NAME

     sync — schedule file system updates

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     void
     sync(void);

DESCRIPTION

     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 kernel process syncer(4) (about every 30
     seconds).

     The fsync(2) system call may be used to synchronize individual file descriptor attributes.

SEE ALSO

     fsync(2), syncer(4), sync(8)

HISTORY

     The sync() function appeared in Version 3 AT&T UNIX.

BUGS

     The sync() system call may return before the buffers are completely flushed.