std::basic_filebuf<CharT,Traits>::operator=

 

C++

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Feature test macros (C++20)

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Technical specifications

Symbols index

External libraries

 

Input/output library

I/O manipulators

Print functions (C++23)

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

basic_spanbuf (C++23)

strstreambuf (C++98/26*)

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

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basic_istringstream

basic_ostringstream

basic_stringstream

Array I/O

basic_ispanstream (C++23)

basic_ospanstream (C++23)

basic_spanstream (C++23)

istrstream (C++98/26*)

ostrstream (C++98/26*)

strstream (C++98/26*)

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::native_handle (C++26)

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)

 

std::basic_filebuf& operator=( std::basic_filebuf&& rhs );	(1)	(since C++11)
std::basic_filebuf& operator=( const std::basic_filebuf& rhs ) = delete;	(2)

Assigns another basic_filebuf object.

1) First calls close() to close the associated file, then moves the contents of rhs into *this: the put and get buffers, the associated file, the locale, the openmode, the is_open flag, and any other state. After the move, rhs is not associated with a file and rhs.is_open() == false.

2) The copy assignment operator is deleted; basic_filebuf is not CopyAssignable.

Parameters

rhs

-

another basic_filebuf that will be moved from

Return value

*this

Example

Run this code

#include <cassert>
#include <fstream>
#include <iostream>
#include <string>
 
int main()
{
    std::ofstream{"test.in"} << "test\n"; // writes via a temporary object
    std::ifstream fin("test.in"); // read-only stream
    std::ofstream fout("test.out"); // write-only stream
 
    std::string s;
    std::getline(fin, s);
    std::cout << "s = [" << s << "]\n"; // s contains "test"
 
    assert(fout.is_open());
    *fin.rdbuf() = std::move(*fout.rdbuf());
    assert(!fout.is_open());
 
    std::getline(fin, s);
    std::cout << "s = [" << s << "]\n"; // s is empty input
}

Output:

s = [test]
s = []

See also

(constructor)	constructs a basic_filebuf object (public member function)
swap (C++11)	swaps two basic_filebuf objects (public member function)