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From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: HELP PLEASE: select() in BSD
Message-ID: <6444@brl-smoke.ARPA>
Date: Sun, 20-Sep-87 21:18:18 EDT
Article-I.D.: brl-smok.6444
Posted: Sun Sep 20 21:18:18 1987
Date-Received: Mon, 21-Sep-87 03:42:02 EDT
References: <307@picuxa.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 22

In article <307@picuxa.UUCP> gp@picuxa.UUCP (Greg Pasquariello X1190) writes:
>	According to an associate, there is a function in BSD called
>	select().  This function is similar to sleep(), except that
>	when awakened,  the function can tell who or what woke it (i.e
>	another computer, a port, etc.).  Does anyone no if there is
>	a similar function in System 5 V 3.1?  If not, is there any
>	way to create one?  Thanks in advance.

(This question should have been posted to comp.unix.questions.)

select() tests for activity on a specified set of read/write/exception
file descriptors, with an optional timeout to abort the select() if no
activity happens.

The UNIX System V Release 3.0 (or later) equivalent is poll(), which
is found in the Programmer's Reference Manual under POLL(2).  Note that
it works only with STREAMS files, and that not all devices that could
be are STREAMS devices.  In particular, the terminal handler is not
(yet) a STREAMS device.  To test for activity on a terminal, System V
programs typically use MIN,TIME (described under TERMIO(7), usually in
the Administrator's Reference Manual) or O_NDELAY mode (see READ(2) and
WRITE(2)).