[fstream.members]

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

## 31.10 File-based streams [[file.streams]](file.streams#fstream.members)

### 31.10.6 Class template basic_fstream [[fstream]](fstream#members)

#### 31.10.6.4 Member functions [fstream.members]

[🔗](#lib:rdbuf,basic_fstream)

`basic_filebuf<charT, traits>* rdbuf() const;
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12479)

*Returns*: const_cast<basic_filebuf<charT, traits>*>(addressof(*sb*))[.](#1.sentence-1)

[🔗](#lib:native_handle,basic_fstream)

`native_handle_type native_handle() const noexcept;
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12490)

*Effects*: Equivalent to: return rdbuf()->native_handle();

[🔗](#lib:is_open,basic_fstream)

`bool is_open() const;
`

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12501)

*Returns*: rdbuf()->is_open()[.](#3.sentence-1)

[🔗](#lib:open,basic_fstream)

`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]](fstream.syn "31.10.1 Header <fstream> synopsis")
`

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12517)

*Effects*: Callsrdbuf()->open(s, mode)[.](#4.sentence-1)

If that function does not return a null pointer calls clear(),
otherwise callssetstate(failbit) (which may throwios_base​::​failure) ([[iostate.flags]](iostate.flags "31.5.4.4 Flags functions"))[.](#4.sentence-2)

[🔗](#lib:open,basic_fstream_)

`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);
`

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12539)

*Effects*: Calls open(s.c_str(), mode)[.](#5.sentence-1)

[🔗](#lib:close,basic_fstream)

`void close();
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12550)

*Effects*: Callsrdbuf()->close() and, if that function
returns a null pointer,
callssetstate(failbit) (which may throwios_base​::​failure) ([[iostate.flags]](iostate.flags "31.5.4.4 Flags functions"))[.](#6.sentence-1)