sync(S)

sync -- update super block

Syntax

cc ... -lc

void sync ()

Description

The sync system call causes all information in memory that should be on disk to be written out. This includes modified super blocks, modified inodes, and delayed block I/O.

It should be used by programs which examine a filesystem, for example, fsck, df, and so on. It is mandatory before a reboot.

The writing, although scheduled, is not necessarily complete upon return from sync.

Standards conformance

sync is not part of any currently supported standard; it was developed by UNIX System Laboratories, Inc. and is maintained by The SCO Group.