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From: rer@hpfcdc.HP.COM (Rob Robason)
Newsgroups: comp.sys.hp
Subject: Re: why is TIOCNOTTY not defined?  what is TIOCNOTTY?
Message-ID: <5570279@hpfcdc.HP.COM>
Date: 28 Aug 89 19:04:50 GMT
References: <8709@batcomputer.tn.cornell.edu>
Organization: HP Ft. Collins, Co.
Lines: 35

> I notice that in my ioctl.h file (in /usr/include/sys) that the
> definition for TIOCNOTTY is ifdef'ed out.  Anybody know why?

> I've built code, specifically the kip code for managing an
> Appletalk network, that requires TIOCNOTTY by simply removing
> the conditional ifdef, thus, making TIOCNOTTY defined.  Everything
> works.  But I have to admit, I don't understand what's going
> on here.   Any light that can be shed on this issue would be
> most appreciated.

The BSD reference says:

"A process can remove the association it has with its controlling
terminal by opening the file /dev/tty and issuing an

	ioctl(f, TIOCNOTTY, 0);

This is often desirable in server processes."

This same function may be accomplished in HP-UX with setpgrp(2).

I wouldn't bet that "Everything Works" in my application, if I were you.
Terminal affiliation is pretty confusing, and there may be side effects
you haven't noticed *yet*.

If the function described above is what your application needs,
I would suggest that you ifdef your code something like:

#ifdef TIOCNOTTY
	ioctl(f, TIOCNOTTY, 0);
#else
	setpgrp();
#endif

Rob Robason