.\" Copyright (C) 2003 Free Software Foundation, Inc.
+.\"
+.\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
.\" This file is distributed according to the GNU General Public License.
-.\" See the file COPYING in the top level source directory for details.
+.\" %%%LICENSE_END
.\"
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-.TH IO_SETUP 2 2008-06-18 "Linux" "Linux Programmer's Manual"
+.TH IO_SETUP 2 2013-06-21 "Linux" "Linux Programmer's Manual"
.SH NAME
io_setup \- create an asynchronous I/O context
-.SH "SYNOPSIS"
+.SH SYNOPSIS
.nf
-.\" .ad l
-.\" .hy 0
-.B #include <libaio.h>
-.\" #include <linux/aio.h>
-.sp
-.\" .HP 15
-.BI "int io_setup(unsigned " nr_events ", aio_context_t *" ctxp );
-.\" .ad
-.\" .hy
-.sp
-Link with \fI\-laio\fP.
+.BR "#include <linux/aio_abi.h>" " /* Defines needed types */"
+
+.BI "int io_setup(unsigned " nr_events ", aio_context_t *" ctx_idp );
.fi
-.SH "DESCRIPTION"
+
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
+.SH DESCRIPTION
.PP
+The
.BR io_setup ()
-creates an asynchronous I/O context capable of receiving
-at least \fInr_events\fP.
-\fIctxp\fP must not point to an AIO context that already exists, and must
+system call
+creates an asynchronous I/O context suitable for concurrently processing
+\fInr_events\fP operations.
+The
+.I 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, \fI*ctxp\fP is filled in
+On successful creation of the AIO context, \fI*ctx_idp\fP is filled in
with the resulting handle.
-.SH "RETURN VALUE"
+.SH RETURN VALUE
On success,
.BR io_setup ()
returns 0.
For the failure return, see NOTES.
-.SH "ERRORS"
+.SH ERRORS
.TP
.B EAGAIN
-The specified \fInr_events\fP exceeds the user's limit of available events.
+The specified \fInr_events\fP exceeds the user's limit of available events,
+as defined in
+.IR /proc/sys/fs/aio-max-nr .
.TP
.B EFAULT
-An invalid pointer is passed for \fIctxp\fP.
+An invalid pointer is passed for \fIctx_idp\fP.
.TP
.B EINVAL
-\fIctxp\fP is not initialized, or the specified \fInr_events\fP
+\fIctx_idp\fP is not initialized, or the specified \fInr_events\fP
exceeds internal limits.
\fInr_events\fP should be greater than 0.
.TP
.B ENOSYS
.BR io_setup ()
is not implemented on this architecture.
-.SH "VERSIONS"
+.SH VERSIONS
.PP
-The asynchronous I/O system calls first appeared in Linux 2.5, August 2002.
-.SH "CONFORMING TO"
+The asynchronous I/O system calls first appeared in Linux 2.5.
+.SH CONFORMING TO
.PP
.BR io_setup ()
is Linux-specific and should not be used in programs
that are intended to be portable.
.SH NOTES
Glibc does not provide a wrapper function for this system call.
+You could invoke it using
+.BR syscall (2).
+But instead, you probably want to use the
+.BR io_setup ()
+wrapper function provided by
+.\" http://git.fedorahosted.org/git/?p=libaio.git
+.IR libaio .
-The wrapper provided in
+Note that the
.I libaio
-for
-.BR io_setup ()
-does not follow the usual C library conventions for indicating error:
+wrapper function uses a different type
+.RI ( "io_context_t\ *" )
+.\" But glibc is confused, since <libaio.h> uses 'io_context_t' to declare
+.\" the system call.
+for the
+.I ctx_idp
+argument.
+Note also that the
+.I 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
indicating an error: \-1, with
.I errno
set to a (positive) value that indicates the error.
-.SH "SEE ALSO"
+.SH SEE ALSO
.BR io_cancel (2),
.BR io_destroy (2),
.BR io_getevents (2),
.BR io_submit (2),
.BR aio (7)
-.\" .SH "NOTES"
-.\" .PP
-.\" The asynchronous I/O system calls were written by Benjamin LaHaise.
.\" .SH AUTHOR
.\" Kent Yoder.
+.SH COLOPHON
+This page is part of release 3.79 of the Linux
+.I man-pages
+project.
+A description of the project,
+information about reporting bugs,
+and the latest version of this page,
+can be found at
+\%http://www.kernel.org/doc/man\-pages/.