debian man page for io_prep_fsync

io_prep_fsync(3)						       Linux							  io_prep_fsync(3)

NAME
       io_prep_fsync - Synchronize a file's complete in-core state with that on disk

SYNOPSYS
       #include <errno.h>

       #include <libaio.h>

       static inline void io_prep_fsync(struct iocb *iocb, int fd);

       struct iocb {
	    void      *data;
	    unsigned  key;
	    short	   aio_lio_opcode;
	    short	   aio_reqprio;
	    int       aio_fildes;
       };

DESCRIPTION
       This is an inline convenience function for setting up an iocbv for a FSYNC request.
       The file for which

       iocb->aio_fildes = fd
	      is a descriptor is set up with the command

       iocb->aio_lio_opcode = IO_CMD_FSYNC

       The  io_prep_fsync()  function  shall  set up an IO_CMD_FSYNC operation to asynchronously force all I/O operations associated with the file
       indicated by the file descriptor aio_fildes member of the iocb structure referenced by the iocb argument and queued at the time of the call
       to io_submit() to the synchronized I/O completion state. The function call shall return when the synchronization request has been initiated
       or queued to the file or device (even when the data cannot be synchronized immediately).

       All currently queued I/O operations shall be completed as if by a call to fsync(); that is, as defined for synchronized I/O file  integrity
       completion.  If	the operation queued by io_prep_fsync() fails, then, as for fsync(), outstanding I/O operations are not guaranteed to have
       been completed.

       If io_prep_fsync() succeeds, then it is only the I/O that was queued at the time of the call to io_submit() that is guaranteed to be forced
       to  the	relevant completion state. The completion of subsequent I/O on the file descriptor is not guaranteed to be completed in a synchro-
       nized fashion.

       This function returns immediately. To schedule the operation, the function io_submit must be called.

       Simultaneous asynchronous operations using the same iocb produce undefined results.

RETURN VALUES
       None.

ERRORS
       None.

SEE ALSO
       io(3),  io_cancel(3),   io_fsync(3),   io_getevents(3),	 io_prep_pread(3),   io_prep_pwrite(3),   io_queue_init(3),   io_queue_release(3),
       io_queue_run(3), io_queue_wait(3), io_set_callback(3), io_submit(3), errno(3).

Linux 2.4							    2009-06-10							  io_prep_fsync(3)