std::is_compound (3) - Linux Manuals

std::is_compound: std::is_compound

NAME

std::is_compound - std::is_compound

Synopsis

Defined in header <type_traits>
template< class T > (since C++11)
struct is_compound;

If T is a compound type (that is, array, function, object pointer, function pointer, member object pointer, member function pointer, reference, class, union, or enumeration, including any cv-qualified variants), provides the member constant value equal true. For any other type, value is false.

Template parameters

T - a type to check

Helper variable template

template< class T > (since C++17)
inline constexpr bool is_compound_v = is_compound<T>::value;

Inherited from std::integral_constant

Member constants

value true if T is a compound type , false otherwise
         (public static member constant)
[static]

Member functions

              converts the object to bool, returns value
operator bool (public member function)

operator() returns value
              (public member function)
(C++14)

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>

Notes

Compound types are the types that are constructed from fundamental types. Any C++ type is either fundamental or compound.

Possible implementation

  template< class T >
  struct is_compound : std::integral_constant<bool, !std::is_fundamental<T>::value> {};

Example

// Run this code

  #include <iostream>
  #include <type_traits>

  int main() {
      class cls {};
      std::cout << (std::is_compound<cls>::value
                       ? "T is compound"
                       : "T is not a compound") << '\n';
      std::cout << (std::is_compound<int>::value
                       ? "T is compound"
                       : "T is not a compound") << '\n';
  }

Output:

  T is compound
  T is not a compound