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std::basic_ofstream<CharT,Traits>::swap

From cppreference.com
< cpp‎ | io‎ | basic ofstream
 
 
 
 
void swap( basic_ofstream& other );
(since C++11)

Exchanges the state of the stream with those of other.

This is done by calling basic_ostream<CharT, Traits>::swap(other) and rdbuf()->swap(other.rdbuf()).

Contents

[edit] Parameters

other - stream to exchange the state with

[edit] Return value

(none)

[edit] Exceptions

May throw implementation-defined exceptions.

[edit] Example

#include <fstream>
#include <iomanip>
#include <iostream>
#include <string>
 
bool create_stream(std::fstream& fs, const std::string& path) {
    try {
        std::fstream fst { path, std::ios::trunc | std::ios::in | std::ios::out };
        if (fst.is_open()) {
            fst.swap( fs );
            return true;
        }
    } catch (...) {
        std::cout << "Exception!\n";
    }
    return false;
}
 
void use_stream(std::fstream& fs) {
    fs.seekg(0);
    std::string data;
    fs >> data;
    std::cout << "data: " << std::quoted(data) << '\n';
}
 
int main() {
    std::fstream fs;
    std::string path = "/tmp/test_file.txt";
    if (create_stream(fs, path)) {
        fs.write(path.c_str(), path.length());
        use_stream(fs);
    }
}

Possible output:

data: "/tmp/test_file.txt"

[edit] See also

(C++11)
moves the file stream
(public member function) [edit]
(C++11)
swaps two basic_filebuf objects
(public member function of std::basic_filebuf<CharT,Traits>) [edit]