.\"
.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for
.\" permission to reproduce portions of its copyrighted documentation.
.\" Original documentation from The Open Group can be obtained online at
.\" http://www.opengroup.org/bookstore/.
.\"
.\" The Institute of Electrical and Electronics Engineers and The Open
.\" Group, have given us permission to reprint portions of their
.\" documentation.
.\"
.\" In the following statement, the phrase ``this text'' refers to portions
.\" of the system documentation.
.\"
.\" Portions of this text are reprinted and reproduced in electronic form
.\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
.\" Standard for Information Technology -- Portable Operating System
.\" Interface (POSIX), The Open Group Base Specifications Issue 6,
.\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
.\" Engineers, Inc and The Open Group.  In the event of any discrepancy
.\" between these versions and the original IEEE and The Open Group
.\" Standard, the original IEEE and The Open Group Standard is the referee
.\" document.  The original Standard can be obtained online at
.\" http://www.opengroup.org/unix/online.html.
.\"
.\" This notice shall appear on any product containing this material.
.\"
.\" The contents of this file are subject to the terms of the
.\" Common Development and Distribution License (the "License").
.\" You may not use this file except in compliance with the License.
.\"
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
.\" or http://www.opensolaris.org/os/licensing.
.\" See the License for the specific language governing permissions
.\" and limitations under the License.
.\"
.\" When distributing Covered Code, include this CDDL HEADER in each
.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
.\" If applicable, add the following below this CDDL HEADER, with the
.\" fields enclosed by brackets "[]" replaced with your own identifying
.\" information: Portions Copyright [yyyy] [name of copyright owner]
.\"
.\"
.\" Copyright 1989 AT&T
.\" Portions Copyright (c) 1992, X/Open Company Limited  All Rights Reserved
.\" Copyright (c) 2008, Sun Microsystems, Inc.  All Rights Reserved
.\"
.TH AIO_RETURN 3C "Feb 5, 2008"
.SH NAME
aio_return \- retrieve return status of an asynchronous I/O operation
.SH SYNOPSIS
.LP
.nf
#include <aio.h>

\fBssize_t\fR \fBaio_return\fR(\fBstruct aiocb *\fR\fIaiocbp\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBaio_return()\fR function returns the return status associated with the
\fBaiocb\fR structure referenced by the \fIaiocbp\fR argument. The return
status for an asynchronous I/O operation is the value that would be returned by
the corresponding \fBread\fR(2), \fBwrite\fR(2), or \fBfsync\fR(3C) function
call. If the error status for the operation is equal to \fBEINPROGRESS\fR, then
the return status for the operation is undefined. The \fBaio_return()\fR
function may be called exactly once to retrieve the return status of a given
asynchronous operation; thereafter, if the same \fBaiocb\fR structure is used
in a call to \fBaio_return()\fR or \fBaio_error\fR(3C), an error may be
returned. When the \fBaiocb\fR structure referred to by \fIaiocbp\fR is used to
submit another asynchronous operation, then \fBaio_return()\fR may be
successfully used to retrieve the return status of that operation.
.SH RETURN VALUES
.sp
.LP
If the asynchronous I/O operation has completed, then the return status, as
described for \fBread\fR(2), \fBwrite\fR(2), and \fBfsync\fR(3C), is returned.
If the asynchronous I/O operation has not yet completed, the results of
\fBaio_return()\fR are undefined.
.SH ERRORS
.sp
.LP
The \fBaio_return()\fR function will fail if:
.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
The \fIaiocbp\fR argument does not refer to an asynchronous operation whose
return status has not yet been retrieved.
.RE

.sp
.ne 2
.na
\fB\fBENOSYS\fR\fR
.ad
.RS 10n
The \fBaio_return()\fR function is not supported by the system.
.RE

.SH USAGE
.sp
.LP
The \fBaio_return()\fR function has a transitional interface for 64-bit file
offsets.  See \fBlf64\fR(5).
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
_
MT-Level	Async-Signal-Safe
_
Standard	See \fBstandards\fR(5).
.TE

.SH SEE ALSO
.sp
.LP
\fBclose\fR(2), \fBexec\fR(2), \fBexit\fR(2), \fBfork\fR(2), \fBlseek\fR(2),
\fBread\fR(2), \fBwrite\fR(2), \fBfsync\fR(3C), \fBaio.h\fR(3HEAD),
\fBsignal.h\fR(3HEAD), \fBaio_cancel\fR(3C), \fBaio_fsync\fR(3C),
\fBaio_read\fR(3C), \fBlio_listio\fR(3C), \fBattributes\fR(5), \fBlf64\fR(5),
\fBstandards\fR(5)
.SH NOTES
.sp
.LP
Solaris 2.6 was the first release to support the Asynchronous Input and Output
option. Prior to this release, this function always returned \fB\(mi1\fR and
set \fBerrno\fR to \fBENOSYS\fR.