allocator<void>

class allocator<void> {
    typedef void *pointer;
    typedef const void *const_pointer;
    typedef void value_type;
    allocator();
    template<class U>
        allocator(const allocator<U>);
    template<class U>
        operator=(const allocator<U>);
    };

The class explicitly specializes template class allocator for type void. It defines only the types const_pointer, pointer, and value_type.