Provided by: manpages-posix-dev_2013a-2_all bug


       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.


       aio_cancel — cancel an asynchronous I/O request


       #include <aio.h>

       int aio_cancel(int fildes, struct aiocb *aiocbp);


       The  aio_cancel()  function  shall attempt to cancel one or more asynchronous 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  outstanding  cancelable  asynchronous  I/O  requests  against  fildes  shall  be

       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

       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 initiated, unspecified results occur.

       Which operations are cancelable is implementation-defined.


       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 operations have already completed.  Otherwise, the function shall return −1 and
       set errno to indicate the error.


       The aio_cancel() function shall fail if:

       EBADF  The fildes argument is not a valid file descriptor.

       The following sections are informative.










       aio_read(), aio_write()

       The Base Definitions volume of POSIX.1‐2008, <aio.h>


       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 .

       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 .