<code></code>If the parameter <code>copy_from</code> is <code>NULL</code>, a new value is created and given initial values. If it is non-<code>NULL</code>, the value is copied into a new age value.<br>
<h3><a name="xref_value"></a>struct xref_value</h3>
<code></code>If the parameter <code>copy_from</code> is <code>NULL</code>, a new value is created and given initial values. If it is non-<code>NULL</code>, the value is copied into a new age value.<br>
<h3><a name="xref_value"></a>struct xref_value</h3>