s="special">;</span>
  <span class="keyword">typedef</span> <span class="identifier">System</span>              <a name="boost.units.unit.system_type"></a><span class="identifier">system_type</span><span class="special">;</span>   

  <span class="comment">// <a class="link" href="unit.html#boost.units.unitconstruct-copy-destruct">construct/copy/destruct</a></span>
  <a class="link" href="unit.html#idp109872528-bb"><span class="identifier">unit</span></a><span class="special">(</span><span class="special">)