std::basic_ostream::swap

From cppreference.com


protected: void swap(basic_ostream& rhs);		(since C++11)

Calls basic_ios::swap(rhs) to swap all data members of the base class, except for rdbuf(), between *this and rhs. This swap function is protected: it is called by the swap functions of the swappable output stream classes std::basic_ofstream and std::basic_ostringstream, which know how to correctly swap the associated streambuffers.

[edit] Parameters

rhs

-

a basic_ostream of the same type to swap with

[edit] Example

run this code

#include <sstream>
#include <iostream>
#include <utility>
int main()
{
    std::ostringstream s1("hello");
    std::ostringstream s2("bye");
 
    s1.swap(s2); // OK, ostringstream has a public swap()
    std::swap(s1, s2); // OK, calls s1.swap(s2)
 
//  std::cout.swap(s2); // ERROR: swap is a protected member
 
    std::cout << s1.str() << '\n';
}

Output:

hello

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