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From: Fernando Cacciola (fernando_cacciola_at_[hidden])
Date: 2007-10-04 14:49:37

Miles Bader wrote:
> "Fernando Cacciola" <fernando_cacciola_at_[hidden]> writes:
>>> I also suspect that CGAL (which apparently is not as free as boost)
>> CGAL is modularized and each package has its own license.
>> Many packages, like Basic Kernels, Number Types, 2D Polygons, etc
>> are released under the LPGL [...]
>> which is not as free as the boost license but it's close enough for
>> most applications.
> The problem is that taken as a whole, the CGAL license situation is a
> huge mess -- _most_ of the library seems to be under the
> ultra-obnoxious QPL, and there are inter-package "dependencies" that
> sometimes cause a LGPL'd CGAL package to more or less "depend" on a
> QPL'd package!
That's because the dual licensing scheme is new, so it might still need
improvement, but also because in principle each package author chooses LGPL
or QPL.

> for instance, the CGAL "surface subdivision" package, which is
> licensed under the LGPL, is template-parameterized with an underlying
> 3d polygon type -- however the appropriate CGAL 3d polygon type uses
> the QPL!
This is clearly a problem but is fair to say the the problem exists
precisely because the author of the that subdivision package wanted his code
to be free (as far as LPGL goes), but it not up to him to decide the license
for its dependencies.

This is definitely something that should be reported (I'll do that).

> I put "dependencies" in quotes, because the template parameterization
> means it's a "defacto" dependency rather than hard one. However,
> given the range of functionality used by the SS package, it doesn't
> look particularly trivial to replace the underlying polygon type with
> one's one code.
Right, it is not.

> I think many users that would be otherwise OK with the LGPL would be
> put off by this confusing situation, as I am.
Of course.
But I wasn't aware of it, and probably the Polyhedron author, and the Board,
aren't either.
I consider this a "licensing bug". It might be fixable.

>> Furthermore, CGAL is now open-source, which means everyone can
>> participate. ... For this reason I usually recommend people to
>> contribute geometric libraries to CGAL rather than boost.
> I would never consider contributing to CGAL, nor using it, until they
> straighten out the licensing.
Fair enough.
What would you propose?

Please respond off list, I've stolen too much bandwidth already.


Fernando Cacciola

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