[fstream.cons]

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

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

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

#### 31.10.6.2 Constructors [fstream.cons]

[🔗](#lib:basic_fstream,constructor)

`basic_fstream();
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12369)

*Effects*: Initializes the base class withbasic_iostream<charT, traits>(addressof(*sb*)) ([[iostream.cons]](iostream.cons "31.7.5.7.2 Constructors"))
and*sb* with basic_filebuf<charT, traits>()[.](#1.sentence-1)

[🔗](#lib:basic_fstream,constructor_)

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

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12388)

*Effects*: Initializes the base class withbasic_iostream<charT, traits>(addressof(*sb*)) ([[iostream.cons]](iostream.cons "31.7.5.7.2 Constructors"))
and*sb* with basic_filebuf<charT, traits>()[.](#2.sentence-1)

Then callsrdbuf()->open(s, mode)[.](#2.sentence-2)

If that function returns a null pointer, callssetstate(failbit)[.](#2.sentence-3)

[🔗](#lib:basic_fstream,constructor__)

`explicit basic_fstream(
  const string& s,
  ios_base::openmode mode = ios_base::in | ios_base::out);
`

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12408)

*Effects*: Equivalent to basic_fstream(s.c_str(), mode)[.](#3.sentence-1)

[🔗](#lib:basic_fstream,constructor___)

`template<class T>
  explicit basic_fstream(const T& s, ios_base::openmode mode = ios_base::in | ios_base::out);
`

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12420)

*Constraints*: is_same_v<T, filesystem​::​path> is true[.](#4.sentence-1)

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12424)

*Effects*: Equivalent to basic_fstream(s.c_str(), mode)[.](#5.sentence-1)

[🔗](#lib:basic_fstream,constructor____)

`basic_fstream(basic_fstream&& rhs);
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12435)

*Effects*: Move constructs the base class, and the contained basic_filebuf[.](#6.sentence-1)

Then calls basic_istream<charT, traits>​::​set_rdbuf(​addressof(*sb*)) to install the contained basic_filebuf[.](#6.sentence-2)