1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>basic_stream::async_connect (2 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="overload1.html" title="basic_stream::async_connect (1 of 5 overloads)"> 10<link rel="next" href="overload3.html" title="basic_stream::async_connect (3 of 5 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="../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="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__basic_stream.async_connect.overload2"></a><a class="link" href="overload2.html" title="basic_stream::async_connect (2 of 5 overloads)">basic_stream::async_connect 28 (2 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.overload2.h0"></a> 34 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_connect.overload2.synopsis"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__basic_stream.async_connect.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 href="../../../../../../../../doc/html/boost_asio/reference/EndpointSequence.html" target="_top"><span class="emphasis"><em>EndpointSequence</em></span></a><span class="special">,</span> 37 <span class="keyword">class</span> <a href="../../../../../../../../doc/html/boost_asio/reference/RangeConnectHandler.html" target="_top"><span class="emphasis"><em>RangeConnectHandler</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> 38<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> 39<span class="identifier">async_connect</span><span class="special">(</span> 40 <span class="identifier">EndpointSequence</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">endpoints</span><span class="special">,</span> 41 <span class="identifier">RangeConnectHandler</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> 42</pre> 43<h7><a name="beast.ref.boost__beast__basic_stream.async_connect.overload2.h1"></a> 44 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_connect.overload2.description"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__basic_stream.async_connect.overload2.description">Description</a> 45 </h7><p> 46 This function attempts to connect the stream to one of a sequence of 47 endpoints by trying each endpoint until a connection is successfully 48 established. The underlying socket is automatically opened if needed. 49 An automatically opened socket is not returned to the closed state upon 50 failure. The algorithm, known as a <span class="emphasis"><em>composed asynchronous operation</em></span>, 51 is implemented in terms of calls to the underlying socket's <code class="computeroutput"><span class="identifier">async_connect</span></code> function. If the timeout 52 timer expires while the operation is outstanding, the current connection 53 attempt will be canceled and the completion handler will be invoked with 54 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>. 55 </p> 56<h7><a name="beast.ref.boost__beast__basic_stream.async_connect.overload2.h2"></a> 57 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_connect.overload2.parameters"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__basic_stream.async_connect.overload2.parameters">Parameters</a> 58 </h7><div class="informaltable"><table class="table"> 59<colgroup> 60<col> 61<col> 62</colgroup> 63<thead><tr> 64<th> 65 <p> 66 Name 67 </p> 68 </th> 69<th> 70 <p> 71 Description 72 </p> 73 </th> 74</tr></thead> 75<tbody> 76<tr> 77<td> 78 <p> 79 <code class="computeroutput"><span class="identifier">endpoints</span></code> 80 </p> 81 </td> 82<td> 83 <p> 84 A sequence of endpoints. This this object must meet the requirements 85 of <span class="emphasis"><em>EndpointSequence</em></span>. 86 </p> 87 </td> 88</tr> 89<tr> 90<td> 91 <p> 92 <code class="computeroutput"><span class="identifier">handler</span></code> 93 </p> 94 </td> 95<td> 96 <p> 97 The completion handler to invoke when the operation completes. 98 The implementation takes ownership of the handler by performing 99 a decay-copy. The equivalent function signature of the handler 100 must be: 101 </p> 102<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> 103 <span class="comment">// Result of operation. if the sequence is empty, set to</span> 104 <span class="comment">// net::error::not_found. Otherwise, contains the</span> 105 <span class="comment">// error from the last connection attempt.</span> 106 <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">error</span><span class="special">,</span> 107 108 <span class="comment">// On success, the successfully connected endpoint.</span> 109 <span class="comment">// Otherwise, a default-constructed endpoint.</span> 110 <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">endpoint</span> 111<span class="special">);</span> 112</pre> 113 <p> 114 Regardless of whether the asynchronous operation completes 115 immediately or not, the handler will not be invoked from within 116 this function. Invocation of the handler will be performed 117 in a manner equivalent to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>. 118 </p> 119 </td> 120</tr> 121</tbody> 122</table></div> 123</div> 124<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 125<td align="left"></td> 126<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 127 Falco<p> 128 Distributed under the Boost Software License, Version 1.0. (See accompanying 129 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>) 130 </p> 131</div></td> 132</tr></table> 133<hr> 134<div class="spirit-nav"> 135<a accesskey="p" href="overload1.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="overload3.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 136</div> 137</body> 138</html> 139
