io_cancel(2) System Calls Manual io_cancel(2)
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 oper-
ation previously submitted with io_submit(2). The iocb argument de-
scribes the operation to be canceled and the ctx_id argument is the AIO
context to which the operation was submitted. If the operation is suc-
cessfully 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 VER-
SIONS.
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_con-
text_t) for the ctx_id argument. Note also that the libaio wrapper does
not follow the usual C library conventions for indicating errors: on er-
ror 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)
Linux man-pages 6.9.1 2024-05-02 io_cancel(2)
Generated by dwww version 1.16 on Tue Dec 16 04:03:59 CET 2025.