ruct"></a><code class="computeroutput">old_value_copy</code> 
        public
       construct/copy/destruct</h3>
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<pre class="literallayout"><span class="keyword">explicit</span> <a name="idm36463-bb"></a><span class="identifier">old_value_copy</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&amp;</span> old<span class="special">)</span><span class="sp