opensolaris man page for fsync

fsync(3C)						   Standard C Library Functions 						 fsync(3C)

NAME
       fsync - synchronize changes to a file

SYNOPSIS
       #include <unistd.h>

       int fsync(int fildes);

DESCRIPTION
       The  fsync()  function  moves all modified data and attributes of the file descriptor fildes to a storage device. When fsync() returns, all
       in-memory modified copies of buffers associated with fildes have been written to the physical medium. The  fsync()  function  is  different
       from sync(), which schedules disk I/O for all files  but returns before the I/O completes. The fsync() function forces all outstanding data
       operations to synchronized file integrity completion (see fcntl.h(3HEAD) definition of O_SYNC.)

       The fsync() function forces all currently queued I/O operations associated with the file indicated by the file  descriptor  fildes  to  the
       synchronized I/O completion state. All I/O operations are completed as defined for synchronized I/O file integrity completion.

RETURN VALUES
       Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error. If the fsync() function fails,
       outstanding I/O operations are not guaranteed to have been completed.

ERRORS
       The fsync() function will fail if:

       EBADF	    The fildes argument is not a valid file descriptor.

       EINTR	    A signal was caught during execution of the fsync() function.

       EIO	    An I/O error occurred while reading from or writing to the file system.

       ENOSPC	    There was no free space remaining on the device containing the file.

       ETIMEDOUT    Remote connection timed out. This occurs when the file is  on  an	NFS  file  system  mounted  with  the	soft  option.  See
		    mount_nfs(1M).

       In the event that any of the queued I/O operations fail, fsync() returns the error conditions defined for read(2) and write(2).

USAGE
       The fsync() function should be used by applications that require that a file be in a known state. For example, an application that contains
       a simple transaction facility might use	fsync() to ensure that all changes to a file or files caused by a given transaction were  recorded
       on a storage medium.

       The  manner  in	which  the  data reach the physical medium depends on both implementation and hardware.  The fsync() function returns when
       notified by the device driver that the write has taken place.

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

SEE ALSO
       mount_nfs(1M), read(2), sync(2), write(2), fcntl.h(3HEAD), fdatasync(3C), attributes(5), standards(5)

SunOS 5.11							    5 Feb 2008								 fsync(3C)