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From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.wizards
Subject: Re: How are mailfiles locked under 4.n and System III/V?
Message-ID: <6664@mimsy.UUCP>
Date: Wed, 13-May-87 17:56:38 EDT
Article-I.D.: mimsy.6664
Posted: Wed May 13 17:56:38 1987
Date-Received: Sat, 16-May-87 06:45:17 EDT
References: <7384@boring.mcvax.cwi.nl>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 14

In article <7384@boring.mcvax.cwi.nl> jack@mcvax.cwi.nl (Jack Jansen) writes:
>I know about V7 (make a file /usr/tmp/lock.USERNAME, yuck) and
>2.9BSD (set the execute bits, slightly-less-yuck), but not how
>other unices do this.

4.3BSD /bin/mail (not sendmail) uses flock().  4.1 and 4.2 /bin/mail
use a V7 style scheme, but the filename is /usr/spool/mail/USERNAME.lock.
Sun Unices still use the 4.2 scheme, at least up through Sun 3.0.

Mail file locking is one of those horrible things that is different
everywhere: we had hacked our software to use flock under 4.2BSD.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
Domain:	chris@mimsy.umd.edu	Path:	seismo!mimsy!chris