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.\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu) and
.\" and Copyright 2006 Michael Kerrisk <mtk.manpages@gmail.com>
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.\" Modified 21 Aug 1994 by Michael Chastain <mec@shell.portal.com>:
.\"   Removed note about old libc (pre-4.5.26) translating to 'sync'.
.\" Modified 15 Apr 1995 by Michael Chastain <mec@shell.portal.com>:
.\"   Added `see also' section.
.\" Modified 13 Apr 1996 by Markus Kuhn <mskuhn@cip.informatik.uni-erlangen.de>
.\"   Added remarks about fdatasync.
.\" Modified Fri Jan 31 16:27:42 1997 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 31 Jan 1997 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 18 Apr 2001 by Andi Kleen
.\"   Fix description to describe what it really does; add a few caveats.
.\" 2006-04-28, mtk, substantial rewrite of various parts.
.\"
.\" Japanese Version Copyright (c) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 1997-02-22, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Modified 2001-05-19, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated 2005-09-06, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2006-07-30, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2007-10-13, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v2.65
.\"
.\"WORD:	core			
.\"WORD:	disk			ǥ
.\"WORD:	synchronize		Ʊ
..\"
.TH FSYNC 2 2007-07-26 "Linux" "Linux Programmer's Manual"
.SH ̾
fsync \- ˤեƤ򥹥ȥ졼ǥХΤΤƱ
.SH 
.B #include <unistd.h>
.sp
.BI "int fsync(int " fd );
.sp
.BI "int fdatasync(int " fd );
.sp
.in -4n
glibc εǽޥ׷
.RB ( feature_test_macros (7)
):
.in
.sp
.BR fsync ():
_BSD_SOURCE || _XOPEN_SOURCE
.br
.BR fdatasync ():
_POSIX_C_SOURCE\ >=\ 199309L || _XOPEN_SOURCE\ >=\ 500
.SH 
.BR fsync ()
ϡե뵭һ
.I fd
ǻȤեǻäƤǡ
(ĤޤХåեåڡ) Τ줿ǡ
Υե뤬°ǥǥХ (ޤϤ¾α³ȥ졼ǥХ)
ž (֥եå) 롣
θƤӽФžäȥǥХ𤹤ޤǥ֥å롣
ޤե˷ӤĤ᥿ǡ
.RB ( stat (2)
) եå夹롣

.BR fsync ()
θƤӽФϡե뤬¸ߤƤǥ쥯ȥΥȥ꤬ǥ
񤭹ޤ줿Ȥݾڤ櫓ǤϤʤ
ݾڤ뤿ˤŪˤΥǥ쥯ȥΥե뵭һҤФƤ
.BR fsync ()
ɬפ롣

.BR fdatasync ()

.BR fsync ()
ƱͤǤ뤬᥿ǡΰۤʤ롣
.BR fdatasync ()
ϡʹߤΥǡɤ߹ߤˤΥ᥿ǡɬפ
ʤʤ¤ꡢѹ줿᥿ǡեå夷ʤ
㤨С
st_atime  st_mtime
(줾ǽǽ;
.BR stat (2)
) ѹϥեåɬפȤʤ
ʤʤ餳ϤʹߤΥǡɤ߹ߤ
ɬפǤϤʤǤ롣
ե륵
.RB ( ftruncate (2)
Ǥ
.IR st_size )
ѹϥ᥿ǡΥեå夬ɬפǤ롣
.BR fdatasync ()
ϡƤΥ᥿ǡǥƱɬפΤʤ
ץꥱФơǥ򸺤餹ȤǤ롣
.SH ֤
硢Υƥॳϥ֤
顼ξ硢\-1 ֤졢
.I errno
Ŭڤꤵ롣
.SH 顼
.TP
.B EBADF
.I fd
񤭹ߤΤ˥ץ󤵤줿ե뵭һҤǤʤ
.TP
.B EIO
Ʊδ֤˥顼ȯ
.TP
.BR EROFS ", " EINVAL
.I fd
Ʊ򥵥ݡȤƤʤüʥե򻲾ȤƤ롣
.SH 
4.3BSD, POSIX.1-2001
.SH 
.BR fdatasync ()
Ѳǽ POSIX ƥǤϡ
.B _POSIX_SYNCHRONIZED_IO

.I <unistd.h>
 0 礭ͤ
.RB ( sysconf (3)
)
.\" POSIX.1-2001: It shall be defined to -1 or 0 or 200112L.
.\" -1: unavailable, 0: ask using sysconf().
.\" glibc defines them to 1.
.SH 
ǡ١ե˥륢ץꥱϡ
˾ʥǡҤν񤭹ߤԤθ夹
.BR fsync ()
ƤӽФơ񤭹ǡϡɥǥʪŪ
μ¤˳Ǽ褦ˤ뤳Ȥ¿
ǰʤ顢
.BR fsync ()
Ͼ 2Ĥν񤭹򳫻Ϥ롣
ĤϿ񤭹ޤ줿ǡФΤǤꡢ
⤦Ĥ inode ˳Ǽ뽤 (modification time) 
뤿ΤΤǤ롣
ιԲʬ (ȥ󥶥) ΰǤϤʤ硢
.BR fdatasync ()
ȤȤǡɬפ inode Υǥ񤭹򤱤뤳ȤǤ롣

ǡ֤Ƥϡɥǥν񤭹ߥå夬ͭ
ʤäƤ硢
.BR fsync ()
/
.BR fdatasync ()
äƤȤƤ⡢Υǡϼºݤˤϱ³ŪʵΤ
ǼƤʤ⤷ʤ
.\" IDE ǥΥå̵ˤˡˤĤƤ
.\" .BR hdparm (8)
.\" 򻲾ȤΤȡ
.LP
ext2 ե롦ƥब
.I sync
ץĤǥޥȤƤ硢
.BR fsync ()
ǥǥ쥯ȥꡦȥۤΤƱ롣
.LP
2.4 ΥͥǤϵʥե
.BR fsync ()
Ѥ뤳ȤϸΨ礬롣
̤ˡȤ
.BR open (2)
κݤ
.B O_SYNC
ե饰ѤΤɤ⤷ʤ

Linux 2.2 Ǥϡ
.BR fdatasync ()

.BR fsync ()
Ǥꡢǽ̤ǤΥåȤϤʤ
.SH Ϣ
.BR bdflush (2),
.BR open (2),
.BR sync (2),
.BR sync_file_range (2),
.BR hdparm (8),
.BR mount (8),
.BR sync (8),
.BR update (8)