Standard library header <syncstream>

 

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Language support <cfloat> <climits> <compare> (C++20) <coroutine> (C++20) <csetjmp> <csignal> <cstdarg> <cstddef> <cstdint> (C++11) <cstdlib> <exception> <initializer_list> (C++11)    <limits> <new> <source_location> (C++20) <stdfloat> (C++23) <typeinfo> <version> (C++20) Concepts <concepts> (C++20) Diagnostics <cassert> <cerrno> <debugging> (C++26) <stacktrace> (C++23) <stdexcept> <system_error> (C++11) Memory management <memory> <memory_resource> (C++17) <scoped_allocator> (C++11) Metaprogramming <type_traits> (C++11) <ratio> (C++11)

General utilities <any> (C++17) <bitset> <bit> (C++20) <charconv> (C++17) <expected> (C++23) <format> (C++20) <functional> <optional> (C++17) <tuple> (C++11) <typeindex> (C++11) <utility> <variant> (C++17) Containers <array> (C++11) <deque> <flat_map> (C++23) <flat_set> (C++23) <forward_list> (C++11) <inplace_vector> (C++26)    <list> <map> <mdspan> (C++23) <queue> <set> <span> (C++20) <stack> <unordered_map> (C++11) <unordered_set> (C++11) <vector> Iterators <iterator> Ranges <generator> (C++23) <ranges> (C++20)

Algorithms <algorithm> <numeric> Strings <cctype> <cstring> <cuchar> (C++11) <cwchar> <cwctype> <string_view> (C++17) <string> Text processing <clocale> <codecvt> (C++11/17/26*) <locale> <regex> (C++11) <text_encoding> (C++26)    Numerics <cfenv> (C++11) <cmath> <complex> <linalg> (C++26) <numbers> (C++20) <random> (C++11) <valarray> Time <chrono> (C++11) <ctime> C compatibility <ccomplex> (C++11/17/20*) <ciso646> (until C++20) <cstdalign> (C++11/17/20*) <cstdbool> (C++11/17/20*) <ctgmath> (C++11/17/20*)

Input/output <cinttypes> (C++11) <cstdio> <filesystem> (C++17) <fstream> <iomanip> <iosfwd> <iostream> <ios> <istream> <ostream> <print> (C++23) <spanstream> (C++23) <sstream> <streambuf> <strstream> (C++98/26*) <syncstream> (C++20) Concurrency support <atomic> (C++11) <barrier> (C++20) <condition_variable> (C++11) <future> (C++11) <hazard_pointer> (C++26) <latch> (C++20) <mutex> (C++11) <rcu> (C++26) <semaphore> (C++20) <shared_mutex> (C++14) <stdatomic.h> (C++23) <stop_token> (C++20) <thread> (C++11) Execution support <execution> (C++17)

 

This header is part of the Input/Output library.

Includes
<ostream>
Classes
basic_syncbuf (C++20)	synchronized output device wrapper (class template)
basic_osyncstream (C++20)	synchronized output stream wrapper (class template)
Typedefs
syncbuf	basic_syncbuf<char>
wsyncbuf	basic_syncbuf<wchar_t>
osyncstream	basic_osyncstream<char>
wosyncstream	basic_osyncstream<wchar_t>
Functions
std::swap(std::basic_syncbuf) (C++20)	specializes the std::swap algorithm (function template)

Synopsis

namespace std {
template <class CharT,
          class Traits = char_traits<CharT>,
          class Allocator = allocator<CharT>>
  class basic_syncbuf;
 
using syncbuf  = basic_syncbuf<char>;
using wsyncbuf = basic_syncbuf<wchar_t>;
 
template <class CharT,
          class Traits = char_traits<CharT>,
          class Allocator = allocator<CharT>>
  class basic_osyncstream;
 
using osyncstream  = basic_osyncstream<char>;
using wosyncstream = basic_osyncstream<wchar_t>;
 
template <class CharT, class Traits, class Allocator>
  void swap( std::basic_syncbuf<CharT, Traits, Allocator>& lhs,
             std::basic_syncbuf<CharT, Traits, Allocator>& rhs );
 
}

Class std::basic_syncbuf

template <class CharT,
          class Traits = char_traits<CharT>,
          class Allocator = allocator<CharT>>
class basic_syncbuf
  : public basic_streambuf<CharT, Traits> {
 
public:
  using char_type      = CharT;
  using int_type       = typename Traits::int_type;
  using pos_type       = typename Traits::pos_type;
  using off_type       = typename Traits::off_type;
  using Traits_type    = Traits;
  using allocator_type = Allocator;
 
  using streambuf_type = basic_streambuf<CharT, Traits>;
 
  // Constructors/destructor:
  explicit
  basic_syncbuf(streambuf_type* obuf = nullptr)
    : basic_syncbuf(obuf, Allocator()) {}
  basic_syncbuf(streambuf_type* ,
                const Allocator&);
  basic_syncbuf(basic_syncbuf&&);
  ~basic_syncbuf();
 
  // Assign/swap:
  basic_syncbuf& operator=(basic_syncbuf&&);
  void swap(basic_syncbuf &);
 
  // Members:
  bool emit();
  streambuf_type* get_wrapped()   const noexcept;
  allocator_type  get_allocator() const noexcept;
  void            set_emit_on_sync(bool) noexcept;
 
protected:
  // Overridden virtual functions:
  int sync() override;
 
private:
  streambuf_type *wrapped;       // exposition only
  bool            emit_on_sync{};// exposition only
};

Class std::basic_osyncstream

template <class CharT,
          class Traits = char_traits<CharT>,
          class Allocator = allocator<CharT>>
class basic_osyncstream
  : public basic_ostream<CharT, Traits>
{
public:
  using char_type      = CharT;
  using int_type       = typename Traits::int_type;
  using pos_type       = typename Traits::pos_type;
  using off_type       = typename Traits::off_type;
  using Traits_type    = Traits;
  using allocator_type = Allocator;
  using streambuf_type = basic_streambuf<CharT, Traits>;
  using syncbuf_type   = basic_syncbuf<CharT, Traits, Allocator>;
 
  // Constructors/destructor:
  basic_osyncstream(streambuf_type *, const Allocator &);
  explicit basic_osyncstream(streambuf_type *obuf)
    : basic_osyncstream(obuf, Allocator()) {}
  basic_osyncstream(basic_ostream<CharT,Traits> &os, const Allocator &allocator)
    : basic_osyncstream(os.rdbuf(), allocator){}
  explicit basic_osyncstream(basic_ostream<CharT,Traits> &os)
    : basic_osyncstream(os, Allocator()) {}
  basic_osyncstream(basic_osyncstream&&) noexcept;
  ~basic_osyncstream();
 
  // Assign:
  basic_osyncstream& operator=(basic_osyncstream&&) noexcept;
 
  // Members:
  void emit();
  streambuf_type* get_wrapped() const noexcept;
  syncbuf_type* rdbuf() const noexcept { return &sb ; }
 
private:
  syncbuf_type sb; // exposition only
};