.\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl)

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.TH AIO_CANCEL 3 2015-03-02  "" "Linux Programmer's Manual"

.SH NAME

aio_cancel \- cancel an outstanding asynchronous I/O request

.SH SYNOPSIS

.B "#include <aio.h>"

.PP

.BI "int aio_cancel(int " fd ", struct aiocb *" aiocbp );

.PP

Link with \fI\-lrt\fP.

.SH DESCRIPTION

The

.BR aio_cancel ()

function attempts to cancel outstanding asynchronous I/O requests

for the file descriptor

.IR fd .

If

.I aiocbp

is NULL, all such requests are canceled.

Otherwise, only the request

described by the control block pointed to by

.I aiocbp

is canceled.

(See

.BR aio (7)

for a description of the

.I aiocb

structure.)

.PP

Normal asynchronous notification occurs for canceled requests (see

.BR aio (7)

and

.BR sigevent (7)).

The request return status

.RB ( aio_return (3))

is set to \-1, and the request error status

.RB ( aio_error (3))

is set to

.BR ECANCELED .

The control block of requests that cannot be canceled is not changed.

.PP

If the request could not be canceled,

then it will terminate in the usual way after performing the I/O operation.

(In this case,

.BR aio_error (3)

will return the status

.BR EINPROGRESSS .)

.PP

If

.I aiocbp

is not NULL, and

.I fd

differs from the file descriptor with which the asynchronous operation

was initiated, unspecified results occur.

.PP

Which operations are cancelable is implementation-defined.

.\" FreeBSD: not those on raw disk devices.

.SH RETURN VALUE

The

.BR aio_cancel ()

function returns one of the following values:

.TP

.B AIO_CANCELED

All requests were successfully canceled.

.TP

.B AIO_NOTCANCELED

At least one of the

requests specified was not canceled because it was in progress.

In this case, one may check the status of individual requests using

.BR aio_error (3).

.TP

.B AIO_ALLDONE

All requests had already been completed before the call.

.TP

\-1

An error occurred.

The cause of the error can be found by inspecting

.IR errno .

.SH ERRORS

.TP

.B EBADF

.I fd

is not a valid file descriptor.

.TP

.B ENOSYS

.BR aio_cancel ()

is not implemented.

.SH VERSIONS

The

.BR aio_cancel ()

function is available since glibc 2.1.

.SH ATTRIBUTES

For an explanation of the terms used in this section, see

.BR attributes (7).

.TS

allbox;

lb lb lb

l l l.

Interface	Attribute	Value

T{

.BR aio_cancel ()

T}	Thread safety	MT-Safe

.TE

.SH CONFORMING TO

POSIX.1-2001, POSIX.1-2008.

.SH EXAMPLE

See

.BR aio (7).

.SH SEE ALSO

.BR aio_error (3),

.BR aio_fsync (3),

.BR aio_read (3),

.BR aio_return (3),

.BR aio_suspend (3),

.BR aio_write (3),

.BR lio_listio (3),

.BR aio (7)

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I man-pages

project.

A description of the project,

information about reporting bugs,

and the latest version of this page,

can be found at

\%https://www.kernel.org/doc/man\-pages/.