io_setup - create an asynchronous I/O context
Standard C library (libc, -lc)
Alternatively, Asynchronous I/O library (libaio,
-laio); see VERSIONS.
#include <linux/aio_abi.h> /* Defines needed types */
long io_setup(unsigned int nr_events, aio_context_t *ctx_idp);Note: There is no glibc wrapper for this system call; see
VERSIONS.
Note: this page describes the raw Linux system call
interface. The wrapper function provided by libaio uses a
different type for the ctx_idp argument. See VERSIONS.
The io_setup() system call creates an asynchronous
I/O context suitable for concurrently processing nr_events
operations. The ctx_idp argument must not point to an AIO
context that already exists, and must be initialized to 0 prior to the
call. On successful creation of the AIO context, *ctx_idp is
filled in with the resulting handle.
On success, io_setup() returns 0. For the failure return, see VERSIONS.
The specified nr_events exceeds the limit of available
events, as defined in /proc/sys/fs/aio-max-nr (see
proc(5)).
An invalid pointer is passed for ctx_idp.
ctx_idp is not initialized, or the specified
nr_events exceeds internal limits. nr_events should be
greater than 0.
Insufficient kernel resources are available.
io_setup() is not implemented on this architecture.
glibc does not provide a wrapper for this system call. You could
invoke it using syscall(2). But instead, you probably
want to use the io_setup() wrapper function provided by
libaio.
Note that the libaio wrapper function uses a different type
(io_context_t *) for the ctx_idp 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.
Linux.
Linux 2.5.
io_cancel(2), io_destroy(2), io_getevents(2), io_submit(2), aio(7)