tmp/tmpi59ov9f1/{from.md → to.md}
RENAMED
|
@@ -0,0 +1,85 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
#### General <a id="filebuf.general">[[filebuf.general]]</a>
|
| 2 |
+
|
| 3 |
+
``` cpp
|
| 4 |
+
namespace std {
|
| 5 |
+
template<class charT, class traits = char_traits<charT>>
|
| 6 |
+
class basic_filebuf : public basic_streambuf<charT, traits> {
|
| 7 |
+
public:
|
| 8 |
+
using char_type = charT;
|
| 9 |
+
using int_type = typename traits::int_type;
|
| 10 |
+
using pos_type = typename traits::pos_type;
|
| 11 |
+
using off_type = typename traits::off_type;
|
| 12 |
+
using traits_type = traits;
|
| 13 |
+
|
| 14 |
+
// [filebuf.cons], constructors/destructor
|
| 15 |
+
basic_filebuf();
|
| 16 |
+
basic_filebuf(const basic_filebuf&) = delete;
|
| 17 |
+
basic_filebuf(basic_filebuf&& rhs);
|
| 18 |
+
virtual ~basic_filebuf();
|
| 19 |
+
|
| 20 |
+
// [filebuf.assign], assignment and swap
|
| 21 |
+
basic_filebuf& operator=(const basic_filebuf&) = delete;
|
| 22 |
+
basic_filebuf& operator=(basic_filebuf&& rhs);
|
| 23 |
+
void swap(basic_filebuf& rhs);
|
| 24 |
+
|
| 25 |
+
// [filebuf.members], members
|
| 26 |
+
bool is_open() const;
|
| 27 |
+
basic_filebuf* open(const char* s, ios_base::openmode mode);
|
| 28 |
+
basic_filebuf* open(const filesystem::path::value_type* s,
|
| 29 |
+
ios_base::openmode mode); // wide systems only; see [fstream.syn]
|
| 30 |
+
basic_filebuf* open(const string& s,
|
| 31 |
+
ios_base::openmode mode);
|
| 32 |
+
basic_filebuf* open(const filesystem::path& s,
|
| 33 |
+
ios_base::openmode mode);
|
| 34 |
+
basic_filebuf* close();
|
| 35 |
+
|
| 36 |
+
protected:
|
| 37 |
+
// [filebuf.virtuals], overridden virtual functions
|
| 38 |
+
streamsize showmanyc() override;
|
| 39 |
+
int_type underflow() override;
|
| 40 |
+
int_type uflow() override;
|
| 41 |
+
int_type pbackfail(int_type c = traits::eof()) override;
|
| 42 |
+
int_type overflow (int_type c = traits::eof()) override;
|
| 43 |
+
|
| 44 |
+
basic_streambuf<charT, traits>* setbuf(char_type* s,
|
| 45 |
+
streamsize n) override;
|
| 46 |
+
pos_type seekoff(off_type off, ios_base::seekdir way,
|
| 47 |
+
ios_base::openmode which
|
| 48 |
+
= ios_base::in | ios_base::out) override;
|
| 49 |
+
pos_type seekpos(pos_type sp,
|
| 50 |
+
ios_base::openmode which
|
| 51 |
+
= ios_base::in | ios_base::out) override;
|
| 52 |
+
int sync() override;
|
| 53 |
+
void imbue(const locale& loc) override;
|
| 54 |
+
};
|
| 55 |
+
}
|
| 56 |
+
```
|
| 57 |
+
|
| 58 |
+
The class `basic_filebuf<charT, traits>` associates both the input
|
| 59 |
+
sequence and the output sequence with a file.
|
| 60 |
+
|
| 61 |
+
The restrictions on reading and writing a sequence controlled by an
|
| 62 |
+
object of class `basic_filebuf<charT, traits>` are the same as for
|
| 63 |
+
reading and writing with the C standard library `FILE`s.
|
| 64 |
+
|
| 65 |
+
In particular:
|
| 66 |
+
|
| 67 |
+
- If the file is not open for reading the input sequence cannot be read.
|
| 68 |
+
- If the file is not open for writing the output sequence cannot be
|
| 69 |
+
written.
|
| 70 |
+
- A joint file position is maintained for both the input sequence and
|
| 71 |
+
the output sequence.
|
| 72 |
+
|
| 73 |
+
An instance of `basic_filebuf` behaves as described in [[filebuf]]
|
| 74 |
+
provided `traits::pos_type` is `fpos<traits::{}state_type>`. Otherwise
|
| 75 |
+
the behavior is undefined.
|
| 76 |
+
|
| 77 |
+
In order to support file I/O and multibyte/wide character conversion,
|
| 78 |
+
conversions are performed using members of a facet, referred to as
|
| 79 |
+
`a_codecvt` in following subclauses, obtained as if by
|
| 80 |
+
|
| 81 |
+
``` cpp
|
| 82 |
+
const codecvt<charT, char, typename traits::state_type>& a_codecvt =
|
| 83 |
+
use_facet<codecvt<charT, char, typename traits::state_type>>(getloc());
|
| 84 |
+
```
|
| 85 |
+
|