From: John M Collins <jmc@xisl.com>
To: Hugh Dickins <hugh@veritas.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Question about memory-mapped files
Date: Wed, 28 May 2003 20:20:03 +0100 [thread overview]
Message-ID: <3ED50BE3.8090105@xisl.com> (raw)
In-Reply-To: Pine.LNX.4.44.0305281818230.1427-100000@localhost.localdomain
Hugh Dickins wrote:
>On Wed, 28 May 2003, John M Collins wrote:
>
>
>>If I invoke mmap to map a file to memory, and it succeeds, can I safely
>>close the original file descriptor and rely on the memory still being
>>mapped and the file still updated (possibly with mysnc)?
>>
>>
>
>Yes, that's definitely a part of the specification of mmap,
>even if it's not mentioned on the man page.
>
>Note that the file on disk is likely not to be updated until
>some time after you unmap it, unless you use msync to force it.
>
Thanks - FYI the file mod time eventually got updated on HP-UX but not
on Solaris (2.9) or Linux (2.4.21) - and it doesn't seem to update it
even if you don't close the f.d. I think that has to be wrong if the
manual page is anything to go by.
--
John Collins Xi Software Ltd www.xisl.com
next prev parent reply other threads:[~2003-05-28 19:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-28 16:32 Question about memory-mapped files John M Collins
2003-05-28 17:26 ` Hugh Dickins
2003-05-28 19:20 ` John M Collins [this message]
2003-05-29 6:17 ` Hugh Dickins
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