NAME

       io_cancel - cancel an outstanding asynchronous I/O operation

SYNOPSIS

       #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.

DESCRIPTION

       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.

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.

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.  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.

SEE ALSO

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

COLOPHON

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