std::swap(std::function)

Since C++11

Header: <functional>

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

# Declarations

template< class R, class... Args >
void swap( std::function<R(Args...)>& lhs, std::function<R(Args...)>& rhs ) noexcept;

(since C++11)

# Parameters

lhs, rhs: polymorphic function wrappers whose states to swap

# Return value

(none)

# Example

#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::function<void(const char*, int)> f1{foo};
    std::function<void(const char*, int)> f2{bar};
 
    f1("f1", 1);
    f2("f2", 2);
 
    std::cout << "std::swap(f1, f2);\n";
    std::swap(f1, f2);
 
    f1("f1", 1);
    f2("f2", 2);
}

# Defect reports

DR	Applied to	Behavior as published	Correct behavior
LWG 2062	C++11	overload of swap for function was not required to be noexcept	required

std::swap(std::function)

# Declarations

# Parameters

# Return value

# Example

# Defect reports

# See also