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From: roberto@keltia.frmug.fr.net (Ollivier Robert)
Newsgroups: comp.unix.programmer,comp.unix.questions,comp.unix.bsd
Subject: Re: mmap memory/disk synchronization
Date: 4 Jun 1994 13:14:47 +0200
Organization: A Happy FreeBSD-current Usenet Site
Lines: 39
Message-ID: <2spnnl$e9@keltia.frmug.fr.net>
References: <2so8tj$fkp@netnews.upenn.edu>
Reply-To: roberto@hsc.fr.net (Ollivier Robert)
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In article <2so8tj$fkp@netnews.upenn.edu>,
David Blackman <blackman@hodgkin.med.upenn.edu> wrote:
>Using SunOS 4.x, is there a way to insure that a disk file and a
>segment of memory mapped with mmap are consistent - i.e. to guarantee
>that all writes to the memory segment are on disk? I would like
>something like fflush but fflush wants a FILE * parameter and mmap
>wants an int fd.
I don't have a Sun handy but check whether it has msync(2) :
------------------------------------------------------------
NAME
msync - synchronize a mapped region
SYNOPSIS
msync(addr, len)
caddr_t addr;
int len;
DESCRIPTION
The msync system call writes any modified pages back to
the filesystem and updates the file modification time. If
len is 0, all modified pages within the region containing
addr will be flushed; if len is non-zero, only the pages
containing addr and len succeeding locations will be exam-
ined. Any required synchronization of memory caches will
also take place at this time. Filesystem operations on a
file that is mapped for shared modifications are unpre-
dictable except after an msync.
SEE ALSO
msync.2, munmap.2, mprotect.2, madvise.2, mincore.2
May 27, 1991 1
------------------------------------------------------------
Extracted from FreeBSD.
--
Ollivier ROBERT roberto@hsc.fr.net
Hervé Schauer Consultants Ollivier.Robert@keltia.frmug.fr.net
PERL / MIME / PGP 2.6ui FreeBSD keltia 1.1.0(Current) CURRENT_092#0 i386