aio_fsync.2 (2010 09)

a
aio_fsync(2) aio_fsync(2)
NAME
aio_fsync() - force outstanding asynchronous operations on a file to the synchronized state
SYNOPSIS
#include <aio.h>
int aio_fsync(int op, struct aiocb *aiocbp);
DESCRIPTION
The aio_fsync() function asynchronously forces all I/O operations that are enqueued at the time of
the call for the file or device referenced by
aiocbp->aio_fildes
to the synchronized I/O state. The
function call returns when the synchronization request has been enqueued to the file or device (even
when the data cannot be synchronized immediately).
Successful completion of the
aio_fsync() request indicates that all modified data for
aiocbp-
>fildes has been moved to a permanent storage device. The
aio_fsync() function affects only those
asynchronous I/O operations enqueued at the time of the call. Subsequently enqueued operations are not
included in the synchronizing operation.
The
aio_fsync() function supports synchronized I/O for regular files, block special files, and character
special files.
If the
op is O_DSYNC, all currently enqueued asynchronous I/O operations for aiocbp->fildes
are
completed as if by a call to
fdatasync(). All data is forced to permanent storage but the meta-data
(such as modification times) for the file descriptor is not necessarily updated. If the
op is O_SYNC, all
currently enqueued asynchronous I/O operations for
aiocbp->fildes
are completed as if by a call to
fsync(). All data is forced to permanent storage and the file descriptor metadata is updated.
If an
aio_fsync() request is issued for a file when there is already a pending aio_fsync()
request,
the first request is treated as though it were part of the second, and the second request will not complete
until the first has completed.
The
aio_fsync() function returns when the fsync request has been enqueued for the referenced file or
device. The aio_error() and aio_return() functions must be used to retrieve the status of the
synchronization operation via the
aiocb referenced by aiocbp. The status returned will be EINPRO-
GRESS until the last operation addressed by the initial request completes. If all operations complete suc-
cessfully, the error status will be 0 (zero). Otherwise, the error status will be the error status that will be
returned for the read or write operation that failed.
If
aiocbp->aio_sigevent
is a valid signal event structure, then the designated signal will be
delivered when the requested synchronization operation completes, either when all subject requests have
completed successfully or when any one of the requests has failed.
To use this function, link in the realtime library by specifying
-lrt on the compiler or linker command
line.
RETURN VALUE
If the
aio_fsync() function fails, -1 is returned and errno is set to indicate the error.
ERRORS
If
aio_fsync() detects one of the following error conditions, errno is set to the indicated value:
[EAGAIN] The request could not be queued because a per-process or system-wide limit on
asynchronous I/O operations or asynchronous threads would have been exceeded.
[EBADF] The
aiocbp->aio_fildes is not a valid file descriptor open for writing.
[EINVAL] Synchronized I/O is not supported for the file specified by
aiocbp->aio_fildes
.
[EINVAL] The
aiocb->aio_sigevent is not a valid address in the process virtual address
space.
[EINVAL] The parameters of the indicated
sigevent in aiocb->aio_sigevent are
invalid.
SEE ALSO
aio_cancel(2), aio_error(2), aio_read(2), aio_return(2), aio_suspend(2), aio_write(2), fdatasync(2), fsync(2),
lio_listio(2), read(2), write(2), aio(5).
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1