.\" Copyright (C) 2003 Free Software Foundation, Inc.
.\" This file is distributed according to the GNU General Public License.
.\" See the file COPYING in the top level source directory for details.
.\"
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.TH "IO_SETUP" 2 "2003-02-21" "Linux 2.4" "Linux Programmer's Manual"
.SH NAME
io_setup \- create an asynchronous I/O context
.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
.fi
.SH "DESCRIPTION"
.PP
\fBio_setup\fR() creates an asynchronous I/O context capable of receiving
at least \fInr_events\fR.
\fIctxp\fR 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\fR is filled in
with the resulting handle.
.SH "RETURN VALUE"
.PP
\fBio_setup\fR() returns 0 on success;
on failure, it returns one of the errors listed under ERRORS.
.SH "ERRORS"
.TP
.B EINVAL
\fIctxp\fR is not initialized, or the specified \fInr_events\fR
exceeds internal limits. \fInr_events\fR should be greater than 0.
.TP
.B EFAULT
An invalid pointer is passed for \fIctxp\fR.
.TP
.B ENOMEM
Insufficient kernel resources are available.
.TP
.B EAGAIN
The specified \fInr_events\fR exceeds the user's limit of available events.
.TP
.B ENOSYS
\fBio_setup\fR() is not implemented on this architecture.
.SH "CONFORMING TO"
.PP
\fBio_setup\fR() is Linux specific and should not be used in programs
that are intended to be portable.
.SH "VERSIONS"
.PP
The asynchronous I/O system calls first appeared in Linux 2.5, August 2002.
.SH "SEE ALSO"
.PP
\fBio_destroy\fR(2), \fBio_getevents\fR(2), \fBio_submit\fR(2),
\fBio_cancel\fR(2).
.\" .SH "NOTES"
.\" .PP
.\" The asynchronous I/O system calls were written by Benjamin LaHaise.
.\" .SH AUTHOR
.\" Kent Yoder.