RetroSearch Browse

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://cplusplus.com/reference/type_traits/is_trivially_constructible/ below:

class template

<type_traits>

std::is_trivially_constructible

template <class T, class... Args> struct is_trivially_constructible;

Is trivially constructible

Trait class that identifies whether T is a trivially constructible type with the set of argument types specified by Arg.

For this class, a trivially constructible type is a type which can be trivially default-, copy- or move- constructed, depending on the particular set of argument types used as Args (see is_trivially_default_constructible, is_trivially_copy_constructible and is_trivially_move_constructible).

is_trivially_constructible inherits from integral_constant as being either true_type or false_type, depending on whether T is trivially constructible with the list of arguments Args.

Template parameters

T: A complete type, or void (possible cv-qualified), or an array of unknown bound.
Args: A list of complete types (or void, possibly cv-qualified, or an array of unknown bound) representing the argument types for the constructor form, in the same order as in the constructor.
If omitted, it checks whether the type is trivilly default-constructible.

Member types Inherited from integral_constant:

Member constants Inherited from integral_constant:
member constant definition value either true or false
Member functions Inherited from integral_constant:

operator bool: Returns value (public member function)

Example

// is_trivially_constructible example
#include <iostream>
#include <type_traits>

struct A { };
struct B { B(){} };  // non-trivial default ctor.

int main() {
  std::cout << std::boolalpha;
  std::cout << "is_trivially_constructible:" << std::endl;
  std::cout << "A(): " << std::is_trivially_constructible<A>::value << std::endl;
  std::cout << "A(A): " << std::is_trivially_constructible<A,A>::value << std::endl;
  std::cout << "B(): " << std::is_trivially_constructible<B>::value << std::endl;
  std::cout << "B(B): " << std::is_trivially_constructible<B,B>::value << std::endl;
  return 0;
}

Output:

is_trivially_constructible:
A(): true
A(A): true
B(): false
B(B): true