io_cancel – cancel an outstanding asynchronous I/O operation


       io_cancel - cancel an outstanding asynchronous I/O operation


       #include           /* 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


       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_context_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)


       This page is part of release 3.55 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can
       be found at

Linux                            2013-04-10                     IO_CANCEL(2)