标准库头文件 <ostream>

 

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标准库头文件

语言支持 <cfloat> <climits> <compare> (C++20) <contracts> (C++26) <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) 概念 <concepts> (C++20) 诊断 <cassert> <cerrno> <debugging> (C++26) <stacktrace> (C++23) <stdexcept> <system_error> (C++11) 内存管理 <memory> <memory_resource> (C++17) <scoped_allocator> (C++11) 元编程 <type_traits> (C++11) <ratio> (C++11)

通用工具 <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) 容器 <array> (C++11) <deque> <flat_map> (C++23) <flat_set> (C++23) <forward_list> (C++11) <hive> (C++26) <inplace_vector> (C++26)    <list> <map> <mdspan> (C++23) <queue> <set> <span> (C++20) <stack> <unordered_map> (C++11) <unordered_set> (C++11) <vector> 迭代器 <iterator> 范围 <generator> (C++23) <ranges> (C++20)

算法 <algorithm> <numeric> 字符串 <cctype> <cstring> <cuchar> (C++11) <cwchar> <cwctype> <string_view> (C++17) <string> 文本处理 <clocale> <codecvt> (C++11/17/26*) <locale> <regex> (C++11) <text_encoding> (C++26)    数值 <cfenv> (C++11) <cmath> <complex> <linalg> (C++26) <numbers> (C++20) <random> (C++11) <simd> (C++26) <valarray> 时间 <chrono> (C++11) <ctime> C 兼容性 <ccomplex> (C++11/17/20*) <ciso646> (直到 C++20) <cstdalign> (C++11/17/20*) <cstdbool> (C++11/17/20*) <ctgmath> (C++11/17/20*)

输入/输出 <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) 并发支持 <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) 执行支持 <execution> (C++17)

 

此头文件是 输入/输出 库的一部分。

类
basic_ostream	封装给定的抽象设备 (std::basic_streambuf) 并提供高级输出接口 (类模板)
std::ostream	std::basic_ostream<char> (类型定义)
std::wostream	std::basic_ostream<wchar_t> (类型定义)
函数
operator<<(std::basic_ostream)	插入字符数据或插入到右值流 (函数模板)
print(std::ostream) (C++23)	输出参数的格式化表示 (函数模板)
println(std::ostream) (C++23)	输出参数的格式化表示，并附加 '\n' (函数模板)
vprint_unicode(std::ostream) (C++23)	使用类型擦除的参数表示执行 Unicode 感知输出 (函数)
vprint_nonunicode(std::ostream) (C++23)	使用类型擦除的参数表示输出字符数据 (函数)
操纵算符
endl	输出 '\n' 并刷新输出流 (函数模板)
ends	输出 '\0' (函数模板)
flush	刷新输出流 (函数模板)
emit_on_flushnoemit_on_flush (C++20)	控制流的 basic_syncbuf 是否在刷新时发送 (函数模板)
flush_emit (C++20)	刷新流并在使用 basic_syncbuf 时发送内容 (函数模板)

概要

namespace std {
  template<class CharT, class Traits = char_traits<CharT>>
    class basic_ostream;
 
  using ostream  = basic_ostream<char>;
  using wostream = basic_ostream<wchar_t>;
 
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& endl(basic_ostream<CharT, Traits>& os);
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& ends(basic_ostream<CharT, Traits>& os);
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& flush(basic_ostream<CharT, Traits>& os);
 
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& emit_on_flush(basic_ostream<CharT, Traits>& os);
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& noemit_on_flush(basic_ostream<CharT, Traits>& os);
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& flush_emit(basic_ostream<CharT, Traits>& os);
 
  template<class Ostream, class T>
    Ostream&& operator<<(Ostream&& os, const T& x);
 
  // print functions
  template<class... Args>
    void print(ostream& os, format_string<Args...> fmt, Args&&... args);
  template<class... Args>
    void println(ostream& os, format_string<Args...> fmt, Args&&... args);
  void println(ostream& os);
 
  void vprint_unicode(ostream& os, string_view fmt, format_args args);
  void vprint_nonunicode(ostream& os, string_view fmt, format_args args);
}

类模板 std::basic_ostream

namespace std {
  template<class CharT, class Traits = char_traits<CharT>>
  class basic_ostream : virtual public basic_ios<CharT, Traits> {
  public:
    // types (inherited from basic_ios)
    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;
 
    // constructor/destructor
    explicit basic_ostream(basic_streambuf<char_type, Traits>* sb);
    virtual ~basic_ostream();
 
    // prefix/suffix
    class sentry;
 
    // formatted output
    basic_ostream& operator<<(basic_ostream& (*pf)(basic_ostream&));
    basic_ostream& operator<<(basic_ios<CharT, Traits>& (*pf)(basic_ios<CharT, Traits>&));
    basic_ostream& operator<<(ios_base& (*pf)(ios_base&));
 
    basic_ostream& operator<<(bool n);
    basic_ostream& operator<<(short n);
    basic_ostream& operator<<(unsigned short n);
    basic_ostream& operator<<(int n);
    basic_ostream& operator<<(unsigned int n);
    basic_ostream& operator<<(long n);
    basic_ostream& operator<<(unsigned long n);
    basic_ostream& operator<<(long long n);
    basic_ostream& operator<<(unsigned long long n);
    basic_ostream& operator<<(float f);
    basic_ostream& operator<<(double f);
    basic_ostream& operator<<(long double f);
    basic_ostream& operator<<(/*extended-floating-point-type*/ f);
 
    basic_ostream& operator<<(const void* p);
    basic_ostream& operator<<(const volatile void* p);
    basic_ostream& operator<<(nullptr_t);
    basic_ostream& operator<<(basic_streambuf<char_type, Traits>* sb);
 
    // unformatted output
    basic_ostream& put(char_type c);
    basic_ostream& write(const char_type* s, streamsize n);
 
    basic_ostream& flush();
 
    // seeks
    pos_type tellp();
    basic_ostream& seekp(pos_type);
    basic_ostream& seekp(off_type, ios_base::seekdir);
 
  protected:
    // copy/move constructor
    basic_ostream(const basic_ostream&) = delete;
    basic_ostream(basic_ostream&& rhs);
 
    // assignment and swap
    basic_ostream& operator=(const basic_ostream&) = delete;
    basic_ostream& operator=(basic_ostream&& rhs);
    void swap(basic_ostream& rhs);
  };
 
  // character inserters
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& operator<<(basic_ostream<CharT, Traits>&, CharT);
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& operator<<(basic_ostream<CharT, Traits>&, char);
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&, char);
 
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&, signed char);
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&, unsigned char);
 
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&,
                                            wchar_t) = delete;
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&,
                                            char8_t) = delete;
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&,
                                            char16_t) = delete;
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&,
                                            char32_t) = delete;
  template<class Traits>
    basic_ostream<wchar_t, Traits>&
      operator<<(basic_ostream<wchar_t, Traits>&, char8_t) = delete;
  template<class Traits>
    basic_ostream<wchar_t, Traits>&
      operator<<(basic_ostream<wchar_t, Traits>&, char16_t) = delete;
  template<class Traits>
    basic_ostream<wchar_t, Traits>&
      operator<<(basic_ostream<wchar_t, Traits>&, char32_t) = delete;
 
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& operator<<(basic_ostream<CharT, Traits>&, const CharT*);
  template<class CharT, class Traits>
    basic_ostream<CharT, Traits>& operator<<(basic_ostream<CharT, Traits>&, const char*);
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&, const char*);
 
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&,
                                            const signed char*);
  template<class Traits>
    basic_ostream<char, Traits>& operator<<(basic_ostream<char, Traits>&,
                                            const unsigned char*);
 
  template<class Traits>
    basic_ostream<char, Traits>&
      operator<<(basic_ostream<char, Traits>&, const wchar_t*) = delete;
  template<class Traits>
    basic_ostream<char, Traits>&
      operator<<(basic_ostream<char, Traits>&, const char8_t*) = delete;
  template<class Traits>
    basic_ostream<char, Traits>&
      operator<<(basic_ostream<char, Traits>&, const char16_t*) = delete;
  template<class Traits>
    basic_ostream<char, Traits>&
      operator<<(basic_ostream<char, Traits>&, const char32_t*) = delete;
  template<class Traits>
    basic_ostream<wchar_t, Traits>&
      operator<<(basic_ostream<wchar_t, Traits>&, const char8_t*) = delete;
  template<class Traits>
    basic_ostream<wchar_t, Traits>&
      operator<<(basic_ostream<wchar_t, Traits>&, const char16_t*) = delete;
  template<class Traits>
    basic_ostream<wchar_t, Traits>&
      operator<<(basic_ostream<wchar_t, Traits>&, const char32_t*) = delete;
}

类 std::basic_ostream::sentry

namespace std {
  template<class CharT, class Traits>
  class basic_ostream<CharT, Traits>::sentry {
    bool ok_;       // exposition only
  public:
    explicit sentry(basic_ostream& os);
    ~sentry();
    explicit operator bool() const { return ok_; }
 
    sentry(const sentry&) = delete;
    sentry& operator=(const sentry&) = delete;
  };
}