Linking and the GPL

Angelo Schneider angelo.schneider at
Fri Oct 19 14:15:00 UTC 2001

Hi all,

some legal(not so legal) terms:

"fair use", you got a legal copy of some work, now you may create
further copies for your own personal use. What own personal use is is
usualy defined in the copyright law or in court roulings.
E.g. buying a Audio CD, burning copies from it and distributing them to
friends is only fair use if you have less than 13 copies. That is a
court ruling in germany. The law only says: "limited copying is allowed
and coverd by certain fees ...." Background: in europe you pay a fee on
each paper copy a photo copier does to a central registration authority,
redistributing the fees according to published numbers back to the
The same is true for empty CD burnables, you pay 10 cent or so which go
to the recording companies and/or artists.
So: fair use has a monetary compensation somewhere, but that is not
directly bound to the original work but to the infrastructure, like
burners, copiers, tape machines etc.
ALSO: fair use implies, limited numbers and royality free distribution.
So burning 10 CDs and selling them, note: 10 < 13, is NOT fair use.

What "fair use" means is explicitly defined in copyright law. 

"derived work", that is also a term defined in the law.

See below.

email at wrote:
> >
> On Fri, 19 October 2001, Angelo Schneider wrote:
> > email at wrote:
> > > 1) the GPL does not  prohibit linking
> > Wy should it?
> > If it would prohibit linking a lot of work published under GPL would be
> > useless, e.g. all libraries.
> ar, my bad, yet again. serves me right for trying to
> catch up on my email at 2 in the morning. how about:
> 1) (v1.1)  The GPL makes no claims that linking
> other software is a derived work of the original source.

I do not realy understand what you mean with: The GPL makes no claim
what "derived work" is.

The copyright law defines what "derived work" is!!

> The LGPL says this is the case.
> is this based on a court ruling,
> or a law that says as much?
> this is the best analogy I can think of:
> I copyright a JPEG.
> I assume fair use says users can translate the
> JPEG mumbo-jumbo into a two-dimensional array
> or RGB values (i.e. DERIVE).


Fair use says: if you do translate it into RGB values you may not
redistribute it. 
Making a "derived work" falls fully under copy right law, there is no
FAIR USE clause applyable to "derived work".

However you could redistribute the original work for personal purpose:
to show it a friend e.g.

> Can I impose a restriction on what you
> do with that 2-D array once you have it?

Basicly Yes!
However first you need a license to distribute your "derived work".
YOU as the author of teh 2-D array hav full copyrights on the 2-D array.
However teh 2-D array is a "derived work". On the original work, the
JPG, and thus on the derived work the original author retains his

That means: as long as you do not get a redistribution permission, you
have no right at all to redistribute it.
Exception: fair use, make a limited amount of copies for private perpose
(showing it, gifting it to your friends)

> i.e. I copyright source code under GPL.
> I'm assuming fair use says users can translate
> the source into usable machine instructions.

Not sure, I think yes it is fair use as you only make *one*

> Can I impose a restriction on what you
> can do with that machine level array once
> you have it?


Your "derived work" is only fair use as long as YOU USE it FAIR.
Redistribution is not fair use. FIRST: the original author needs to give
you rights for redistribution, e.g. restricted rights like the (L)GPL
gives you.

> can I prevent you from displaying my translated
> JPEG adjacent to proprietary images?

SURE!!! All that is copyright about!
Copyright law forbidds it by default! I'm not allowed to public display
your images!
I'm not allowed to change them (for public view)
I'm not allowed to adapt, rework, translate them etc. (for public view)
I'm not allowed to combine them with my images in a _public_ visible
photo album.
But: you can not restrict me to do that privatly in a limited fashion,
as this is "fair use"!

> Greg


Angelo Schneider         OOAD/UML         Angelo.Schneider at
Putlitzstr. 24       Patterns/FrameWorks          Fon: +49 721 9812465
76137 Karlsruhe           C++/JAVA                Fax: +49 721 9812467
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