IO_CANCEL(2)		   Linux Programmers Manual		 IO_CANCEL(2)



NAME
       io_cancel - cancel an outstanding asynchronous I/O operation

SYNOPSIS
       #include 

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

       Link with -laio.

DESCRIPTION
       io_cancel() attempts to cancel an asynchronous I/O operation previously
       submitted with io_submit(2).  ctx_id is the AIO context ID of the oper
       ation  to  be canceled.	If the AIO context is found, the event will be
       canceled and then copied into the memory pointed to by  result  without
       being placed into the completion queue.

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

ERRORS
       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.

VERSIONS
       The asynchronous I/O system calls first appeared in Linux  2.5,	August
       2002.

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

NOTES
       Glibc does not provide a wrapper function for this system call.

       The wrapper provided in libaio for  io_cancel()	does  not  follow  the
       usual C library conventions for indicating error: 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.

SEE ALSO
       io_destroy(2), io_getevents(2), io_setup(2), io_submit(2)

COLOPHON
       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



Linux				  2008-06-18			  IO_CANCEL(2)