Re: [OctDev] Octave-forge packaging

[John W. Eaton]

On 23-Apr-2005, Rafael Laboissiere <address@hidden> wrote:

| * John W. Eaton <address@hidden> [2005-04-23 10:26]:
| 
| > On 23-Apr-2005, Rafael Laboissiere <address@hidden> wrote:
| > 
| > | Indeed, octave-gpc is released under the GNU GPL.  However, octave-gpc
| > | links against the General Polygon Clipping Library
| > | (http://www.cs.man.ac.uk/aig/staff/alan/software/gpc.html), which has a
| > | non-free license.
| > 
| > Doesn't that mean that you can't distribute the result, because the
| > whole cannot be distributed under the terms of the GPL?
| 
| I am not fully confident on this issue, but I think it works the other
| way around: if a library is released under the GPL, then the linked
| result *_must_* also be released under the GPL.

I suggest reading

  http://www.gnu.org/licenses/gpl-faq.html#FSWithNFLibs

and

  http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs

Note that the answer to the second question explains that you can add
an exception to the GPL so that software you write can link to
non-free libraries.  But that will only work if ALL the parts of your
code are covered by a license with the exception.  Since you are also
linking with Octave, which does not include an exception to allow
linking with non-free software, then linking to non-free libraries is
not allowed.

| I wrote the octave-gpc binding and decided to release it under the GPL.
| This means that if one day someone writes a GPLed drop-in replacement for
| GPC, then the binding can be used freely.

But until then, you have a problem because you only have the non-free
library to link with, and the GPL does not permit this by default.

| Notice also that the octave-gpc package in Debian is in the contrib
| section, not in main.

I don't think that where the package is stored in the collection makes
any difference.

jwe