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To: "Noel L Yap" <yap_noel AT jpmorgan DOT com>
Cc: cygwin AT cygwin DOT com
Subject: Re: link(2) and atomic file creation on NFS
References: <85256AB7 DOT 0071B8B2 DOT 00 AT nyc-ntgw-n01 DOT ny DOT jpmorgan DOT com>
From: James Youngman <jay AT gnu DOT org>
Date: 29 Aug 2001 22:11:41 +0100
In-Reply-To: <85256AB7.0071B8B2.00@nyc-ntgw-n01.ny.jpmorgan.com>
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"Noel L Yap" <yap_noel AT jpmorgan DOT com> writes:

> Would a mkdir do the trick?
> 
> Noel

Ordinarily, yes.  (As CVS does, of course).

However, SCCS itself (i.e. the venerable AT&T-as-was product) uses
lock _files_ of the form z.foo.  I hesitate before using lock
directories instead, because interoperability is the only (!) priority
of CSSC; I cannot afford to asopt a strategy which may fail to
interoperate completely with SCCS itself. 


> I have some existing code which uses link(2) to achieve atomic locking
> on Unix over NFS (since O_EXCL does not work over NFS).  The
> application (a GPLed SCCS clone) now compiles under Cygwin, but one
> remaining problem is that the lockfile code uses link(2) to create a
> hard link to an open file.


[snip]

-- 
James Youngman
Manchester, UK.  +44 161 226 7339
PGP (GPG) key ID for <jay AT gnu DOT org> is 64A95EE5 (F1B83152).

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