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  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>
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  29 <p>
  30           <a class="indexterm" name="idm45873473274640"></a>
  31 Send a websocket close control frame asynchronously.
  32         </p>
  33 <h6>
  34 <a name="beast.ref.boost__beast__websocket__stream.async_close.h0"></a>
  35           <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>
  36         </h6>
  37 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
  38     <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">&lt;</span><span class="identifier">executor_type</span><span class="special">&gt;&gt;</span>
  39 <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>
  40 <span class="identifier">async_close</span><span class="special">(</span>
  41     <span class="identifier">close_reason</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">cr</span><span class="special">,</span>
  42     <span class="identifier">CloseHandler</span><span class="special">&amp;&amp;</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">&lt;</span> <span class="identifier">executor_type</span> <span class="special">&gt;{});</span>
  43 </pre>
  44 <h6>
  45 <a name="beast.ref.boost__beast__websocket__stream.async_close.h1"></a>
  46           <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>
  47         </h6>
  48 <p>
  49           This function is used to asynchronously send a <a href="https://tools.ietf.org/html/rfc6455#section-5.5.1" target="_top">close
  50           frame</a>, which begins the websocket closing handshake. The session
  51           ends when both ends of the connection have sent and received a close frame.
  52           This call always returns immediately. The asynchronous operation will continue
  53           until one of the following conditions is true:
  54         </p>
  55 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  56 <li class="listitem">
  57               The close frame finishes sending.
  58             </li>
  59 <li class="listitem">
  60               An error occurs.
  61             </li>
  62 </ul></div>
  63 <p>
  64           The algorithm, known as a <span class="emphasis"><em>composed asynchronous operation</em></span>,
  65           is implemented in terms of calls to the next layer's <code class="computeroutput"><span class="identifier">async_write_some</span></code>
  66           function. No other operations except for message reading operations should
  67           be initiated on the stream after a close operation is started. After beginning
  68           the closing handshake, the program should not write further message data,
  69           pings, or pongs. Instead, the program should continue reading message data
  70           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">websocket</span><span class="special">::</span><span class="identifier">closed</span></code></a> indicates a successful
  71           connection closure.
  72         </p>
  73 <h6>
  74 <a name="beast.ref.boost__beast__websocket__stream.async_close.h2"></a>
  75           <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>
  76         </h6>
  77 <div class="informaltable"><table class="table">
  78 <colgroup>
  79 <col>
  80 <col>
  81 </colgroup>
  82 <thead><tr>
  83 <th>
  84                   <p>
  85                     Name
  86                   </p>
  87                 </th>
  88 <th>
  89                   <p>
  90                     Description
  91                   </p>
  92                 </th>
  93 </tr></thead>
  94 <tbody>
  95 <tr>
  96 <td>
  97                   <p>
  98                     <code class="computeroutput"><span class="identifier">cr</span></code>
  99                   </p>
 100                 </td>
 101 <td>
 102                   <p>
 103                     The reason for the close. If the close reason specifies a close
 104                     code other than beast::websocket::close_code::none, the close
 105                     frame is sent with the close code and optional reason string.
 106                     Otherwise, the close frame is sent with no payload.
 107                   </p>
 108                 </td>
 109 </tr>
 110 <tr>
 111 <td>
 112                   <p>
 113                     <code class="computeroutput"><span class="identifier">handler</span></code>
 114                   </p>
 115                 </td>
 116 <td>
 117                   <p>
 118                     The completion handler to invoke when the operation completes.
 119                     The implementation takes ownership of the handler by performing
 120                     a decay-copy. The equivalent function signature of the handler
 121                     must be:
 122                   </p>
 123 <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>
 124     <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">ec</span>     <span class="comment">// Result of operation</span>
 125 <span class="special">);</span>
 126 </pre>
 127                   <p>
 128                     Regardless of whether the asynchronous operation completes immediately
 129                     or not, the handler will not be invoked from within this function.
 130                     Invocation of the handler will be performed in a manner equivalent
 131                     to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>.
 132                   </p>
 133                 </td>
 134 </tr>
 135 </tbody>
 136 </table></div>
 137 <h6>
 138 <a name="beast.ref.boost__beast__websocket__stream.async_close.h3"></a>
 139           <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
 140           Also</a>
 141         </h6>
 142 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
 143               <a href="https://tools.ietf.org/html/rfc6455#section-7.1.2" target="_top">Websocket
 144               Closing Handshake (RFC6455)</a>
 145             </li></ul></div>
 146 </div>
 147 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 148 <td align="left"></td>
 149 <td align="right"><div class="copyright-footer">Copyright &#169; 2016-2019 Vinnie
 150       Falco<p>
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 152         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>)
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