std::basic_istream::~basic_istream

From cppreference.com
< cpplrm; | iolrm; | basic istream
virtual ~basic_istream();

Destructs the input stream.

Notes

This destructor does not perform any operation on the underlying streambuffer (rdbuf()): the destructors of the derived input streams such as std::basic_ifstream and std::basic_istringstream are responsible for calling the destructors of the streambuffers.

Example

#include <sstream>
#include <iostream>

void print_stringbuf(std::streambuf* p)
{
    std::istream buf(p); // buf shares the buffer with s1
    int n;
    buf >> n;
    std::cout << n;
} // calls the destructor of buf. p remains unaffected

int main()
{
    std::istringstream s1("10 20");
    print_stringbuf(s1.rdbuf());
    int n;
    s1 >> n;
    std::cout << ',' << n << '\n';
}

Output:

10,20