Re: GPL and Plug-INs and XML\Ada

[Frank Ranner <franner@tpg.com.au>]

David Botton wrote:
> 
> If a person wrote an executable that had a plug-in architecture, would it be
> possible then to include GPL'd plug-ins with out the application becoming
> GPL'd?
>
The best bet would be to make the plug-ins LGPL, which explicitly allows
dynamic
linking from a non-Free application.

Otherwise, if you are the author of both the non-Free app and the GPL
plug-in you
can do whatever you want. Now, if XML/Ada is GPLd and not written by
you, you cannot
link it the way you suggest, ie as a dll/so. You can link it the way
Gimp does it's
plugins, ie as a sub-executable that is forked and piped to. This is
obviously allowed,
otherwise you couldn't even pipe the output from a proprietary program
into any gnu
utility.
 
> For example, If I wrote an application that had a closed lic. and it allowed
> features to be plugged-in. One such group of features was for file "import".
> So, I throw together a GPL'd plug-in that included XML\Ada and dropped that
> dll in the dir and it is picked up at run time by the closed lic.
> application.
> 
> This would be different than:
> 
> I write an XML COM object that uses XML\Ada and now my XML COM object is of
> course GPL'd, but closed lic. programs (say in VB or Ada) could now use my
> XML COM object to access XML.
> 
> I could see where this case would be problematic (although I question that
> also), but the previous cases seems to be no problem. Would including a
> GPL'd COM / Corba object virus to my app and make it GPL'd?
> 
The whole situation of linking has become much more complicated since
the early
days where you had pipe, static link, or dynamic link. Now there is RPC,
DCE, Corba, 
Java Beans, SOAP, Sockets and who knows what other means of
communication between modules.
For those modules to start comparing licences would appear absurd.

Nevertheless, Richard Stallman is at work on GPL version 3 which will
attempt to address
the issue of Free/non-Free links.

Disclaimer, I am not a lawyer; my opinion is based only on reading many
discussions on
the same subject by many other non-lawyers.

Regards,
Frank Ranner