SYNC(2) BSD System Calls Manual SYNC(2)
NAME
sync -- synchronize disk block in-core status with that on disk
SYNOPSIS
#include <unistd.h>
void
sync(void);
DESCRIPTION
The sync() function 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()
call is issued frequently by the user process update(8) (about every 30 seconds).
The function fsync(2) may be used to synchronize individual file descriptor attributes.
SEE ALSO
fsync(2), sync(8), update(8)
BUGS
Sync() may return before the buffers are completely flushed.
HISTORY
A sync() function call appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution June 4, 1993 4th Berkeley Distribution
