AIO_FSYNC(3) | Library Functions Manual | AIO_FSYNC(3)

# NAME

`aio_fsync` —
asynchronous data synchronization of file (REALTIME)

# LIBRARY

POSIX Real-time Library (librt, -lrt)

# 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.

# 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.

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`.

# SEE ALSO

fcntl(2), fdatasync(2), fsync(2), aio(3)

# STANDARDS

The `aio_fsync`() system call is expected to conform to the IEEE Std 1003.1-2001 (“POSIX.1”) standard.

# HISTORY

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

May 17, 2010 | NetBSD 9.0