e</span>   <a name="boost.units.add_t_1_3_44_10_2_36_1_1_4.value_type"></a><span class="identifier">value_type</span><span class="special">;</span>
  <span class="keyword">typedef</span> <a class="link" href="unit.html" title="Class template unit">unit</a><span class="special">&lt;</span> <span class="identifier">Dim</span><span class="special">,</span> <span class="identifier">System</span> <span class="special">&gt;</span>               <a name="boost.units.add_t_1_3_44_10_2_36_1_1_4.unit_type"></a><span 