aio_write(2)

NAME

aio_write - asynchronous write to a file (REALTIME)

Standard C Library (libc, -lc)

#include <aio.h>
int
aio_write(struct aiocb *iocb);

The aio_write() system call allows the calling process to
write
iocb->aio_nbytes from the buffer pointed to by iocb->aio_buf
to the
descriptor iocb->aio_fildes. The call returns immediately
after the write request has been enqueued to the descriptor; the write
may or may not have completed at the time the call returns. If the re
quest could not be enqueued, generally due to invalid arguments, the
call returns without having enqueued the request.
If O_APPEND is set for iocb->aio_fildes, aio_write() opera
tions append to the file in the same order as the calls were made. If O_AP
PEND is not set for the file descriptor, the write operation will occur
at the absolute position from the beginning of the file plus
iocb->aio_offset.
If _POSIX_PRIORITIZED_IO is defined, and the descriptor sup
ports 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 is successfully enqueued, the value of
iocb->aio_offset
can be modified during the request as context, so this value
must not be referenced after the request is enqueued.

The aio_write() system call will fail if:

[EAGAIN] The request was not queued because of
system resource: limitations.
[ENOSYS] The aio_write() system call is not sup
ported.
The following conditions may be synchronously detected when
the
aio_write() system call is made, or asynchronously, at any
time thereafter. If they are detected at call time, aio_write() re
turns -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 invalid,
or is not: opened for writing.
[EINVAL] The offset iocb->aio_offset is not valid,
the priority: specified by iocb->aio_reqprio is not a; valid priority, or the number of bytes specified by
iocb->aio_nbytes is not valid.
If the request is successfully enqueued, but subsequently
canceled or an
error occurs, the value returned by the aio_return() system
call is per the write(2) system call, and the value returned by the
aio_error() system call is either one of the error returns from the
write(2) system call, or one of:
[EBADF] The iocb->aio_fildes argument is invalid
for writing.
[ECANCELED] The request was explicitly canceled via a
call to: aio_cancel().
[EINVAL] The offset iocb->aio_offset would be in
valid.

The aio_write() system call first appeared in FreeBSD 3.0.