ComposedConnectHandler.html 7.7 KB

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  19. <div class="titlepage"><div><div><h3 class="title">
  20. <a name="asio.reference.ComposedConnectHandler"></a><a class="link" href="ComposedConnectHandler.html" title="Composed connect handler requirements">Composed connect
  21. handler requirements</a>
  22. </h3></div></div></div>
  23. <p>
  24. A composed connect handler must meet the requirements for a <a class="link" href="Handler.html" title="Handlers">handler</a>.
  25. A value <code class="computeroutput"><span class="identifier">h</span></code> of a composed connect
  26. handler class should work correctly in the expression <code class="computeroutput"><span class="identifier">h</span><span class="special">(</span><span class="identifier">ec</span><span class="special">,</span>
  27. <span class="identifier">i</span><span class="special">)</span></code>,
  28. where <code class="computeroutput"><span class="identifier">ec</span></code> is an lvalue of
  29. type <code class="computeroutput"><span class="keyword">const</span> <span class="identifier">error_code</span></code>
  30. and <code class="computeroutput"><span class="identifier">i</span></code> is an lvalue of the
  31. type <code class="computeroutput"><span class="identifier">Iterator</span></code> used in the
  32. corresponding <code class="computeroutput"><span class="identifier">connect</span><span class="special">()</span></code>
  33. or async_connect()` function.
  34. </p>
  35. <h5>
  36. <a name="asio.reference.ComposedConnectHandler.h0"></a>
  37. <span><a name="asio.reference.ComposedConnectHandler.examples"></a></span><a class="link" href="ComposedConnectHandler.html#asio.reference.ComposedConnectHandler.examples">Examples</a>
  38. </h5>
  39. <p>
  40. A free function as a composed connect handler:
  41. </p>
  42. <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">connect_handler</span><span class="special">(</span>
  43. <span class="keyword">const</span> <span class="identifier">asio</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&amp;</span> <span class="identifier">ec</span><span class="special">,</span>
  44. <span class="identifier">asio</span><span class="special">::</span><span class="identifier">ip</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">iterator</span><span class="special">)</span>
  45. <span class="special">{</span>
  46. <span class="special">...</span>
  47. <span class="special">}</span>
  48. </pre>
  49. <p>
  50. A composed connect handler function object:
  51. </p>
  52. <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">connect_handler</span>
  53. <span class="special">{</span>
  54. <span class="special">...</span>
  55. <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">&gt;</span>
  56. <span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()(</span>
  57. <span class="keyword">const</span> <span class="identifier">asio</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&amp;</span> <span class="identifier">ec</span><span class="special">,</span>
  58. <span class="identifier">Iterator</span> <span class="identifier">iterator</span><span class="special">)</span>
  59. <span class="special">{</span>
  60. <span class="special">...</span>
  61. <span class="special">}</span>
  62. <span class="special">...</span>
  63. <span class="special">};</span>
  64. </pre>
  65. <p>
  66. A non-static class member function adapted to a composed connect handler
  67. using <code class="computeroutput"><span class="identifier">bind</span><span class="special">()</span></code>:
  68. </p>
  69. <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">my_class</span><span class="special">::</span><span class="identifier">connect_handler</span><span class="special">(</span>
  70. <span class="keyword">const</span> <span class="identifier">asio</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&amp;</span> <span class="identifier">ec</span><span class="special">,</span>
  71. <span class="identifier">asio</span><span class="special">::</span><span class="identifier">ip</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">iterator</span><span class="special">)</span>
  72. <span class="special">{</span>
  73. <span class="special">...</span>
  74. <span class="special">}</span>
  75. <span class="special">...</span>
  76. <span class="identifier">asio</span><span class="special">::</span><span class="identifier">async_connect</span><span class="special">(...,</span>
  77. <span class="identifier">boost</span><span class="special">::</span><span class="identifier">bind</span><span class="special">(&amp;</span><span class="identifier">my_class</span><span class="special">::</span><span class="identifier">connect_handler</span><span class="special">,</span>
  78. <span class="keyword">this</span><span class="special">,</span> <span class="identifier">asio</span><span class="special">::</span><span class="identifier">placeholders</span><span class="special">::</span><span class="identifier">error</span><span class="special">,</span>
  79. <span class="identifier">asio</span><span class="special">::</span><span class="identifier">placeholders</span><span class="special">::</span><span class="identifier">iterator</span><span class="special">));</span>
  80. </pre>
  81. </div>
  82. <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
  83. <td align="left"></td>
  84. <td align="right"><div class="copyright-footer">Copyright &#169; 2003-2014 Christopher M. Kohlhoff<p>
  85. Distributed under the Boost Software License, Version 1.0. (See accompanying
  86. 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>)
  87. </p>
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