A Program use xfoil (GPL) but is not GPL. Is this possible?

[Thomas Charron]

On Tue, Nov 4, 2008 at 7:02 AM, thomas <thomas at jpberlin.de> wrote:
> Hi,
> I found the Program Profili2 (don't know the license, but not GPL
> compatible). This program uses XFoil (GPL, see
> http://web.mit.edu/drela/Public/web/xfoil/ ). Must Profili use GPL, too?
> There is no sourcecode for Profili available.
> The Answer was:
> No, Profili is not a GPL application, as it uses XFoil executable and
> not XFoil source code.

  That is correct.  I downloaded and double checked to make sure.  He
is using XFoil by executing it.

  Additionally, he has a page in the help file describing xfoil, and
mentioning the GPL.  A don't see a copy of the GPL itself, however,
anywhere in the help files, etc..  I suspect a poor understanding of
the GPL, but given the text in the help file, he encourages people to
muck with it if they wish to.

-- 
-- Thomas