swap(std::move_only_function)

Since C++23

Overloads the std::swap algorithm for std::move_only_function. Exchanges the state of lhs with that of rhs. Effectively calls lhs.swap(rhs).

# Declarations

friend void swap( std::move_only_function& lhs, std::move_only_function& rhs ) noexcept;

(since C++23)

# Parameters

# Return value

(none)

# Example

#include <concepts>
#include <functional>
#include <iostream>
 
void foo(const char* str, int x)
{
    std::cout << "foo(\"" << str << "\", " << x << ")\n";
}
 
void bar(const char* str, int x)
{
    std::cout << "bar(\"" << str << "\", " << x << ")\n";
}
 
int main()
{
    std::move_only_function<void(const char*, int) const> f1{foo};
    std::move_only_function<void(const char*, int) const> f2{bar};
 
    f1("f1", 1);
    f2("f2", 2);
 
    std::cout << "std::ranges::swap(f1, f2);\n";
    std::ranges::swap(f1, f2); // finds the hidden friend
 
    f1("f1", 1);
    f2("f2", 2);
}

# See also