Tribblix: manual page: aio

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

NAME

aio_fsync - asynchronous file synchronization

SYNOPSIS

#include <aio.h>

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

DESCRIPTION

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.

RETURN VALUES

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.

ERRORS

The aio_fsync() function will fail if:

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

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

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

EINVAL
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).

USAGE

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

ATTRIBUTES