🚀 go-pugleaf

In article <1ijsrmINN8jr@shelley.u.washington.edu> tzs@carson.u.washington.edu (Tim Smith) writes:
>If the GPL does prevent someone from doing this with a DLL, then how are
>people able to distribute ports of Emacs for proprietary operating
>systems?

There's an explicit exception in the GPL for OS libraries:

    For an executable file, complete source code means all the source code for
    all modules it contains; but, as a special exception, it need not include
    source code for modules which are standard libraries that accompany the
    operating system on which the executable file runs.

As for the DLL question, I think this applies:

    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.

If you wrote the DLL merely to make your Emacs port effectively
proprietary, I don't think it can be "reasonably considered independent and
separate".  However, if you have a proprietary database system implemented
as a DLL, and you make a version of Emacs that uses it, I don't think you
would have to copyleft the database library (however, if you use a
non-dynamic library, the linked version is a derivative of Emacs, and
therefore all parts of it must be copylefted).

-- 
Barry Margolin
System Manager, Thinking Machines Corp.

barmar@think.com          {uunet,harvard}!think!barmar