io_cancel

IO_CANCEL(2)                Linux Programmer's Manual               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
       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 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.

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 5.10 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.



Linux                              2020-12-21                       IO_CANCEL(2)