Defined in header <tuple> | ||
|---|---|---|
template <class T, class Tuple> constexpr T make_from_tuple(Tuple&& t); | (since C++17) |
Construct an object of type T, using the elements of the tuple t as the arguments to the constructor.
| t | - | tuple whose elements to be used as arguments to the constructor of T |
The constructed T object.
The tuple need not be std::tuple, and instead may be anything that supports std::get and std::tuple_size; in particular, std::array and std::pair may be used.
Due to guaranteed copy elision, T need not be movable.
namespace detail {
template <class T, class Tuple, std::size_t... I>
constexpr T make_from_tuple_impl( Tuple&& t, std::index_sequence<I...> )
{
return T(std::get<I>(std::forward<Tuple>(t))...);
}
} // namespace detail
template <class T, class Tuple>
constexpr T make_from_tuple( Tuple&& t )
{
return detail::make_from_tuple_impl<T>(std::forward<Tuple>(t),
std::make_index_sequence<std::tuple_size_v<std::decay_t<Tuple>>>{});
} |
creates a tuple object of the type defined by the argument types (function template) |
|
creates a tuple of rvalue references (function template) |
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(C++17) | calls a function with a tuple of arguments (function template) |
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