Re: [boost] A possible addition to the boost license FAQ

From: Bjørn Roald (bjorn_at_[hidden])
Date: 2006-08-07 02:24:20

Felipe Magno de Almeida wrote:
> If you can dual-license with boost software license and a payed one
> for a organization that may want to pay, then how couldnt you
> dual-license on gpl and boost license?
>   
I think you can dual-license GPL with  _more_ restrictive licenses, Such 
licensing simply adds the freedoms of the GPL (GNU world) to the 
software.  See e.g.

http://www.trolltech.com/products/qt/licenses/licensing/licensingoverview

I don't think you can dual license GPL with _less_ restrictive licenses, 
e.g. the Boost license.  Those licenses add too much freedom.  Freedom  
to use and hide is not compatible with the GPL. That said, you can use 
Boost Software Licensed software in a GPL project.  That is what the GPL 
compatibility pages is about:

http://www.gnu.org/philosophy/license-list.html#GPLCompatibleLicenses

These pages does not suggest that dual licensing is possible.  Just that 
dependencies or even direct use of software licensed under Boost  
Software License within a project licensed with GPL is possible without 
breaking the GPL.  I.e. you should never see the two licenses together 
on the same artifact (FSF view).

Boost Software License has no restriction affecting such dual licensing, 
the issue is with the GPL copyleft restrictions.

Q:  Can I use software licensed with the Boost Software License in my 
GPL licensed project?
A: Yes,  see: 
http://www.gnu.org/philosophy/license-list.html#GPLCompatibleLicenses

Q: Can I dual-license my software under both the GPL and the Boost 
Software License?
A: The Boost Software License allow this, but not the GPL.  This is not 
allowed due to the copyleft restrictions in the GPL.  See: 
http://www.gnu.org/copyleft/#WhatIsCopyleft.  Specifically, the problem 
is with the GPL requiring all modified and extended versions of the 
program to be free as well.  The Boost Software License allow the 
licensee to make non-free modified and extended versions of the program.

My understanding anyway!  I am no legal expert but think I have this one 
right, at least until somebody correct me ;-)

Bjørn