>00063     difference_type step()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> _step_fn.step(); }
<a name="l00064"></a>00064 
<a name="l00065"></a>00065 <span class="keyword">protected</span>:
<a name="l00066"></a>00066     SFn _step_fn;
<a name="l00067"></a>00067 <span class="keyword">private</span>:
<a name="l00068"></a>00068     <span class="keyword">friend</span> <span class="keyword">class </span>boost::iterator_core_access;
<a name="l00069"></a>00069 
<a name="l00070"><