function::swap

Swap two callable objects.

void swap(function& right);

Parameters

• right
  The function object to swap with.

Remarks

The member function swaps the target objects between *this and right. It does so in constant time and throws no exceptions.

Example

// std_tr1__functional__function_swap.cpp 
// compile with: /EHsc 
#include <functional> 
#include <iostream> 
 
int neg(int val) 
    { 
    return (-val); 
    } 
 
int main() 
    { 
    std::function<int (int)> fn0(neg); 
    std::cout << std::boolalpha << "empty == " << !fn0 << std::endl; 
    std::cout << "val == " << fn0(3) << std::endl; 
 
    std::function<int (int)> fn1; 
    std::cout << std::boolalpha << "empty == " << !fn1 << std::endl; 
    std::cout << std::endl; 
 
    fn0.swap(fn1); 
    std::cout << std::boolalpha << "empty == " << !fn0 << std::endl; 
    std::cout << std::boolalpha << "empty == " << !fn1 << std::endl; 
    std::cout << "val == " << fn1(3) << std::endl; 
 
    return (0); 
    } 
 

empty == false
val == -3
empty == true

empty == true
empty == false
val == -3

Requirements

Header: <functional>

Namespace: std

See Also

Reference

function Class

function::operator=