+template <typename T> struct is_pointer<T* const> : true_type {};
+template <typename T> struct is_pointer<T* volatile> : true_type {};
+template <typename T> struct is_pointer<T* const volatile> : true_type {};
+
+/// \brief Metafunction that determines whether the given type is either an
+/// integral type or an enumeration type.
+///
+/// Note that this accepts potentially more integral types than we whitelist
+/// above for is_integral because it is based on merely being convertible
+/// implicitly to an integral type.
+template <typename T> class is_integral_or_enum {
+ // Provide an overload which can be called with anything implicitly
+ // convertible to an unsigned long long. This should catch integer types and
+ // enumeration types at least. We blacklist classes with conversion operators
+ // below.
+ static double check_int_convertible(unsigned long long);
+ static char check_int_convertible(...);
+
+ typedef typename remove_reference<T>::type UnderlyingT;
+ static UnderlyingT &nonce_instance;
+
+public:
+ enum {
+ value = (!is_class<UnderlyingT>::value && !is_pointer<UnderlyingT>::value &&
+ !is_same<UnderlyingT, float>::value &&
+ !is_same<UnderlyingT, double>::value &&
+ sizeof(char) != sizeof(check_int_convertible(nonce_instance)))
+ };
+};