std::tuple<Types...>::swap
Defined in header <tuple>
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void swap( tuple& other ) noexcept(/* see below */); |
(1) | (since C++11) (constexpr since C++20) |
constexpr void swap( const tuple& other ) noexcept(/* see below */) const; |
(2) | (since C++23) |
Calls swap
(which might be std::swap, or might be found via ADL) for each element in *this and its corresponding element in other.
If any selected |
(until C++23) |
If any selected |
(since C++23) |
Contents |
[edit] Parameters
other | - | tuple of values to swap |
[edit] Return value
(none)
[edit] Exceptions
noexcept specification:
noexcept( noexcept(swap(std::declval<T0&>>(), std::declval<T0&>())) && In the expression above, the identifier |
(until C++17) |
1)
noexcept specification:
noexcept((std::is_nothrow_swappable_v<Types> && ...)) 2) noexcept specification:
noexcept((std::is_nothrow_swappable_v<const Types> && ...)) |
(since C++17) |
[edit] Example
#include <iostream> #include <string> #include <tuple> int main() { std::tuple<int, std::string, float> p1{42, "ABCD", 2.71}, p2; p2 = std::make_tuple(10, "1234", 3.14); auto print_p1_p2 = [&](auto rem) { std::cout << rem << "p1 = {" << std::get<0>(p1) << ", " << std::get<1>(p1) << ", " << std::get<2>(p1) << "}, " << "p2 = {" << std::get<0>(p2) << ", " << std::get<1>(p2) << ", " << std::get<2>(p2) << "}\n"; }; print_p1_p2("Before p1.swap(p2): "); p1.swap(p2); print_p1_p2("After p1.swap(p2): "); swap(p1, p2); print_p1_p2("After swap(p1, p2): "); }
Output:
Before p1.swap(p2): p1 = {42, ABCD, 2.71}, p2 = {10, 1234, 3.14} After p1.swap(p2): p1 = {10, 1234, 3.14}, p2 = {42, ABCD, 2.71} After swap(p1, p2): p1 = {42, ABCD, 2.71}, p2 = {10, 1234, 3.14}
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
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LWG 2456 | C++11 | the noexcept specification is ill-formed
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made to work |
[edit] See also
(C++11) |
specializes the std::swap algorithm (function template) |
(C++11) |
swaps the contents (public member function of std::pair<T1,T2> )
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