ss="cf">for</span> (<span class="dt">int64_t</span> i=<span class="dv">0</span>; i&lt;num_threads; ++i)</a>
<a class="sourceLine" id="cb2-37" title="37">        threads[i]-&gt;join();</a>
<a class="sourceLine" id="cb2-38" title="38">}</a></code></pre></div>
<p>Using multiple threads, we are able to populate the <em>parallel_flat_hash_map</em> (inserting 100 million values) three times faster than the standard <em>flat_hash_map</em> (which we could not have populated from multiple threads without explicit lo