| sync.2 (107788) | sync.2 (108028) |
|---|---|
| 1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)sync.2 8.1 (Berkeley) 6/4/93 | 1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)sync.2 8.1 (Berkeley) 6/4/93 |
| 33.\" $FreeBSD: head/lib/libc/sys/sync.2 107788 2002-12-12 17:26:04Z ru $ | 33.\" $FreeBSD: head/lib/libc/sys/sync.2 108028 2002-12-18 09:22:32Z ru $ |
| 34.\" 35.Dd June 4, 1993 36.Dt SYNC 2 37.Os 38.Sh NAME 39.Nm sync 40.Nd "schedule file system updates" 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In unistd.h 45.Ft void 46.Fn sync void 47.Sh DESCRIPTION 48The 49.Fn sync | 34.\" 35.Dd June 4, 1993 36.Dt SYNC 2 37.Os 38.Sh NAME 39.Nm sync 40.Nd "schedule file system updates" 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In unistd.h 45.Ft void 46.Fn sync void 47.Sh DESCRIPTION 48The 49.Fn sync |
| 50function forces a write of dirty (modified) buffers | 50system call forces a write of dirty (modified) buffers |
| 51in the block buffer cache out 52to disk. 53The kernel keeps this information in core to reduce 54the number of disk I/O transfers required by the system. | 51in the block buffer cache out 52to disk. 53The kernel keeps this information in core to reduce 54the number of disk I/O transfers required by the system. |
| 55As information in the cache is lost after a system crash a | 55As information in the cache is lost after a system crash, a |
| 56.Fn sync | 56.Fn sync |
| 57call is issued | 57system call is issued |
| 58frequently 59by the user process 60.Xr syncer 4 61(about every 30 seconds). 62.Pp | 58frequently 59by the user process 60.Xr syncer 4 61(about every 30 seconds). 62.Pp |
| 63The function | 63The |
| 64.Xr fsync 2 | 64.Xr fsync 2 |
| 65system call |
|
| 65may be used to synchronize individual file descriptor 66attributes. 67.Sh SEE ALSO 68.Xr fsync 2 , 69.Xr syncer 4 , 70.Xr sync 8 71.Sh BUGS | 66may be used to synchronize individual file descriptor 67attributes. 68.Sh SEE ALSO 69.Xr fsync 2 , 70.Xr syncer 4 , 71.Xr sync 8 72.Sh BUGS |
| 72.Fn Sync | 73The 74.Fn sync 75system call |
| 73may return before the buffers are completely flushed. 74.Sh HISTORY | 76may return before the buffers are completely flushed. 77.Sh HISTORY |
| 75A | 78The |
| 76.Fn sync | 79.Fn sync |
| 77function call appeared in | 80function appeared in |
| 78.At v6 . | 81.At v6 . |