std::basic_ostream<CharT,Traits>:: basic_ostream

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C++
Input/output library
std::basic_ostream
explicit basic_ostream ( std:: basic_streambuf < CharT, Traits > * sb ) ;
(1)
protected :
basic_ostream ( const basic_ostream & rhs ) = delete ;
(2) (since C++11)
protected :
basic_ostream ( basic_ostream && rhs ) ;
(3) (since C++11)
1) Constructs the basic_ostream object, assigning initial values to the base class by calling basic_ios::init(sb) .
2) The copy constructor is protected, and is deleted. Output streams are not copyable.
3) The move constructor uses basic_ios < CharT, Traits > :: move ( rhs ) to move all basic_ios members, except for the rdbuf() , from rhs into * this . This move constructor is protected: it is called by the move constructors of movable output stream classes std::basic_ofstream and std::basic_ostringstream , which know how to correctly move the associated streambuffer.

Parameters

sb - streambuffer to use as output sequence
rhs - basic_ostream to initialize from

Notes

Because basic_ios::init(sb) sets badbit when sb is a null pointer, and because basic_ostream::sentry does nothing if the stream is already in a failed state, writing to a stream constructed from a null pointer sb is a no-op.

Example

Run this code 
#include <iostream>
#include <sstream>
#include <utility>
 
int main()
{
    // ERROR: copy ctor is deleted
//  std::ostream myout(std::cout);
 
    // OK: shares buffer with cout
    std::ostream myout(std::cout.rdbuf());
 
    // ERROR: move constructor is protected
//  std::ostream s2(std::move(std::ostringstream() << 7.1));
 
    // OK: move ctor called through the derived class
    std::ostringstream s2(std::ostringstream() << 7.1);
    myout << s2.str() << '\n';
 
    std::ostream dev_null{nullptr}; // see Notes above
    dev_null << "no-op";
}

Output: 

7.1
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