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- <div class="titlepage"><div><div><h1 style="clear: both">String refs</h1></div></div></div>
- <p><code><system_error2></code> does not use <code>std::string</code> to return possibly statically
- or dynamically allocated strings, and thus avoids dragging in a lot of the
- standard library which impacts build times.</p>
- <p>Instead status code domains have a <a href="https://ned14.github.io/status-code/doc_status_code_domain.html#standardese-system_error2__status_code_domain__string_ref"><code>string_ref</code></a>,
- which has a polymorphic implementation which may or may not <a href="https://ned14.github.io/status-code/doc_status_code_domain.html#standardese-system_error2__status_code_domain__atomic_refcounted_string_ref">manage a dynamic
- memory allocation using an atomic reference counter</a>. Due to this polymorphism, you don’t
- need to worry which implementation is actually in use under the bonnet
- when you pass around <code>string_ref</code> instances.</p>
- <p><code>string_ref</code> provides the same member functions as a <code>span<const char></code>,
- and so participates ordinarily in STL algorithms and containers. In
- particular, if you need to string search or slice it, you can construct a
- <code>string_view</code> on top easily.</p>
- <div class="code-snippet"><div class="highlight"><pre class="chroma"><code class="language-c++" data-lang="c++"> <span class="c1">// Return the name of our custom code domain
- </span><span class="c1"></span> <span class="k">virtual</span> <span class="n">_base</span><span class="o">::</span><span class="n">string_ref</span> <span class="n">name</span><span class="p">()</span> <span class="k">const</span> <span class="k">noexcept</span> <span class="k">override</span> <span class="k">final</span> <span class="c1">// NOLINT
- </span><span class="c1"></span> <span class="p">{</span>
- <span class="k">static</span> <span class="n">string_ref</span> <span class="n">v</span><span class="p">(</span><span class="s">"file i/o error domain"</span><span class="p">);</span>
- <span class="k">return</span> <span class="n">v</span><span class="p">;</span> <span class="c1">// NOLINT
- </span><span class="c1"></span> <span class="p">}</span>
- </code></pre></div><a href="https://github.com/boostorg/outcome/tree/master/doc/src/snippets/experimental_status_code.cpp#L103" class="code-snippet-url" target="_blank">View this code on Github</a></div>
- <p>Now you understand what <code>string_ref</code> does, returning the name of the
- status code domain is self describing. Note we use the non-managing
- constructor of <code>string_ref</code>, as the string <code>"file i/o error domain"</code>
- is statically stored. We cache the returned value locally in static
- storage.</p>
- </div><p><small>Last revised: January 26, 2019 at 23:38:56 UTC</small></p>
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