mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-20 11:11:24 +00:00
74 lines
2.7 KiB
Groff
74 lines
2.7 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)sync.2 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt SYNC 2
|
|
.Os BSD 4
|
|
.Sh NAME
|
|
.Nm sync
|
|
.Nd "synchronize disk block in-core status with that on disk"
|
|
.Sh SYNOPSIS
|
|
.Fd #include <unistd.h>
|
|
.Ft void
|
|
.Fn sync void
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn sync
|
|
function forces a write of dirty (modified) buffers
|
|
in the block buffer cache out
|
|
to disk. The kernel keeps this information in core to reduce
|
|
the number of disk I/O transfers required by the system.
|
|
As information in the cache is lost after a system crash a
|
|
.Fn sync
|
|
call is issued
|
|
frequently
|
|
by the user process
|
|
.Xr update 4
|
|
(about every 30 seconds).
|
|
.Pp
|
|
The function
|
|
.Xr fsync 2
|
|
may be used to synchronize individual file descriptor
|
|
attributes.
|
|
.Sh SEE ALSO
|
|
.Xr fsync 2 ,
|
|
.Xr update 4 ,
|
|
.Xr sync 8
|
|
.Sh BUGS
|
|
.Fn Sync
|
|
may return before the buffers are completely flushed.
|
|
.Sh HISTORY
|
|
A
|
|
.Nm
|
|
function call appeared in Version 6 AT&T UNIX.
|