NAME

       aio_fsync - asynchronous file synchronization (REALTIME)

SYNOPSIS

       #include <aio.h>

       int aio_fsync(int op, struct aiocb *aiocbp);

DESCRIPTION

       The aio_fsync() function shall asynchronously force all I/O operations associated with the file indicated
       by  the  file  descriptor  aio_fildes member of the aiocb structure referenced by the aiocbp argument and
       queued at the time of the call to aio_fsync() 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).

       If  op is O_DSYNC, all currently queued I/O operations shall be completed as if by a call to fdatasync();
       that is, as defined for synchronized I/O data integrity completion. If op is O_SYNC, 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 aio_fsync() function fails, or if the operation queued by aio_fsync()
       fails, then, as for fsync() and fdatasync(), outstanding I/O operations are not guaranteed to  have  been
       completed.

       If  aio_fsync()  succeeds, then it is only the I/O that was queued at the time of the call to aio_fsync()
       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 synchronized fashion.

       The aiocbp argument refers to an asynchronous I/O control block.  The aiocbp value  may  be  used  as  an
       argument  to  aio_error()  and  aio_return()  in  order  to determine the error status and return status,
       respectively, of the asynchronous operation while it is proceeding. When the request is queued, the error
       status for the operation is [EINPROGRESS].  When all data has been successfully  transferred,  the  error
       status  shall  be  reset  to  reflect the success or failure of the operation.  If the operation does not
       complete successfully, the error status for the operation shall  be  set  to  indicate  the  error.   The
       aio_sigevent  member  determines the asynchronous notification to occur as specified in Signal Generation
       and Delivery when all operations have achieved synchronized I/O completion.  All  other  members  of  the
       structure referenced by aiocbp are ignored.  If the control block referenced by aiocbp becomes an illegal
       address prior to asynchronous I/O completion, then the behavior is undefined.

       If  the aio_fsync() function fails or aiocbp indicates an error condition, data is not guaranteed to have
       been successfully transferred.

RETURN VALUE

       The aio_fsync() function shall return the value 0  to  the  calling  process  if  the  I/O  operation  is
       successfully  queued;  otherwise,  the  function  shall return the value -1 and set errno to indicate the
       error.

ERRORS

       The aio_fsync() function shall fail if:

       EAGAIN The requested asynchronous operation was not queued due to temporary resource limitations.

       EBADF  The aio_fildes member of the aiocb structure referenced by the aiocbp argument is not a valid file
              descriptor open for writing.

       EINVAL This implementation does not support synchronized I/O for this file.

       EINVAL A value of op other than O_DSYNC or O_SYNC was specified.

       In the event that any of the queued I/O operations fail, aio_fsync() shall  return  the  error  condition
       defined  for  read() and write().  The error is returned in the error status for the asynchronous fsync()
       operation, which can be retrieved using aio_error().

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The aio_fsync() function is part of the Asynchronous Input and Output option and need not be available on
       all implementations.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       fcntl() , fdatasync() ,  fsync()  ,  open()  ,  read()  ,  write()  ,  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <aio.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                                   2003                                          AIO_FSYNC(P)