Subject: Re: [OT] Must the copyright owner release GPLv3 derivative works?
From: Matthew Flaschen <>
Date: Mon, 10 Sep 2007 20:41:32 -0400

Mick Semb Wever wrote:
> Say for example the third party has a module E that they want to release 
> also as GPL, but the propriety license restricts it, could they still do 
> so against the GPL versions of modules A, B, and C?

Yes, if E is derived from GPL modules A, B, C, it can be released under GPL.

> Would the the propriety license require a clause to explicitly state this 
> was possible?


> ps does fsf have any official objection to dual-licenses?

No, though you shouldn't expect them (or indeed OSI) to give it any
notice if the second license is proprietary.

> the case that i'm interested in, and the example that i'm using, is not 
> so much about removing the user's freedoms under the propriety license 
> but offering customers the opportunity to write derivative works they 
> wish to remain private and not to distribute (in binary form or source).

> The LGPL does not work because we do not wish customers/competitors to 
> write and distribute propriety derivative works.

What do you mean by this, exactly?  LGPL still requires the library
itself (and modifications thereof) remain under LGPL.  Only the code
linking to the library can be proprietary.  There isn't necessarily a
clear line, but the difference is apparent in most cases.

Matt Flaschen