redhat man page for sync

SYNC(2) 						     Linux Programmer's Manual							   SYNC(2)

NAME
       sync - commit buffer cache to disk.

SYNOPSIS
       #include <unistd.h>

       void sync(void);

DESCRIPTION
       sync first commits inodes to buffers, and then buffers to disk.

CONFORMING TO
       SVr4, SVID, X/OPEN, BSD 4.3

BUGS
       According  to the standard specification (e.g., SVID), sync() schedules the writes, but may return before the actual writing is done.  How-
       ever, since version 1.3.20 Linux does actually wait.  (This still does not guarantee data integrity: modern disks have large caches.)

NOTES
       Since glibc 2.2.2 the Linux prototype is as listed above, following the various standards. In libc4, libc5, and glibc up to  2.2.1  it  was
       "int sync(void)", and sync always returned 0.

SEE ALSO
       bdflush(2), fsync(2), fdatasync(2), update(8), sync(8)

Linux 2.4							    2001-10-10								   SYNC(2)