NAME

aio_cancel —

cancel an outstanding asynchronous I/O operation (REALTIME)

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <aio.h>

int
aio_cancel(int fildes, struct aiocb *iocb);

DESCRIPTION

The aio_cancel() system call cancels the outstanding asynchronous I/O request for the file descriptor specified in fildes. If iocb 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_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).
[AIO_ALLDONE]: All of the requests meeting the criteria have finished.

ERRORS

An error return from aio_cancel() indicates:

[EBADF]: The fildes argument is an invalid file descriptor.

STANDARDS

The aio_cancel() system call is expected to conform to the IEEE Std 1003.1 (“POSIX.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

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.