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 framework

Examples:

 identity<float>::value f = 3.14159f;
 true == is_same<identity<int>::value, int>::value;

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TemplateMetaprogrammingTechniques CategoryCppTemplates