std::basic_filebuf::swap

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Input/output library

I/O manipulators

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

strstreambuf (deprecated in C++98)

basic_syncbuf (C++20)

Streams

Abstractions

ios_base

basic_ios

basic_istream

basic_ostream

basic_iostream

File I/O

basic_ifstream

basic_ofstream

basic_fstream

String I/O

basic_istringstream

basic_ostringstream

basic_stringstream

Array I/O

istrstream (deprecated in C++98)

ostrstream (deprecated in C++98)

strstream (deprecated in C++98)

Synchronized Output

basic_osyncstream (C++20)

Types

streamoff

streamsize

fpos

Error category interface

iostream_category (C++11)

io_errc (C++11)

 

std::basic_filebuf

Public member functions

basic_filebuf::basic_filebuf

basic_filebuf::~basic_filebuf

basic_filebuf::operator= (C++11)

basic_filebuf::swap (C++11)

basic_filebuf::is_open

basic_filebuf::open

basic_filebuf::close

Protected member functions

basic_filebuf::showmanyc

basic_filebuf::underflow

basic_filebuf::uflow

basic_filebuf::pbackfail

basic_filebuf::overflow

basic_filebuf::setbuf

basic_filebuf::seekoff

basic_filebuf::seekpos

basic_filebuf::sync

basic_filebuf::imbue

Non-member functions

swap(std::basic_filebuf) (C++11)

 

void swap( std::basic_filebuf& rhs );		(since C++11)

Swaps the state and the contents of *this and rhs.

Parameters

rhs

-

another basic_filebuf

Return value

(none)

Notes

This function is called automatically when swapping std::fstream objects, it is rarely necessary to call it directly.

Example

Run this code

#include <fstream>
#include <string>
#include <iostream>
 
int main()
{
    std::ifstream fin("test.in"); // read-only
    std::ofstream fout("test.out"); // write-only
 
    std::string s;
    getline(fin, s);
    std::cout << s << '\n'; // outputs the first line of test.in
 
    fin.rdbuf()->swap(*fout.rdbuf()); //swap the underlying buffers
 
    getline(fin, s); // fails: cannot read from a write-only filebuf
    std::cout << s << '\n'; // prints empty line
}

See also

operator= (C++11)	assigns a basic_filebuf object (public member function)
std::swap(std::basic_filebuf) (C++11)	specializes the std::swap algorithm (function template)
swap (C++11)	swaps two file streams (public member function of std::basic_fstream)