[ifstream.general]

# 31 Input/output library [[input.output]](./#input.output)

## 31.10 File-based streams [[file.streams]](file.streams#ifstream.general)

### 31.10.4 Class template basic_ifstream [[ifstream]](ifstream#general)

#### 31.10.4.1 General [ifstream.general]

[🔗](#lib: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; using native_handle_type = typename basic_filebuf<charT, traits>::native_handle_type; // [[ifstream.cons]](ifstream.cons "31.10.4.2 Constructors"), 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; see [[fstream.syn]](fstream.syn "31.10.1 Header <fstream> synopsis")explicit basic_ifstream(const string& s,
 ios_base::openmode mode = ios_base::in); template<class T>explicit basic_ifstream(const T& s, ios_base::openmode mode = ios_base::in);
 basic_ifstream(const basic_ifstream&) = delete;
 basic_ifstream(basic_ifstream&& rhs);

 basic_ifstream& operator=(const basic_ifstream&) = delete;
 basic_ifstream& operator=(basic_ifstream&& rhs); // [[ifstream.swap]](ifstream.swap "31.10.4.3 Swap"), swapvoid swap(basic_ifstream& rhs); // [[ifstream.members]](ifstream.members "31.10.4.4 Member functions"), members basic_filebuf<charT, traits>* rdbuf() const;
 native_handle_type native_handle() const noexcept; 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; see [[fstream.syn]](fstream.syn "31.10.1 Header <fstream> synopsis")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*};}

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L11821)

The classbasic_ifstream<charT, traits> supports reading from named files[.](#1.sentence-1)

It uses abasic_filebuf<​charT, traits> object to control the associated
sequence[.](#1.sentence-2)

For the sake of exposition, the maintained data is presented here as:

- [(1.1)](#1.1)

*sb*, the filebuf object[.](#1.sentence-3)