From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Mon, 10 Oct 2005 19:01:31 GMT
Subject: Re: First cut at git port to Cygwin
Message-ID: <Pine.LNX.4.63.0510102100010.7688@wbgn013.biozentrum.uni-wuerzburg.de>
In-Reply-To: <434AB663.8050205@zytor.com>

Hi,

On Mon, 10 Oct 2005, H. Peter Anvin wrote:

> Junio C Hamano wrote:
> > 
> > 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.
> > 
> 
> Then PROT_READ probably makes more sense?

Not necessarily. Sometimes you need to annotate the data from the index, 
and this does not need to be written back to the index file.

> > Yes.  It might have been overkill that you supported writing
> > changes back, though.
> 
> Not just overkill; if we do MAP_PRIVATE it's actively WRONG.

See above.

BTW, is there a mechanism to make sure that the index file is locked 
between reading and writing?

Ciao,
Dscho