ctor called by this library <code class="computeroutput">f()</code> to assign old value copies just before the body is executed but after entry invariants (when they apply) and preconditions are checked. Old value pointers within this functor call are usually assigned using <code class="computeroutput"><code class="computeroutput"><a class="link" href="../../BOOST_CONTRACT_OLDOF.html" title="Macro BOOST_CONTRACT_OLDOF">BOOST_CONTRACT_OLDOF</a></code></code>. Any exception thrown by a call to this functor wi