std::is_standard_layout

#include <iostream>
#include <type_traits>

struct Example {
    int x;
    double y;
};

int main() {
    if (std::is_standard_layout<Example>::value) {
        std::cout << "Example is a standard layout type." << std::endl;
    } else {
        std::cout << "Example is not a standard layout type." << std::endl;
    }

    return 0;
}