identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">target</span><span class="special">,</span> <span class="identifier">error_code</span><span class="special">&amp;</span> <span class="identifier">ec</span><span class="special">)</span>
<span class="special">{</span>
    <span class="comment">// It is the responsibility of the algorithm to clear the error first.</span>
    <