Re: Using non-GPL libraries in a GPL program

[Dave Crossland]

On May 28, 1:39 pm, Alexander Terekhov <terek...@web.de> wrote:
> Dave Crossland wrote:
>
> [...]
>
> > The works that are subject to copyright must be licensed "as a whole"
> > under the GPL. The works that are public domain are not subject to
> > copyright. Hence it is absolutely trivial to have a derivative work
> > based on preexisting public domain material copyright licensed under
> > the GPL.
>
> Given: D is a derivative work "as a whole" employing public domain
> expression P.
>
> The copyright on D (i.e. stuff that you can copyright license) covers
> only D - P = C expression. "As a whole" expression is C + P = D. To
> repeat: stuff that can be copyright licensed is only C and not P. Hence
> (now try concentrate your brain power)
>
>                                 C < D
>
> which means that D can not be licensed "as a whole" under the GPL.
>
> That's impossible because C < D.

The copyright on D covers only D - P = C expression, so D can be
licensed "as a whole" under the GPL but the the GPL only applies to C,
you can re-distribute P under any terms.

Supposing your are right, and GPL can't include PD works: What free
software programs in use today are GPL and include public domain works?