IO_SETUP
Section: Linux Programmer's Manual (2)
Updated: 2017-09-15
Index
Return to Main Contents
NAME
io_setup - create an asynchronous I/O context
SYNOPSIS
#include <linux/aio_abi.h> /* Defines needed types */
int io_setup(unsigned nr_events, aio_context_t *ctx_idp);
Note:
There is no glibc wrapper for this system call; see NOTES.
DESCRIPTION
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.
RETURN VALUE
On success,
io_setup()
returns 0.
For the failure return, see NOTES.
ERRORS
- EAGAIN
-
The specified nr_events exceeds the user's limit of available events,
as defined in
/proc/sys/fs/aio-max-nr.
- EFAULT
-
An invalid pointer is passed for ctx_idp.
- EINVAL
-
ctx_idp is not initialized, or the specified nr_events
exceeds internal limits.
nr_events should be greater than 0.
- ENOMEM
-
Insufficient kernel resources are available.
- ENOSYS
-
io_setup()
is not implemented on this architecture.
VERSIONS
The asynchronous I/O system calls first appeared in Linux 2.5.
CONFORMING TO
io_setup()
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_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.
SEE ALSO
io_cancel(2),
io_destroy(2),
io_getevents(2),
io_submit(2),
aio(7)
COLOPHON
This page is part of release 4.13 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
|
|
- Running on 
-
:
: 