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Message-ID: <3AE5E506.41D660D6@ece.gatech.edu>
Date: Tue, 24 Apr 2001 16:41:42 -0400
From: Charles Wilson <cwilson AT ece DOT gatech DOT edu>
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To: cygwin-developers AT sources DOT redhat DOT com
Subject: Re: Looking for something to work on...
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> > What is the difficulty with the licensing?
> 
> Cygwin source can be exported to GPL but not vice versa. 
>  

That's one issue.  An author (copyright owner) can reissue a given piece
of code under a different license -- but that doesn't help cygwin, since
Cygnus (now Red Hat) requires copyright of contributions to be signed
over to them as a prequisite for inclusion in the cygwin core.

So, to include cygipc within cygwin you'd need copyright assignment from
:original authors Philippe Chapuy and Ludovic Lange, plus major
contributions by Malcolm Blue, Fred Yankowski, Yutaka Tanida, Corinna
Vinschen, Pete Forman, Daniel Horak, Eric Fifer, Andrea Malagoli, and
me. While many of the latter group are still around and would probably
agree easily, the original auhors have been MIA for several years. 
Thus, cygIPC code cannot be included in cygwin.

Worse, anybody who has studied the cygIPC code (this would include
everybody in the above list) is "contaminated" and cannot cleanly
contribute ANY code to a separate implementation.  Depending on your
lawyer, this contamination may also extend to people who have merely
LOOKED at the cygIPC code.

> I'm more than happy to collaborate on the remaining areas. They are
> * Persistence.
> * sem.h declared routines.
> * msg.h declared routines.
> 
> > I guess we should move this discussion to cygwin-developers...
> >
> > John was asking for something interesting to do.  He suggested POSIX
> > IPC stuff, which I (possibly erroneously) assumed was the same as what
> > cygipc provided.
> 
> It is.

Yep. cygipc is basically POSIX IPC, but because of copyright problems it
can't be directly incorporated into cygwin.  Over time, I and others
have added some non-POSIX extensions (mainly debugging entry points) and
the run-as-service stuff in cygipc's daemon.

> See http://www.opengroup.org/onlinepubs/7908799/xsh/ipc.html -
> it's essential sysV IPC. 

Also see the Linux Programmer's Guide section on SysV IPC:

http://www.linuxdoc.org/LDP/lpg/node21.html#SECTION00740000000000000000

--Chuck