std::tuple<Types...>::swap (3) - Linux Manuals

std::tuple<Types...>::swap: std::tuple<Types...>::swap

NAME

std::tuple<Types...>::swap - std::tuple<Types...>::swap

Synopsis

Defined in header <tuple>
void swap( tuple& other ) noexcept(/* see below */); (since C++11)
                                                                (until C++20)
constexpr void swap( tuple& other ) noexcept(/* see below */); (since C++20)

Calls swap (which might be std::swap, or might be found via ADL) for each element in *this and its corresponding element in other.

Parameters

other - tuple of values to swap

Return value

(none)

Exceptions

noexcept specification:
noexcept(
noexcept(swap(std::declval<T0&>>(), std::declval<T0&>())) &&
noexcept(swap(std::declval<T1&>>(), std::declval<T1&>())) && (until C++17)
noexcept(swap(std::declval<T2&>>(), std::declval<T2&>())) &&
...
)
In the expression above, the identifier swap is looked up in the same manner as the one used by the C++17 std::is_nothrow_swappable trait.
noexcept specification:
noexcept(
std::is_nothrow_swappable_v<T0> &&
std::is_nothrow_swappable_v<T1> && (since C++17)
std::is_nothrow_swappable_v<T2> &&
...
)

Example

// Run this code

  #include <iostream>
  #include <tuple>
  #include <string>

  int main()
  {
      std::tuple<int, std::string, float> p1, p2;
      p1 = std::make_tuple(10, "test", 3.14);
      p2.swap(p1);
      std::cout << "(" << std::get<0>(p2)
                << ", " << std::get<1>(p2)
                << ", " << std::get<2>(p2) << ")\n";
  }

Output:

  (10, test, 3.14)

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG_2456 C++11 the noexcept specification is ill-formed made to work