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std::is_compound

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

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

a type to check

Helper variable template

template< class T >
inline constexpr bool is_compound_v = is_compound<T>::value;

(since C++17)

Inherited from std::integral_constant

Member constants

value

[static]

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

Member functions

operator bool	converts the object to `bool`, returns `value` (public member function)
operator() (C++14)	returns `value` (public member function)

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

#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

is_fundamental (C++11)	checks if a type is fundamental type (class template)
is_scalar (C++11)	checks if a type is scalar type (class template)
is_object (C++11)	checks if a type is object type (class template)
is_array (C++11)	checks if a type is an array type (class template)