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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2004 IEEE and The Open Group, All Rights Reserved --><title>aio_return</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="aio_return"></a> <a name="tag_03_18"></a><!-- aio_return --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2004 Edition<br>Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_18_01"></a>NAME</h4><blockquote>aio_return - retrieve return status of an asynchronous I/O operation (<b>REALTIME</b>)</blockquote><h4><a name="tag_03_18_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('AIO')">AIO</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> #include <<a href="../basedefs/aio.h.html">aio.h</a>><br><br> ssize_t aio_return(struct aiocb *</tt><i>aiocbp</i><tt>); <img src="../images/opt-end.gif" alt="[Option End]" border="0"></tt></code></div><tt><br></tt></blockquote><h4><a name="tag_03_18_03"></a>DESCRIPTION</h4><blockquote><p>The <i>aio_return</i>() function shall return the return status associated with the <b>aiocb</b> structure referenced by the<i>aiocbp</i> argument. The return status for an asynchronous I/O operation is the value that would be returned by thecorresponding <a href="../functions/read.html"><i>read</i>()</a>, <a href="../functions/write.html"><i>write</i>()</a>, or <a href="../functions/fsync.html"><i>fsync</i>()</a> function call. If the error status for the operation is equal to [EINPROGRESS], thenthe return status for the operation is undefined. The <i>aio_return</i>() function may be called exactly once to retrieve thereturn status of a given asynchronous operation; thereafter, if the same <b>aiocb</b> structure is used in a call to<i>aio_return</i>() or <a href="../functions/aio_error.html"><i>aio_error</i>()</a>, an error may be returned. When the<b>aiocb</b> structure referred to by <i>aiocbp</i> is used to submit another asynchronous operation, then <i>aio_return</i>() maybe successfully used to retrieve the return status of that operation.</p></blockquote><h4><a name="tag_03_18_04"></a>RETURN VALUE</h4><blockquote><p>If the asynchronous I/O operation has completed, then the return status, as described for <a href="../functions/read.html"><i>read</i>()</a>, <a href="../functions/write.html"><i>write</i>()</a>, and <a href="../functions/fsync.html"><i>fsync</i>()</a>, shall be returned. If the asynchronous I/O operation has not yet completed, theresults of <i>aio_return</i>() are undefined.</p></blockquote><h4><a name="tag_03_18_05"></a>ERRORS</h4><blockquote><p>The <i>aio_return</i>() function may fail if:</p><dl compact><dt>[EINVAL]</dt><dd>The <i>aiocbp</i> argument does not refer to an asynchronous operation whose return status has not yet been retrieved.</dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_18_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_18_07"></a>APPLICATION USAGE</h4><blockquote><p>The <i>aio_return</i>() function is part of the Asynchronous Input and Output option and need not be available on allimplementations.</p></blockquote><h4><a name="tag_03_18_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_18_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_18_10"></a>SEE ALSO</h4><blockquote><p><a href="aio_cancel.html"><i>aio_cancel</i>()</a>, <a href="aio_error.html"><i>aio_error</i>()</a>, <a href="aio_fsync.html"><i>aio_fsync</i>()</a>, <a href="aio_read.html"><i>aio_read</i>()</a>, <a href="aio_write.html"><i>aio_write</i>()</a>, <a href="close.html"><i>close</i>()</a>, <a href="exec.html"><i><a href="../functions/exec.html">exec</a></i>()</a>, <a href="exit.html"><i>exit</i>()</a>, <a href="fork.html"><i>fork</i>()</a>, <ahref="lio_listio.html"><i>lio_listio</i>()</a>, <a href="lseek.html"><i>lseek</i>()</a>, <a href="read.html"><i>read</i>()</a>,the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/aio.h.html"><i><aio.h></i></a></p></blockquote><h4><a name="tag_03_18_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 5. Included for alignment with the POSIX Realtime Extension.</p></blockquote><h4><a name="tag_03_18_12"></a>Issue 6</h4><blockquote><p>The [ENOSYS] error condition has been removed as stubs need not be provided if an implementation does not support theAsynchronous Input and Output option.</p><p>The APPLICATION USAGE section is added.</p><p>The [EINVAL] error condition is made optional. This is for consistency with the DESCRIPTION.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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