Re: GSL within Public Domain Software

[Jason Beegan <jtb at kurwenal dot com>]

> On Sat, 05 May 2001, Peter Hopfgartner wrote:
> > Basically, linking with a GPL library, means that you should put your
> > program under a similar license as the GPL, too. You must allow access
> > to the source.
> > 

I think this is a bit misleading.  It depends what you mean by
similar.  As long as the software is distributed under a free license
which is compatible with the GPL there is no problem.  Examples of
compatible licenses include

       Public domain

       X11 License
	   
       BSD License (without the advertising clause)
       The original BSD license (which has an advertising clause)
       is incompatible.

I highly recommend that you read

	 http://www.gnu.org/philosophy/license-list.html

for more information on these matters.


> > In your case this would be a quite natural choice, since you want to
> > distribute both, source code and binaries. The GPL would protect also
> > YOUR work. No other party would be allowed to distribute MODIFIED
> > versions of your code without giving a link to the source code of the
> > MODIFIED version.
> > 
> > Sounds good, doesn't it?
> 
> Yes, but the problem is that our software has been distributed into the
> public domain for years and we really don't want to change that aspect (even if
> the government officials would let us).
> 
> In my vision of a perfect world, the GPL would say something to the affect that
> GPL'd libraries may be linked with software of a "lesser", or "more free?",
> copyright.  In other words, it seems like public domain software, which is
> about as free as you can get, poses no threat to the GPL.


The GPL does allow this.  Again, see that page on GNU's web site (URL
above).

I know of many pieces of software under the GPL which have important
components under less restrictive licenses.  Some of these are even
official GNU projects, eg.

     Octave uses a number of public domain Fortran libraries
	(LAPACK being one of them).

     GNU Mach is based on Mach released by Carnegie-Mellon University
     under the CMU License.


In my opinion it is important to use one of the existing licenses and
avoid causing extra confusion and problems with a new license.  Few
people are experts in licenses and of these very few are programmers.
Some licenses are drawn up by lawyers with no knowledge of the needs
of free software users.


- Jason


PS.  I'm not connected with GNU, except as a user and supporter.