aio_cancel(2)

NAME

aio_cancel - cancel an outstanding asynchronous I/O opera

tion (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 asyn

chronous I/O

request for the file descriptor specified in fildes. If

iocb is specified, only that specific asynchronous I/O request is can

celled.

Normal asynchronous notification occurs for cancelled re

quests. 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 al

ways return

AIO_NOTCANCELED for file descriptors associated with raw

disk devices.

RETURN VALUES

The aio_cancel() system call returns -1 to indicate an er

ror, 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.

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

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 FreeB

SD 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.

BSD January 19, 2000

BSD