29 Input/output library [input.output]

29.9 File-based streams [file.streams]

29.9.5 Class template basic_­fstream [fstream]

29.9.5.1 General [fstream.general]

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; // [fstream.cons], 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; see [fstream.syn] 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); // [fstream.assign], assign and swap basic_fstream& operator=(const basic_fstream&) = delete; basic_fstream& operator=(basic_fstream&& rhs); void swap(basic_fstream& rhs); // [fstream.members], 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; see [fstream.syn] 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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The class template basic_­fstream<charT, traits> supports reading and writing from named files.
It uses a basic_­filebuf<charT, traits> object to control the associated sequences.
For the sake of exposition, the maintained data is presented here as:
  • (1.1)
    sb, the basic_­filebuf object.