83 lines
2.9 KiB
Markdown
83 lines
2.9 KiB
Markdown
[ifstream.cons]
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# 31 Input/output library [[input.output]](./#input.output)
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## 31.10 File-based streams [[file.streams]](file.streams#ifstream.cons)
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### 31.10.4 Class template basic_ifstream [[ifstream]](ifstream#cons)
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#### 31.10.4.2 Constructors [ifstream.cons]
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[ð](#lib:basic_ifstream,constructor)
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`basic_ifstream();
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`
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L11843)
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*Effects*: Initializes the base class withbasic_istream<charT, traits>(addressof(*sb*)) ([[istream.cons]](istream.cons "31.7.5.2.2 Constructors"))
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and *sb* withbasic_filebuf<charT, traits>() ([[filebuf.cons]](filebuf.cons "31.10.3.2 Constructors"))[.](#1.sentence-1)
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[ð](#lib:basic_ifstream,constructor_)
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`explicit basic_ifstream(const char* s,
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ios_base::openmode mode = ios_base::in);
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explicit basic_ifstream(const filesystem::path::value_type* s,
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ios_base::openmode mode = ios_base::in); // wide systems only; see [[fstream.syn]](fstream.syn "31.10.1 Header <fstream> synopsis")
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`
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L11860)
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*Effects*: Initializes the base class withbasic_istream<charT, traits>(addressof(*sb*)) ([[istream.cons]](istream.cons "31.7.5.2.2 Constructors"))
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and *sb* withbasic_filebuf<charT, traits>() ([[filebuf.cons]](filebuf.cons "31.10.3.2 Constructors")),
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then callsrdbuf()->open(s, mode | ios_base::in)[.](#2.sentence-1)
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If that function returns a null pointer, callssetstate(failbit)[.](#2.sentence-2)
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[ð](#lib:basic_ifstream,constructor__)
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`explicit basic_ifstream(const string& s,
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ios_base::openmode mode = ios_base::in);
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`
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[3](#3)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L11879)
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*Effects*: Equivalent to basic_ifstream(s.c_str(), mode)[.](#3.sentence-1)
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[ð](#lib:basic_ifstream,constructor___)
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`template<class T>
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explicit basic_ifstream(const T& s, ios_base::openmode mode = ios_base::in);
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`
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[4](#4)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L11891)
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*Constraints*: is_same_v<T, filesystem::path> is true[.](#4.sentence-1)
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[5](#5)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L11895)
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*Effects*: Equivalent to basic_ifstream(s.c_str(), mode)[.](#5.sentence-1)
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[ð](#lib:basic_ifstream,constructor____)
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`basic_ifstream(basic_ifstream&& rhs);
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`
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[6](#6)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L11906)
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*Effects*: Move constructs the base class, and the contained basic_filebuf[.](#6.sentence-1)
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Then calls basic_istream<charT, traits>::set_rdbuf(addressof(*sb*)) to install the contained basic_filebuf[.](#6.sentence-2)
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