1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html><meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 3<title>throw_bad_result_access<EC> - Boost.Outcome documentation</title> 4<link rel="stylesheet" href="../../css/boost.css" type="text/css"> 5<meta name="generator" content="Hugo 0.52 with Boostdoc theme"> 6<meta name="viewport" content="width=device-width,initial-scale=1.0"/> 7 8<link rel="icon" href="../../images/favicon.ico" type="image/ico"/> 9<body><div class="spirit-nav"> 10<a accesskey="p" href="../../reference/policies/terminate.html"><img src="../../images/prev.png" alt="Prev"></a> 11 <a accesskey="u" href="../../reference/policies.html"><img src="../../images/up.png" alt="Up"></a> 12 <a accesskey="h" href="../../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="../../reference/types.html"><img src="../../images/next.png" alt="Next"></a></div><div id="content"> 13 <div class="titlepage"><div><div><h1 style="clear: both"><code>throw_bad_result_access<EC></code></h1></div></div></div> 14 <p>Policy class defining that <a href="../../reference/types/bad_result_access_with.html" class="api-reference"><code>bad_result_access_with<EC></code></a> 15 should be thrown on incorrect wide value observation. The primary purpose of this policy is to enable standing in for 16<a href="https://wg21.link/P0323" class="api-reference" target="_blank"><i class="fa fa-book" aria-hidden="true"></i> P0323 <code>std::expected<T, E></code></a> 17 which throws a <code>bad_expected_access<E></code> on incorrect wide value observation. This is why it is only ever <code>EC</code> which is thrown with <code>bad_result_access_with<EC></code> on value observation only, and only when there is an error available.</p> 18 19<p>If used in <code>basic_outcome</code>, and the outcome is exceptioned and so no error is available, incorrect wide value observation performs instead:</p> 20<div class="highlight"><pre class="chroma"><code class="language-c++" data-lang="c++"><span class="n">BOOST_OUTCOME_THROW_EXCEPTION</span><span class="p">(</span><span class="n">bad_result_access</span><span class="p">(</span><span class="s">"no value"</span><span class="p">));</span> 21</code></pre></div> 22<p>Incorrect wide error observation performs:</p> 23<div class="highlight"><pre class="chroma"><code class="language-c++" data-lang="c++"><span class="n">BOOST_OUTCOME_THROW_EXCEPTION</span><span class="p">(</span><span class="n">bad_result_access</span><span class="p">(</span><span class="s">"no error"</span><span class="p">));</span> 24</code></pre></div> 25<p>Incorrect wide exception observation performs:</p> 26<div class="highlight"><pre class="chroma"><code class="language-c++" data-lang="c++"><span class="n">BOOST_OUTCOME_THROW_EXCEPTION</span><span class="p">(</span><span class="n">bad_outcome_access</span><span class="p">(</span><span class="s">"no exception"</span><span class="p">));</span> 27</code></pre></div> 28<p>Inherits publicly from <a href="../../reference/policies/base.html" class="api-reference"><code>base</code></a> 29, and its narrow value, error and exception observer policies are inherited from there.</p> 30 31<p><em>Requires</em>: Nothing.</p> 32 33<p><em>Namespace</em>: <code>BOOST_OUTCOME_V2_NAMESPACE::policy</code></p> 34 35<p><em>Header</em>: <code><boost/outcome/policy/throw_bad_result_access.hpp></code></p> 36 37 38 </div><p><small>Last revised: January 23, 2019 at 01:27:31 UTC</small></p> 39<hr> 40<div class="spirit-nav"> 41<a accesskey="p" href="../../reference/policies/terminate.html"><img src="../../images/prev.png" alt="Prev"></a> 42 <a accesskey="u" href="../../reference/policies.html"><img src="../../images/up.png" alt="Up"></a> 43 <a accesskey="h" href="../../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="../../reference/types.html"><img src="../../images/next.png" alt="Next"></a></div></body> 44</html> 45
