std::basic_osyncstream<CharT,Traits,Allocator>::emit

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Input/output library

I/O manipulators

Print functions (C++23)

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

basic_spanbuf (C++23)

strstreambuf (C++98/26*)

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

basic_ispanstream (C++23)

basic_ospanstream (C++23)

basic_spanstream (C++23)

istrstream (C++98/26*)

ostrstream (C++98/26*)

strstream (C++98/26*)

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 (C++20)

basic_osyncstream::operator= (C++20)

basic_osyncstream::~basic_osyncstream (C++20)

basic_osyncstream::rdbuf (C++20)

basic_osyncstream::get_wrapped (C++20)

basic_osyncstream::emit (C++20)

 

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 <iostream>
#include <syncstream>
 
int main()
{
    {
        std::osyncstream bout(std::cout);
        bout << "Hello," << '\n'; // no flush
        bout.emit(); // characters transferred; cout not flushed
        bout << "World!" << std::endl; // flush noted; cout not flushed
        bout.emit(); // characters transferred; cout flushed
        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<CharT,Traits,Allocator>)