Std::tuple::swap (3) Linux Manual Page

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

std::tuple::swap (3) Linux Manual Page