Date: Mon, 19 Mar 2001 10:54:30 -0800 From: Peter Wemm <peter@netplex.com.au> To: Terry Lambert <tlambert@primenet.com> Cc: andre@netvision.com.br, fs@FreeBSD.ORG Subject: Re: Truncating a file. Message-ID: <200103191854.f2JIsUh36403@mobile.wemm.org> In-Reply-To: <200103160600.XAA04319@usr05.primenet.com>
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Terry Lambert wrote:
> > With ftruncate, you can remove part of the end of a file. Is there a way
to
> > remove part of the beginning of a file?
> > I'm developing a SOCKS5 server that stores the data received from the fir
st
> > connection to a local file, and when the second connection is writable, rea
d
> > that file and write the data to this second connection. As data is read fro
m
> > the local file, its beginning becomes useless, so I'd like to truncate it
> > out. Is it possible?
>
> FreeBSD doesn't support the defacto industry standard F_FREESP
> fcntl(2) command argument (which would free the area referred
> to by the contents of a flock structure).
F_FREESP is not truncating. It just makes a hole. Truncating from the
beginning means to take a 10MB file, truncate the first 1MB off the
beginning and be left with a 9MB file..
VIVAFS implements this, but it was based on 4.3-net2 and BSD/OS 2.x and
was considered "tainted" pending a reimplementation.
Cheers,
-Peter
--
Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au
"All of this is for nothing if we don't go to the stars" - JMS/B5
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