Creates a std::array whose size is equal to the number of arguments and whose elements are initialized from the corresponding arguments. Returns std::array<VT, sizeof...(Types)>{std::forward<Types>(t)...}.
If D is void, then the deduced type VT is std::common_type_t<Types...>. Otherwise, it is D.
If D is void and any of std::decay_t<Types>... is a specialization of std::reference_wrapper, the program is ill-formed.
make_array is removed in Library Fundamentals TS v3 because the deduction guide for std::array and std::to_array have been already in C++20.
namespace details
{
template<class> struct is_ref_wrapper : std::false_type{};
template<class T> struct is_ref_wrapper<std::reference_wrapper<T>> : std::true_type{};
template<class T>
using not_ref_wrapper = std::negation<is_ref_wrapper<std::decay_t<T>>>;
template<class D, class...> struct return_type_helper { using type = D; };
template<class... Types>
struct return_type_helper<void, Types...> : std::common_type<Types...>
{
static_assert(std::conjunction_v<not_ref_wrapper<Types>...>,
"Types cannot contain reference_wrappers when D is void");
};
template<class D, class... Types>
using return_type = std::array<typename return_type_helper<D, Types...>::type,
sizeof...(Types)>;
}
template<class D = void, class... Types>
constexpr details::return_type<D, Types...> make_array(Types&&... t)
{
return {std::forward<Types>(t)...};
}[edit] Example
#include <experimental/array>
#include <iostream>
#include <type_traits>
int main()
{
auto arr = std::experimental::make_array(1, 2, 3, 4, 5);
bool is_array_of_5_ints = std::is_same<decltype(arr), std::array<int, 5>>::value;
std::cout << "Returns an array of five ints? ";
std::cout << std::boolalpha << is_array_of_5_ints << '\n';
}
Output:
Returns an array of five ints? true[edit] See also
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