linux 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);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       sync():
	   _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

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

ERRORS
       This function is always successful.

CONFORMING TO
       SVr4, 4.3BSD, POSIX.1-2001.

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.

BUGS
       According to the standard specification (e.g., POSIX.1-2001), sync() schedules the writes, but may return  before  the  actual  writing	is
       done.   However,  since	version  1.3.20  Linux does actually wait.  (This still does not guarantee data integrity: modern disks have large
       caches.)

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

COLOPHON
       This page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2010-09-20								   SYNC(2)