::multiply_typeof_helper</a><span class="special">&lt;</span> <a class="link" href="../units/quantity.html" title="Class template quantity">boost::units::quantity</a><span class="special">&lt;</span> <span class="identifier">Unit1</span><span class="special">,</span> <span class="identifier">Y</span> <span class="special">&gt;</span><span class="special">,</span> <a class="link" href="../units/unit.html" title="Class template unit">boost::units::unit</a><span class="special">&lt;</span> <span class="identif