| | 1 | .\" $NetBSD: sync.2,v 1.4 1995/02/27 12:38:41 cgd Exp $ |
| | 2 | .\" |
| | 3 | .\" Copyright (c) 1980, 1991, 1993 |
| | 4 | .\" The Regents of the University of California. All rights reserved. |
| | 5 | .\" |
| | 6 | .\" Redistribution and use in source and binary forms, with or without |
| | 7 | .\" modification, are permitted provided that the following conditions |
| | 8 | .\" are met: |
| | 9 | .\" 1. Redistributions of source code must retain the above copyright |
| | 10 | .\" notice, this list of conditions and the following disclaimer. |
| | 11 | .\" 2. Redistributions in binary form must reproduce the above copyright |
| | 12 | .\" notice, this list of conditions and the following disclaimer in the |
| | 13 | .\" documentation and/or other materials provided with the distribution. |
| | 14 | .\" 3. All advertising materials mentioning features or use of this software |
| | 15 | .\" must display the following acknowledgement: |
| | 16 | .\" This product includes software developed by the University of |
| | 17 | .\" California, Berkeley and its contributors. |
| | 18 | .\" 4. Neither the name of the University nor the names of its contributors |
| | 19 | .\" may be used to endorse or promote products derived from this software |
| | 20 | .\" without specific prior written permission. |
| | 21 | .\" |
| | 22 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| | 23 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| | 24 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| | 25 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| | 26 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| | 27 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| | 28 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| | 29 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| | 30 | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| | 31 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| | 32 | .\" SUCH DAMAGE. |
| | 33 | .\" |
| | 34 | .\" @(#)sync.2 8.1 (Berkeley) 6/4/93 |
| | 35 | .\" |
| | 36 | .Dd June 4, 1993 |
| | 37 | .Dt SYNC 2 |
| | 38 | .Os BSD 4 |
| | 39 | .Sh NAME |
| | 40 | .Nm sync |
| | 41 | .Nd "synchronize disk block in-core status with that on disk" |
| | 42 | .Sh SYNOPSIS |
| | 43 | .Fd #include <unistd.h> |
| | 44 | .Ft void |
| | 45 | .Fn sync void |
| | 46 | .Sh DESCRIPTION |
| | 47 | The |
| | 48 | .Fn sync |
| | 49 | function forces a write of dirty (modified) buffers |
| | 50 | in the block buffer cache out |
| | 51 | to disk. The kernel keeps this information in core to reduce |
| | 52 | the number of disk I/O transfers required by the system. |
| | 53 | As information in the cache is lost after a system crash a |
| | 54 | .Fn sync |
| | 55 | call is issued |
| | 56 | frequently |
| | 57 | by the user process |
| | 58 | .Xr update 8 |
| | 59 | (about every 30 seconds). |
| | 60 | .Pp |
| | 61 | The function |
| | 62 | .Xr fsync 2 |
| | 63 | may be used to synchronize individual file descriptor |
| | 64 | attributes. |
| | 65 | .Sh SEE ALSO |
| | 66 | .Xr fsync 2 , |
| | 67 | .Xr sync 8 , |
| | 68 | .Xr update 8 |
| | 69 | .Sh BUGS |
| | 70 | .Fn Sync |
| | 71 | may return before the buffers are completely flushed. |
| | 72 | .Sh HISTORY |
| | 73 | A |
| | 74 | .Fn sync |
| | 75 | function call appeared in |
| | 76 | .At v6 . |
projects / apple / xnu.git / blame_incremental