2004-11-03 13:51:07 +00:00
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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" Modified by Michael Haardt <michael@moria.de>
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.\" Modified Sat Jul 24 12:02:47 1993 by Rik Faith <faith@cs.unc.edu>
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.\" Modified 15 Apr 1995 by Michael Chastain <mec@shell.portal.com>:
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.\" Added reference to `bdflush(2)'.
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.\" Modified 960414 by Andries Brouwer <aeb@cwi.nl>:
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.\" Added the fact that since 1.3.20 sync actually waits.
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.\" Modified Tue Oct 22 22:27:07 1996 by Eric S. Raymond <esr@thyrsus.com>
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.\" Modified 2001-10-10 by aeb, following Michael Kerrisk.
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.\"
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_exit.2, brk.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, getdtablesize.2, gethostname.2, getpagesize.2, getsid.2, killpg.2, mknod.2, mknodat.2, poll.2, posix_fadvise.2, pread.2, readlink.2, setpgid.2, setreuid.2, sigaltstack.2, stat.2, symlink.2, sync.2, truncate.2, vfork.2, wait.2, wait4.2, a64l.3, abs.3, acos.3, acosh.3, asin.3, asinh.3, atan.3, atan2.3, atoi.3, cbrt.3, ceil.3, copysign.3, cosh.3, dirfd.3, div.3, ecvt.3, erf.3, erfc.3, exp.3, exp2.3, fabs.3, fdim.3, ffs.3, floor.3, fma.3, fmax.3, fmin.3, fmod.3, fpclassify.3, frexp.3, ftw.3, fwide.3, gcvt.3, getcwd.3, getdate.3, getgrent.3, gethostid.3, getpass.3, getpwent.3, getsubopt.3, getw.3, hypot.3, ilogb.3, index.3, isalpha.3, isgreater.3, iswblank.3, j0.3, ldexp.3, lockf.3, log.3, log10.3, log1p.3, logb.3, lrint.3, lround.3, mkstemp.3, mktemp.3, modf.3, mq_receive.3, mq_send.3, nan.3, nextafter.3, posix_fallocate.3, posix_memalign.3, printf.3, qecvt.3, random.3, realpath.3, remainder.3, remquo.3, rint.3, round.3, scalb.3, scalbln.3, scanf.3, siginterrupt.3, signbit.3, sigset.3, sinh.3, sqrt.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strfry.3, strpbrk.3, strsep.3, strspn.3, strstr.3, strtod.3, strtok.3, strtol.3, strtoul.3, strxfrm.3, tanh.3, tgamma.3, trunc.3, ttyslot.3, ualarm.3, usleep.3, wprintf.3, armscii-8.7, cp1251.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-3.7, iso_8859-5.7, iso_8859-6.7, iso_8859-8.7, koi8-u.7: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-19 17:19:13 +00:00
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.TH SYNC 2 2010-09-20 "Linux" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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sync \- commit buffer cache to disk
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.SH SYNOPSIS
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.B #include <unistd.h>
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.sp
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.B void sync(void);
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2007-07-08 12:11:40 +00:00
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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.BR sync ():
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2010-09-18 09:10:20 +00:00
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.ad l
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.RS 4
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brk.2, chroot.2, faccessat.2, fchmodat.2, fchownat.2, fstatat.2, futimesat.2, getdtablesize.2, getpagesize.2, getsid.2, linkat.2, mkdirat.2, mknodat.2, openat.2, pread.2, readlinkat.2, renameat.2, setpgid.2, sigaltstack.2, symlinkat.2, sync.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, unlinkat.2, utimensat.2, vfork.2, acosh.3, asinh.3, atanh.3, dirfd.3, dprintf.3, ecvt.3, expm1.3, fexecve.3, fmemopen.3, gcvt.3, getcwd.3, gethostid.3, getpass.3, getsubopt.3, getw.3, mbsnrtowcs.3, mkfifoat.3, mkstemp.3, mktemp.3, opendir.3, posix_memalign.3, rint.3, siginterrupt.3, stpcpy.3, stpncpy.3, strdup.3, strerror.3, strnlen.3, strsignal.3, strtol.3, strtoul.3, ualarm.3, usleep.3, wcpcpy.3, wcpncpy.3, wcscasecmp.3, wcsdup.3, wcsncasecmp.3, wcsnlen.3, wcsnrtombs.3: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-19 06:02:38 +00:00
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_BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
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_XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
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2010-09-18 09:10:20 +00:00
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.RE
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.ad
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2004-11-03 13:51:07 +00:00
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.SH DESCRIPTION
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2005-10-19 06:54:38 +00:00
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.BR sync ()
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2011-09-07 23:59:14 +00:00
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causes all buffered modifications to file metadata and data to be
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written to the underlying file systems.
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2004-11-03 13:51:07 +00:00
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.SH ERRORS
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2011-09-07 23:59:14 +00:00
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.BR sync ()
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is always successful.
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2004-11-03 13:51:07 +00:00
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.SH "CONFORMING TO"
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2011-09-07 23:59:14 +00:00
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.BR sync ():
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2006-08-03 13:57:17 +00:00
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SVr4, 4.3BSD, POSIX.1-2001.
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2007-05-18 16:30:46 +00:00
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.SH NOTES
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2011-09-07 23:59:14 +00:00
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Since glibc 2.2.2 the Linux prototype for
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.BR sync ()
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is as listed above,
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2007-05-18 16:30:46 +00:00
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following the various standards.
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In libc4, libc5, and glibc up to 2.2.1
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it was "int sync(void)", and
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.BR sync ()
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always returned 0.
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2004-11-03 13:51:07 +00:00
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.SH BUGS
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2006-08-03 13:57:17 +00:00
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According to the standard specification (e.g., POSIX.1-2001),
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2007-05-12 09:06:04 +00:00
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.BR sync ()
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schedules the writes, but may return before the actual
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2004-11-03 13:51:07 +00:00
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writing is done.
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However, since version 1.3.20 Linux does actually wait.
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(This still does not guarantee data integrity: modern disks have
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large caches.)
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.SH "SEE ALSO"
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.BR bdflush (2),
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.BR fdatasync (2),
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.BR fsync (2),
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.BR sync (8),
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.BR update (8)
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