标准库头文件 <ostream>

 

C++

语言

标准库头文件

自立与有宿主实现

具名要求

语言支持库

概念库 (C++20)

诊断库

工具库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

本地化库

输入/输出库

文件系统库 (C++17)

正则表达式库 (C++11)

原子操作库 (C++11)

线程支持库 (C++11)

技术规范

 

标准库头文件

语言支持
<cstddef> <cstdlib> <version> <limits> <climits>	<cfloat> <cstdint> <new> <typeinfo>	<source_location> <exception> <initializer_list>     <compare>	<coroutine> <csignal> <csetjmp> <cstdarg>
概念
<concepts>
诊断
<stdexcept>	<cassert>	<cerrno>	<system_error>
通用工具
<utility> <memory> <memory_resource> <scoped_allocator>	<bitset> <tuple> <optional> <any>	<variant> <type_traits> <ratio> <chrono>	<typeindex> <functional> <stacktrace> <ctime>
字符串
<string> <string_view> <cstring>	<charconv> <format>	<cctype> <cwctype>	<cwchar> <cuchar>
本地化
<locale>	<codecvt>	<clocale>
容器
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
迭代器
<iterator>
范围
<ranges>
算法
<algorithm>	<execution>
数值
<complex> <random>	<valarray> <numeric>	<bit> <numbers>	<cfenv> <cmath>
输入/输出
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <spanstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
正则表达式
<regex>
文件系统
<filesystem>
线程支持
<thread> <atomic> <mutex>	<shared_mutex> <condition_variable>     <future>	<stop_token> <semaphore>	<latch> <barrier>
C 兼容
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath> <stdatomic.h>

 

此头文件是输入/输出库的一部分。

类
basic_ostream	包装给定的抽象设备（std::basic_streambuf） 并提供高层输出接口 (类模板)
std::ostream	std::basic_ostream<char> (typedef)
std::wostream	std::basic_ostream<wchar_t> (typedef)
函数
operator<<(std::basic_ostream)	插入字符数据 (函数)
操纵符
endl	输出 '\n' 并冲洗输出流 (函数模板)
ends	输出 '\0' (函数模板)
flush	冲洗输出流 (函数模板)
emit_on_flushnoemit_on_flush (C++20)	控制流的 basic_syncbuf 是否在冲入时发射 (函数模板)
flush_emit (C++20)	冲入流，而若它使用 basic_syncbuf 则发射其内容 (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);
}

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:
    // 类型（继承自 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;
 
    // 构造函数/析构函数
    explicit basic_ostream(basic_streambuf<char_type, Traits>* sb);
    virtual ~basic_ostream();
 
    // 前置工序/后置工序
    class sentry;
 
    // 有格式输出
    basic_ostream<CharT, Traits>&
      operator<<(basic_ostream<CharT, Traits>& (*pf)(basic_ostream<CharT, Traits>&));
    basic_ostream<CharT, Traits>&
      operator<<(basic_ios<CharT, Traits>& (*pf)(basic_ios<CharT, Traits>&));
    basic_ostream<CharT, Traits>&
      operator<<(ios_base& (*pf)(ios_base&));
 
    basic_ostream<CharT, Traits>& operator<<(bool n);
    basic_ostream<CharT, Traits>& operator<<(short n);
    basic_ostream<CharT, Traits>& operator<<(unsigned short n);
    basic_ostream<CharT, Traits>& operator<<(int n);
    basic_ostream<CharT, Traits>& operator<<(unsigned int n);
    basic_ostream<CharT, Traits>& operator<<(long n);
    basic_ostream<CharT, Traits>& operator<<(unsigned long n);
    basic_ostream<CharT, Traits>& operator<<(long long n);
    basic_ostream<CharT, Traits>& operator<<(unsigned long long n);
    basic_ostream<CharT, Traits>& operator<<(float f);
    basic_ostream<CharT, Traits>& operator<<(double f);
    basic_ostream<CharT, Traits>& operator<<(long double f);
 
    basic_ostream<CharT, Traits>& operator<<(const void* p);
    basic_ostream<CharT, Traits>& operator<<(const volatile void* val);
    basic_ostream<CharT, Traits>& operator<<(nullptr_t);
    basic_ostream<CharT, Traits>& operator<<(basic_streambuf<char_type, Traits>* sb);
 
    // 无格式输出
    basic_ostream<CharT, Traits>& put(char_type c);
    basic_ostream<CharT, Traits>& write(const char_type* s, streamsize n);
 
    basic_ostream<CharT, Traits>& flush();
 
    // 巡位
    pos_type tellp();
    basic_ostream<CharT, Traits>& seekp(pos_type);
    basic_ostream<CharT, Traits>& seekp(off_type, ios_base::seekdir);
 
  protected:
    // 复制/移动构造函数
    basic_ostream(const basic_ostream&) = delete;
    basic_ostream(basic_ostream&& rhs);
 
    // 赋值与交换
    basic_ostream& operator=(const basic_ostream&) = delete;
    basic_ostream& operator=(basic_ostream&& rhs);
    void swap(basic_ostream& rhs);
  };
 
  // 字符插入器
  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 = char_traits<CharT>>
  class basic_ostream<CharT, Traits>::sentry {
    bool ok_;       // 仅用于阐释
  public:
    explicit sentry(basic_ostream<CharT, Traits>& os);
    ~sentry();
    explicit operator bool() const { return ok_; }
 
    sentry(const sentry&) = delete;
    sentry& operator=(const sentry&) = delete;
  };
}