AIO_FSYNC(3C) Standard C Library Functions AIO_FSYNC(3C)


aio_fsync - asynchronous file synchronization


#include <aio.h>

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


The aio_fsync() function asynchronously forces all 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() to the synchronized I/O
completion state. The function call returns when the synchronization
request has been initiated or queued to the file or device (even when the
data cannot be synchronized immediately).

If op is O_DSYNC, all currently queued I/O operations are completed as if
by a call to fdatasync(3C); that is, as defined for synchronized I/O data
integrity completion. If op is O_SYNC, all currently queued I/O
operations are completed as if by a call to fsync(3C); 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, as for fsync(3C) and fdatasync(3C), outstanding I/O
operations 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(3C) and
aio_return(3C) 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 will be
reset to reflect the success or failure of the operation. If the
operation does not complete successfully, the error status for the
operation will be set to indicate the error. The aio_sigevent member
determines the asynchronous notification to occur when all operations
have achieved synchronized I/O completion (see signal.h(3HEAD)). 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 the aiocbp indicates an error
condition, data is not guaranteed to have been successfully transferred.

If aiocbp is NULL, then no status is returned in aiocbp, and no signal is
generated upon completion of the operation.


The aio_fsync() function returns 0 to the calling process if the I/O
operation is successfully queued; otherwise, the function returns -1 and
sets errno to indicate the error.


The aio_fsync() function will fail if:

The requested asynchronous operation was not queued due to
temporary resource limitations.

The aio_fildes member of the aiocb structure referenced by the
aiocbp argument is not a valid file descriptor open for

The system does not support synchronized I/O for this file.

A value of op other than O_DSYNC or O_SYNC was specified.

In the event that any of the queued I/O operations fail, aio_fsync()
returns the error condition defined for read(2) and write(2). The error
will be returned in the error status for the asynchronous fsync(3C)
operation, which can be retrieved using aio_error(3C).


The aio_fsync() function has a transitional interface for 64-bit file
offsets. See lf64(7).


See attributes(7) for descriptions of the following attributes:

|Interface Stability | Committed |
|MT-Level | MT-Safe |
|Standard | See standards(7). |


fcntl(2), open(2), read(2), write(2), aio_error(3C), aio_return(3C),
fdatasync(3C), fsync(3C), aio.h(3HEAD), fcntl.h(3HEAD), signal.h(3HEAD),
attributes(7), lf64(7), standards(7)

February 5, 2008 AIO_FSYNC(3C)