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

class template

<type_traits>

std::is_trivially_copyable

template <class T> struct is_trivially_copyable;

Is trivially copyable

Trait class that identifies whether T is a trivially copyable type.

A trivially copyable type is a type whose storage is contiguous (and thus its copy implies a trivial memory block copy, as if performed with memcpy), either cv-qualified or not. This is true for scalar types, trivially copyable classes and arrays of any such types.

A trivially copyable class is a class (defined with class, struct or union) that:

uses the implicitly defined copy and move constructors, copy and move assignments, and destructor.
has no virtual members.
its base class and non-static data members (if any) are themselves also trivially copyable types.

This class inherits from integral_constant as being either true_type or false_type, depending on whether T is a trivially copyable type.

Template parameters

T: A complete type, or void (possible cv-qualified), or an array of unknown bound of a complete element type.

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_copiable example
#include <iostream>
#include <type_traits>

struct A { int i; };

struct B {
  int i,j;
  B (const B& x) : i(x.i), j(1) {};  // copy ctor
};

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

Output:

is_trivially_copyable:
int: true
A: true
B: false