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Standard library header <strstream> (deprecated in C++98) (removed in C++26)

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C++
Standard library headers

此头文件是 输入/输出 库的组成部分。

目录

类

(C++98 中已弃用) (C++26 中移除)
实现原始字符数组设备
(类)
(C++98 中已弃用) (C++26 中移除)
实现字符数组输入操作
(类)
(C++98 中已弃用) (C++26 中移除)
实现字符数组输出操作
(类)
(C++98 中已弃用) (C++26 中移除)
实现字符数组输入/输出操作
(类)

注释

<strstream> 在 C++98 中已被弃用，并在 C++26 中移除（参见 P2867R1 ）。

移除的原因在于 C++20 和 C++23 提供了更优越的替代功能，例如能够高效地从 std::stringstream 中移动字符串（自 C++20 起，参见 P0408R7 ），以及 <spanstream> 库（自 C++23 起，参见 P0448R4 ）。

概要 

namespace std {
  class strstreambuf;
  class istrstream;
  class ostrstream;
  class strstream;
}

类 std::strstreambuf 

namespace std {
  class strstreambuf : public basic_streambuf<char> {
  public:
    strstreambuf() : strstreambuf(0) {}
    explicit strstreambuf(streamsize alsize_arg);
    strstreambuf(void* (*palloc_arg)(size_t), void (*pfree_arg)(void*));
    strstreambuf(char* gnext_arg, streamsize n, char* pbeg_arg = nullptr);
    strstreambuf(const char* gnext_arg, streamsize n);
    strstreambuf(signed char* gnext_arg, streamsize n,
                 signed char* pbeg_arg = nullptr);
    strstreambuf(const signed char* gnext_arg, streamsize n);
    strstreambuf(unsigned char* gnext_arg, streamsize n,
                 unsigned char* pbeg_arg = nullptr);
    strstreambuf(const unsigned char* gnext_arg, streamsize n);
    virtual ~strstreambuf();
    void  freeze(bool freezefl = true);
    char* str();
    int   pcount();
  protected:
    int_type overflow (int_type c = EOF) override;
    int_type pbackfail(int_type c = EOF) override;
    int_type underflow() override;
    pos_type seekoff(off_type off, ios_base::seekdir way,
                     ios_base::openmode which = ios_base::in | ios_base::out) override;
    pos_type seekpos(pos_type sp,
                     ios_base::openmode which = ios_base::in | ios_base::out) override;
    streambuf* setbuf(char* s, streamsize n) override;
  private:
    using strstate = /*位掩码类型*/;  // 仅作说明
    static const strstate allocated;    // 仅作说明
    static const strstate constant;     // 仅作说明
    static const strstate dynamic;      // 仅作说明
    static const strstate frozen;       // 仅作说明
    strstate strmode;                   // 仅作说明
    streamsize alsize;                  // 仅作说明
    void* (*palloc)(size_t);            // 仅作说明
    void (*pfree)(void*);               // 仅作说明
  };
}

类 std::istrstream 

namespace std {
  class istrstream : public basic_istream<char> {
  public:
    explicit istrstream(const char* s);
    explicit istrstream(char* s);
    istrstream(const char* s, streamsize n);
    istrstream(char* s, streamsize n);
    virtual ~istrstream();
    strstreambuf* rdbuf() const;
    char* str();
  private:
    strstreambuf sb;            // 仅作说明用途
  };
}

类 std::ostrstream 

namespace std {
  class ostrstream : public basic_ostream<char> {
  public:
    ostrstream();
    ostrstream(char* s, int n, ios_base::openmode mode = ios_base::out);
    virtual ~ostrstream();
    strstreambuf* rdbuf() const;
    void freeze(bool freezefl = true);
    char* str();
    int pcount() const;
  private:
    strstreambuf sb;            // 仅作说明用途
  };
}

类 std::strstream 

namespace std {
  class strstream
    : public basic_iostream<char> {
  public:
    // 类型定义
    using char_type = char;
    using int_type  = char_traits<char>::int_type;
    using pos_type  = char_traits<char>::pos_type;
    using off_type  = char_traits<char>::off_type;
    // 构造函数/析构函数
    strstream();
    strstream(char* s, int n,
              ios_base::openmode mode = ios_base::in | ios_base::out);
    virtual ~strstream();
    // 成员函数
    strstreambuf* rdbuf() const;
    void freeze(bool freezefl = true);
    int pcount() const;
    char* str();
  private:
    strstreambuf sb;            // 仅用于说明
  };
}