AIO_CANCEL(3)		   Linux Programmer's Manual		 AIO_CANCEL(3)



NAME
       aio_cancel - cancel an outstanding asynchronous I/O request

SYNOPSIS
       #include <aio.h>

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

       Link with -lrt.

DESCRIPTION
       The  aio_cancel()  function attempts to cancel outstanding asynchronous
       I/O requests for the file descriptor fd.	 If aiocbp is NULL,  all  such
       requests	 are  canceled.	  Otherwise, only the request described by the
       control block pointed to by aiocbp is  canceled.	  (See	aio(7)	for  a
       description of the aiocb structure.)

       Normal  asynchronous  notification  occurs  for	canceled requests (see
       aio(7) and sigevent(7)).	 The request return status (aio_return(3))  is
       set  to -1, and the request error status (aio_error(3)) is set to ECAN-
       CELED.  The control block of requests that cannot be  canceled  is  not
       changed.

       If  the	request	 could	not be canceled, then it will terminate in the
       usual  way  after  performing  the  I/O	operation.   (In  this	 case,
       aio_error(3) will return the status EINPROGRESSS.)

       If  aiocbp  is  not  NULL, and fd differs from 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 returns one of the following values:

       AIO_CANCELED
	      All requests were successfully canceled.

       AIO_NOTCANCELED
	      At  least one of the requests specified was not canceled because
	      it was in progress.  In this case, one may check the  status  of
	      individual requests using aio_error(3).

       AIO_ALLDONE
	      All requests had already been completed before the call.

       -1     An  error	 occurred.   The  cause	 of  the error can be found by
	      inspecting errno.

ERRORS
       EBADF  fd is not a valid file descriptor.

       ENOSYS aio_cancel() is not implemented.

VERSIONS
       The aio_cancel() function is available since glibc 2.1.

ATTRIBUTES
       For  an	explanation  of	 the  terms  used   in	 this	section,   see
       attributes(7).

       +-------------+---------------+---------+
       |Interface    | Attribute     | Value   |
       +-------------+---------------+---------+
       |aio_cancel() | Thread safety | MT-Safe |
       +-------------+---------------+---------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

EXAMPLE
       See aio(7).

SEE ALSO
       aio_error(3), aio_fsync(3), aio_read(3), aio_return(3), aio_suspend(3),
       aio_write(3), lio_listio(3), aio(7)

COLOPHON
       This page is part of release 4.10 of the Linux  man-pages  project.   A
       description  of	the project, information about reporting bugs, and the
       latest	 version    of	  this	  page,	   can	   be	  found	    at
       https://www.kernel.org/doc/man-pages/.



				  2015-03-02			 AIO_CANCEL(3)