ove object-like macros for defining our user-defined
      subtype to the udef_vmd_macros.hpp header file we have a new data type which
      we can use generically just like we can use numbers or v-types generically.
      It is important to include the header udef_vmd_macros.hpp in some translation
      unit whenever we need the VMD functionality for our new data type. So in our
      examples we will assume that an '#include udef_vmd_macros.hpp' precedes each
      example.
    </p>
<pre class="programl