NAME

       aio_fsync — asynchronous file synchronization (REALTIME)

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <aio.h>

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

DESCRIPTION

       The  aio_fsync()  system  call  allows  the calling process to move all modified data associated with the
       descriptor iocb->aio_fildes to a permanent storage  device.   The  call  returns  immediately  after  the
       synchronization  request  has  been  enqueued  to the descriptor; the synchronization may or may not have
       completed at the time the call returns.

       The op argument can only be set to O_SYNC to cause all currently queued I/O operations to be completed as
       if by a call to fsync(2).

       If _POSIX_PRIORITIZED_IO is defined, and the descriptor supports  it,  then  the  enqueued  operation  is
       submitted at a priority equal to that of the calling process minus iocb->aio_reqprio.

       The  iocb  pointer  may  be  subsequently used as an argument to aio_return() and aio_error() in order to
       determine return or error status for the enqueued operation while it is in progress.

       If the request could not be enqueued (generally due to  invalid  arguments),  the  call  returns  without
       having enqueued the request.

       The  iocb->aio_sigevent  structure  can  be used to request notification of the operation's completion as
       described in aio(4).

RESTRICTIONS

       The Asynchronous I/O Control Block structure pointed to by iocb must remain valid until the operation has
       completed.

       The asynchronous I/O control buffer iocb should be zeroed before the aio_fsync() call  to  avoid  passing
       bogus context information to the kernel.

       Modification of the Asynchronous I/O Control Block structure is not allowed while the request is queued.

RETURN VALUES

       The  aio_fsync()  function  returns the value 0 if successful; otherwise the value -1 is returned and the
       global variable errno is set to indicate the error.

ERRORS

       The aio_fsync() system call will fail if:

       [EAGAIN]           The request was not queued because of system resource limitations.

       [EINVAL]           The asynchronous notification method in iocb->aio_sigevent.sigev_notify is invalid  or
                          not supported.

       [EOPNOTSUPP]       Asynchronous  file  synchronization operations on the file descriptor iocb->aio_fildes
                          are unsafe and unsafe asynchronous I/O operations are disabled.

       [EINVAL]           A value of the op argument is not set to O_SYNC.

       The following conditions may be synchronously detected when the  aio_fsync()  system  call  is  made,  or
       asynchronously,  at  any  time thereafter.  If they are detected at call time, aio_fsync() returns -1 and
       sets errno appropriately; otherwise the aio_return() system call must be called, and will return -1,  and
       aio_error() must be called to determine the actual value that would have been returned in errno.

       [EBADF]            The iocb->aio_fildes argument is not a valid descriptor.

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

       If  the  request  is  successfully  enqueued,  but  subsequently  cancelled or an error occurs, the value
       returned by the aio_return() system call is per the read(2) and write(2)  system  calls,  and  the  value
       returned  by  the aio_error() system call is one of the error returns from the read(2) or write(2) system
       calls.

SEE ALSO

       aio_cancel(2),   aio_error(2),   aio_read(2),   aio_return(2),    aio_suspend(2),    aio_waitcomplete(2),
       aio_write(2), fsync(2), sigevent(3), siginfo(3), aio(4)

STANDARDS

       The aio_fsync() system call is expected to conform to the IEEE Std 1003.1 (“POSIX.1”) standard.

HISTORY

       The aio_fsync() system call first appeared in FreeBSD 7.0.

Debian                                           August 19, 2016                                    AIO_FSYNC(2)