Section: POSIX Programmer's Manual (3P)
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.
--- cancel an asynchronous I/O request
int aio_cancel(int fildes, struct aiocb *aiocbp);
function shall attempt to cancel one or more asynchronous I/O requests
currently outstanding against file descriptor
argument points to the asynchronous I/O control block for a particular
request to be canceled. If
is NULL, then all outstanding cancelable asynchronous I/O requests
shall be canceled.
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.
For requested operations that are successfully canceled, the associated
error status shall be set to
and the return status shall be -1. For requested operations that are
not successfully canceled, the
shall not be modified by
is not NULL, then if
does not have the same value as the file descriptor with which the
asynchronous operation was initiated, unspecified results occur.
Which operations are cancelable is implementation-defined.
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
is not indicated by the return value of
The application may determine the state of affairs for these operations
The value AIO_ALLDONE
is returned if all of the operations have already completed.
Otherwise, the function shall return -1 and set
to indicate the error.
function shall fail if:
argument is not a valid file descriptor.
The following sections are informative.
The Base Definitions volume of POSIX.1-2017,
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
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
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