20 General utilities library [utilities]

20.10 Metaprogramming and type traits [meta]

20.10.4 Unary type traits [meta.unary] Primary type categories [meta.unary.cat]

The primary type categories correspond to the descriptions given in section [basic.types] of the C++ standard.

For any given type T, the result of applying one of these templates to T and to cv-qualified T shall yield the same result.

Note: For any given type T, exactly one of the primary type categories has a value member that evaluates to true.  — end note ]

Table 47 — Primary type category predicates
template <class T>
struct is_void;
T is void
template <class T>
struct is_null_pointer;
T is std::nullptr_t ([basic.fundamental])
template <class T>
struct is_integral;
T is an integral type ([basic.fundamental])
template <class T>
struct is_floating_point;
T is a floating point type ([basic.fundamental])
template <class T>
struct is_array;
T is an array type ([basic.compound]) of known or unknown extent Class template array ([array]) is not an array type.
template <class T>
struct is_pointer;
T is a pointer type ([basic.compound]) Includes pointers to functions but not pointers to non-static members.
template <class T>
struct is_lvalue_reference;
T is an lvalue reference type ([dcl.ref])
template <class T>
struct is_rvalue_reference;
T is an rvalue reference type ([dcl.ref])
template <class T>
struct is_member_object_pointer;
T is a pointer to non-static data member
template <class T>
struct is_member_function_pointer;
T is a pointer to non-static member function
template <class T>
struct is_enum;
T is an enumeration type ([basic.compound])
template <class T>
struct is_union;
T is a union type ([basic.compound])
template <class T>
struct is_class;
T is a class type but not a union type ([basic.compound])
template <class T>
struct is_function;
T is a function type ([basic.compound])