std::experimental::make_array

 

C++

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Standard library headers

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Utilities library

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Regular expressions library (C++11)

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Technical Specifications

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Extensions for concurrency (concurrency TS)

Concepts (concepts TS)

Ranges (ranges TS)

Special mathematical functions (special math TR)

 

Library fundamentals v2

experimental::propagate_const

experimental::not_fn

experimental::observer_ptr

experimental::make_array

experimental::to_array

experimental::ostream_joiner

experimental::gcd

experimental::lcm

experimental::source_location

experimental::randint

detection idiom

uniform container erasure

logical operator type traits

 

Defined in header <experimental/array>
template <class D = void, class... Types> constexpr std::array<VT /* see below */, sizeof...(Types)> make_array(Types&&... t);		(library fundamentals TS v2)

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.

Possible implementation

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::experimental::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::experimental::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)... }; }

Example

Run this code

#include <experimental/array>
#include <iostream>
#include <type_traits>
 
int main()
{
    decltype(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

See also

to_array

Creates a std::array object from a built-in array (function template)