sync -- schedule file system updates
Standard C Library (libc, -lc)
The sync() system call 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 sync() system
call is issued frequently by the user process syncer(4) (about every 30
The fsync(2) system call may be used to synchronize individual file
fsync(2), syncer(4), sync(8)
The sync() system call may return before the buffers are completely
The sync() function appeared in Version 6 AT&T UNIX.
FreeBSD 5.2.1 June 4, 1993 FreeBSD 5.2.1 [ Back ]