[License-discuss] License incompatibility (was Re: Open source license chooser choosealicense.com

Till Jaeger jaeger at jbb.de
Tue Sep 10 17:24:49 UTC 2013

Dear list,

Bradley and Larry have asked me to share my view as a European lawyer on the
question if linking of software components (necessarily) results in a
"derivative work" as understood by the GPL. In a nutshell, my thoughts are
the following (a more comprehensive overview can be found at
http://www.ifross.org/Druckfassung/Ziffer%202.pdf, unfortunately in German

As far as I know there is no relevant case law on the question of what may
be considered a "derivative work" under European copyright law for software.

European software copyright law has been harmonized
since 1991.

In my opinion "derivative work" in software law should have a different
meaning than in other fields of copyright law.

Software is typically interacting with other software, and dependencies
(e.g. an application running on an operating system) do not necessarily mean
that two components form a derivative work.

GPLv3 refers to copyright law ('To “modify” a work means to copy from or
adapt all or part of the work in a fashion requiring copyright permission,
other than the making of an exact copy') whereas GPLv2 might be interpreted
in a way that the understanding of "derivative work" is broader. In this
regard the GPLv2 seems to be a bit contradictory to me. On the one hand it
defines 'a "work based on the Program"'as  “either the Program or any
derivative work under copyright law", on the other hand sec. 2 contains a
more detailed explanation of what the term "derivative work" is supposed to
mean within the scope of the GPLv2 ("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."). Apparently, a computer program which is _not_ derived from GPL
code has nonetheless to be licensed under the GPLv2 when the original GPL
code and the program are not distributed "as separate works".

If you do not want to ignore that language you have to find a meaningful
interpretation for this sentence in sec. 2 of the GPLv2. To me, it makes
sense to understand "distribute them as separate work" as a formal
criterion, i.e. distributing one binary blob makes it "one work" instead of
two or more "separate works". Of course, other interpretations are possible.

I think it is very difficult to predict how the European Court of Justice
(ECJ) would interpret the phrase "adaptation, arrangement and any other
alteration of a computer program" as used in Article 4.1 (b) of the
Directive 2009/24/EC.

The only hint you may find is Article 6 which says that decompilation is
allowed under certain circumstances to "achieve the interoperability of an
independently created computer program with other programs". There is a
definition of interoperability in recital 10: 'The parts of the program
which provide for such interconnection and interaction between elements of
software and hardware are generally known as "interfaces". This functional
interconnection and interaction is generally known as "interoperability";
such interoperability can be defined as the ability to exchange information
and mutually to use the information which has been exchanged. '

Therefore, my understanding of the directive is that software, that is
independently created and exchanges information with other software through
an interface, is independent software and not a derivative work.

However, it is unclear which kinds of interfaces fall within the scope of
the directive. The text is from 1991 when Java and other object oriented
programming was not known at that time (or not as common as it is today).

If linked software should be considered a derivative work (under the
GPLv2 and GPLv3) is truly difficult to judge. With regard to the
aforementioned criteria I come to the following conclusions:

>From the perspective of copyright law the way how two parts of a program
interact _technically_ with each other may provide an indication about the
derivative work question. However, the technical fact by itself that two
components are linked with each other does not necessarily lead to the
conclusion that the combination is or is not a derivative work.

If a developer modifies an existing program and puts the added code in a
library instead of the existing files the code in the library would still be
a derivative work. A modified program is a modified program, and one might
not circumvent this legal effect just by moving code into a library.

However, the situation might be different if an independently created
application uses an existing standard library. You could argue
that the application uses the interface of the library, and linking is just
a matter of interoperability, which seems convincing to me. But you might
also consider that there is a widely accepted opinion that linking results
regularly in creating a derivative work under the GPL, and accordingly a
customary business practice has been brought into existence.

The situation might be different in the case of statically linked libraries.
If you agree with the interpretation of the GPLv2 I proposed above, the
program and the statically linked library are not distributed "as separate
works" and therefore the copyleft applies.

The situation is far from being clear. I do not claim to have the
"right" answer to the question on hand. But I think that we need more
exchange between lawyers and software engineers for developing our view on
the issue of linking, an issue courts will have to deal with one day.

Best regards,


Dr. Till Jaeger
Certified Copyright and Media Law Attorney

JBB Rechtsanwälte
Jaschinski Biere Brexl Partnerschaft
Christinenstraße 18/19 | 10119 Berlin
Tel. +49.30.443 765 0  |  Fax +49.30.443 765 22
Sitz der Gesellschaft: Berlin | Registergericht AG Charlottenburg | PR 609 B

Am 29.08.2013 22:33, schrieb Bradley M. Kuhn:
> Larry, I will be more direct since you aren't getting my subtle hints.  If
> you think I've misquoted Till and am somehow damaging his professional
> reputation, then just say that, simply, to Till, and give him the source, and
> I'm sure Till will take the matter up with me if he agrees with you.
> Larry, I think what you're actually doing is wasting Till's valuable time.
> Till, just in case you do want to see it, without having to search around, the
> email where I referenced you is at:
> http://projects.opensource.org/pipermail/license-discuss/2013-August/001181.html
> The specific text that I wrote that mentions you is:
>>> BTW, if you are interested in how the European lawyers view this question,
>>> I refer you to an excellent talk by Till Jaeger at FOSDEM 2013:
>>> http://www.faif.us/cast/2013/mar/26/0x39/
> As you can see, Larry, I didn't, as you claim, represent that Till supported
> any of my positions.
> Till, thanks again for giving that excellent talk on our track at FOSDEM 2013!
> I'm truly sorry that you've been dragged in to this conversation, and I had
> no idea that sharing the audio of your useful talk with others would cause
> these sorts of unsolicited emails from Larry.
>    -- bkuhn
> .

More information about the License-discuss mailing list