AIO_FSYNC(3)

NAME
aio_fsync - asynchronous data synchronization of file (REALTIME)

LIBRARY
librt

SYNOPSIS
#include <aio.h>
int
aio_fsync(int op, struct aiocb *aiocbp);

DESCRIPTION
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 descriptor; 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 operation is submitted at a priority equal to that of the calling process minus aiocbp-aio_reqprio.

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 progress.

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

Modifications of the Asynchronous I/O Control Block structure after the request has been enqueued, but before the request has completed, are not allowed.

RETURN VALUES

ERRORS
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.

[EINVAL]
    The op argument is neither set to O_DSYNC nor O_SYNC.

SEE ALSO
fcntl(2), fdatasync(2), fsync(2), aio_error(3), aio_read(3), aio_write(3)

STANDARDS
The aio_fsync() system call is expected to conform to the p1003.1-2001 standard.

HISTORY
The aio_fsync() system call first appeared in NetBSD 5.0.