trusty (3) aio_cancel.3posix.gz

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NAME
       aio_cancel - cancel an asynchronous I/O request (REALTIME)


SYNOPSIS
       #include <aio.h>

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


DESCRIPTION
       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 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
       [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.


RETURN VALUE
       The  aio_cancel()  function  shall  return the value AIO_CANCELED to the calling process 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.


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
       The  aio_cancel()  function is part of the Asynchronous Input and Output option and need not be available
       on all implementations.


RATIONALE
       None.


FUTURE DIRECTIONS
       None.


SEE ALSO
       aio_read() , aio_write() , the Base Definitions volume of IEEE Std 1003.1-2001, <aio.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 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 http://www.opengroup.org/unix/online.html .