std::basic_osyncstream::emit

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Input/output library

I/O manipulators

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

strstreambuf (deprecated in C++98)

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

String I/O

basic_istringstream

basic_ostringstream

basic_stringstream

Array I/O

istrstream (deprecated in C++98)

ostrstream (deprecated in C++98)

strstream (deprecated in C++98)

Synchronized Output

basic_osyncstream (C++20)

Types

streamoff

streamsize

fpos

Error category interface

iostream_category (C++11)

io_errc (C++11)

 

std::basic_osyncstream

Public member functions

basic_osyncstream::basic_osyncstream

basic_osyncstream::operator=

basic_osyncstream::~basic_osyncstream

basic_osyncstream::rdbuf

basic_osyncstream::get_wrapped

basic_osyncstream::emit

 

void emit();

Emits all buffered output and executes any pending flushes, by calling emit() on the underlying std::basic_syncbuf.

Parameters

(none)

Example

Run this code

#include <syncstream>
#include <iostream>
int main()
{
  {
    std::osyncstream bout(std::cout);
    std::bout << "Hello," << '\n'; // no flush
    std::bout.emit(); // characters transferred; cout not flushed
    std::bout << "World!" << std::endl; // flush noted; cout not flushed
    std::bout.emit(); // characters transferred; cout flushed
    std::bout << "Greetings." << '\n'; // no flush
  } // destructor calls emit(): characters transferred; cout not flushed
 
  // emit can be used for local exception-handling on the wrapped stream
  std::osyncstream bout(std::cout);
  bout << "Hello, " << "World!" << '\n';
  try {
    bout.emit();
  } catch (...) {
    // handle exceptions
  }
}

Output:

Hello,
World!
Greetings.
Hello, World!

See also

(destructor)	destroys the basic_osyncstream and emits its internal buffer (public member function)
emit	atomically transmits the entire internal buffer to the wrapped streambuf (public member function of std::basic_syncbuf)