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From: mouse@mcgill-vision.UUCP
Newsgroups: comp.unix.wizards
Subject: Re: bizarre output from getpgrp()
Message-ID: <731@mcgill-vision.UUCP>
Date: Mon, 6-Apr-87 23:04:43 EST
Article-I.D.: mcgill-v.731
Posted: Mon Apr  6 23:04:43 1987
Date-Received: Sun, 12-Apr-87 05:43:05 EST
References: <704@avec.UUCP>
Organization: McGill University, Montreal
Lines: 28

In article <704@avec.UUCP>, sean@avec.UUCP (Sean McGuire) writes:
> This is to a Xenix (with V7 tty drivers) and a 68020 chip.  The
> manufacturer will remain anonymous.  Their call to getpgrp() returns
> the pid.  My understanding is that the default process group is the
> pid of your login shell unless you set it otherwise (via setprgp()).

Depends on the shell.  Any shell that does job control (such as most
(all?) implementations of the csh) must place jobs in process groups of
their own.  Normally, the process group is the PID of the group leader;
if there is only one process in the job (the usual case), this means
that the group ID is the process ID.

If, on the other hand, the following prints "broken", then they have
changed the semantics significantly:

	int old,new;
	old=getpgrp(getpid());
	if (fork())
	 { new=getpgrp(getpid());
	   if (new != old) printf("broken\n");
	 }

					der Mouse

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