std::basic_ostream<CharT,Traits>::basic_ostream - cppreference.com (original) (raw)

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.

[edit] Parameters

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

[edit] 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.

[edit] Example

#include #include #include   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"; }

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