 <span class="keyword">const</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span></pre></li>
<li class="listitem"><pre class="literallayout"><span class="keyword">virtual</span> <span class="identifier">duration_type</span> <a name="id-1_3_12_15_3_20_1_1_1_7_4-bb"></a><span class="identifier">get_neg_offset</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">date_type</span> <span class="special">&amp;</span> current<sp