NAME¶

std::swap(std::basic_fstream) - std::swap(std::basic_fstream)

Synopsis¶

template< class CharT, class Traits >
void swap( basic_fstream<CharT, Traits>& lhs, basic_fstream<CharT, Traits>& rhs );

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

Parameters¶

lhs, rhs - streams whose state to swap

Return value¶

(none)

Exceptions¶

May throw implementation-defined exceptions.

Example¶

// Run this code

#include <fstream>
#include <iostream>
#include <string>

bool create_stream(std::fstream& fs)
{
try
{
std::string some_name = "/tmp/test_file.txt";
std::ios_base::openmode some_flags = fs.trunc; // | other flags

if (std::fstream ts{some_name, some_flags}; ts.is_open())
{
std::swap(ts, fs); // stream objects are not copyable => swap
return true;
}
}
catch (...)
{
std::cout << "Exception!\n";
}
return false;
}

int main()
{
if (std::fstream fs; create_stream(fs))
{
// use fs stream
}
}

See also¶

swap swaps two file streams
(C++11) (public member function)