IO_CANCEL

Section: Linux Programmer's Manual (2)
Updated: 2008-06-18
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NAME

io_cancel - cancel an outstanding asynchronous I/O operation

SYNOPSIS

#include <libaio.h>

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

Link with -laio.

DESCRIPTION

io_cancel() attempts to cancel an asynchronous I/O operation previously submitted with io_submit(2). ctx_id 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, August 2002.

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.

The wrapper provided in libaio for io_cancel() does not follow the usual C library conventions for indicating error: 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.

COLOPHON

This page is part of release 3.22 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/.