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  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="boost_asio.reference.spawn"></a><a class="link" href="spawn.html" title="spawn">spawn</a>
  28 </h3></div></div></div>
  29 <p>
  30         <a class="indexterm" name="idp193586880"></a>
  31 Start a new stackful coroutine.
  32       </p>
  33 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
  34     <span class="keyword">typename</span> <a class="link" href="Handler.html" title="Handlers">Handler</a><span class="special">,</span>
  35     <span class="keyword">typename</span> <span class="identifier">Function</span><span class="special">&gt;</span>
  36 <span class="keyword">void</span> <a class="link" href="spawn/overload1.html" title="spawn (1 of 4 overloads)">spawn</a><span class="special">(</span>
  37     <span class="identifier">Handler</span> <span class="identifier">handler</span><span class="special">,</span>
  38     <span class="identifier">Function</span> <span class="identifier">function</span><span class="special">,</span>
  39     <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span> <span class="special">&amp;</span> <span class="identifier">attributes</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span><span class="special">());</span>
  40   <span class="emphasis"><em>&#187; <a class="link" href="spawn/overload1.html" title="spawn (1 of 4 overloads)">more...</a></em></span>
  41
  42 <span class="keyword">template</span><span class="special">&lt;</span>
  43     <span class="keyword">typename</span> <a class="link" href="Handler.html" title="Handlers">Handler</a><span class="special">,</span>
  44     <span class="keyword">typename</span> <span class="identifier">Function</span><span class="special">&gt;</span>
  45 <span class="keyword">void</span> <a class="link" href="spawn/overload2.html" title="spawn (2 of 4 overloads)">spawn</a><span class="special">(</span>
  46     <span class="identifier">basic_yield_context</span><span class="special">&lt;</span> <span class="identifier">Handler</span> <span class="special">&gt;</span> <span class="identifier">ctx</span><span class="special">,</span>
  47     <span class="identifier">Function</span> <span class="identifier">function</span><span class="special">,</span>
  48     <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span> <span class="special">&amp;</span> <span class="identifier">attributes</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span><span class="special">());</span>
  49   <span class="emphasis"><em>&#187; <a class="link" href="spawn/overload2.html" title="spawn (2 of 4 overloads)">more...</a></em></span>
  50
  51 <span class="keyword">template</span><span class="special">&lt;</span>
  52     <span class="keyword">typename</span> <span class="identifier">Function</span><span class="special">&gt;</span>
  53 <span class="keyword">void</span> <a class="link" href="spawn/overload3.html" title="spawn (3 of 4 overloads)">spawn</a><span class="special">(</span>
  54     <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">strand</span> <span class="identifier">strand</span><span class="special">,</span>
  55     <span class="identifier">Function</span> <span class="identifier">function</span><span class="special">,</span>
  56     <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span> <span class="special">&amp;</span> <span class="identifier">attributes</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span><span class="special">());</span>
  57   <span class="emphasis"><em>&#187; <a class="link" href="spawn/overload3.html" title="spawn (3 of 4 overloads)">more...</a></em></span>
  58
  59 <span class="keyword">template</span><span class="special">&lt;</span>
  60     <span class="keyword">typename</span> <span class="identifier">Function</span><span class="special">&gt;</span>
  61 <span class="keyword">void</span> <a class="link" href="spawn/overload4.html" title="spawn (4 of 4 overloads)">spawn</a><span class="special">(</span>
  62     <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">&amp;</span> <span class="identifier">io_service</span><span class="special">,</span>
  63     <span class="identifier">Function</span> <span class="identifier">function</span><span class="special">,</span>
  64     <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span> <span class="special">&amp;</span> <span class="identifier">attributes</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">coroutines</span><span class="special">::</span><span class="identifier">attributes</span><span class="special">());</span>
  65   <span class="emphasis"><em>&#187; <a class="link" href="spawn/overload4.html" title="spawn (4 of 4 overloads)">more...</a></em></span>
  66 </pre>
  67 <p>
  68         The <code class="computeroutput"><span class="identifier">spawn</span><span class="special">()</span></code>
  69         function is a high-level wrapper over the Boost.Coroutine library. This function
  70         enables programs to implement asynchronous logic in a synchronous manner,
  71         as illustrated by the following example:
  72       </p>
  73 <pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">spawn</span><span class="special">(</span><span class="identifier">my_strand</span><span class="special">,</span> <span class="identifier">do_echo</span><span class="special">);</span>
  74
  75 <span class="comment">// ...</span>
  76
  77 <span class="keyword">void</span> <span class="identifier">do_echo</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">yield_context</span> <span class="identifier">yield</span><span class="special">)</span>
  78 <span class="special">{</span>
  79   <span class="keyword">try</span>
  80   <span class="special">{</span>
  81     <span class="keyword">char</span> <span class="identifier">data</span><span class="special">[</span><span class="number">128</span><span class="special">];</span>
  82     <span class="keyword">for</span> <span class="special">(;;)</span>
  83     <span class="special">{</span>
  84       <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">length</span> <span class="special">=</span>
  85         <span class="identifier">my_socket</span><span class="special">.</span><span class="identifier">async_read_some</span><span class="special">(</span>
  86           <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">(</span><span class="identifier">data</span><span class="special">),</span> <span class="identifier">yield</span><span class="special">);</span>
  87
  88       <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">async_write</span><span class="special">(</span><span class="identifier">my_socket</span><span class="special">,</span>
  89           <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">(</span><span class="identifier">data</span><span class="special">,</span> <span class="identifier">length</span><span class="special">),</span> <span class="identifier">yield</span><span class="special">);</span>
  90     <span class="special">}</span>
  91   <span class="special">}</span>
  92   <span class="keyword">catch</span> <span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">exception</span><span class="special">&amp;</span> <span class="identifier">e</span><span class="special">)</span>
  93   <span class="special">{</span>
  94     <span class="comment">// ...</span>
  95   <span class="special">}</span>
  96 <span class="special">}</span>
  97 </pre>
  98 <h5>
  99 <a name="boost_asio.reference.spawn.h0"></a>
 100         <span class="phrase"><a name="boost_asio.reference.spawn.requirements"></a></span><a class="link" href="spawn.html#boost_asio.reference.spawn.requirements">Requirements</a>
 101       </h5>
 102 <p>
 103         <span class="emphasis"><em>Header: </em></span><code class="literal">boost/asio/spawn.hpp</code>
 104       </p>
 105 <p>
 106         <span class="emphasis"><em>Convenience header: </em></span>None
 107       </p>
 108 </div>
 109 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 110 <td align="left"></td>
 111 <td align="right"><div class="copyright-footer">Copyright &#169; 2003-2014 Christopher M. Kohlhoff<p>
 112         Distributed under the Boost Software License, Version 1.0. (See accompanying
 113         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>)
 114       </p>
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