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Re: Use of GPL'd code with proprietary programs

From: Arnoud Engelfriet
Subject: Re: Use of GPL'd code with proprietary programs
Date: Tue, 6 Jul 2004 11:11:09 +0200
User-agent: Mutt/1.5.6i

Haakon Riiser wrote:
> I haven't personally read it yet, but I'll do so ASAP.  If this
> is the case for our license, we have to consider if it's even
> worth bothering with WMV9. :-(  I can't even believe why they
> would do such a thing -- are they afraid of getting infected by
> the GPL license in some way?  Do they mention the GPL specifically?

Microsoft has publicly stated that the purpose of this clause is to
ensure that licensees do not release MS code under GPL or similar
terms. In my opinion, the clause is much too broad for that purpose.
For instance, it forbids the type of bundling that the GPL calls
"mere aggregation". But I also seen instances where the clause is
limited to essentially "you are not allowed to do anything to our
code that would require our code to be released under GPL".

Of course everybody knows that Microsoft does not like Linux
and other free software. So it is to be expected that they would
not do anything to encourage use of GPL software.

They don't specifically single out the GPL but use a definition that
covers the GPL, the LGPL and most other OSI approved licenses.
Sometimes they mention the GPL as an example of a covered license.
The terms to look out for are "Publicly Available Software",
"Potentially Viral Software" and "Identified Software".

> Here's what our lawyer said (more or less):

Of course you should follow your lawyer's advice instead of
the comments of some random stranger on the Internet. :)

> All restrictions on distribution of the GPL'd program appears under
> GPL section 2, which specifically targets modified copies only:

I believe this is not entirely accurate. Section 2b specifically
talks about "any work that you distribute or publish, that in whole
or in part contains or is derived from the Program or any part
thereof". And "Program" is defined as the original (section 0).

If the argument is that section 2b does not apply because the Program
is not modified, then the question is which section does give you the
right to distribute the GPL work. Perhaps section 3 does? It grants
rights to distribute "the Program (or a work based on it, under
Section 2)". But then you must accompany it with the complete
corresponding machine-readable source code (or include an offer). So
you can only distribute a "work based on the Program" if you make
available the source code of the entire "work based on the Program".

>   2. You may MODIFY your copy or copies of the Program or any
>      portion of it, THUS FORMING A WORK BASED ON THE PROGRAM, and
>      copy and distribute such MODIFICATIONS or work under the terms
>      of Section 1 above, provided that you also meet all of these
>      conditions:
>      [...]
> Since "a work based on the Program" is defined as "modified GPL
> code", all the conditions and requirements that follow do not apply
> when all we do is link an unmodified GPL library to our program.
> Or so we were told.

GPL section 0:
[A] "work based on the Program" means either the Program or any
derivative work under copyright law: that is to say, a work
containing the Program or a portion of it, either verbatim or with
modifications and/or translated into another language. (Hereinafter,
translation is included without limitation in the term

I believe the first sentence of section 2 is an explanation ("if you
make a modification, which means that you are making a work based on
the Program") rather than a definition of "work based on the
Program". Clearly section 0 provides a definition and it is unusual
for a later section to override such an important definition.

> > "Work based on" is defined as derivative work under copyright law
> > and so this requirement kicks in for modified GPL code. But it
> > also applies to the original, unmodified work. And according
> > to the FSF it also applies to any work that links to the GPL
> > code.
> In light of what I said above, would you say that linking binary
> code is included in "modify your copy of the Program"?

As I understand it, the interpretation of the FSF is that linking
creates a "work based on the Program". Therefore, the work linked to
the GPL program can only be distributed in accordance with the terms
of the GPL and full source code must be provided.

This interpretation is based on the assumption that linking creates a
so-called derivative work under copyright law. As far as I know there
is no case law on this point, so it is difficult to be certain about
this. I would expect a prudent lawyer to recommend to his clients to
interpret the license in the 'worst' light, i.e. to assume that
linking does create a derivative work.

> But again, I was told that none of this matters since the people
> who wrote the license apparently had screwed up.  Their intention
> was to prohibit linking, but that's not what the actual text says,
> and that is the only thing a judge would consider.

If the license is unclear, a court normally uses the intent of the
parties to interpret what was meant. Furthermore I think that you (or
your lawyer) is focusing only on a very small part of the GPL.

You need permission to distribute the GPL-licensed work linked
against your application. Permission to distribute is granted in
section 2, which you consider inapplicable because the GPL-licensed
work was not modified. Permission to distribute is also granted in
section 3, but this section also requires you to release source code
for something that is called a "work based on the Program." Therefore
we must determine what this is. I believe section 0 provides the
definition, and not section 2 since by your own reasoning section 2
only applies if the original work is modified. A section that does
not always apply cannot provide a definition for other cases (think
of definitions as constants and sections as functions; the definition
of section 2 then is a local constant that is undeclared in section

Therefore the only question is whether a work linked to the
GPL-licensed program qualifies as a "work based on the Program". See
my comments above.


Arnoud Engelfriet, Dutch patent attorney - Speaking only for myself
Patents, copyright and IPR explained for techies:

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