1.\" 2.\" Copyright 1989 AT&T Copyright (c) 1997, Sun Microsystems, Inc. All Rights Reserved 3.\" Copyright 2024 Oxide Computer Company 4.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License. 5.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License. 6.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 7.Dd July 2, 2024 8.Dt SYNC 2 9.Os 10.Sh NAME 11.Nm sync 12.Nd update super block 13.Sh SYNOPSIS 14.In unistd.h 15.Ft void 16.Fo sync 17.Fa void 18.Fc 19.Sh DESCRIPTION 20The 21.Fn sync 22function writes all information in memory that should be on disk, including 23modified super blocks, modified inodes, and delayed block I/O. 24.Pp 25Unlike 26.Xr fsync 3C , 27which completes the writing before it returns, 28.Fn sync 29schedules but does not necessarily complete the writing before returning. 30To perform a blocking synchronization of a single file system, use the 31.Xr syncfs 3C 32function. 33.Sh USAGE 34The 35.Fn sync 36function should be used by applications that examine a file system, such as 37.Xr fsck 8 , 38.Xr df 8 , 39and is mandatory before rebooting. 40.Sh INTERFACE STABILITY 41.Sy Committed 42.Sh SEE ALSO 43.Xr fsync 3C , 44.Xr syncfs 3C , 45.Xr attributes 7 , 46.Xr standards 7 , 47.Xr df 8 , 48.Xr fsck 8 49