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Re: More GPL questions

From: Stefaan A Eeckels
Subject: Re: More GPL questions
Date: Tue, 17 Oct 2006 10:50:14 +0200

On Tue, 17 Oct 2006 10:04:23 +0200
David Kastrup <> wrote:

> Stefaan A Eeckels <> writes:
> > On Mon, 16 Oct 2006 18:05:58 +0200
> > Merijn de Weerd <> wrote:
> >
> >> On 2006-10-16, Alfred M. Szmidt <> wrote:
> >> >    This example program would dynamically link to both Qt and my
> >> > sdk's library.
> >> >
> >> > This would make this non-free SDK library a derivate of Qt and
> >> > the example program.
> >> 
> >> I disagree. The example program is a derivative of both the
> >> SDK library and the Qt library. 
> >
> > The example in source format is an original work. Only when turned
> > into an executable can it become a "derivative" of the library, and
> > IMHO only then when it contains substantial parts of that
> > library.
> If its main purpose is to serve as an illustration, that is quite
> likely what will ensue.  For example, if it is a printed example in a
> book, or part of a tutorial.
> If its main purpose is to be compiled and run, things are different.

The "purpose" of a copyrighted work has no relevance on its status as a
derivative work. Little source code is written for inclusion in a book,
but none of it is (provided, obviously, it's not a copy-and-paste job)
a derivative work of the language it's written in, or the libraries it

#include <stdio.h>

int main(int argc, char *argv[]) {
    fprintf("The quick brown fox jumps over the lazy dog");

is not a derivative work of the Unix standard IO library, and this
doesn't depend on there being more than one implementation of said
library. It's not a derivative work of the 'C' language, or the Unix
OS, or anything. It's an original work.

Once you start transforming it through compilers and linkers the
picture might change, depending on how much of the library is included
in the transformed source code. If, for example, you execute 'cc -E',
the resulting source code will contain the whole of "stdio.h", and as
such it's now most definitely something that is affected by the stdio.h
copyright (I leave it to Alexander to define if it's a derivative work,
a compilation, or anything he wishes).

But source code as such is never a derivative work of the stuff that
might or might not be called when the compiled program is executing. 

> For example, if one distributed an "install kit" that would
> mechanically compile and link proprietary software with GPLed
> libraries, it is perfectly conceivable that a court would rule that
> going against the "licensed as a whole" demand of the GPL.

This is a weird example - distributing source code of a proprietary
product in order to compile and link it with GPLed libraries smacks of
putting the cart in front of the horse. 

> However, it would be hard to really nail down the infringing copy of
> the GPLed library in this process as long as the distributor refrains
> from providing his own copies or download tools for creating such
> copies and no library stubs have been integrated into creating his
> product.

Is a URL a "download tool"? Does the fact that there are instructions,
or even another package ("Build tools for Schmoo") turn Schmoo into a
derivative work of the GPLed library it needs to be useful? Most
certainly not - the copyright status of the source code of Schmoo
doesn't depend on how useful its compiled version is with or without
something, but if the Schmoo source code is _itself_ a derivative work
- in other words, did the author use only his own work or did he
include source code from other authors. 

What we write, as programmers, is source code. All the rest is merely
mechanical transformation, and has no effect whatsoever on the
copyright status _of the source code_.

> > The OP is proposing to add source code examples to his
> > library. Assuming he did not base his source on existing source code
> > examples of Qt, these examples are his original work, and not
> > affected by the Qt, X, OpenGL, or whatever other license.
> That would be my gut feeling too (unless code passages were actually
> taken from differently licensed example code) in this case (and
> anyway, since the library is available identically in a non-free
> version, one can't claim the particular protection of the GPLed
> version), but there is also a murky borderline where things become
> less clear even when the compiling and/or linking is done at the
> client side.

The copyright status of the source code is not affected by where, how
and by whom it might be compiled, or the fact that it is quite "useless"
without being compiled and linked.

Stefaan A Eeckels
Modesty personified:
This was a thread between ignorant people until I jumped in. 
                             -- richard in gnu.misc.discuss

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