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valueorerror.html

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  13.   <div class="titlepage"><div><div><h1 style="clear: both"><code>ValueOrError&lt;T, E&gt;</code></h1></div></div></div>
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  14.   <p>If on C++ 20 or the Concepts TS is enabled, a boolean concept matching types with a public <code>.has_value()</code> observer which returns <code>bool</code>, a public <code>.value()</code> observer function, and a public <code>.error()</code> observer function.</p>
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  16. <p>If without Concepts, a static constexpr bool which is true for types matching the same requirements, using a SFINAE based emulation.</p>
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  18. <p>This concept matches expected-like types such as 
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  19. <a href="https://wg21.link/P0323" class="api-reference" target="_blank"><i class="fa fa-book" aria-hidden="true"></i> P0323 <code>std::expected&lt;T, E&gt;</code></a>
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  20. , one of which is <a href="../../reference/types/basic_result.html" class="api-reference"><code>basic_result&lt;T, E, NoValuePolicy&gt;</code></a>
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  21. . Be aware it does not differentiate between value-or-error types and value-and-error types if they present the interface matched above.</p>
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  23. <p><em>Namespace</em>: <code>BOOST_OUTCOME_V2_NAMESPACE::convert</code></p>
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  25. <p><em>Header</em>: <code>&lt;boost/outcome/convert.hpp&gt;</code></p>
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  28.         </div><p><small>Last revised: December 13, 2018 at 17:36:11 UTC</small></p>
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