GFDL/GPL issues

[Joseph S. Myers]

On Thu, 27 May 2010, Basile Starynkevitch wrote:

> However, could you (or some other well informed person) elaborate on
> that incompatibility. What exactly is incompatible? Is it some paragraph
> of GPLv3 versus another paragraph of GFDL1.2 - which ones? Or why is it
> incompatible?

Any two non-identical copyleft licenses are generally incompatible with 
each other, since a copyleft license permits distribution only under the 
terms of exactly that license and not under some other license with 
similar terms.  (The LGPL achieves compatibility with the GPL by allowing 
you to remove the additional permissions the LGPL grants and distribute 
the result under the GPL alone.  Similarly, the FSF could grant 
permissions on documentation and code it owns to allow them to be 
distributed under both the GPL and the GFDL, and that is what we want 
them to do.)

-- 
Joseph S. Myers
joseph@codesourcery.com