1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>websocket::stream::read_some (2 of 4 overloads)</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="../read_some.html" title="websocket::stream::read_some"> 9<link rel="prev" href="overload1.html" title="websocket::stream::read_some (1 of 4 overloads)"> 10<link rel="next" href="overload3.html" title="websocket::stream::read_some (3 of 4 overloads)"> 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="overload1.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../read_some.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="overload3.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h6 class="title"> 27<a name="beast.ref.boost__beast__websocket__stream.read_some.overload2"></a><a class="link" href="overload2.html" title="websocket::stream::read_some (2 of 4 overloads)">websocket::stream::read_some 28 (2 of 4 overloads)</a> 29</h6></div></div></div> 30<p> 31 Read some message data. 32 </p> 33<h7><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.h0"></a> 34 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.synopsis"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__websocket__stream.read_some.overload2.synopsis">Synopsis</a> 35 </h7><pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 36 <span class="keyword">class</span> <a class="link" href="../../../concepts/DynamicBuffer.html" title="DynamicBuffer"><span class="emphasis"><em>DynamicBuffer</em></span></a><span class="special">></span> 37<span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> 38<span class="identifier">read_some</span><span class="special">(</span> 39 <span class="identifier">DynamicBuffer</span><span class="special">&</span> <span class="identifier">buffer</span><span class="special">,</span> 40 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">limit</span><span class="special">,</span> 41 <span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">ec</span><span class="special">);</span> 42</pre> 43<h7><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.h1"></a> 44 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.description"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__websocket__stream.read_some.overload2.description">Description</a> 45 </h7><p> 46 This function is used to read some message data. The call blocks until 47 one of the following is true: 48 </p> 49<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 50<li class="listitem"> 51 Some message data is received. 52 </li> 53<li class="listitem"> 54 A close frame is received. In this case the error indicated by the 55 function will be <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>. 56 </li> 57<li class="listitem"> 58 An error occurs. 59 </li> 60</ul></div> 61<p> 62 The algorithm, known as a <span class="emphasis"><em>composed operation</em></span>, is 63 implemented in terms of calls to the next layer's <code class="computeroutput"><span class="identifier">read_some</span></code> 64 and <code class="computeroutput"><span class="identifier">write_some</span></code> functions. 65 Received message data is appended to the buffer. The functions <a class="link" href="../got_binary.html" title="websocket::stream::got_binary"><code class="computeroutput"><span class="identifier">got_binary</span></code></a> and <a class="link" href="../got_text.html" title="websocket::stream::got_text"><code class="computeroutput"><span class="identifier">got_text</span></code></a> may be used to query 66 the stream and determine the type of the last received message. The function 67 <a class="link" href="../is_message_done.html" title="websocket::stream::is_message_done"><code class="computeroutput"><span class="identifier">is_message_done</span></code></a> may be called 68 to determine if the message received by the last read operation is complete. 69 Until the call returns, the implementation will read incoming control 70 frames and handle them automatically as follows: 71 </p> 72<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 73<li class="listitem"> 74 The <a class="link" href="../control_callback/overload1.html" title="websocket::stream::control_callback (1 of 2 overloads)"><code class="computeroutput"><span class="identifier">control_callback</span></code></a> will be 75 invoked for each control frame. 76 </li> 77<li class="listitem"> 78 For each received ping frame, a pong frame will be automatically 79 sent. 80 </li> 81<li class="listitem"> 82 If a close frame is received, the WebSocket closing handshake is 83 performed. In this case, when the function returns, the error <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> will be indicated. 84 </li> 85</ul></div> 86<h7><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.h2"></a> 87 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.return_value"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__websocket__stream.read_some.overload2.return_value">Return 88 Value</a> 89 </h7><p> 90 The number of message payload bytes appended to the buffer. 91 </p> 92<h7><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.h3"></a> 93 <span class="phrase"><a name="beast.ref.boost__beast__websocket__stream.read_some.overload2.parameters"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__websocket__stream.read_some.overload2.parameters">Parameters</a> 94 </h7><div class="informaltable"><table class="table"> 95<colgroup> 96<col> 97<col> 98</colgroup> 99<thead><tr> 100<th> 101 <p> 102 Name 103 </p> 104 </th> 105<th> 106 <p> 107 Description 108 </p> 109 </th> 110</tr></thead> 111<tbody> 112<tr> 113<td> 114 <p> 115 <code class="computeroutput"><span class="identifier">buffer</span></code> 116 </p> 117 </td> 118<td> 119 <p> 120 A dynamic buffer to append message data to. 121 </p> 122 </td> 123</tr> 124<tr> 125<td> 126 <p> 127 <code class="computeroutput"><span class="identifier">limit</span></code> 128 </p> 129 </td> 130<td> 131 <p> 132 An upper limit on the number of bytes this function will append 133 into the buffer. If this value is zero, then a reasonable size 134 will be chosen automatically. 135 </p> 136 </td> 137</tr> 138<tr> 139<td> 140 <p> 141 <code class="computeroutput"><span class="identifier">ec</span></code> 142 </p> 143 </td> 144<td> 145 <p> 146 Set to indicate what error occurred, if any. 147 </p> 148 </td> 149</tr> 150</tbody> 151</table></div> 152</div> 153<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 154<td align="left"></td> 155<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 156 Falco<p> 157 Distributed under the Boost Software License, Version 1.0. (See accompanying 158 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>) 159 </p> 160</div></td> 161</tr></table> 162<hr> 163<div class="spirit-nav"> 164<a accesskey="p" href="overload1.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../read_some.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="overload3.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 165</div> 166</body> 167</html> 168
