#include <type_traits>

template <class T> 
struct is_trivially_copy_constructible;

std::is_trivially_copy_constructible<int>::value
std::is_trivially_copy_constructible<class T>::value

// C++ program to illustrate
// is_trivially_copy_constructible
#include <iostream>
#include <type_traits>
using namespace std;
  
// Struct Class
struct A {
};
struct B {
    B(const B&) {}
};
struct C {
    virtual void fn() {}
};
  
// Driver Code
int main()
{
    cout << boolalpha;
    cout << "is_trivially_copy_constructible: "
         << endl;
    cout << "int: " << is_trivially_copy_constructible<int>::value
         << endl;
    cout << "A: " << is_trivially_copy_constructible<A>::value
         << endl;
    cout << "B: " << is_trivially_copy_constructible<B>::value
         << endl;
    cout << "C: " << is_trivially_copy_constructible<C>::value
         << endl;
    return 0;
}

is_trivially_copy_constructible: 
int: true
A: true
B: false
C: false

// C++ program to illustrate
// is_trivially_copy_constructible
#include <iostream>
#include <type_traits>
using namespace std;
  
// Structure
struct Ex1 {
    string str;
};
struct Ex2 {
    int n;
    Ex2(const Ex2&) = default;
};
  
// Driver Code
int main()
{
    cout << boolalpha;
    cout << "Ex1 is copy-constructible吗？ ";
  
    cout << is_copy_constructible<Ex1>::value
         << endl;
  
    cout << "Ex1 是否平凡复制可构造? ";
  
    cout << is_trivially_copy_constructible<Ex1>::value
         << endl;
  
    cout << "Ex2 是否平凡复制可构造? ";
  
    cout << is_trivially_copy_constructible<Ex2>::value
         << endl;
  
    cout << "Ex2 是否无异常复制可构造? ";
  
    cout << is_nothrow_copy_constructible<Ex2>::value
         << endl;
}

Ex1 is copy-constructible? true
Ex1 是否平凡复制可构造? false
Ex2 是否平凡复制可构造? true
Ex2 是否无异常复制可构造? true