1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Requirements on asynchronous socket operations</title> 5<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../boost_asio.html" title="Boost.Asio"> 8<link rel="up" href="../reference.html" title="Reference"> 9<link rel="prev" href="synchronous_socket_operations.html" title="Requirements on synchronous socket operations"> 10<link rel="next" href="AcceptableProtocol.html" title="Acceptable protocol requirements"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td> 15<td align="center"><a href="../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="synchronous_socket_operations.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../boost_asio.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="AcceptableProtocol.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h3 class="title"> 27<a name="boost_asio.reference.asynchronous_socket_operations"></a><a class="link" href="asynchronous_socket_operations.html" title="Requirements on asynchronous socket operations">Requirements 28 on asynchronous socket operations</a> 29</h3></div></div></div> 30<p> 31 In this library, <span class="emphasis"><em>asynchronous socket operations</em></span> are 32 those member functions having prefix <code class="computeroutput">async_</code>. 33 </p> 34<p> 35 For an object <code class="computeroutput">s</code>, a program may initiate asynchronous socket 36 operations such that there are multiple simultaneously outstanding asynchronous 37 operations. 38 </p> 39<p> 40 When there are multiple outstanding asynchronous <a class="link" href="read_write_operations.html" title="Requirements on read and write operations">read 41 operations</a> on <code class="computeroutput">s</code>: 42 </p> 43<p> 44 — having no argument <code class="computeroutput">flags</code> of type <code class="computeroutput">socket_base::message_flags</code>, 45 or 46 </p> 47<p> 48 — having an argument <code class="computeroutput">flags</code> of type <code class="computeroutput">socket_base::message_flags</code> 49 but where <code class="computeroutput">(flags & socket_base::message_out_of_band) == 0</code> 50 </p> 51<p> 52 then the <code class="computeroutput">buffers</code> are filled in the order in which these operations 53 were issued. The order of invocation of the completion handlers for these 54 operations is unspecified. 55 </p> 56<p> 57 When there are multiple outstanding asynchronous <a class="link" href="read_write_operations.html" title="Requirements on read and write operations">read 58 operations</a> on <code class="computeroutput">s</code> having an argument <code class="computeroutput">flags</code> 59 of type <code class="computeroutput">socket_base::message_flags</code> where <code class="computeroutput">(flags & 60 socket_base::message_out_of_band) != 0</code> then the <code class="computeroutput">buffers</code> 61 are filled in the order in which these operations were issued. 62 </p> 63<p> 64 When there are multiple outstanding asynchronous <a class="link" href="read_write_operations.html" title="Requirements on read and write operations">write 65 operations</a> on <code class="computeroutput">s</code>, the <code class="computeroutput">buffers</code> are transmitted 66 in the order in which these operations were issued. The order of invocation 67 of the completion handlers for these operations is unspecified. 68 </p> 69</div> 70<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 71<td align="left"></td> 72<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 73 Kohlhoff<p> 74 Distributed under the Boost Software License, Version 1.0. (See accompanying 75 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 76 </p> 77</div></td> 78</tr></table> 79<hr> 80<div class="spirit-nav"> 81<a accesskey="p" href="synchronous_socket_operations.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../boost_asio.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="AcceptableProtocol.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 82</div> 83</body> 84</html> 85
