IO_CANCEL(2)

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 ctx_id argument is the AIO context ID of the operation 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.

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
This page is part of release 3.50 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/.