NAME
aio_fsync —
asynchronous file synchronization
(REALTIME)
LIBRARY
library “libc”
SYNOPSIS
#include
<aio.h>
int
aio_fsync(int
op, struct aiocb
*iocb);
DESCRIPTION
Theaio_fsync()
system call allows the calling process to move all modified data associated
with the descriptor iocb->aio_fildes to a permanent
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.
The op argument can only be set to
O_SYNC to cause all currently queued I/O operations
to be completed as if by a call to
fsync(2).
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 iocb->aio_reqprio.
The iocb 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.
If the request could not be enqueued (generally due to invalid arguments), the call returns without having enqueued the request.
The iocb->aio_sigevent structure can be used to request notification of the operation's completion as described in aio(4).
RESTRICTIONS
The Asynchronous I/O Control Block structure pointed to by iocb must remain valid until the operation has completed.
The asynchronous I/O control buffer
iocb should be zeroed before the
aio_fsync()
call to avoid passing bogus context information to the kernel.
Modification of the Asynchronous I/O Control Block structure is not allowed while the request is queued.
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.
- [
EINVAL] - The asynchronous notification method in iocb->aio_sigevent.sigev_notify is invalid or not supported.
- [
EOPNOTSUPP] - Asynchronous file synchronization operations on the file descriptor iocb->aio_fildes are unsafe and unsafe asynchronous I/O operations are disabled.
- [
EINVAL] - A value of the op argument is not set to
O_SYNC.
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 iocb->aio_fildes argument is not a valid descriptor.
- [
EINVAL] - This implementation does not support synchronized I/O for this file.
If the request is successfully enqueued, but subsequently
cancelled or an error occurs, the value returned by the
aio_return() system call is per the
read(2) and
write(2) system calls, and the value returned by the
aio_error() system call is one of the error returns
from the read(2) or
write(2) system calls.
SEE ALSO
aio_cancel(2), aio_error(2), aio_read(2), aio_return(2), aio_suspend(2), aio_waitcomplete(2), aio_write(2), fsync(2), sigevent(3), siginfo(3), aio(4)
STANDARDS
The aio_fsync() system call is expected to
conform to the IEEE Std 1003.1
(“POSIX.1”) standard.
HISTORY
The aio_fsync() system call first appeared
in FreeBSD 7.0.