"A SHM-classic interface around a single SHM pool with allocation-algorithm services by boost....">shm::classic::Pool_arena</a>) <code>Arena</code>s can always both read and write, allocate and deallocate. By contrast, shm::arena_lend has allocate/write-capable <code>Arena</code> and, on the borrower side, read-only borrower-quasi-<code>Arena</code>. If one needs to merely <em>read</em> a SHM-stored STL-compliant structure with such an <code>Arena</code>, then <b>only the <code>Pointer</code> type requireme