From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <junkio@cox.net>
Subject: Re: First cut at git port to Cygwin
Date: Sat, 08 Oct 2005 11:44:01 -0700
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Cc: git@vger.kernel.org, Linus Torvalds <torvalds@osdl.org>
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To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
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	(Johannes Schindelin's message of "Sat, 8 Oct 2005 20:27:06 +0200
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Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> Am I missing something? I don't see where the changes are written back to 
> the fd. After all, mmap() is called with PROT_WRITE...

PROT_WRITE is true, but we do MAP_PRIVATE, and if I recall
correctly we do not write file via mmap -- at least we do not
intend to.

 - index file is mapped for reading, long ago it was mapped
   read-only but these days we do PROT_WRITE, but updates are
   done via opening a new file and writing afresh.

 - objects are mapped for reading, but, never updated once
   created.  Creation side is regular open - write - close.

 - diff reads original by mapping, but obviously has no business
   writing.

 - local-fetch reads original by mapping for copying.

> *shameless plug* Of course, this problem does not come up with
> my NO_MMAP patch.

Yes.  It might have been overkill that you supported writing
changes back, though.
.