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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