MirBSD manpage: sync(2)
SYNC(2) BSD Programmer's Manual SYNC(2)
sync - synchronize disk block in-core status with that on disk
#include <unistd.h>
void
sync(void);
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 in-
formation in the cache is lost after a system crash a sync() call is is-
sued frequently by the in-kernel process update(8) (about every 30
seconds).
The function fsync(2) may be used to synchronize individual file descrip-
tor attributes.
fsync(2), sync(8), update(8)
A sync() function call appeared in Version 2 AT&T UNIX.
sync() may return before the buffers are completely flushed.
MirBSD #10-current June 4, 1993 1