[Asterisk-Dev] GPL Licensing Question

[Thomas Horsten]

On Fri, 15 Oct 2004, Michael Giagnocavo wrote:

> I understand that Asterisk is GPL'd, but Digium retains copyright, and thus
> can grant exceptions. So a company would need this if they modified the
> Asterisk code and wanted to sell it as a proprietary, closed-source
> solution. On the other end, anything just using Asterisk formats or
> protocols (say IAX, dropping a .call file in the outgoing spool, or editing
> .conf) wouldn't need any licensing.
>
> How exactly does this work in regards to modules? As I understand, code that
> links to GPL code needs to be GPL also. Does this mean I can't write a
> module that links to Mono (which is LGPL and MIT X11 licensed) even if my
> module code is GPL?

IANAL, standard disclaimer applies, but as far as I understand it you can
link to LGPL code because all LGPL code is inherently dual-licensed
under the GPL, refer to the following clause in the LGPL:

3. You may opt to apply the terms of the ordinary GNU General Public
License instead of this License to a given copy of the Library. To do
this, you must alter all the notices that refer to this License, so that
they refer to the ordinary GNU General Public License, version 2, instead
of to this License. (If a newer version than version 2 of the ordinary GNU
General Public License has appeared, then you can specify that version
instead if you wish.) Do not make any other change in these notices.

Thomas