From owner-freebsd-hackers  Wed Dec  6 06:02:34 1995
Return-Path: owner-hackers
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.3/8.7.3) id GAA13463
          for hackers-outgoing; Wed, 6 Dec 1995 06:02:34 -0800 (PST)
Received: from bigbird.vmicls.com (bigbird.vmicls.com [198.17.96.3])
          by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id GAA13456
          for <hackers@freebsd.org>; Wed, 6 Dec 1995 06:02:31 -0800 (PST)
Received: from gonzo by bigbird.vmicls.com (8.6.9/SMI-4.1-vmicls-master-host-1)
	id JAA26164; Wed, 6 Dec 1995 09:03:36 -0500
From: Jerry.Kendall@vmicls.com (Jerry Kendall)
Organization: VMI Communications and Learning Systems
Received: by gonzo (5.0/vmi-client-host-1) id AA25707; Wed, 6 Dec 1995 09:03:34 +0500
Date: Wed, 6 Dec 1995 09:03:34 +0500
Message-Id: <9512061403.AA25707.gonzo@vmicls.com>
To: m_tanaka@pa.yokogawa.co.jp, hackers@freebsd.org
Subject: Re: samaphore remains
X-Sun-Charset: US-ASCII
Sender: owner-hackers@freebsd.org
Precedence: bulk

> From owner-freebsd-hackers@freefall.freebsd.org Wed Dec  6 07:42:37 1995
 
> Hi All,
> 
> Currently I'm using FreeBSD-R2.1.0-RELEASE on GATEWAY 2000 P5-90.
> 
> I found the trouble that if a program using semaphore died
> anbormally, the semaphore which was created remains on kernel.
> I think it should be released by kernel's exit() function.
> 

When an app creates a semaphore, it is primarily(in my experience)
created at system startup. This semaphore is used to control access 
to some facility that must be carefully accessed.

If you wish for some app to create, utilize, and remove a semaphore,
then use the 'semctl()' system call.

In my experience, semaphores are created for some multi-programed
application and created ate startup(ie: rc.local).

Jerry