pan class="identifier">force_type</span><span class="special">,</span> <span class="number">1</span><span class="special">&gt;</span> <span class="special">{};</span>
<span class="comment">// define the conversion factor</span>
<span class="identifier">BOOST_UNITS_DEFINE_CONVERSION_FACTOR</span><span class="special">(</span><span class="identifier">my_unit_tag</span><span class="special">,</span> <span class="identifier">SI</span><span class="special">::</span><span class="identifier">force</span><span clas