Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!lll-tis!ames!rutgers!mtune!codas!usfvax2!jc3b21!jra
From: jra@jc3b21.UUCP (Jay R. Ashworth)
Newsgroups: comp.unix.wizards
Subject: Re: /dev/tty doesn't exist?
Message-ID: <243@jc3b21.UUCP>
Date: 4 Jan 88 04:28:13 GMT
References: <445@minya.UUCP>
Organization: A&P Productions
Lines: 25

In article <445@minya.UUCP>, jc@minya.UUCP (John Chambers) says:
> 
> Anyone have an idea what my program X might be doing to screw up /dev/tty?
[ Yes. ]
> Some hints:  This is a rather generic Unix Sys/V.2, so the problem should
> be similar to most ATT Unices.  The most unusual thing about how X is run
> is that it isn't being started by a login shell; it is started as a daemon
> by init, and in some cases, decides to grab a terminal (whose name is on
> its command line, and which doesn't have getty on it) and run a program
> there.  This is a useful thing to do if, for instance, you are playing
> around with process-control applications.   
> John Chambers <{adelie,ima,maynard,mit-eddie}!minya!{jc,root}> (617/484-6393)
Aha.  As I understand the way these things work, and I'm sure someone
will clarify what I'm about to say :-), /dev/tty is set by the kernel
to point to the control terminal of a process group.  Background
process, those running as daemons, have no control terminal.  Look at
a ps listing.  Also, when was the last time you tried to make an rc
script read the console?  My last time, I discovered that I had to use
/dev/console (Yes, ack, this was on a tandy 6000), just /dev/tty
bombed.  Good luck.
-- jra
-- 
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