Class shared_ptr

uspace/lib/cpp/include/__bits/memory/shared_ptr.hpp:66–407

    template<class T>
    class shared_ptr
    {
        public:
            using element_type = T;

            /**
             * 20.8.2.2.1, constructors:
             */

            constexpr shared_ptr() noexcept
                : payload_{}, data_{}
            { /* DUMMY BODY */ }

            template<class U>
            explicit shared_ptr(
                U* ptr,
                enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
            )
                : payload_{}, data_{ptr}
            {
                try
                {
                    payload_ = new aux::shared_payload<T>{ptr};
                }
                catch (const bad_alloc&)
                {
                    delete ptr;

                    throw;
                }
            }

            template<class U, class D>
            shared_ptr(
                U* ptr, D deleter,
                enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
            )
                : shared_ptr{}
            {
                try
                {
                    payload_ = new aux::shared_payload<T, D>{ptr, deleter};
                }
                catch (const bad_alloc&)
                {
                    deleter(ptr);

                    throw;
                }
            }

            template<class U, class D, class A>
            shared_ptr(
                U* ptr, D deleter, A,
                enable_if_t<is_convertible_v<U*, element_type*>>* = nullptr
            )
                : shared_ptr{}
            {