27 Input/output library [input.output]

27.9 File-based streams [file.streams]

27.9.1 File streams [fstreams] Class template basic_ifstream [ifstream]

namespace std {
  template <class charT, class traits = char_traits<charT> >
  class basic_ifstream : public basic_istream<charT,traits> {
    typedef charT                     char_type;
    typedef typename traits::int_type int_type;
    typedef typename traits::pos_type pos_type;
    typedef typename traits::off_type off_type;
    typedef traits                    traits_type;

    // [ifstream.cons] Constructors:
    explicit basic_ifstream(const char* s,
        ios_base::openmode mode = ios_base::in);
    explicit basic_ifstream(const string& s,
        ios_base::openmode mode = ios_base::in);
    basic_ifstream(const basic_ifstream& rhs) = delete;
    basic_ifstream(basic_ifstream&& rhs);

    // [ifstream.assign] Assign/swap:
    basic_ifstream& operator=(const basic_ifstream& rhs) = delete;
    basic_ifstream& operator=(basic_ifstream&& rhs);
    void swap(basic_ifstream& rhs);

    // [ifstream.members] 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 string& s, ios_base::openmode mode = ios_base::in);
    void close();
    basic_filebuf<charT,traits> sb; // exposition only

  template <class charT, class traits>
  void swap(basic_ifstream<charT, traits>& x,
            basic_ifstream<charT, traits>& y);

The class basic_ifstream<charT, traits> supports reading from named files. It uses a basic_filebuf<charT, traits> object to control the associated sequence. For the sake of exposition, the maintained data is presented here as:

  • sb, the filebuf object.