1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>basic_stream::async_connect (5 of 5 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="../async_connect.html" title="basic_stream::async_connect"> 9<link rel="prev" href="overload4.html" title="basic_stream::async_connect (4 of 5 overloads)"> 10<link rel="next" href="../read_some.html" title="basic_stream::read_some"> 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="overload4.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../async_connect.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="../read_some.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__basic_stream.async_connect.overload5"></a><a class="link" href="overload5.html" title="basic_stream::async_connect (5 of 5 overloads)">basic_stream::async_connect 28 (5 of 5 overloads)</a> 29</h6></div></div></div> 30<p> 31 Establishes a connection by trying each endpoint in a sequence asynchronously. 32 </p> 33<h7><a name="beast.ref.boost__beast__basic_stream.async_connect.overload5.h0"></a> 34 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_connect.overload5.synopsis"></a></span><a class="link" href="overload5.html#beast.ref.boost__beast__basic_stream.async_connect.overload5.synopsis">Synopsis</a> 35 </h7><pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 36 <span class="keyword">class</span> <span class="identifier">Iterator</span><span class="special">,</span> 37 <span class="keyword">class</span> <a href="../../../../../../../../doc/html/boost_asio/reference/ConnectCondition.html" target="_top"><span class="emphasis"><em>ConnectCondition</em></span></a><span class="special">,</span> 38 <span class="keyword">class</span> <a href="../../../../../../../../doc/html/boost_asio/reference/IteratorConnectHandler.html" target="_top"><span class="emphasis"><em>IteratorConnectHandler</em></span></a> <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="basic_stream::executor_type">executor_type</a><span class="special">>></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_connect</span><span class="special">(</span> 41 <span class="identifier">Iterator</span> <span class="identifier">begin</span><span class="special">,</span> 42 <span class="identifier">Iterator</span> <span class="identifier">end</span><span class="special">,</span> 43 <span class="identifier">ConnectCondition</span> <span class="identifier">connect_condition</span><span class="special">,</span> 44 <span class="identifier">IteratorConnectHandler</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="basic_stream::executor_type">executor_type</a> <span class="special">>{});</span> 45</pre> 46<h7><a name="beast.ref.boost__beast__basic_stream.async_connect.overload5.h1"></a> 47 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_connect.overload5.description"></a></span><a class="link" href="overload5.html#beast.ref.boost__beast__basic_stream.async_connect.overload5.description">Description</a> 48 </h7><p> 49 This function attempts to connect the stream to one of a sequence of 50 endpoints by trying each endpoint until a connection is successfully 51 established. The algorithm, known as a <span class="emphasis"><em>composed asynchronous 52 operation</em></span>, is implemented in terms of calls to the underlying 53 socket's <code class="computeroutput"><span class="identifier">async_connect</span></code> 54 function. If the timeout timer expires while the operation is outstanding, 55 the current connection attempt will be canceled and the completion handler 56 will be invoked with the error <a class="link" href="../../boost__beast__error.html" title="error"><code class="computeroutput"><span class="identifier">error</span><span class="special">::</span><span class="identifier">timeout</span></code></a>. 57 </p> 58<h7><a name="beast.ref.boost__beast__basic_stream.async_connect.overload5.h2"></a> 59 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_connect.overload5.parameters"></a></span><a class="link" href="overload5.html#beast.ref.boost__beast__basic_stream.async_connect.overload5.parameters">Parameters</a> 60 </h7><div class="informaltable"><table class="table"> 61<colgroup> 62<col> 63<col> 64</colgroup> 65<thead><tr> 66<th> 67 <p> 68 Name 69 </p> 70 </th> 71<th> 72 <p> 73 Description 74 </p> 75 </th> 76</tr></thead> 77<tbody> 78<tr> 79<td> 80 <p> 81 <code class="computeroutput"><span class="identifier">begin</span></code> 82 </p> 83 </td> 84<td> 85 <p> 86 An iterator pointing to the start of a sequence of endpoints. 87 </p> 88 </td> 89</tr> 90<tr> 91<td> 92 <p> 93 <code class="computeroutput"><span class="identifier">end</span></code> 94 </p> 95 </td> 96<td> 97 <p> 98 An iterator pointing to the end of a sequence of endpoints. 99 </p> 100 </td> 101</tr> 102<tr> 103<td> 104 <p> 105 <code class="computeroutput"><span class="identifier">connect_condition</span></code> 106 </p> 107 </td> 108<td> 109 <p> 110 A function object that is called prior to each connection attempt. 111 The signature of the function object must be: 112 </p> 113<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">bool</span> <span class="identifier">connect_condition</span><span class="special">(</span> 114 <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">ec</span><span class="special">,</span> 115 <span class="keyword">typename</span> <span class="identifier">Protocol</span><span class="special">::</span><span class="identifier">endpoint</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">next</span><span class="special">);</span> 116</pre> 117 </td> 118</tr> 119<tr> 120<td> 121 <p> 122 <code class="computeroutput"><span class="identifier">handler</span></code> 123 </p> 124 </td> 125<td> 126 <p> 127 The completion handler to invoke when the operation completes. 128 The implementation takes ownership of the handler by performing 129 a decay-copy. The equivalent function signature of the handler 130 must be: 131 </p> 132<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> 133 <span class="comment">// Result of operation. if the sequence is empty, set to</span> 134 <span class="comment">// net::error::not_found. Otherwise, contains the</span> 135 <span class="comment">// error from the last connection attempt.</span> 136 <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">error</span><span class="special">,</span> 137 138 <span class="comment">// On success, an iterator denoting the successfully</span> 139 <span class="comment">// connected endpoint. Otherwise, the end iterator.</span> 140 <span class="identifier">Iterator</span> <span class="identifier">iterator</span> 141<span class="special">);</span> 142</pre> 143 <p> 144 Regardless of whether the asynchronous operation completes 145 immediately or not, the handler will not be invoked from within 146 this function. Invocation of the handler will be performed 147 in a manner equivalent to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>. 148 </p> 149 </td> 150</tr> 151</tbody> 152</table></div> 153</div> 154<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 155<td align="left"></td> 156<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 157 Falco<p> 158 Distributed under the Boost Software License, Version 1.0. (See accompanying 159 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>) 160 </p> 161</div></td> 162</tr></table> 163<hr> 164<div class="spirit-nav"> 165<a accesskey="p" href="overload4.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../async_connect.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="../read_some.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 166</div> 167</body> 168</html> 169
