class="special">(</span><span class="identifier">c</span><span class="special">))</span>
   <span class="special">{</span>
      <span class="comment">// use logarithmic growth stategy, in case</span>
      <span class="comment">// in_avail (above) returned zero:</span>
      <span class="keyword">if</span><span class="special">(</span><span class="identifier">s</span><span class="special">.</span><span class="identifier">capacity</span><span class="special">()</span> <span class="special">==</span> <span c