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Subject: Re: [boost] BOOST license & GPL
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2017-04-01 10:58:45

On 04/01/17 07:20, Oliver Kowalke via Boost wrote:
> Hi,
> I encountered a open source project that is released under GPL and uses
> Boost - that's OK, because GPL and Boost license should be compatible.
> But the developers of those project copied code from Boost into their own
> library.
> The question is, is this new library now GPL or Boost license?

[Standard disclaimer that I'm not a lawyer, and the following is my

Boost license (BSL) requires to "be included in all copies of the
Software, in whole or in part, and all derivative works of the Software,
unless such copies or derivative works are solely in the form of
machine-executable object code generated by a source language
processor." So the copied part is still under the Boost license (and the
license must be present in that project in a way that makes it clear
what code it applies to). However, the developers of that project can
distribute their project as a whole under the GPL, including the parts
under the BSL. They cannot distribute the BSL parts alone under another
license, such as GPL.

Here are some related info:

Explains about including public domain code into a GPL-ed program; I
don't see why the same wouldn't apply to BSL-ed code:

Describes combining a module with a GPL-ed program:

Describes how GPL applies to combined work:

> Additionally, because they copied the code from several Boost files into
> one, they mixed up copyright statements. As a result, some people get
> copyright on code they never wrote.

Yes, the copyright list is confusing, IMHO. As I understand it, the list
of copyright holders shows the parties that have written/modified
substantal *parts* of the source file. This follows from the normal use
of this list: when you modify a lot of content in a file, you typically
*add* yourself to the existing list of copyright holders; you don't have
to rewrite the file from scratch for that.

The point is that, for example, in case of changing the license on the
code all copyright holders in the list have to be contacted for
approval, even though each copyright holder alone did not write the
whole file. Each copyright holder can give the permission on the part he
wrote. Determining who wrote which part can be difficult, so "all or
none" approach is quite possible in such cases.

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