[erlang-questions] GNU GPL, MIT, BSD and compatibility

David-Sarah Hopwood <>
Fri Apr 11 15:35:15 CEST 2008


Richard Carlsson wrote:
[...]
> I see now more exactly what it is you are saying: that the GPL would apply
> only to the combined software as a whole. But here is what the license (v2)
> actually says:
>   "These requirements apply to the modified work as a whole. If identifiable
>    sections of that work are not derived from the Program, and can be
>    reasonably considered independent and separate works in themselves, then
>    this License, and its terms, do not apply to those sections when you
>    distribute them as separate works. But when you distribute the same
>    sections as part of a whole which is a work based on the Program, the
>    distribution of the whole must be on the terms of this License, whose
>    permissions for other licensees extend to the entire whole, and thus to
>    each and every part regardless of who wrote it."
> 
> Note in particular: "the entire whole, and thus to each and every part".
> This means that if such a part was previously only published under e.g.
> an MIT license, it (the particular version used by the combined software)
> must now also be published *also* under the GPL, and can from that point on
> be used by anyone under the GPL even as an isolated component, *even if this
> is not what you as the author of the MIT-licensed part would like*.

Actually this is only true because the MIT license allows such publication
(and similarly for other GPL-compatible licenses). That is, the MIT license
does not limit republication under a more restrictive license, whether that
is the GPL or something else. This is not a problem.

-- 
David-Sarah Hopwood



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