 the allocators (including implementation-specific ones) determine the type of the underlying Pool, with the exception of the first parameter T, whose size is used instead.</p>
<p>Since the size of T is used to determine the type of the underlying Pool, each allocator for different types of the same size will share the same underlying pool. The tag class prevents pools from being shared between pool_allocator and fast_pool_allocator. For example, on a system where <code class="computeroutput">sizeof(int) ==