void swap( priority_queue& other ) noexcept(/* see below */);
(since C++11)
Exchanges the contents of the container adaptor with those of other. Effectively calls
using std::swap;
swap(c, other.c);
swap(comp, other.comp);


[edit] Parameters

other - container adaptor to exchange the contents with

[edit] Return value


[edit] Exceptions

noexcept specification:  
noexcept(noexcept(swap(c, other.c)) && noexcept(swap(comp, other.comp)))

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.

(since C++11)
(until C++17)
noexcept specification:  
noexcept(std::is_nothrow_swappable_v<Container> &&
(since C++17)

[edit] Complexity

Same as underlying container (typically constant).


Some implementations (e.g. libc++) provide the swap member function as an extension to pre-C++11 modes.

[edit] Example

#include <iostream>
#include <concepts>
#include <functional>
#include <queue>
#include <string>
#include <string_view>
#include <vector>
template<typename Adaptor>
requires (std::ranges::input_range<typename Adaptor::container_type>)
void print(std::string_view name, const Adaptor& adaptor)
    struct Printer : Adaptor // to use protected Adaptor::Container c;
        void print(std::string_view name) const
            std::cout << name << " [" << std::size(this->c) << "]: ";
            for (auto const& elem : this->c)
                std::cout << elem << ' ';
            std::cout << '\n';
    static_cast<Printer const&>(adaptor).print(name);
int main()
    std::vector<std::string> v1{"1","2","3","4"},
    std::priority_queue s1(std::less<>(), std::move(v1));
    std::priority_queue s2(std::less<>(), std::move(v2));
    print("s1", s1);
    print("s2", s2);
    print("s1", s1);
    print("s2", s2);


s1 [4]: 4 3 2 1
s2 [5]: Ǝ D Ɔ B Ɐ
s1 [5]: Ǝ D Ɔ B Ɐ
s2 [4]: 4 3 2 1

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

[edit] See also

specializes the std::swap algorithm
(function template) [edit]