1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>async_connect (5 of 6 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="../../../boost_asio.html" title="Boost.Asio"> 8<link rel="up" href="../async_connect.html" title="async_connect"> 9<link rel="prev" href="overload4.html" title="async_connect (4 of 6 overloads)"> 10<link rel="next" href="overload6.html" title="async_connect (6 of 6 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="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="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload6.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="boost_asio.reference.async_connect.overload5"></a><a class="link" href="overload5.html" title="async_connect (5 of 6 overloads)">async_connect 28 (5 of 6 overloads)</a> 29</h4></div></div></div> 30<p> 31 (Deprecated: Use range overload.) Asynchronously establishes a socket connection 32 by trying each endpoint in a sequence. 33 </p> 34<pre class="programlisting">template< 35 typename <a class="link" href="../Protocol.html" title="Protocol requirements">Protocol</a>, 36 typename <a class="link" href="../Executor1.html" title="Executor requirements">Executor</a>, 37 typename Iterator, 38 typename <a class="link" href="../ConnectCondition.html" title="Connect condition requirements">ConnectCondition</a>, 39 typename <a class="link" href="../IteratorConnectHandler.html" title="Iterator connect handler requirements">IteratorConnectHandler</a> = <a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>> 40<a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type"><span class="emphasis"><em>DEDUCED</em></span></a> async_connect( 41 basic_socket< Protocol, Executor > & s, 42 Iterator begin, 43 ConnectCondition connect_condition, 44 IteratorConnectHandler && handler = <a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>, 45 typename enable_if<!is_endpoint_sequence< Iterator >::value >::type * = 0); 46</pre> 47<p> 48 This function attempts to connect a socket to one of a sequence of endpoints. 49 It does this by repeated calls to the socket's <code class="computeroutput">async_connect</code> 50 member function, once for each endpoint in the sequence, until a connection 51 is successfully established. 52 </p> 53<h6> 54<a name="boost_asio.reference.async_connect.overload5.h0"></a> 55 <span class="phrase"><a name="boost_asio.reference.async_connect.overload5.parameters"></a></span><a class="link" href="overload5.html#boost_asio.reference.async_connect.overload5.parameters">Parameters</a> 56 </h6> 57<div class="variablelist"> 58<p class="title"><b></b></p> 59<dl class="variablelist"> 60<dt><span class="term">s</span></dt> 61<dd><p> 62 The socket to be connected. If the socket is already open, it will 63 be closed. 64 </p></dd> 65<dt><span class="term">begin</span></dt> 66<dd><p> 67 An iterator pointing to the start of a sequence of endpoints. 68 </p></dd> 69<dt><span class="term">connect_condition</span></dt> 70<dd> 71<p> 72 A function object that is called prior to each connection attempt. 73 The signature of the function object must be: 74</p> 75<pre class="programlisting">bool connect_condition( 76 const boost::system::error_code& ec, 77 const typename Protocol::endpoint& next); 78</pre> 79<p> 80 The <code class="computeroutput">ec</code> parameter contains the result from the most recent 81 connect operation. Before the first connection attempt, <code class="computeroutput">ec</code> 82 is always set to indicate success. The <code class="computeroutput">next</code> parameter 83 is the next endpoint to be tried. The function object should return 84 true if the next endpoint should be tried, and false if it should 85 be skipped. 86 </p> 87</dd> 88<dt><span class="term">handler</span></dt> 89<dd> 90<p> 91 The handler to be called when the connect operation completes. Copies 92 will be made of the handler as required. The function signature of 93 the handler must be: 94</p> 95<pre class="programlisting">void handler( 96 // Result of operation. if the sequence is empty, set to 97 // boost::asio::error::not_found. Otherwise, contains the 98 // error from the last connection attempt. 99 const boost::system::error_code& error, 100 101 // On success, an iterator denoting the successfully 102 // connected endpoint. Otherwise, the end iterator. 103 Iterator iterator 104); 105</pre> 106<p> 107 Regardless of whether the asynchronous operation completes immediately 108 or not, the handler will not be invoked from within this function. 109 On immediate completion, invocation of the handler will be performed 110 in a manner equivalent to using <a class="link" href="../post.html" title="post"><code class="computeroutput">post</code></a>. 111 </p> 112</dd> 113</dl> 114</div> 115<h6> 116<a name="boost_asio.reference.async_connect.overload5.h1"></a> 117 <span class="phrase"><a name="boost_asio.reference.async_connect.overload5.remarks"></a></span><a class="link" href="overload5.html#boost_asio.reference.async_connect.overload5.remarks">Remarks</a> 118 </h6> 119<p> 120 This overload assumes that a default constructed object of type <code class="computeroutput">Iterator</code> 121 represents the end of the sequence. This is a valid assumption for iterator 122 types such as <code class="computeroutput">boost::asio::ip::tcp::resolver::iterator</code>. 123 </p> 124</div> 125<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 126<td align="left"></td> 127<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 128 Kohlhoff<p> 129 Distributed under the Boost Software License, Version 1.0. (See accompanying 130 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>) 131 </p> 132</div></td> 133</tr></table> 134<hr> 135<div class="spirit-nav"> 136<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="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload6.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 137</div> 138</body> 139</html> 140
