[vtk-developers] Scope of VTK and it's potential as a common research language

[Benoit Jacob]

2010/1/31 Bill Lorensen <bill.lorensen at gmail.com>:
> Benoit,
>
> From:
> http://www.gnu.org/licenses/lgpl.html
>
> 3. Object Code Incorporating Material from Library Header Files.
>
> The object code form of an Application may incorporate material from a
> header file that is part of the Library. You may convey such object
> code under terms of your choice, provided that, if the incorporated
> material is not limited to numerical parameters, data structure
> layouts and accessors, or small macros, inline functions and templates
> (ten or fewer lines in length), you do both of the following:
>
>    * a) Give prominent notice with each copy of the object code that
> the Library is used in it and that the Library and its use are covered
> by this License.
>    * b) Accompany the object code with a copy of the GNU GPL and this
> license document.
>
> ---------------
>
> I'm guessing that a few of your templates have more than 10 lines of
> code.

Indeed: 99% of Eigen's code is templated.

> If so, we will have to supply a copy of the LGPLv3 AND GPL
> license.

Yes. Just like if Eigen were BSD-licensed, its users would have to
supply a copy of the BSD license.

> I don't understand why a copy of the GPL has to accompany the
> code.

That's just because the LGPL is implemented as an addendum to the GPL,
adding more permissions.

My personal opinion (which might be irrelevant) is that instead of
shipping copies of the license it should be enough to give its URL.

>
> IANAL,  but this would seem to add to the confusion for commercial
> customers of VTK.

I can't speak about that, but the same applies to the commercial users
of any package that uses e.g. Qt under LGPL license.

Benoit