an><span class="special">(</span><span class="special">)</span><span class="special">)</span> 
    <span class="special">==</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">date_time</span><span class="special">::</span><span class="identifier">is_not_in_dst</span><span class="special">)</span> 
<span class="special">{</span>

<span class="special">}</span>
</pre>
<p> This generates a type suitable for the calculation of dst transitions for the United State