Path: utzoo!dptcdc!jarvis.csri.toronto.edu!mailrus!ukma!cwjcc!hal!ncoast!allbery
From: allbery@ncoast.ORG (Brandon S. Allbery)
Newsgroups: comp.mail.uucp
Subject: Re: Bidirectional Modem Lines under SunOS 4.0.1
Message-ID: <13570@ncoast.ORG>
Date: 15 Apr 89 16:51:44 GMT
References: <160@osc.COM> <743@key.COM> <2209@laidbak.UUCP> <1404@auspex.auspex.com> <3774@ficc.uu.net>
Reply-To: allbery@ncoast.UUCP (Brandon S. Allbery)
Followup-To: comp.mail.uucp
Organization: Cleveland Public Access UN*X, Cleveland, Oh
Lines: 31

As quoted from <3774@ficc.uu.net> by peter@ficc.uu.net (Peter da Silva):
+---------------
| We do it this way on Xenix 3.5, because it's the only way to do it, and I'm
| having to rewrite init to track this multiple-tty-name stuff and clear
| BOTH entries. It's a pain.
+---------------

Uh, Peter, is SCO Xenix *really* so broken that O_NDELAY and/or CLOCAL don't
work?  I've used them in Microsoft Xenix 3.x (untouched by SCO) and UNIX
System III; they work fine.

	fd = open("/dev/ttyxx", O_RDWR|O_NDELAY);
	ioctl(fd, TCGETA, &ttyinfo);
	ttyinfo.c_cflag |= CLOCAL;
	ioctl(fd, TCSETA, &ttyinfo);
	fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NDELAY);
	signal(SIGALRM, timeout);
	alarm(120);
	/* send the dial command to the modem */
	ttyinfo.c_cflag &= ~CLOCAL;
	ioctl(fd, TCSETAW, &ttyinfo);
	/* wait for response; timeout() catches failure */

I've never understood why SCO uses the two-file kluge.

++Brandon
-- 
Brandon S. Allbery, moderator of comp.sources.misc	     allbery@ncoast.org
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