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Standard library header <fstream>

This header is part of the Input/Output library.

Classes
implements raw file device
(class template)
implements high-level file stream input operations
(class template)
implements high-level file stream output operations
(class template)
implements high-level file stream input/output operations
(class template)
filebuf std::basic_filebuf<char>
(typedef)
wfilebuf std::basic_filebuf<wchar_t>
(typedef)
ifstream std::basic_ifstream<char>
(typedef)
wifstream std::basic_ifstream<wchar_t>
(typedef)
ofstream std::basic_ofstream<char>
(typedef)
wofstream std::basic_ofstream<wchar_t>
(typedef)
fstream std::basic_fstream<char>
(typedef)
wfstream std::basic_fstream<wchar_t>
(typedef)

Functions
(C++11)
 specializes the std::swap algorithm
(function template)
(C++11)
 specializes the std::swap algorithm
(function template)
(C++11)
 specializes the std::swap algorithm
(function template)
(C++11)
 specializes the std::swap algorithm
(function template)

Synopsis

namespace std {
  template<class CharT, class Traits = char_traits<CharT>>
    class basic_filebuf;
  using filebuf  = basic_filebuf<char>;
  using wfilebuf = basic_filebuf<wchar_t>;
 
  template<class CharT, class Traits = char_traits<CharT>>
    class basic_ifstream;
  using ifstream  = basic_ifstream<char>;
  using wifstream = basic_ifstream<wchar_t>;
 
  template<class CharT, class Traits = char_traits<CharT>>
    class basic_ofstream;
  using ofstream  = basic_ofstream<char>;
  using wofstream = basic_ofstream<wchar_t>;
 
  template<class CharT, class Traits = char_traits<CharT>>
    class basic_fstream;
  using fstream  = basic_fstream<char>;
  using wfstream = basic_fstream<wchar_t>;
}

Class template std::basic_filebuf 

namespace std {
  template<class CharT, class Traits = char_traits<CharT>>
  class basic_filebuf : 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;
 
    // constructors/destructor
    basic_filebuf();
    basic_filebuf(const basic_filebuf&) = delete;
    basic_filebuf(basic_filebuf&& rhs);
    virtual ~basic_filebuf();
 
    // assign and swap
    basic_filebuf& operator=(const basic_filebuf&) = delete;
    basic_filebuf& operator=(basic_filebuf&& rhs);
    void swap(basic_filebuf& rhs);
 
    // members
    bool is_open() const;
    basic_filebuf* open(const char* s, ios_base::openmode mode);
    basic_filebuf* open(const filesystem::path::value_type* s,
                        ios_base::openmode mode);   // wide systems only
    basic_filebuf* open(const string& s,
                        ios_base::openmode mode);
    basic_filebuf* open(const filesystem::path& s,
                        ios_base::openmode mode);
    basic_filebuf* close();
 
  protected:
    // overridden virtual functions
    streamsize showmanyc() override;
    int_type underflow() override;
    int_type uflow() override;
    int_type pbackfail(int_type c = Traits::eof()) override;
    int_type overflow (int_type c = Traits::eof()) override;
 
    basic_streambuf<CharT, Traits>* setbuf(char_type* s,
                                           streamsize n) 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;
    int      sync() override;
    void     imbue(const locale& loc) override;
  };
 
  template<class CharT, class Traits>
    void swap(basic_filebuf<CharT, Traits>& x,
              basic_filebuf<CharT, Traits>& y);
}

Class template std::basic_ifstream 

namespace std {
  template<class CharT, class Traits = char_traits<CharT>>
  class basic_ifstream : public basic_istream<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;
 
    // constructors
    basic_ifstream();
    explicit basic_ifstream(const char* s,
                            ios_base::openmode mode = ios_base::in);
    explicit basic_ifstream(const filesystem::path::value_type* s,
                            ios_base::openmode mode = ios_base::in);// wide systems only
    explicit basic_ifstream(const string& s,
                            ios_base::openmode mode = ios_base::in);
    explicit basic_ifstream(const filesystem::path& s,
                            ios_base::openmode mode = ios_base::in);
    basic_ifstream(const basic_ifstream&) = delete;
    basic_ifstream(basic_ifstream&& rhs);
 
    // assign and swap
    basic_ifstream& operator=(const basic_ifstream&) = delete;
    basic_ifstream& operator=(basic_ifstream&& rhs);
    void swap(basic_ifstream& rhs);
 
    // members
    basic_filebuf<CharT, Traits>* rdbuf() const;
 
    bool is_open() const;
    void open(const char* s, ios_base::openmode mode = ios_base::in);
    void open(const filesystem::path::value_type* s,
              ios_base::openmode mode = ios_base::in);  // wide systems only
    void open(const string& s, ios_base::openmode mode = ios_base::in);
    void open(const filesystem::path& s, ios_base::openmode mode = ios_base::in);
    void close();
  private:
    basic_filebuf<CharT, Traits> sb;    // exposition only
  };
 
  template<class CharT, class Traits>
    void swap(basic_ifstream<CharT, Traits>& x,
              basic_ifstream<CharT, Traits>& y);
}

Class template std::basic_ofstream 

namespace std {
  template<class CharT, class Traits = char_traits<CharT>>
  class basic_ofstream : 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;
 
    // constructors
    basic_ofstream();
    explicit basic_ofstream(const char* s,
                            ios_base::openmode mode = ios_base::out);
    explicit basic_ofstream(const filesystem::path::value_type* s,  // wide systems only
                            ios_base::openmode mode = ios_base::out);
    explicit basic_ofstream(const string& s,
                            ios_base::openmode mode = ios_base::out);
    explicit basic_ofstream(const filesystem::path& s,
                            ios_base::openmode mode = ios_base::out);
    basic_ofstream(const basic_ofstream&) = delete;
    basic_ofstream(basic_ofstream&& rhs);
 
    // assign and swap
    basic_ofstream& operator=(const basic_ofstream&) = delete;
    basic_ofstream& operator=(basic_ofstream&& rhs);
    void swap(basic_ofstream& rhs);
 
    // members
    basic_filebuf<CharT, Traits>* rdbuf() const;
 
    bool is_open() const;
    void open(const char* s, ios_base::openmode mode = ios_base::out);
    void open(const filesystem::path::value_type* s,
              ios_base::openmode mode = ios_base::out);     // wide systems only
    void open(const string& s, ios_base::openmode mode = ios_base::out);
    void open(const filesystem::path& s, ios_base::openmode mode = ios_base::out);
    void close();
  private:
    basic_filebuf<CharT, Traits> sb;    // exposition only
  };
 
  template<class CharT, class Traits>
    void swap(basic_ofstream<CharT, Traits>& x,
              basic_ofstream<CharT, Traits>& y);
}

Class template std::basic_fstream 

namespace std {
  template<class CharT, class Traits = char_traits<CharT>>
  class basic_fstream : public basic_iostream<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;
 
    // constructors
    basic_fstream();
    explicit basic_fstream(
      const char* s,
      ios_base::openmode mode = ios_base::in | ios_base::out);
    explicit basic_fstream(
      const filesystem::path::value_type* s,
      ios_base::openmode mode = ios_base::in | ios_base::out);    // wide systems only
    explicit basic_fstream(
      const string& s,
      ios_base::openmode mode = ios_base::in | ios_base::out);
    explicit basic_fstream(
      const filesystem::path& s,
      ios_base::openmode mode = ios_base::in | ios_base::out);
    basic_fstream(const basic_fstream&) = delete;
    basic_fstream(basic_fstream&& rhs);
 
    // assign and swap
    basic_fstream& operator=(const basic_fstream&) = delete;
    basic_fstream& operator=(basic_fstream&& rhs);
    void swap(basic_fstream& rhs);
 
    // members
    basic_filebuf<CharT, Traits>* rdbuf() const;
    bool is_open() const;
    void open(
      const char* s,
      ios_base::openmode mode = ios_base::in | ios_base::out);
    void open(
      const filesystem::path::value_type* s,
      ios_base::openmode mode = ios_base::in | ios_base::out);    // wide systems only
    void open(
      const string& s,
      ios_base::openmode mode = ios_base::in | ios_base::out);
    void open(
      const filesystem::path& s,
      ios_base::openmode mode = ios_base::in | ios_base::out);
    void close();
 
  private:
    basic_filebuf<CharT, Traits> sb;    // exposition only
  };
 
  template<class CharT, class Traits>
    void swap(basic_fstream<CharT, Traits>& x,
              basic_fstream<CharT, Traits>& y);
}

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