 class="keyword">typedef</span> <span class="identifier">date_time</span><span class="special">::</span><span class="identifier">time_zone_base</span><span class="special">&lt;</span> <span class="identifier">posix_time</span><span class="special">::</span><span class="identifier">ptime</span><span class="special">,</span> <span class="identifier">CharT</span> <span class="special">&gt;</span> <a name="boost.local_time.custom_time_zone_base.base_type"></a><span class="identifier">base_type</span><span class