="white-space: normal"><pre>
class construct_from 
{ 
    ... 
}; 

void main(){ 
    ... 
    Y y; 
    construct_from x(y); 
    ar &lt;&lt; x; 
} 
</pre></code>

Suppose that the above message is not displayed and the code is used as is.
<ol>
  <li>this example compiles and executes fine. No tracking is done because 
  construct_from has never been serialized through a pointer. Now some time 
  later, the next programmer(2) comes along and makes an enhancement. He 
  wants the archive to be sort of a log