io_cancel - cancel an outstanding asynchronous I/O operation
Standard C library (
libc,
-lc)
Alternatively, Asynchronous I/O library (
libaio,
-laio); see
NOTES.
#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);
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.
On success,
io_cancel() returns 0. For the failure return, see NOTES.
- 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.
The asynchronous I/O system calls first appeared in Linux 2.5.
io_cancel() is Linux-specific and should not be used in programs that are
intended to be portable.
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.
io_destroy(2),
io_getevents(2),
io_setup(2),
io_submit(2),
aio(7)