The identity metafunction stores the type provided in value. The is_same metafunction uses partial template specialization to determine at compile time if two object types are the same.
namespace framework { namespace meta { template <typename T> struct identity { typedef T value; }; template <typename T0, typename T1> struct is_same { enum { value = false }; }; template <typename T> struct is_same<T, T> { enum { value = true }; }; } // namespace meta } // namespace frameworkExamples:
identity<float>::value f = 3.14159f; true == is_same<identity<int>::value, int>::value;