io_setup(2) - Linux manual page (original) (raw)
iosetup(2) System Calls Manual iosetup(2)
NAME top
io_setup - create an asynchronous I/O contextLIBRARY top
Standard C library (_libc_, _-lc_)
Alternatively, Asynchronous I/O library (_libaio_, _-laio_); see
VERSIONS.SYNOPSIS top
**#include <linux/aio_abi.h>** /* Defines needed types */
**long io_setup(unsigned int** _nrevents_**, aio_context_t ***_ctxidp_**);**
_Note_: There is no glibc wrapper for this system call; see
VERSIONS.DESCRIPTION top
_Note_: this page describes the raw Linux system call interface.
The wrapper function provided by _libaio_ uses a different type for
the _ctxidp_ argument. See VERSIONS.
The **io_setup**() system call creates an asynchronous I/O context
suitable for concurrently processing _nrevents_ operations. The
_ctxidp_ 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, _*ctxidp_ is filled in with
the resulting handle.RETURN VALUE top
On success, **io_setup**() returns 0. For the failure return, see
VERSIONS.ERRORS top
**EAGAIN** The specified _nrevents_ exceeds the limit of available
events, as defined in _/proc/sys/fs/aio-max-nr_ (see
[proc(5)](../man5/proc.5.html)).
**EFAULT** An invalid pointer is passed for _ctxidp_.
**EINVAL** _ctxidp_ is not initialized, or the specified _nrevents_
exceeds internal limits. _nrevents_ should be greater than
0.
**ENOMEM** Insufficient kernel resources are available.
**ENOSYS io_setup**() is not implemented on this architecture.VERSIONS top
glibc does not provide a wrapper for this system call. You could
invoke it using [syscall(2)](../man2/syscall.2.html). 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
(_iocontextt *_) for the _ctxidp_ 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)](../man2/syscall.2.html), then the return value follows the
usual conventions for indicating an error: -1, with _[errno](../man3/errno.3.html)_ set to a
(positive) value that indicates the error.STANDARDS top
Linux.HISTORY top
Linux 2.5.SEE ALSO top
[io_cancel(2)](../man2/io%5Fcancel.2.html), [io_destroy(2)](../man2/io%5Fdestroy.2.html), [io_getevents(2)](../man2/io%5Fgetevents.2.html), [io_submit(2)](../man2/io%5Fsubmit.2.html), [aio(7)](../man7/aio.7.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 iosetup(2)
Pages that refer to this page:fork(2), io_cancel(2), io_destroy(2), io_getevents(2), io_submit(2), syscalls(2), proc_sys_fs(5), systemd.exec(5), aio(7)