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AIO_FSYNC(3P)              POSIX Programmer's Manual             AIO_FSYNC(3P)
PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       aio_fsync -- asynchronous file synchronization
SYNOPSIS
       #include <aio.h>
       int aio_fsync(int op, struct aiocb *aiocbp);
DESCRIPTION
       The aio_fsync() function shall asynchronously perform a  file  synchro-
       nization operation, as specified by the op argument, for 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().  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  immedi-
       ately).
       If  op  is  O_DSYNC,  all currently queued I/O operations shall be com-
       pleted as if by a call to fdatasync(); that is, as defined for synchro-
       nized 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 outstanding I/O  opera-
       tions 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 opera-
       tion 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 Section 2.4.1,
       Signal Generation and Delivery when all operations have  achieved  syn-
       chronized 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  condi-
       tion, data is not guaranteed to have been successfully transferred.
RETURN VALUE
       The  aio_fsync() function shall return the value 0 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 tem-
              porary 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 The aio_fildes member of the aiocb structure refers to a file on
              which an fsync() operation is not possible.
       EINVAL A  value  of  op  other than O_DSYNC or O_SYNC was specified, or
              O_DSYNC was specified and the implementation  does  not  provide
              runtime support for the Synchronized Input and Output option, or
              O_SYNC was specified and the  implementation  does  not  provide
              runtime support for the File Synchronization option.
       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 operation,
       which can be retrieved using aio_error().
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       None.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       fcntl(), fdatasync(), fsync(), open(), read(), write()
       The Base Definitions volume of POSIX.1-2008, <aio.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) 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.unix.org/online.html .
       Any  typographical  or  formatting  errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files  to  man page format. To report such errors, see https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                        AIO_FSYNC(3P)