Standard library header <syncstream> (C++20)

 

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Standard Library headers

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<cstddef> <cstdlib> <version> (C++20) <limits> <climits>	<cfloat> <cstdint> (C++11) <new> <typeinfo>	<source_location> (C++20) <exception> <initializer_list> (C++11)   <compare> (C++20)	<coroutine> (C++20) <csignal> <csetjmp> <cstdarg>
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<concepts> (C++20)
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<stdexcept>	<cassert>	<cerrno>	<system_error> (C++11)
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<utility> <memory> <memory_resource> (C++17) <scoped_allocator> (C++11)   <expected> (C++23)	<bitset> <tuple> (C++11) <optional> (C++17) <any> (C++17)	<variant> (C++17) <type_traits> (C++11) <ratio> (C++11) <chrono> (C++11)	<typeindex> (C++11) <functional> <stacktrace> (C++23) <ctime>
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<string> <string_view> (C++17) <cstring>	<charconv> (C++17) <format> (C++20)	<cctype> <cwctype>	<cwchar> <cuchar> (C++11)
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<locale> <clocale>	<codecvt> (C++11/17)
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<span> (C++20) <array> (C++11) <vector>	<deque> <forward_list> (C++11) <list>	<map> <set> <queue>	<unordered_map> (C++11) <unordered_set> (C++11) <stack>
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<iterator>
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<ranges> (C++20)
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<algorithm>	<execution> (C++17)
Numerics
<complex> <random> (C++11)	<valarray> <numeric>	<bit> (C++20) <numbers> (C++20)	<cfenv> (C++11) <cmath>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<syncstream> (C++20) <spanstream> (C++23) <sstream> <fstream>	<cstdio> <cinttypes> (C++11) <strstream> (C++98/)
Regular expressions
<regex> (C++11)
Filesystem support
<filesystem> (C++17)
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<thread> (C++11) <atomic> (C++11) <mutex> (C++11)	<shared_mutex> (C++14) <condition_variable> (C++11)   <future> (C++11)	<stop_token> (C++20) <semaphore> (C++20)	<latch> (C++20) <barrier> (C++20)
C compatibility
<cstdbool> (C++11/17/20) <ccomplex> (C++11/17/20)	<ctgmath> (C++11/17/20) <cstdalign> (C++11/17/20)	<ciso646> (until C++20) <stdatomic.h>

 

This header is part of the Input/Output library.

Includes
<ostream>	std::basic_ostream, std::basic_iostream class templates and several typedefs
Classes
basic_syncbuf (C++20)	synchronized output device wrapper (class template)
basic_osyncstream (C++20)	synchronized output stream wrapper (class template)
syncbuf (C++20)	std::basic_syncbuf<char> (typedef)
wsyncbuf (C++20)	std::basic_syncbuf<wchar_t> (typedef)
osyncstream (C++20)	std::basic_osyncstream<char> (typedef)
wosyncstream (C++20)	std::basic_osyncstream<wchar_t> (typedef)
Functions
std::swap(std::basic_syncbuf) (C++20)	specializes the std::swap algorithm (function template)

Synopsis

#include <ostream>
 
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>;
}

Class template std::basic_syncbuf

namespace std {
  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>;
 
    // construction and destruction
    basic_syncbuf()
      : basic_syncbuf(nullptr) {}
    explicit basic_syncbuf(streambuf_type* obuf)
      : basic_syncbuf(obuf, Allocator()) {}
    basic_syncbuf(streambuf_type*, const Allocator&);
    basic_syncbuf(basic_syncbuf&&);
    ~basic_syncbuf();
 
    // assignment and swap
    basic_syncbuf& operator=(basic_syncbuf&&);
    void swap(basic_syncbuf&);
 
    // member functions
    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
  };
 
  // specialized algorithms
  template<class CharT, class Traits, class Allocator>
    void swap(basic_syncbuf<CharT, Traits, Allocator>&,
              basic_syncbuf<CharT, Traits, Allocator>&);
}

Class template std::basic_osyncstream

namespace std {
  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>;
 
    // construction and destruction
    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();
 
    // assignment
    basic_osyncstream& operator=(basic_osyncstream&&) noexcept;
 
    // member functions
    void emit();
    streambuf_type* get_wrapped() const noexcept;
    syncbuf_type* rdbuf() const noexcept
    { return const_cast<syncbuf_type*>(addressof(sb)); }
 
  private:
    syncbuf_type sb;    // exposition only
  };
}