r_allocator_new_delete</span><span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">singleton_pool</span>
<span class="special">{</span>
  <span class="keyword">public</span><span class="special">:</span>
    <span class="keyword">typedef</span> <span class="identifier">Tag</span> <span class="identifier">tag</span><span class="special">;</span>
    <span class="keyword">typedef</span> <span class="identifier">UserAllocator</span> <span class="identifier">user_allocat