sync(2) [sunos man page]

sync(2) 							   System Calls 							   sync(2)

NAME

       sync - update super block

SYNOPSIS

       #include <unistd.h>

       void sync(void);

DESCRIPTION

       The  sync() function writes all information in memory that should be on disk, including modified super blocks, modified inodes, and delayed
       block I/O.

       Unlike fsync(3C), which completes the writing before it returns, sync() schedules but does not  necessarily  complete  the  writing  before
       returning.

USAGE

       The  sync()  function  should  be  used	by  applications that examine a file system, such as fsck(1M), and df(1M), and is mandatory before
       rebooting.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       df(1M), fsck(1M), fsync(3C), attributes(5), standards(5)

SunOS 5.10							    5 Jul 1990								   sync(2)

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)