Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mandrill!gatech!sbmsg1!scbhq!uahcs1!madhat!alvitar
From: alvitar@madhat.UUCP (Phil Harbison)
Newsgroups: comp.unix.wizards
Subject: Re: I need a SysV select()
Message-ID: <266@madhat.UUCP>
Date: 26 May 88 22:44:45 GMT
References: <9738@sol.ARPA> <7904@brl-smoke.ARPA> <11536@mimsy.UUCP> <2643@c3engr.UUCP>
Organization: DataVision, Huntsville AL
Lines: 24
Posted: Thu May 26 18:44:45 1988

In article <2643@c3engr.UUCP>, charles@c3engr.UUCP (Charles Green) writes:
> 
> My favorite solution is to have several small "multiplexor" processes,
> all identical but exec()ed with a unique numeric argument, reading their
> respective stdins ... When one of the multiplexor processes completes a
> read(), he does a single write() to the pipe containing his unique ID,
> a byte count, and the data.
> 

I use a similar approach on my version of emacs to implement subprocesses
running in emacs windows.  It is a major win on the Sys5 version since the
previous approach used lots of CPU time doing NODELAY reads on the keyboard
and childs stdout pipe.  Another big win is I only have one version of the
code that runs on v7, BSD, and USG flavors of UNIX.  A nice side effect is
that polling the keyboard is simple, since I can do an fstat to discover
how much data is in the IPC pipe.  If anyone wants example code, drop me
a note in the mail.


-- 
Live: Phil Harbison
USPS: 3409 Grassfort Drive, Huntsville, AL 35805-5421
UUCP: clyde!madhat!alvitar
PSTN: 205-881-4317 or 205-830-4310x210