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   4 <title>Class visitation_result</title>
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  18 <div class="refentry">
  19 <a name="boost.log.visitation_result"></a><div class="titlepage"></div>
  20 <div class="refnamediv">
  21 <h2><span class="refentrytitle">Class visitation_result</span></h2>
  22 <p>boost::log::visitation_result &#8212; The class represents attribute value visitation result. </p>
  23 </div>
  24 <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
  25 <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../attributes.html#header.boost.log.attributes.value_visitation_hpp" title="Header &lt;boost/log/attributes/value_visitation.hpp&gt;">boost/log/attributes/value_visitation.hpp</a>&gt;
  26
  27 </span>
  28 <span class="keyword">class</span> <a class="link" href="visitation_result.html" title="Class visitation_result">visitation_result</a> <span class="special">{</span>
  29 <span class="keyword">public</span><span class="special">:</span>
  30
  31   <span class="comment">// Error codes for attribute value visitation. </span>
  32   <span class="keyword">enum</span> <a name="boost.log.visitation_result.error_code"></a>error_code <span class="special">{</span> ok, value_not_found, value_has_invalid_type <span class="special">}</span><span class="special">;</span>
  33   <span class="comment">// <a class="link" href="visitation_result.html#boost.log.visitation_resultconstruct-copy-destruct">construct/copy/destruct</a></span>
  34   <a class="link" href="visitation_result.html#idp62554752-bb"><span class="identifier">visitation_result</span></a><span class="special">(</span><span class="identifier">error_code</span> <span class="special">=</span> <span class="identifier">ok</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span>
  35
  36   <span class="comment">// <a class="link" href="visitation_result.html#idp62545696-bb">public member functions</a></span>
  37   <span class="keyword">explicit</span> <a class="link" href="visitation_result.html#idp62546256-bb"><span class="keyword">operator</span> <span class="keyword">bool</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span>
  38   <span class="keyword">bool</span> <a class="link" href="visitation_result.html#idp62549568-bb"><span class="keyword">operator</span><span class="special">!</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span>
  39   <span class="identifier">error_code</span> <a class="link" href="visitation_result.html#idp62552608-bb"><span class="identifier">code</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span>
  40 <span class="special">}</span><span class="special">;</span></pre></div>
  41 <div class="refsect1">
  42 <a name="idp110330384"></a><h2>Description</h2>
  43 <p>The main purpose of this class is to provide a convenient interface for checking whether the attribute value visitation succeeded or not. It also allows to discover the actual cause of failure, should the operation fail. </p>
  44 <div class="refsect2">
  45 <a name="idp110331296"></a><h3>
  46 <a name="boost.log.visitation_resultconstruct-copy-destruct"></a><code class="computeroutput">visitation_result</code>
  47         public
  48        construct/copy/destruct</h3>
  49 <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
  50 <pre class="literallayout"><a name="idp62554752-bb"></a><span class="identifier">visitation_result</span><span class="special">(</span><span class="identifier">error_code</span> code <span class="special">=</span> <span class="identifier">ok</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span></pre>
  51 <p>Initializing constructor. Creates the result that is equivalent to the specified error code. </p>
  52 </li></ol></div>
  53 </div>
  54 <div class="refsect2">
  55 <a name="idp110340192"></a><h3>
  56 <a name="idp62545696-bb"></a><code class="computeroutput">visitation_result</code> public member functions</h3>
  57 <div class="orderedlist"><ol class="orderedlist" type="1">
  58 <li class="listitem">
  59 <pre class="literallayout"><span class="keyword">explicit</span> <a name="idp62546256-bb"></a><span class="keyword">operator</span> <span class="keyword">bool</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></pre>
  60 <p>Checks if the visitation was successful.</p>
  61 <p>
  62 </p>
  63 <div class="variablelist"><table border="0" class="variablelist compact">
  64 <colgroup>
  65 <col align="left" valign="top">
  66 <col>
  67 </colgroup>
  68 <tbody><tr>
  69 <td><p><span class="term">Returns:</span></p></td>
  70 <td><p><code class="computeroutput">true</code> if the value was visited successfully, <code class="computeroutput">false</code> otherwise. </p></td>
  71 </tr></tbody>
  72 </table></div>
  73 </li>
  74 <li class="listitem">
  75 <pre class="literallayout"><span class="keyword">bool</span> <a name="idp62549568-bb"></a><span class="keyword">operator</span><span class="special">!</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></pre>
  76 <p>Checks if the visitation was unsuccessful.</p>
  77 <p>
  78 </p>
  79 <div class="variablelist"><table border="0" class="variablelist compact">
  80 <colgroup>
  81 <col align="left" valign="top">
  82 <col>
  83 </colgroup>
  84 <tbody><tr>
  85 <td><p><span class="term">Returns:</span></p></td>
  86 <td><p><code class="computeroutput">false</code> if the value was visited successfully, <code class="computeroutput">true</code> otherwise. </p></td>
  87 </tr></tbody>
  88 </table></div>
  89 </li>
  90 <li class="listitem">
  91 <pre class="literallayout"><span class="identifier">error_code</span> <a name="idp62552608-bb"></a><span class="identifier">code</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></pre>
  92 <p>
  93 </p>
  94 <div class="variablelist"><table border="0" class="variablelist compact">
  95 <colgroup>
  96 <col align="left" valign="top">
  97 <col>
  98 </colgroup>
  99 <tbody><tr>
 100 <td><p><span class="term">Returns:</span></p></td>
 101 <td><p>The actual result code of value visitation </p></td>
 102 </tr></tbody>
 103 </table></div>
 104 </li>
 105 </ol></div>
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