std::is_trivial

template< class T >
struct is_trivial;

#include <type_traits>
 
struct A { int m; };
static_assert(std::is_trivial_v<A> == true);
 
struct B { B() {} };
static_assert(std::is_trivial_v<B> == false);
 
// The following class shows why std::is_trivial(_v) may be a pitfall.
class C
{
private:
    C() = default;
};
 
static_assert(std::is_trivial_v<C> == true);
static_assert(std::is_trivially_default_constructible_v<C> == false);
 
int main() {}