Re: [boost] BOOST license & GPL

Subject: Re: [boost] BOOST license & GPL
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2017-04-01 19:13:24

On Sat, Apr 1, 2017 at 9:22 PM, Niklas Angare via Boost
<boost_at_[hidden]> wrote:
>
> But if they distribute the whole thing saying "this is licensed under the
> GPL", doesn't that kind of contradict the requirement to include the Boost
> Software License and the copyright notices?

It does, if their distributed source (as a package or a VCS snapshot)
does not contain BSL with a clear indication of what code is under
BSL.

> It would feel better to me if
> they said "this is licensed under the GPL and, in part, other compatible
> licenses".

It doesn't work like that. A product, as a whole, must be distributed
under a single license. (It can be distributed under multiple
licenses, e.g. proprietary and copyleft, but that is another off-topic
case; each such distribution is independent and whole.)

As I understand it, a license, among other things, defines two sets: a
set of rights granted to the user, and a set of restrictions or
obligations imposed on the user. Two licenses are compatible if the
sets defined by the licenses are non-contradictory and can be
fulfilled combined. BSL is less restrictive than GPL, and in order for
the two of the licenses to be fulfilled the code must be distributed
under the GPL. It doesn't make that BSL part on its own licensed under
the GPL (or rather, you cannot enforce GPL on that part because the
original copyright holders did not allow that).