Path: utzoo!attcan!uunet!mcsun!unido!mikros!mwtech!mecky!walter
From: walter@mecky.UUCP (Walter Mecky)
Newsgroups: comp.unix.wizards
Subject: Re: How to set control tty (Sys5)
Message-ID: <689@mecky.UUCP>
Date: 11 Jul 90 00:41:04 GMT
References: <483@trux.UUCP> <1990Jul06.015108.14622@virtech.uucp>
Reply-To: walter@mecky.UUCP (Walter Mecky)
Organization: MIKROS Systemware, Buettelborn/W-Germany
Lines: 24

In article <1990Jul06.015108.14622@virtech.uucp> cpcahil@virtech.UUCP (Conor P. Cahill) writes:
< In article <483@trux.UUCP> car@trux.UUCP (Chris Rende) writes:
< >However, I can't figure/find out how to set the control tty. I read in
< >TERMIO(7) something like "The first terminal file that gets opened becomes
< >the control terminal". When I wrote a program that disassociates itself from
< >the control terminal and then does a "fd=open("/dev/ttyi00",O_RDWR);"
< >it didn't work. I.e, a "ps -ef" shows "?" for the control tty.
< 
< The other requirement is that no other proces has that terminal as its 
< controlling terminal.  I would guess that your test is failing because
< the tty is the controlling terminal for another process.

The third requirement is that the proces is a process group leader.
According to my manual from SCO UNIX 3.2:
	                            The	very first terminal file
	  opened by the	process	group leader of	a terminal file	not
	  already associated with a process group becomes the for that
	  process group.  The control terminal plays a special role in
	  handling quit	and interrupt signals, as discussed below.
	  The control terminal is inherited by a child process during
	  a fork(S).  A	process	can break this association by changing
	  its process group using setpgrp(S).
-- 
Walter Mecky	[ walter@mecky	or  ...uunet!unido!mecky!walter ]