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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 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

Mac OS X 10.9.1 - Generated Mon Jan 6 18:32:23 CST 2014
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