Xref: utzoo comp.unix.internals:841 comp.unix.sysv386:1559
Path: utzoo!attcan!uunet!timbuk!cs.umn.edu!uc!noc.MR.NET!msi.umn.edu!umeecs!umich!samsung!usc!ucsd!pacbell.com!att!att!watmath!mks.com!femto!eric
From: eric@femto.mks.com (Eric Gisin)
Newsgroups: comp.unix.internals,comp.unix.sysv386
Subject: Re: Can you poll a pipe?
Message-ID: <ERIC.90Oct25125357@femto.mks.com>
Date: 25 Oct 90 19:53:57 GMT
References: <1990Oct24.184556.853@esegue.segue.boston.ma.us>
Sender: eric@mks.com (Eric Gisin)
Distribution: na
Organization: Mortice Kern Systems Inc., Waterloo, Ontario, CANADA
Lines: 8
In-Reply-To: johnl@esegue.segue.boston.ma.us's message of 24 Oct 90 18:45:56 GMT

The ability to poll pipes and ttys is an extension by Interactive (ISC),
and is documented in the manual. select (in libinet) just calls poll.
I understand SCO UNIX added a separate select system call, which
has the ability to check file descriptor that poll can't.
I don't know what ESIX does, since they don't have socket emulation.

I would think that anyone who ports the BSD rsh to SysV would have
to provide poll or select on pipes, otherwise you could not use rsh in pipelines.