</code> defines a boolean flag.  Here are the
types supported:</p>
<ul>
  <li> <code>DEFINE_bool</code>: boolean
  <li> <code>DEFINE_int32</code>: 32-bit integer
  <li> <code>DEFINE_int64</code>: 64-bit integer
  <li> <code>DEFINE_uint64</code>: unsigned 64-bit integer
  <li> <code>DEFINE_double</code>: double
  <li> <code>DEFINE_string</code>: C++ string
</ul>

<p>Note that there are no 'complex' types like lists: the "languages"
flag in our example is a list of strings, but is defined of type
"string", no