Xref: utzoo unix-pc.general:2014 comp.sys.att:5138
Path: utzoo!utgpu!watmath!clyde!att!chinet!les
From: les@chinet.chi.il.us (Leslie Mikesell)
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: termio(7) and read(2) problem!
Message-ID: <7411@chinet.chi.il.us>
Date: 9 Jan 89 16:40:49 GMT
References: <137@zebra.UUCP>
Reply-To: les@chinet.chi.il.us (Leslie Mikesell)
Distribution: na
Organization: Chinet - Public Access Unix
Lines: 15

In article <137@zebra.UUCP> vern@zebra.UUCP (Vernon C. Hoxie) writes:
>
>	I have been trying to write a test program for a Trailblazer.
>It is connected to /dev/tty000.  The program opens this file with:
>
>	fd = open("/dev/tty000", O_RDWR | O_NDELAY);

You probably need to use fcntl() to turn off the O_NDELAY before
trying to use the port (set CLOCAL first if you need it).  Write()s
don't wait for the hardware to be ready if you leave O_NDELAY
set and strange things happen.  I have seen code that indicated that
a close(open(/dev/ttywhatever,2) was needed to force the mode to
changed.  Does anyone know which versions of unix require this?

Les Mikesell