AIO_CANCEL(2)

NAME
aio_cancel - cancel an outstanding asynchronous I/O operation (REALTIME)

LIBRARY
libc

SYNOPSIS
#include <aio.h>
int
aio_cancel(int fildes, struct aiocb *aiocbp);

DESCRIPTION
The aio_cancel() system call cancels the outstanding asynchronous I/O request for the file descriptor specified in fildes. If aiocbp is specified, only that specific asynchronous I/O request is cancelled.

Normal asynchronous notification occurs for cancelled requests. Requests complete with an error result of ECANCELED.

RESTRICTIONS
The aio_cancel() system call does not cancel asynchronous I/O requests for raw disk devices. The aio_cancel() system call will always return AIO_NOTCANCELED for file descriptors associated with raw disk devices.

RETURN VALUES
The aio_cancel() system call returns -1 to indicate an error, or one of the following:

[AIO_ALLDONE]
    All of the requests meeting the criteria have finished.

[AIO_CANCELED]
    All outstanding requests meeting the criteria specified were cancelled.

[AIO_NOTCANCELED]
    Some requests were not cancelled, status for the requests should be checked with aio_error(2).

ERRORS
An error return from aio_cancel() indicates:

[EBADF]
    The fildes argument is not a valid file descriptor.

SEE ALSO
aio_error(2), aio_read(2), aio_return(2), aio_suspend(2), aio_write(2), aio(4)

STANDARDS
The aio_cancel() system call is expected to conform to the p1003.1 standard.

HISTORY
The aio_cancel() system call first appeared in FreeBSD 3.0. The first functional implementation of aio_cancel() appeared in FreeBSD 4.0.

AUTHORS
-nosplit This manual page was originally written by Wes Peters <wes@softweyr.com>. Christopher M Sedore <cmsedore@maxwell.syr.edu> updated it when aio_cancel() was implemented for FreeBSD 4.0.