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AIO_CANCEL(3P)             POSIX Programmer's Manual            AIO_CANCEL(3P)
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.
NAME
       aio_cancel -- cancel an asynchronous I/O request
SYNOPSIS
       #include <aio.h>
       int aio_cancel(int fildes, struct aiocb *aiocbp);
DESCRIPTION
       The aio_cancel() function shall attempt to cancel one or more asynchro-
       nous I/O requests currently outstanding against file descriptor fildes.
       The aiocbp argument points to the asynchronous I/O control block for  a
       particular  request  to  be  canceled. If aiocbp is NULL, then all out-
       standing cancelable asynchronous I/O requests against fildes  shall  be
       canceled.
       Normal asynchronous notification shall occur for asynchronous I/O oper-
       ations that are successfully canceled. If there are requests that  can-
       not  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 [ECANCELED] and the return status shall be
       -1. For requested operations that are not  successfully  canceled,  the
       aiocbp shall not be modified by aio_cancel().
       If  aiocbp  is not NULL, then if fildes does not have the same value as
       the file descriptor with which the asynchronous  operation  was  initi-
       ated, unspecified results occur.
       Which operations are cancelable is implementation-defined.
RETURN VALUE
       The  aio_cancel()  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 aio_cancel() is not
       indicated by the return value of  aio_cancel().   The  application  may
       determine   the   state  of  affairs  for  these  operations  by  using
       aio_error().  The value AIO_ALLDONE is returned if all  of  the  opera-
       tions  have already completed.  Otherwise, the function shall return -1
       and set errno to indicate the error.
ERRORS
       The aio_cancel() function shall fail if:
       EBADF  The fildes argument is not a valid file descriptor.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       None.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       aio_read(), aio_write()
       The Base Definitions volume of POSIX.1-2008, <aio.h>
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 Electri-
       cal 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.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                       AIO_CANCEL(3P)