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.TH AIO_CANCEL "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"

.SH PROLOG

This manual page is part of the POSIX Programmer's Manual.

The Linux implementation of this interface may differ (consult

the corresponding Linux manual page for details of Linux behavior),

or the interface may not be implemented on Linux.

.SH NAME

aio_cancel

\(em cancel an asynchronous I/O request

.SH SYNOPSIS

.LP

.nf

#include <aio.h>

.P

int aio_cancel(int \fIfildes\fP, struct aiocb *\fIaiocbp\fP);

.fi

.SH DESCRIPTION

The

\fIaio_cancel\fR()

function shall attempt to cancel one or more asynchronous I/O requests

currently outstanding against file descriptor

.IR fildes .

The

.IR aiocbp

argument points to the asynchronous I/O control block for a particular

request to be canceled. If

.IR aiocbp

is NULL, then all outstanding cancelable asynchronous I/O requests

against

.IR fildes

shall be canceled.

.P

Normal asynchronous notification shall occur for asynchronous I/O

operations that are successfully canceled. If there are requests that

cannot be canceled, then the normal asynchronous completion process

shall take place for those requests when they are completed.

.P

For requested operations that are successfully canceled, the associated

error status shall be set to

.BR [ECANCELED] 

and the return status shall be \(mi1. For requested operations that are

not successfully canceled, the

.IR aiocbp

shall not be modified by

\fIaio_cancel\fR().

.P

If

.IR aiocbp

is not NULL, then if

.IR fildes

does not have the same value as the file descriptor with which the

asynchronous operation was initiated, unspecified results occur.

.P

Which operations are cancelable is implementation-defined.

.SH "RETURN VALUE"

The

\fIaio_cancel\fR()

function shall return the value AIO_CANCELED

if the requested operation(s) were canceled.

The value AIO_NOTCANCELED

shall be returned if at least one of the requested operation(s) cannot

be canceled because it is in progress. In this case, the state of the

other operations, if any, referenced in the call to

\fIaio_cancel\fR()

is not indicated by the return value of

\fIaio_cancel\fR().

The application may determine the state of affairs for these operations

by using

\fIaio_error\fR().

The value AIO_ALLDONE

is returned if all of the operations have already completed.

Otherwise, the function shall return \(mi1 and set

.IR errno

to indicate the error.

.SH ERRORS

The

\fIaio_cancel\fR()

function shall fail if:

.TP

.BR EBADF

The

.IR fildes

argument is not a valid file descriptor.

.LP

.IR "The following sections are informative."

.SH EXAMPLES

None.

.SH "APPLICATION USAGE"

None.

.SH RATIONALE

None.

.SH "FUTURE DIRECTIONS"

None.

.SH "SEE ALSO"

.IR "\fIaio_read\fR\^(\|)",

.IR "\fIaio_write\fR\^(\|)"

.P

The Base Definitions volume of POSIX.1\(hy2008,

.IR "\fB<aio.h>\fP"

.SH COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form

from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology

-- Portable Operating System Interface (POSIX), The Open Group Base

Specifications Issue 7, Copyright (C) 2013 by the Institute of

Electrical and Electronics Engineers, Inc and The Open Group.

(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the

event of any discrepancy between this version and the original IEEE and

The Open Group Standard, the original IEEE and The Open Group Standard

is the referee document. The original Standard can be obtained online at

http://www.unix.org/online.html .

Any typographical or formatting errors that appear

in this page are most likely

to have been introduced during the conversion of the source files to

man page format. To report such errors, see

https://www.kernel.org/doc/man-pages/reporting_bugs.html .