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- <div class="titlepage"><div><div><h1 style="clear: both"><code>BOOST_OUTCOME_TRY(var, expr)</code></h1></div></div></div>
- <p>Evaluate an expression which results in a type matching the following customisation points, assigning <code>T</code> to a variable called <code>var</code> if successful, immediately returning <a href="../../reference/functions/try_operation_return_as.html" class="api-reference"><code>try_operation_return_as(X)</code></a>
- from the calling function if unsuccessful:</p>
- <ul>
- <li><code>BOOST_OUTCOME_V2_NAMESPACE::</code><a href="../../reference/functions/try_operation_has_value.html" class="api-reference"><code>try_operation_has_value(X)</code></a>
- </li>
- <li><code>BOOST_OUTCOME_V2_NAMESPACE::</code><a href="../../reference/functions/try_operation_return_as.html" class="api-reference"><code>try_operation_return_as(X)</code></a>
- </li>
- <li><code>BOOST_OUTCOME_V2_NAMESPACE::</code><a href="../../reference/functions/try_operation_extract_value.html" class="api-reference"><code>try_operation_extract_value(X)</code></a>
- </li>
- </ul>
- <p>Default overloads for these customisation points are provided. See <a href="../../recipes/foreign-try.html">the recipe for supporting foreign input to <code>BOOST_OUTCOME_TRY</code></a>.</p>
- <p>Hints are given to the compiler that the expression will be successful. If you expect failure, you should use <a href="../../reference/macros/try_failure_likely.html" class="api-reference"><code>BOOST_OUTCOME_TRY_FAILURE_LIKELY(var, expr)</code></a>
- instead.</p>
- <p><em>Overridable</em>: Not overridable.</p>
- <p><em>Definition</em>: See <a href="../../reference/macros/tryv.html" class="api-reference"><code>BOOST_OUTCOME_TRYV(expr)</code></a>
- for most of the mechanics.</p>
- <p>If successful, an <code>auto &&var</code> is initialised to the expression result’s <code>.assume_value()</code> if available, else to its <code>.value()</code>. This binds a reference possibly to the <code>T</code> stored inside the bound result of the expression, but possibly also to a temporary emitted from the value observer function.</p>
- <p><em>Header</em>: <code><boost/outcome/try.hpp></code></p>
- </div><p><small>Last revised: October 16, 2019 at 10:26:35 +0100</small></p>
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