C++ constructors check ...

noncopyable.cc

/*
 * checking some assumptions
 * compile with: clang++ -Weverything -Wno-c++98-compat -std=c++17 -o noncopyable noncopyable.cc
 */

#include <iostream>
#include <type_traits>

class Default {};

class Uncopiable
{
    public:
        Uncopiable() = default;
        Uncopiable(Uncopiable&& _c) = default;
        Uncopiable& operator=(Uncopiable&&) = default;
};

static_assert(std::is_copy_constructible<Uncopiable>::value == false, "Uncopiable must be non copy constructible");
static_assert(std::is_copy_assignable<Uncopiable>::value == false, "Uncopiable must be non copy assignable");

class Unmovable
{
    public:
        ~Unmovable() = default;
};

class No
{
    public:
        No() = delete;
        No(No&&) = delete;
        No(const No&) = delete;

        ~No() { std::cout << "Yes !" << std::endl; }
};

static No yes() { return No{}; }

int main()
{
    std::cout << std::boolalpha
        << "is_default_constructible<Default>: " << std::is_default_constructible<Default>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_constructible<Default>: " << std::is_copy_constructible<Default>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_assignable<Default>: " << std::is_copy_assignable<Default>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_constructible<Default>: " << std::is_move_constructible<Default>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_assignable<Default>: " << std::is_move_assignable<Default>::value << std::endl;

    std::cout << std::endl;

    std::cout << std::boolalpha
        << "is_default_constructible<Uncopiable>: " << std::is_default_constructible<Uncopiable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_constructible<Uncopiable>: " << std::is_copy_constructible<Uncopiable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_assignable<Uncopiable>: " << std::is_copy_assignable<Uncopiable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_constructible<Uncopiable>: " << std::is_move_constructible<Uncopiable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_assignable<Uncopiable>: " << std::is_move_assignable<Uncopiable>::value << std::endl;

    std::cout << std::endl;

    std::cout << std::boolalpha
        << "is_default_constructible<Unmovable>: " << std::is_default_constructible<Unmovable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_constructible<Unmovable>: " << std::is_copy_constructible<Unmovable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_assignable<Unmovable>: " << std::is_copy_assignable<Unmovable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_constructible<Unmovable>: " << std::is_move_constructible<Unmovable>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_assignable<Unmovable>: " << std::is_move_assignable<Unmovable>::value << std::endl;

    std::cout << std::endl;

    std::cout << std::boolalpha
        << "is_default_constructible<No>: " << std::is_default_constructible<No>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_constructible<No>: " << std::is_copy_constructible<No>::value << std::endl;
    std::cout << std::boolalpha
        << "is_copy_assignable<No>: " << std::is_copy_assignable<No>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_constructible<No>: " << std::is_move_constructible<No>::value << std::endl;
    std::cout << std::boolalpha
        << "is_move_assignable<No>: " << std::is_move_assignable<No>::value << std::endl;

    No n = yes();
    (void)n;

    return 0;
}