X-Recipient: archive-cygwin AT delorie DOT com
X-Spam-Check-By: sourceware.org
Date: Fri, 9 Mar 2012 09:43:07 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: rebase keeps last modification time of DLL unchanged
Message-ID: <20120309084307.GA5159@calimero.vinschen.de>
Reply-To: cygwin AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
References: <4F57DC0F DOT 2090401 AT t-online DOT de> <20120308093206 DOT GR5159 AT calimero DOT vinschen DOT de> <4F5918A2 DOT 4090707 AT t-online DOT de>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <4F5918A2.4090707@t-online.de>
User-Agent: Mutt/1.5.21 (2010-09-15)
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Precedence: bulk
List-Id: <cygwin.cygwin.com>
List-Unsubscribe: <mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com

On Mar  8 21:37, Christian Franke wrote:
> Corinna Vinschen wrote:
> >On Mar  7 23:07, Christian Franke wrote:
> >>The rebase tool does not change last modification timestamp of each
> >>DLL even if its data has changed. This is likely because Windows
> >>"may" not update the timestamp for files written through a memory
> >>mapped view.
> >>
> >>Is this an intended behavior of rebase?
> >Why should rebase change the timestamp?  Apart from the rebasing, the
> >DLL is still the same.  If you want to know when it has been last
> >rebased, you can look into the file header:
> >
> >   $ objdump -p cygiconv-2.dll | grep 'Time/Date[^ ]'
> >   Time/Date               Tue Mar  6 23:24:12 2012
> >
> 
> It depends: Changing data without changing st_mtime avoids
> (unneeded|required) file copies during incremental backups, rsync,
> robocopy, ...
> 
> rebase does not explicitly (re)set the timestamp after rebasing. Is
> this by design?
> 
> It relies on weakly defined Windows behavior: "When modifying a file
> through a mapped view, the last modification timestamp *may* not be
> updated automatically."
> http://msdn.microsoft.com/en-us/library/windows/desktop/aa366563.aspx

Well, let me put it like this.  Rebase just does its job.  It doesn't
actually care for the file timestamp, only for the file header
timestamps.  This is not by design, it's just as it is.  So the next
question is obvious.  Do you think it should change the timestamp or
not?  Why?  A patch is simple and I have it actually already waiting in
the scenery.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple