std::basic_ostream<CharT,Traits>* tie() const; | (1) | |
std::basic_ostream<CharT,Traits>* tie( std::basic_ostream<CharT,Traits>* str ); | (2) |
Manages the tied stream. A tied stream is an output stream which is synchronized with the sequence controlled by the stream buffer (rdbuf()
), that is, flush()
is called on the tied stream before any input/output operation on *this
.
str
. Returns the tied stream before the operation. If there is no tied stream, a null pointer is returned.str | - | an output stream to set as the tied stream |
The tied stream, or a null pointer if there was no tied stream.
(none).
By default, the standard streams cin
and cerr
are tied to cout
. Similarly, their wide counterparts wcin
and wcerr
are tied to wcout
.
#include <iostream> #include <fstream> #include <string> int main() { std::ofstream os("test.txt"); std::ifstream is("test.txt"); std::string value("0"); os << "Hello"; is >> value; std::cout << "Result before tie(): \"" << value << "\"\n"; is.clear(); is.tie(&os); is >> value; std::cout << "Result after tie(): \"" << value << "\"\n"; }
Output:
Result before tie(): "0" Result after tie(): "Hello"
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/cpp/io/basic_ios/tie