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From: bruce@segue.segue.com (Bruce Adler)
Newsgroups: comp.unix.internals,comp.unix.sysv386
Subject: Re: Can you poll a pipe?
Message-ID: <4436@segue.segue.com>
Date: 31 Oct 90 20:30:16 GMT
References: <1990Oct24.184556.853@esegue.segue.boston.ma.us> <345@uucs1.UUCP> <1990Oct28.035350.26736@ico.isc.com>
Reply-To: bruce@segue.segue.com (Bruce Adler)
Distribution: na
Organization: Segue Software, Inc. - Santa Monica, CA. +1-213-453-2161
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In the manual "386/ix TCP/IP Programmer's Supplement - Version 1.1.0" 
(which is found within the book titled "386/ix TCP/IP Guide") it says at 
the bottom of page 21: 

	"On the 386/ix Operating System, select essentially provides the
	same functions as the poll system call but uses a different syntax.
	select has the same restrictions as poll, but under 386/ix,
	poll has been extended to support non-STREAMS file descriptors.
	In particular, pipes, pty, and tty devices are supported."

I suspect the 1.2 version of the manual says the same thing, but I will 
verify this later today.  

If, as you say, poll() and select() don't work identically on all 
releases of INTERACTIVE UNIX/386 3.2.x then it's clearly a bug.  The 
only questions in my mind are: 

        1.  Does select have the same extensions as poll (probably but 
        the above paragraph is ambiguous)?  
        
        2.  Does the console qualify as a tty type device?
        
        3.  Is the phrase "tty devices" intended to include all the 
        various brands of multi-port serial cards?  
-- 
bruce@segue.com, ism.isc.com!segue!bruce, aero.org!segue!bruce