io_setup
Section: System Calls (2)
Updated: 202-0-21
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NAME
io_setup - create an asynchronous I/O context
LIBRARY
Standard C library
(
libc,~
-lc)
Alternatively, Asynchronous I/O library
(
libaio,~
-laio);
see VERSIONS.
SYNOPSIS
#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.
DESCRIPTION
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.
RETURN VALUE
On success,
io_setup()
returns 0.
For the failure return, see VERSIONS.
ERRORS
- EAGAIN
-
The specified
nr_events
exceeds the limit of available events,
as defined in
/proc/sys/fs/aio-max-nr
(see
proc(5)).
- 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
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.
STANDARDS
Linux.
HISTORY
Linux 2.5.
SEE ALSO
io_cancel(2),
io_destroy(2),
io_getevents(2),
io_submit(2),
aio(7)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- STANDARDS
-
- HISTORY
-
- SEE ALSO
-
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