| I/O manipulators | ||||
| Print functions(C++23) | ||||
| C-style I/O | ||||
| Buffers | ||||
(C++23) | ||||
(C++98/26*) | ||||
(C++20) | ||||
| Streams | ||||
| Abstractions | ||||
| File I/O | ||||
| String I/O | ||||
| Array I/O | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
(C++98/26*) | ||||
(C++98/26*) | ||||
(C++98/26*) | ||||
| Synchronized Output | ||||
(C++20) | ||||
| Types | ||||
| Error category interface | ||||
(C++11) | ||||
(C++11) |
| Global objects | ||||
| Member functions | ||||
basic_ostream::basic_ostream | ||||
(C++11) | ||||
| Formatted output | ||||
| Unformatted output | ||||
| Positioning | ||||
| Miscellaneous | ||||
(C++11) | ||||
| Member classes | ||||
| Non-member functions | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
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) |
basic_ostream object, assigning initial values to the base class by callingbasic_ios::init(sb).basic_ios members, except for therdbuf(), fromrhs into*this. This move constructor is protected: it is called by the move constructors of movable output stream classesstd::basic_ofstream andstd::basic_ostringstream, which know how to correctly move the associated streambuffer.| sb | - | streambuffer to use as output sequence |
| rhs | - | basic_ostream to initialize from |
Becausebasic_ios::init(sb) setsbadbit whensb is a null pointer, and becausebasic_ostream::sentry does nothing if the stream is already in a failed state, writing to a stream constructed from a null pointersb is a no-op.
#include <iostream>#include <sstream>#include <utility> int main(){// ERROR: copy ctor is deleted// std::ostream myout(std::cout); // OK: shares buffer with coutstd::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 classstd::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
