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| author | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
|---|---|---|
| committer | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
| commit | 1a78a62555be32868418fe52f8e330c9d0f95d5a (patch) | |
| tree | d3765a80e7d3b9640ec2e930743630cd6b9fce2b /doc/html/boost_asio/reference/async_connect/overload4.html | |
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Imported Upstream version 1.49.0upstream/1.49.0
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diff --git a/doc/html/boost_asio/reference/async_connect/overload4.html b/doc/html/boost_asio/reference/async_connect/overload4.html new file mode 100755 index 0000000000..70ca00b2fc --- /dev/null +++ b/doc/html/boost_asio/reference/async_connect/overload4.html @@ -0,0 +1,200 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>async_connect (4 of 4 overloads)</title> +<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../../../boost_asio.html" title="Boost.Asio"> +<link rel="up" href="../async_connect.html" title="async_connect"> +<link rel="prev" href="overload3.html" title="async_connect (3 of 4 overloads)"> +<link rel="next" href="../async_read.html" title="async_read"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<table cellpadding="2" width="100%"><tr> +<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> +<td align="center"><a href="../../../../../index.html">Home</a></td> +<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> +<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> +<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> +<td align="center"><a href="../../../../../more/index.htm">More</a></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="overload3.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="../async_read.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="boost_asio.reference.async_connect.overload4"></a><a class="link" href="overload4.html" title="async_connect (4 of 4 overloads)">async_connect + (4 of 4 overloads)</a> +</h4></div></div></div> +<p> + Asynchronously establishes a socket connection by trying each endpoint + in a sequence. + </p> +<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> + <span class="keyword">typename</span> <a class="link" href="../Protocol.html" title="Protocol requirements">Protocol</a><span class="special">,</span> + <span class="keyword">typename</span> <a class="link" href="../SocketService.html" title="Socket service requirements">SocketService</a><span class="special">,</span> + <span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">,</span> + <span class="keyword">typename</span> <span class="identifier">ConnectCondition</span><span class="special">,</span> + <span class="keyword">typename</span> <a class="link" href="../ComposedConnectHandler.html" title="Composed connect handler requirements">ComposedConnectHandler</a><span class="special">></span> +<span class="keyword">void</span> <span class="identifier">async_connect</span><span class="special">(</span> + <span class="identifier">basic_socket</span><span class="special"><</span> <span class="identifier">Protocol</span><span class="special">,</span> <span class="identifier">SocketService</span> <span class="special">></span> <span class="special">&</span> <span class="identifier">s</span><span class="special">,</span> + <span class="identifier">Iterator</span> <span class="identifier">begin</span><span class="special">,</span> + <span class="identifier">Iterator</span> <span class="identifier">end</span><span class="special">,</span> + <span class="identifier">ConnectCondition</span> <span class="identifier">connect_condition</span><span class="special">,</span> + <span class="identifier">ComposedConnectHandler</span> <span class="identifier">handler</span><span class="special">);</span> +</pre> +<p> + This function attempts to connect a socket to one of a sequence of endpoints. + It does this by repeated calls to the socket's <code class="computeroutput"><span class="identifier">async_connect</span></code> + member function, once for each endpoint in the sequence, until a connection + is successfully established. + </p> +<h6> +<a name="boost_asio.reference.async_connect.overload4.h0"></a> + <span><a name="boost_asio.reference.async_connect.overload4.parameters"></a></span><a class="link" href="overload4.html#boost_asio.reference.async_connect.overload4.parameters">Parameters</a> + </h6> +<div class="variablelist"> +<p class="title"><b></b></p> +<dl> +<dt><span class="term">s</span></dt> +<dd><p> + The socket to be connected. If the socket is already open, it will + be closed. + </p></dd> +<dt><span class="term">begin</span></dt> +<dd><p> + An iterator pointing to the start of a sequence of endpoints. + </p></dd> +<dt><span class="term">end</span></dt> +<dd><p> + An iterator pointing to the end of a sequence of endpoints. + </p></dd> +<dt><span class="term">connect_condition</span></dt> +<dd> +<p> + A function object that is called prior to each connection attempt. + The signature of the function object must be: +</p> +<pre class="programlisting"><span class="identifier">Iterator</span> <span class="identifier">connect_condition</span><span class="special">(</span> + <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">ec</span><span class="special">,</span> + <span class="identifier">Iterator</span> <span class="identifier">next</span><span class="special">);</span> +</pre> +<p> + The <code class="computeroutput"><span class="identifier">ec</span></code> parameter + contains the result from the most recent connect operation. Before + the first connection attempt, <code class="computeroutput"><span class="identifier">ec</span></code> + is always set to indicate success. The <code class="computeroutput"><span class="identifier">next</span></code> + parameter is an iterator pointing to the next endpoint to be tried. + The function object should return the next iterator, but is permitted + to return a different iterator so that endpoints may be skipped. + The implementation guarantees that the function object will never + be called with the end iterator. + </p> +</dd> +<dt><span class="term">handler</span></dt> +<dd> +<p> + The handler to be called when the connect operation completes. Copies + will be made of the handler as required. The function signature of + the handler must be: +</p> +<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span> + <span class="comment">// Result of operation. if the sequence is empty, set to</span> + <span class="comment">// boost::asio::error::not_found. Otherwise, contains the</span> + <span class="comment">// error from the last connection attempt.</span> + <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">error</span><span class="special">,</span> + + <span class="comment">// On success, an iterator denoting the successfully</span> + <span class="comment">// connected endpoint. Otherwise, the end iterator.</span> + <span class="identifier">Iterator</span> <span class="identifier">iterator</span> +<span class="special">);</span> +</pre> +<p> + Regardless of whether the asynchronous operation completes immediately + or not, the handler will not be invoked from within this function. + Invocation of the handler will be performed in a manner equivalent + to using <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">post</span><span class="special">()</span></code>. + </p> +</dd> +</dl> +</div> +<h6> +<a name="boost_asio.reference.async_connect.overload4.h1"></a> + <span><a name="boost_asio.reference.async_connect.overload4.example"></a></span><a class="link" href="overload4.html#boost_asio.reference.async_connect.overload4.example">Example</a> + </h6> +<p> + The following connect condition function object can be used to output information + about the individual connection attempts: + </p> +<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">my_connect_condition</span> +<span class="special">{</span> + <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">></span> + <span class="identifier">Iterator</span> <span class="keyword">operator</span><span class="special">()(</span> + <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">ec</span><span class="special">,</span> + <span class="identifier">Iterator</span> <span class="identifier">next</span><span class="special">)</span> + <span class="special">{</span> + <span class="keyword">if</span> <span class="special">(</span><span class="identifier">ec</span><span class="special">)</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Error: "</span> <span class="special"><<</span> <span class="identifier">ec</span><span class="special">.</span><span class="identifier">message</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Trying: "</span> <span class="special"><<</span> <span class="identifier">next</span><span class="special">-></span><span class="identifier">endpoint</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + <span class="keyword">return</span> <span class="identifier">next</span><span class="special">;</span> + <span class="special">}</span> +<span class="special">};</span> +</pre> +<p> + It would be used with the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">connect</span></code> + function as follows: + </p> +<pre class="programlisting"><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span> <span class="identifier">r</span><span class="special">(</span><span class="identifier">io_service</span><span class="special">);</span> +<span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">query</span> <span class="identifier">q</span><span class="special">(</span><span class="string">"host"</span><span class="special">,</span> <span class="string">"service"</span><span class="special">);</span> +<span class="identifier">tcp</span><span class="special">::</span><span class="identifier">socket</span> <span class="identifier">s</span><span class="special">(</span><span class="identifier">io_service</span><span class="special">);</span> + +<span class="comment">// ...</span> + +<span class="identifier">r</span><span class="special">.</span><span class="identifier">async_resolve</span><span class="special">(</span><span class="identifier">q</span><span class="special">,</span> <span class="identifier">resolve_handler</span><span class="special">);</span> + +<span class="comment">// ...</span> + +<span class="keyword">void</span> <span class="identifier">resolve_handler</span><span class="special">(</span> + <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">ec</span><span class="special">,</span> + <span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">iterator</span> <span class="identifier">i</span><span class="special">)</span> +<span class="special">{</span> + <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">ec</span><span class="special">)</span> + <span class="special">{</span> + <span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">iterator</span> <span class="identifier">end</span><span class="special">;</span> + <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">async_connect</span><span class="special">(</span><span class="identifier">s</span><span class="special">,</span> <span class="identifier">i</span><span class="special">,</span> <span class="identifier">end</span><span class="special">,</span> + <span class="identifier">my_connect_condition</span><span class="special">(),</span> + <span class="identifier">connect_handler</span><span class="special">);</span> + <span class="special">}</span> +<span class="special">}</span> + +<span class="comment">// ...</span> + +<span class="keyword">void</span> <span class="identifier">connect_handler</span><span class="special">(</span> + <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">ec</span><span class="special">,</span> + <span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">iterator</span> <span class="identifier">i</span><span class="special">)</span> +<span class="special">{</span> + <span class="keyword">if</span> <span class="special">(</span><span class="identifier">ec</span><span class="special">)</span> + <span class="special">{</span> + <span class="comment">// An error occurred.</span> + <span class="special">}</span> + <span class="keyword">else</span> + <span class="special">{</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Connected to: "</span> <span class="special"><<</span> <span class="identifier">i</span><span class="special">-></span><span class="identifier">endpoint</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + <span class="special">}</span> +<span class="special">}</span> +</pre> +</div> +<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> +<td align="left"></td> +<td align="right"><div class="copyright-footer">Copyright © 2003-2012 Christopher M. Kohlhoff<p> + Distributed under the Boost Software License, Version 1.0. (See accompanying + 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>) + </p> +</div></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="overload3.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="../async_read.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> |