AIO_FSYNC(3) BSD Library Functions Manual AIO_FSYNC(3)
aio_fsync -- asynchronous data synchronization of file (REALTIME)
POSIX Real-time Library (librt, -lrt)
aio_fsync(int op, struct aiocb *aiocbp);
The aio_fsync() system call allows the calling process to force all modified data associated
with the file descriptor aiocbp->aio_fildes to be flushed to the stable storage device. The
call returns immediately after the synchronization request has been enqueued to the descrip-
tor; the synchronization may or may not have completed at the time the call returns. If the
request could not be enqueued, generally due to invalid arguments, the call returns without
having enqueued the request.
The op argument could be set only to O_DSYNC or O_SYNC. If op is O_DSYNC, then aio_fsync()
does the same as a fdatasync() call, if O_SYNC, then the same as fsync().
If _POSIX_PRIORITIZED_IO is defined, and the descriptor supports it, then the enqueued oper-
ation is submitted at a priority equal to that of the calling process minus
The aiocbp 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
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.
The aio_fsync() system call will fail if:
[EAGAIN] The request was not queued because of system resource limitations.
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 aiocbp->aio_fildes is invalid for writing.
[EINVAL] This implementation does not support synchronized I/O for this file, or
the op argument is neither set to O_DSYNC nor O_SYNC.
fcntl(2), fdatasync(2), fsync(2), aio(3)
The aio_fsync() system call is expected to conform to the IEEE Std 1003.1-2001 (``POSIX.1'')
The aio_fsync() system call first appeared in NetBSD 5.0.
BSD May 17, 2010 BSD