rline"><code class="computeroutput"><a class="link" href="Reference.html#boost.units.quant_1_3_44_10_2_36_1_1_7">quantity_cast</a></code></span>
        to a reference allows direct access to the underlying value of a <span class="underline"><code class="computeroutput"><a class="link" href="../boost/units/quantity.html" title="Class template quantity">quantity</a></code></span>
        variable. An explicit constructor is provided to enable conversion between
        dimensionally compatible quantities in 