Subject: Re: GPL and closed source
From: John Cowan <cowan@mercury.ccil.org>
Date: Fri, 3 Jun 2011 02:30:32 -0400

Dale scripsit:

> 1.if you are the copyright holder of the GPL code then you can do that

Yes.  Licenses don't apply to the licensor.

> 2.if you are the copyright holder of the GPL code then you can do that
> provided that you add a clause to the GPL license that your code can
> be linked against closed source APIs.Although I find that this mostly
> should concern 3rd party developers who want to use your GPL code and
> link it against closed source APIs

Yes, if you want to do that you can.  Or you can switch from the GPL to
the LGPL, which is similar but not exactly the same.

> 3.If you GPL code uses dynamic/runtime linking rather than static,then
> it is ok

That's disputed.  The FSF says no, and most open source people say no.

> 4.If your GPL code accesses another non-GPL but open source library
> and this library calls the closed source API then your GPL code uses
> an intermediate interface which acts as the communication bridge
> between them thus does not access the closed source directly,which is
> ok.I see some people describe that as a 'shim'

Another disputed point.

> It looks like that GPL is too restricive in a sense

If you GPL a library, it's because you want only GPL programmers to have
the benefit of using it.

-- 
John Cowan   cowan@ccil.org    http://ccil.org/~cowan
The known is finite, the unknown infinite; intellectually we stand
on an islet in the midst of an illimitable ocean of inexplicability.
Our business in every generation is to reclaim a little more land,
to add something to the extent and the solidity of our possessions.
        --Thomas Henry Huxley