
<a href=
"https://boost.org/sgi/stl/Assignable.html">Assignable</a>, <a
href=
"https://boost.org/sgi/stl/DefaultConstructible.html">Default
Constructible</a>, <a href=
"https://boost.org/sgi/stl/EqualityComparable.html">Equality
Comparable</a>, <a href=
"https://boost.org/sgi/stl/LessThanComparable.html">LessThan
Comparable</a>.

<h3><a id="type-requirements">Type requirements</a></h3>

<tt>Block</tt> is an unsigned integer type. <tt>Allocator</tt>
satisfies the Standard requirements for an allocator.

<h3