 iterator is attached. Because iterators have a well-defined, common
  interface the iterator wrapper is implemented with the iterator
  adaptor class template <code class="code">__gnu_debug::_Safe_iterator</code>,
  which takes two template parameters:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="code">Iterator</code>: The underlying iterator type, which must
    be either the <code class="code">iterator</code> or <code class="co