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From: jhc@mtune.ATT.COM (Jonathan Clark)
Newsgroups: comp.bugs.sys5
Subject: Re: CLOCAL, or catch-22
Message-ID: <1136@mtune.ATT.COM>
Date: Fri, 7-Aug-87 15:54:11 EDT
Article-I.D.: mtune.1136
Posted: Fri Aug  7 15:54:11 1987
Date-Received: Sun, 9-Aug-87 06:31:54 EDT
References: <325@nsta.UUCP>
Reply-To: jhc@mtune.UUCP (Jonathan Clark)
Distribution: world
Organization: AT&T ISL Middletown NJ USA
Lines: 16
Summary: NDELAY open()

In article <325@nsta.UUCP> amos%nsta@nsc.com (Amos Shapir) writes:
:One of the optional flags of the c_cflag field of termio is CLOCAL ...
: ...  cause the  tty  driver  to ignore  the >'carrier detect' bit  in RS232 
:
:However, the  only way to set  this flag is  by a ioctl call;  the ioctl
:call needs  a file-descriptor  argument; a  file-descriptor can  only be
:obtained by a successfull open call...

Precisely. And to obtain such a file descriptor one should use an open()
with the O_NDELAY flag set. You are referred to the open(2) man page for
further enlightenment.
-- 
Jonathan Clark
[NAC,attmail]!mtune!jhc

An Englishman never enjoys himself except for some noble purpose.