Re: More GPL questions

[David Kastrup]

Stefaan A Eeckels <hoendech@ecc.lu> writes:

> On Mon, 16 Oct 2006 18:05:58 +0200
> Merijn de Weerd <merijn+nospam@realemail.net> wrote:
>
>> On 2006-10-16, Alfred M. Szmidt <ams@gnu.org> 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.
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.

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.

> 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.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum