AIO_FSYNC(3C)AIO_FSYNC(3C)NAMEaio_fsync - asynchronous file synchronization
int aio_fsync(int op, struct aiocb *aiocbp);
The aio_fsync() function asynchronously forces all I/O operations asso‐
ciated 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 can‐
not 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 opera‐
tions 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 sta‐
tus, respectively, of the asynchronous operation while it is proceed‐
ing. 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 sig‐
nal.h(3HEAD)). All other members of the structure referenced by aiocbp
are ignored. If the control block referenced by aiocbp becomes an ille‐
gal address prior to asynchronous I/O completion, then the behavior is
If the aio_fsync() function fails or the aiocbp indicates an error con‐
dition, 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(5).
See attributes(5) for descriptions of the following attributes:
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
│Interface Stability │ Committed │
│MT-Level │ MT-Safe │
│Standard │ See standards(5). │
SEE ALSOfcntl(2), open(2), read(2), write(2), aio_error(3C), aio_return(3C),
aio.h(3HEAD), fcntl.h(3HEAD), fdatasync(3C), fsync(3C), sig‐
nal.h(3HEAD), attributes(5), lf64(5), standards(5)
Feb 5, 2008 AIO_FSYNC(3C)