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  13   <div class="titlepage"><div><div><h1 style="clear: both"><code>is_error_type&lt;E&gt;</code></h1></div></div></div>
  14   <p>A customisable integral constant type true for <code>E</code> types which are to receive
  15 error throwing no-value policies. Special weakened implicit construction enable
  16 is available for integral <code>T</code> types when combined with <code>E</code> types in this
  17 whitelist &ndash; this permits <code>boost_result&lt;int, boost::system::errc::errc_t</code> to
  18 retain its implicit constructors, despite the fact that <code>errc_t</code> as a C enum
  19 has an implicit conversion to <code>int</code>.</p>
  20
  21 <p><em>Overridable</em>: By template specialisation into the <code>trait</code> namespace.</p>
  22
  23 <p><em>Default</em>: False. Specialisations to true exist for:</p>
  24
  25 <ul>
  26 <li><p><code>&lt;boost/outcome/boost_result.hpp&gt;</code></p>
  27
  28 <ul>
  29 <li><code>boost::system::error_code</code></li>
  30 <li><code>boost::system::errc::errc_t</code></li>
  31 <li><code>boost::exception_ptr</code></li>
  32 </ul></li>
  33
  34 <li><p><code>&lt;boost/outcome/std_result.hpp&gt;</code></p>
  35
  36 <ul>
  37 <li><code>std::error_code</code></li>
  38 <li><code>std::errc</code></li>
  39 <li><code>std::exception_ptr</code></li>
  40 </ul></li>
  41 </ul>
  42
  43 <p><em>Namespace</em>: <code>BOOST_OUTCOME_V2_NAMESPACE::trait</code></p>
  44
  45 <p><em>Header</em>: <code>&lt;boost/outcome/trait.hpp&gt;</code></p>
  46
  47
  48         </div><p><small>Last revised: October 11, 2019 at 17:03:05 &#43;0100</small></p>
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