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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 descrip-tor descriptor
     tor 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