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From: Terry Lambert <terry@lambert.org>
Message-Id: <199605281658.JAA11239@phaeton.artisoft.com>
Subject: Re: Forgiving select() call.
To: joerg_wunsch@uriah.heep.sax.de
Date: Tue, 28 May 1996 09:58:46 -0700 (MST)
Cc: kaleb@x.org, terry@lambert.org, chat@freebsd.org
In-Reply-To: <199605280612.IAA03466@uriah.heep.sax.de> from "J Wunsch" at May 28, 96 08:12:17 am
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> (Religious topic, thus moved to chat.)
> 
> As Kaleb S. KEITHLEY wrote:
> 
> > And, FWIW, SVR4 select(3) is implemented using poll(2), so select on
> > SVR4, in and of itself, isn't going to have any better granularity
> > than poll.
> 
> Only very few systems actually implement it as a library function (and
> that's perhaps one of the reasons [along with STREAMS] for the
> sluggishness of their IP functionality).  All the serious ones
> implement it as a system call, too.

Solaris as of 2.3 implementes it as a system call.  I pointed out two
bugs in the library implementation:

1)	Won't run statically linked SunOS binaries

2)	Makes OS non-compliant with SVID III (RT) definition for
	select(), since SVID III makes a distinction between system
	clock and clock update frequency (setitimer(RT), getitimer(RT),
	gettimeofday(RT)).

Pretty much only silly non-SVID III compliant SVR3/SVR4 implementations
use select(3) instead of select(2) implementations.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.