1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>websocket::stream::async_close</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="../../../index.html" title="Chapter 1. Boost.Beast"> 8<link rel="up" href="../boost__beast__websocket__stream.html" title="websocket::stream"> 9<link rel="prev" href="close/overload2.html" title="websocket::stream::close (2 of 2 overloads)"> 10<link rel="next" href="ping.html" title="websocket::stream::ping"> 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="close/overload2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__websocket__stream.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="ping.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h5 class="title"> 27<a name="beast.ref.boost__beast__websocket__stream.async_close"></a><a class="link" href="async_close.html" title="websocket::stream::async_close">websocket::stream::async_close</a> 28</h5></div></div></div> 29<p> 30 <a class="indexterm" name="idm46057518860416"></a> 31 </p> 32<p> 33 Send a websocket close control frame asynchronously. 34 </p> 35<h6> 36<a name="beast.ref.boost__beast__websocket__stream.async_close.h0"></a> 37 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_close.synopsis"></a></span><a class="link" href="async_close.html#beast.ref.boost__beast__websocket__stream.async_close.synopsis">Synopsis</a> 38 </h6> 39<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 40 <span class="keyword">class</span> <span class="identifier">CloseHandler</span> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span><a class="link" href="executor_type.html" title="websocket::stream::executor_type">executor_type</a><span class="special">>></span> 41<a href="../../../../../../../doc/html/boost_asio/reference/asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type" target="_top"><span class="emphasis"><em>DEDUCED</em></span></a> 42<span class="identifier">async_close</span><span class="special">(</span> 43 <span class="identifier">close_reason</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">cr</span><span class="special">,</span> 44 <span class="identifier">CloseHandler</span><span class="special">&&</span> <span class="identifier">handler</span> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span> <a class="link" href="executor_type.html" title="websocket::stream::executor_type">executor_type</a> <span class="special">>{});</span> 45</pre> 46<h6> 47<a name="beast.ref.boost__beast__websocket__stream.async_close.h1"></a> 48 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_close.description"></a></span><a class="link" href="async_close.html#beast.ref.boost__beast__websocket__stream.async_close.description">Description</a> 49 </h6> 50<p> 51 This function is used to asynchronously send a <a href="https://tools.ietf.org/html/rfc6455#section-5.5.1" target="_top">close 52 frame</a>, which begins the websocket closing handshake. The session 53 ends when both ends of the connection have sent and received a close frame. 54 This call always returns immediately. The asynchronous operation will continue 55 until one of the following conditions is true: 56 </p> 57<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 58<li class="listitem"> 59 The close frame finishes sending. 60 </li> 61<li class="listitem"> 62 An error occurs. 63 </li> 64</ul></div> 65<p> 66 The algorithm, known as a <span class="emphasis"><em>composed asynchronous operation</em></span>, 67 is implemented in terms of calls to the next layer's <code class="computeroutput"><span class="identifier">async_write_some</span></code> 68 function. No other operations except for message reading operations should 69 be initiated on the stream after a close operation is started. After beginning 70 the closing handshake, the program should not write further message data, 71 pings, or pongs. Instead, the program should continue reading message data 72 until an error occurs. A read returning <a class="link" href="../boost__beast__websocket__error.html" title="websocket::error"><code class="computeroutput"><span class="identifier">error</span><span class="special">::</span><span class="identifier">closed</span></code></a> indicates a successful 73 connection closure. 74 </p> 75<h6> 76<a name="beast.ref.boost__beast__websocket__stream.async_close.h2"></a> 77 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_close.parameters"></a></span><a class="link" href="async_close.html#beast.ref.boost__beast__websocket__stream.async_close.parameters">Parameters</a> 78 </h6> 79<div class="informaltable"><table class="table"> 80<colgroup> 81<col> 82<col> 83</colgroup> 84<thead><tr> 85<th> 86 <p> 87 Name 88 </p> 89 </th> 90<th> 91 <p> 92 Description 93 </p> 94 </th> 95</tr></thead> 96<tbody> 97<tr> 98<td> 99 <p> 100 <code class="computeroutput"><span class="identifier">cr</span></code> 101 </p> 102 </td> 103<td> 104 <p> 105 The reason for the close. If the close reason specifies a close 106 code other than beast::websocket::close_code::none, the close 107 frame is sent with the close code and optional reason string. 108 Otherwise, the close frame is sent with no payload. 109 </p> 110 </td> 111</tr> 112<tr> 113<td> 114 <p> 115 <code class="computeroutput"><span class="identifier">handler</span></code> 116 </p> 117 </td> 118<td> 119 <p> 120 The completion handler to invoke when the operation completes. 121 The implementation takes ownership of the handler by performing 122 a decay-copy. The equivalent function signature of the handler 123 must be: 124 </p> 125<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span> 126 <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">ec</span> <span class="comment">// Result of operation</span> 127<span class="special">);</span> 128</pre> 129 <p> 130 Regardless of whether the asynchronous operation completes immediately 131 or not, the handler will not be invoked from within this function. 132 Invocation of the handler will be performed in a manner equivalent 133 to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>. 134 </p> 135 </td> 136</tr> 137</tbody> 138</table></div> 139<h6> 140<a name="beast.ref.boost__beast__websocket__stream.async_close.h3"></a> 141 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.async_close.see_also"></a></span><a class="link" href="async_close.html#beast.ref.boost__beast__websocket__stream.async_close.see_also">See 142 Also</a> 143 </h6> 144<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> 145 <a href="https://tools.ietf.org/html/rfc6455#section-7.1.2" target="_top">Websocket 146 Closing Handshake (RFC6455)</a> 147 </li></ul></div> 148</div> 149<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 150<td align="left"></td> 151<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 152 Falco<p> 153 Distributed under the Boost Software License, Version 1.0. (See accompanying 154 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>) 155 </p> 156</div></td> 157</tr></table> 158<hr> 159<div class="spirit-nav"> 160<a accesskey="p" href="close/overload2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__websocket__stream.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="ping.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 161</div> 162</body> 163</html> 164
