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From: jpm@calmasd.UUCP
Newsgroups: comp.graphics
Subject: Re: Using MIT X window-system
Message-ID: <2151@calmasd.CALMA.UUCP>
Date: Fri, 23-Jan-87 18:17:55 EST
Article-I.D.: calmasd.2151
Posted: Fri Jan 23 18:17:55 1987
Date-Received: Sat, 24-Jan-87 16:08:01 EST
References: <502@daimi.UUCP> <102300001@datacube> <275@ci-dandelion.UUCP>
Organization: G.E. CALMA R&D, San Diego, CA
Lines: 32
Summary: select(2) in non-unix systems

In article <275@ci-dandelion.UUCP>, jim@ci-dandelion.UUCP (Jim Fulton) writes:
> > How hard is it to port X to non-unix environments?
> 
> For the server code, it depends on how easily you can emulate select(2).  If
> you can do that (including providing a way for it to be woken up by the
> network and by the input device) then you should have relatively few problems.
We have implemented a server-based user interface toolkit,
originally under 4.2 BSD with ports to VMS and Apollo.  The crux
of the problem in porting servers in general is exactly as Jim
describes - emulating the UNIX select call.  We found ways of
doing this in both VMS and Aegis by using native system facilities.

Actually, this whole problem should be trivial if the non-unix
O.S. people would simply include the select call in their C system
libraries.  All the other usual (UNIX) system calls are present
(open, malloc, etc.), but not select - in my opinion a major
omission.

I would also like to point out that the select call was not our
only portability problem.  User interface tools have to deal with
things like windows and graphics and these CAN be major
portability problems (but not when X and XLib become the universal
standard!).  But then, these are not strictly O.S./Unix issues and
don't relate to the original poster's request...

However, the original requestor is advised to consider the display
end of things when porting X to non-unix environments.  If your
display hardware can't do the things that X expects at that level,
you could have big problems...
-- 
John McNally  GE/Calma  9805 Scranton Rd. San Diego CA 92121
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