1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>http::read (3 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="../boost__beast__http__read.html" title="http::read"> 9<link rel="prev" href="overload2.html" title="http::read (2 of 4 overloads)"> 10<link rel="next" href="overload4.html" title="http::read (4 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="overload2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__http__read.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="overload4.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__http__read.overload3"></a><a class="link" href="overload3.html" title="http::read (3 of 4 overloads)">http::read 28 (3 of 4 overloads)</a> 29</h5></div></div></div> 30<p> 31 Read a complete message from a stream. 32 </p> 33<h6> 34<a name="beast.ref.boost__beast__http__read.overload3.h0"></a> 35 <span class="phrase"><a name="beast.ref.boost__beast__http__read.overload3.synopsis"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__http__read.overload3.synopsis">Synopsis</a> 36 </h6> 37<p> 38 Defined in header <code class="literal"><<a href="../../../../../../../boost/beast/http/read.hpp" target="_top">boost/beast/http/read.hpp</a>></code> 39 </p> 40<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 41 <span class="keyword">class</span> <a href="../../../../../../../doc/html/boost_asio/reference/SyncReadStream.html" target="_top"><span class="emphasis"><em>SyncReadStream</em></span></a><span class="special">,</span> 42 <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> 43 <span class="keyword">bool</span> <span class="identifier">isRequest</span><span class="special">,</span> 44 <span class="keyword">class</span> <a class="link" href="../../concepts/Body.html" title="Body"><span class="emphasis"><em>Body</em></span></a><span class="special">,</span> 45 <span class="keyword">class</span> <a href="https://en.cppreference.com/w/cpp/named_req/Allocator" target="_top"><span class="emphasis"><em>Allocator</em></span></a><span class="special">></span> 46<span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> 47<span class="identifier">read</span><span class="special">(</span> 48 <span class="identifier">SyncReadStream</span><span class="special">&</span> <span class="identifier">stream</span><span class="special">,</span> 49 <span class="identifier">DynamicBuffer</span><span class="special">&</span> <span class="identifier">buffer</span><span class="special">,</span> 50 <span class="identifier">message</span><span class="special"><</span> <span class="identifier">isRequest</span><span class="special">,</span> <span class="identifier">Body</span><span class="special">,</span> <span class="identifier">basic_fields</span><span class="special"><</span> <span class="identifier">Allocator</span> <span class="special">>>&</span> <span class="identifier">msg</span><span class="special">);</span> 51</pre> 52<h6> 53<a name="beast.ref.boost__beast__http__read.overload3.h1"></a> 54 <span class="phrase"><a name="beast.ref.boost__beast__http__read.overload3.description"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__http__read.overload3.description">Description</a> 55 </h6> 56<p> 57 This function is used to read a complete message from a stream into an 58 instance of <a class="link" href="../boost__beast__http__message.html" title="http::message"><code class="computeroutput"><span class="identifier">message</span></code></a>. The call will block until 59 one of the following conditions is true: 60 </p> 61<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 62<li class="listitem"> 63 The entire message is read in. 64 </li> 65<li class="listitem"> 66 An error occurs. 67 </li> 68</ul></div> 69<p> 70 This operation is implemented in terms of one or more calls to the stream's 71 <code class="computeroutput"><span class="identifier">read_some</span></code> function. The 72 implementation may read additional bytes from the stream that lie past 73 the end of the message being read. These additional bytes are stored in 74 the dynamic buffer, which must be preserved for subsequent reads. If the 75 end of file error is received while reading from the stream, then the error 76 returned from this function will be: 77 </p> 78<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 79<li class="listitem"> 80 <a class="link" href="../boost__beast__http__error.html" title="http::error"><code class="computeroutput"><span class="identifier">error</span><span class="special">::</span><span class="identifier">end_of_stream</span></code></a> 81 if no bytes were parsed, or 82 </li> 83<li class="listitem"> 84 <a class="link" href="../boost__beast__http__error.html" title="http::error"><code class="computeroutput"><span class="identifier">error</span><span class="special">::</span><span class="identifier">partial_message</span></code></a> 85 if any bytes were parsed but the message was incomplete, otherwise: 86 </li> 87<li class="listitem"> 88 A successful result. The next attempt to read will return <a class="link" href="../boost__beast__http__error.html" title="http::error"><code class="computeroutput"><span class="identifier">error</span><span class="special">::</span><span class="identifier">end_of_stream</span></code></a> 89 </li> 90</ul></div> 91<h6> 92<a name="beast.ref.boost__beast__http__read.overload3.h2"></a> 93 <span class="phrase"><a name="beast.ref.boost__beast__http__read.overload3.parameters"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__http__read.overload3.parameters">Parameters</a> 94 </h6> 95<div class="informaltable"><table class="table"> 96<colgroup> 97<col> 98<col> 99</colgroup> 100<thead><tr> 101<th> 102 <p> 103 Name 104 </p> 105 </th> 106<th> 107 <p> 108 Description 109 </p> 110 </th> 111</tr></thead> 112<tbody> 113<tr> 114<td> 115 <p> 116 <code class="computeroutput"><span class="identifier">stream</span></code> 117 </p> 118 </td> 119<td> 120 <p> 121 The stream from which the data is to be read. The type must meet 122 the <span class="emphasis"><em>SyncReadStream</em></span> requirements. 123 </p> 124 </td> 125</tr> 126<tr> 127<td> 128 <p> 129 <code class="computeroutput"><span class="identifier">buffer</span></code> 130 </p> 131 </td> 132<td> 133 <p> 134 Storage for additional bytes read by the implementation from 135 the stream. This is both an input and an output parameter; on 136 entry, the parser will be presented with any remaining data in 137 the dynamic buffer's readable bytes sequence first. The type 138 must meet the <span class="emphasis"><em>DynamicBuffer</em></span> requirements. 139 </p> 140 </td> 141</tr> 142<tr> 143<td> 144 <p> 145 <code class="computeroutput"><span class="identifier">msg</span></code> 146 </p> 147 </td> 148<td> 149 <p> 150 The container in which to store the message contents. This message 151 container should not have previous contents, otherwise the behavior 152 is undefined. The type must be meet the <span class="emphasis"><em>MoveAssignable</em></span> 153 and <span class="emphasis"><em>MoveConstructible</em></span> requirements. 154 </p> 155 </td> 156</tr> 157</tbody> 158</table></div> 159<h6> 160<a name="beast.ref.boost__beast__http__read.overload3.h3"></a> 161 <span class="phrase"><a name="beast.ref.boost__beast__http__read.overload3.return_value"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__http__read.overload3.return_value">Return 162 Value</a> 163 </h6> 164<p> 165 The number of bytes transferred from the stream. 166 </p> 167<h6> 168<a name="beast.ref.boost__beast__http__read.overload3.h4"></a> 169 <span class="phrase"><a name="beast.ref.boost__beast__http__read.overload3.exceptions"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__http__read.overload3.exceptions">Exceptions</a> 170 </h6> 171<div class="informaltable"><table class="table"> 172<colgroup> 173<col> 174<col> 175</colgroup> 176<thead><tr> 177<th> 178 <p> 179 Type 180 </p> 181 </th> 182<th> 183 <p> 184 Thrown On 185 </p> 186 </th> 187</tr></thead> 188<tbody><tr> 189<td> 190 <p> 191 <code class="computeroutput"><span class="identifier">system_error</span></code> 192 </p> 193 </td> 194<td> 195 <p> 196 Thrown on failure. 197 </p> 198 </td> 199</tr></tbody> 200</table></div> 201<h6> 202<a name="beast.ref.boost__beast__http__read.overload3.h5"></a> 203 <span class="phrase"><a name="beast.ref.boost__beast__http__read.overload3.remarks"></a></span><a class="link" href="overload3.html#beast.ref.boost__beast__http__read.overload3.remarks">Remarks</a> 204 </h6> 205<p> 206 The function returns the total number of bytes transferred from the stream. 207 This may be zero for the case where there is sufficient pre-existing message 208 data in the dynamic buffer. The implementation will call <a class="link" href="../boost__beast__http__basic_parser/eager/overload1.html" title="http::basic_parser::eager (1 of 2 overloads)"><code class="computeroutput"><span class="identifier">basic_parser</span><span class="special">::</span><span class="identifier">eager</span></code></a> with the value <code class="computeroutput"><span class="keyword">true</span></code> on the parser passed in. 209 </p> 210</div> 211<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 212<td align="left"></td> 213<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 214 Falco<p> 215 Distributed under the Boost Software License, Version 1.0. (See accompanying 216 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>) 217 </p> 218</div></td> 219</tr></table> 220<hr> 221<div class="spirit-nav"> 222<a accesskey="p" href="overload2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__http__read.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="overload4.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 223</div> 224</body> 225</html> 226
