20 General utilities library [utilities]

20.4 Pairs [pairs]

20.4.4 Tuple-like access to pair [pair.astuple]

template <class T1, class T2> struct tuple_size<pair<T1, T2>> : integral_constant<size_t, 2> { };

tuple_element<0, pair<T1, T2>>::type

1

Value: the type T1.

tuple_element<1, pair<T1, T2>>::type

2

Value: the type T2.

template<size_t I, class T1, class T2> constexpr tuple_element_t<I, pair<T1, T2>>& get(pair<T1, T2>& p) noexcept; template<size_t I, class T1, class T2> constexpr const tuple_element_t<I, pair<T1, T2>>& get(const pair<T1, T2>& p) noexcept; template<size_t I, class T1, class T2> constexpr tuple_element_t<I, pair<T1, T2>>&& get(pair<T1, T2>&& p) noexcept; template<size_t I, class T1, class T2> constexpr const tuple_element_t<I, pair<T1, T2>>&& get(const pair<T1, T2>&& p) noexcept;

3

Returns: If I == 0 returns a reference to p.first; if I == 1 returns a reference to p.second; otherwise the program is ill-formed.

template <class T, class U> constexpr T& get(pair<T, U>& p) noexcept; template <class T, class U> constexpr const T& get(const pair<T, U>& p) noexcept; template <class T, class U> constexpr T&& get(pair<T, U>&& p) noexcept; template <class T, class U> constexpr const T&& get(const pair<T, U>&& p) noexcept;

4

Requires: T and U are distinct types. Otherwise, the program is ill-formed.

5

Returns: A reference to p.first.

template <class T, class U> constexpr T& get(pair<U, T>& p) noexcept; template <class T, class U> constexpr const T& get(const pair<U, T>& p) noexcept; template <class T, class U> constexpr T&& get(pair<U, T>&& p) noexcept; template <class T, class U> constexpr const T&& get(const pair<U, T>&& p) noexcept;

6

Requires: T and U are distinct types. Otherwise, the program is ill-formed.

7

Returns: A reference to p.second.