></div><p>
    </p><p> The libstdc++ debug mode replaces unsafe (but efficient) standard
  containers and iterators with semantically equivalent safe standard
  containers and iterators to aid in debugging user programs. The
  following goals directed the design of the libstdc++ debug mode:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><span class="emphasis"><em>Correctness</em></span>: the libstdc++ debug mode must not change
    the semantics