oracular (2) io_cancel.2.gz

NAME

       io_cancel - cancel an outstanding asynchronous I/O operation

LIBRARY

       Standard C library (libc, -lc)

       Alternatively, Asynchronous I/O library (libaio, -laio); see VERSIONS.

SYNOPSIS

       #include <linux/aio_abi.h>    /* Definition of needed types */
       #include <sys/syscall.h>      /* Definition of SYS_* constants */
       #include <unistd.h>

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

DESCRIPTION

       Note:  this  page describes the raw Linux system call interface.  The wrapper function provided by libaio
       uses a different type for the ctx_id argument.  See VERSIONS.

       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 VERSIONS.

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

       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.

STANDARDS

       Linux.

HISTORY

       Linux 2.5.

SEE ALSO

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