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IO_CANCEL(2)		   Linux Programmer's Manual		  IO_CANCEL(2)

       io_cancel - cancel an outstanding asynchronous I/O operation

       #include <linux/aio_abi.h>	   /* Defines needed types */

       int io_cancel(aio_context_t ctx_id, struct iocb *iocb,
		     struct io_event *result);

       Note: There is no glibc wrapper for this system call; see NOTES.

       The  io_cancel()	 system	 call  attempts	 to cancel an asynchronous I/O
       operation previously submitted with io_submit(2).   The	iocb  argument
       describes  the  operation to be canceled and the ctx_id argument is the
       AIO context to which the operation was submitted.  If the operation  is
       successfully canceled, the event will be copied into the memory pointed
       to by result without being placed into the completion queue.

       On success, io_cancel() returns 0.  For the failure return, see NOTES.

       EAGAIN The iocb specified was not canceled.

       EFAULT One of the data structures points to invalid data.

       EINVAL The AIO context specified by ctx_id is invalid.

       ENOSYS io_cancel() is not implemented on this architecture.

       The asynchronous I/O system calls first appeared in Linux 2.5.

       io_cancel() is Linux-specific and should not be used in	programs  that
       are intended to be portable.

       Glibc  does  not	 provide a wrapper function for this system call.  You
       could invoke it using syscall(2).  But instead, you  probably  want  to
       use the io_cancel() wrapper function provided by libaio.

       Note  that  the	libaio wrapper function uses a different type (io_con-
       text_t) for the ctx_id argument.	 Note also  that  the  libaio  wrapper
       does  not follow the usual C library conventions for indicating errors:
       on error it returns a negated error number (the negative of one of  the
       values	listed	in  ERRORS).   If  the	system	call  is  invoked  via
       syscall(2), then the return value follows  the  usual  conventions  for
       indicating  an  error:  -1,  with  errno set to a (positive) value that
       indicates the error.

       io_destroy(2), io_getevents(2), io_setup(2), io_submit(2), aio(7)

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Linux				  2013-04-10			  IO_CANCEL(2)