and my code is dynamically linked
> to it.  I don't think my code is now GPL'd.  As the author of
> the software I have no control over what my code is dynamically
> linked to.

It works because Lesstif is LGPL, not GPL.

>From /usr/share/doc/lesstif2/copyright on my Ubuntu box:

"The libXm and libMrm libraries are copyright the Free Software Foundation,
and are released under the LGPL, with the exception of VaSimple.c, portions
of which are also copyright the X Consortium and freely redistributable. On
Debian GNU/Linux systems, the LGPL can be found in
/usr/share/common-licenses/LGPL ."

I see your point about the source being out of your control after
distribution though. I hate legalese, and couldn't easily find the right
section of the GPL - so don't really know how that works. Why is the GPL
so long and complex???

Anyway.. it seems if you're not distributing the proprietary code with
the library its linking against, then it seems you're ok.

Quoting some of the LGPL:

"Most GNU software, including some libraries, is covered by the
ordinary GNU General Public License.  This license, the GNU Lesser
General Public License, applies to certain designated libraries, and
is quite different from the ordinary General Public License.  We use
this license for certain libraries in order to permit linking those
libraries into non-free programs."

> Here is the text quoted directly from the GPL:
> 
> "...If identifiable sections of that work are not derived from the
> Program, and can be reasonably considered independent and separate
> works in themselves, then this License, and its terms, do not apply to
> those sections when you distribute them as separate works...."
> 
> I think this is very clear.  I can distribute them both but must make
> clear the DLL and the main program are "separate works"

Just saying they are separate works doesn't make it so. If this loophole
were correct, then we'd have a lot more people using it.

Some programs (like ngspice) have code which could link against GNU
libraries like readline. ngspice is NO WAY GPL compatilble, so no
distribution's can / will ship it with that code enabled. I'm not sure
anything stops the user compiling it that way, or whether it puts the
user doing so in breach of the GPL license they received that linked
library under by doing so.

My understanding of the above section, was relating to me taking GPL
library "A", adding functionality "B" (with my own code) to that
library, and then later wanting to split out "B" (which I wrote), then
that is Ok, so long as it is demonstrable that my "B" doesn't derive
from the original "A".

I'm not saying I understand the "legal" behind it though, so will try to
avoid further speculation.

Best wishes,
-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)



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