title: C++ Using a reference to a string as an alias
body: <p>Is it always safe to use a reference of an object as an alias? For example, a string:</p>
  
  <pre><code>std::string test;
  std::string &amp;reftest( test );
  std::cout &lt;&lt; "test before: " &lt;&lt; test &lt;&lt; "\n";
  std::cout &lt;&lt; "reftest before: " &lt;&lt; reftest &lt;&lt; "\n";
  reftest = "abc";
  std::cout &lt;&lt; "test after: " &lt;&lt; test &lt;&lt; "\n";
  std::cout &lt;&lt; "reftest after: " &lt;&lt; reftest &lt;&lt; "\n";
  </code></pre>
  
  <p>Is there a guarantee that reftest and test will always have the same string?</p>