title: Address of map value
body: <p>I have a settings which are stored in <code>std::map</code>. For example, there is <code>WorldTime</code> key with value which updates each main cycle iteration. I don't want to read it from map when I do need (it's also processed each frame), I think it's not fast at all. So,  can I get pointer to the map's value and access it? The code is:</p>
  
  <pre><code>std::map&lt;std::string, int&gt; mSettings;
  
  // Somewhere in cycle:
  mSettings["WorldTime"] += 10; // ms
  
  // Somewhere in another place, also called in cycle
  DrawText(mSettings["WorldTime"]); // Is slow to call each frame
  </code></pre>
  
  <p>So the idea is something like:</p>
  
  <pre><code>int *time = &amp;mSettings["WorldTime"];
  
  // In cycle:
  DrawText(&amp;time);
  </code></pre>
  
  <p>How wrong is it? Should I do something like that?</p>