get()</code> returns
a reference to a default initialized <code>C</code> object unique to
<code>Holder</code>. No invocation of <code>Holder::get()</code>, except possibly
the first one in the program, does throw.
<a href="flyweight.html#flyweight"><code>flyweight</code></a>
privately uses a holder to instantiate a <a href="factories.html#factory">factory</a>
and some additional data (like a <a href="locking.html#preliminary">mutex</a> for
internal synchronization) unique to each instantiation type of the c