For virtuals.</span>
        <span class="identifier">boost</span><span class="special">::</span><span class="identifier">contract</span><span class="special">::</span><span class="identifier">old_ptr</span><span class="special">&lt;</span><span class="keyword">unsigned</span><span class="special">&gt;</span> <span class="identifier">old_size</span> <span class="special">=</span>
                <span class="identifier">BOOST_CONTRACT_OLDOF</span><span class="special">(</span><span class="identifier">v</spa