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typedef codecvt< char_type, char, __state_type > | __codecvt_type |
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typedef __basic_file< char > | __file_type |
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typedef basic_filebuf< char_type, traits_type > | __filebuf_type |
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typedef traits_type::state_type | __state_type |
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typedef basic_streambuf< char_type, traits_type > | __streambuf_type |
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typedef _CharT | char_type |
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typedef traits_type::int_type | int_type |
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typedef traits_type::off_type | off_type |
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typedef traits_type::pos_type | pos_type |
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typedef _Traits | traits_type |
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void | __safe_gbump (streamsize __n) |
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void | __safe_pbump (streamsize __n) |
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void | _M_allocate_internal_buffer () |
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bool | _M_convert_to_external (char_type *, streamsize) |
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| void | _M_create_pback () |
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void | _M_destroy_internal_buffer () throw () |
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| void | _M_destroy_pback () throw () |
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int | _M_get_ext_pos (__state_type &__state) |
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pos_type | _M_seek (off_type __off, ios_base::seekdir __way, __state_type __state) |
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| void | _M_set_buffer (streamsize __off) |
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bool | _M_terminate_output () |
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| void | gbump (int __n) |
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virtual void | imbue (const locale &__loc) |
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| virtual void | imbue (const locale &__loc __attribute__((__unused__))) |
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virtual int_type | overflow (int_type __c=_Traits::eof()) |
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| virtual int_type | overflow (int_type __c __attribute__((__unused__))=traits_type::eof()) |
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virtual int_type | pbackfail (int_type __c=_Traits::eof()) |
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| virtual int_type | pbackfail (int_type __c __attribute__((__unused__))=traits_type::eof()) |
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| void | pbump (int __n) |
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| virtual pos_type | seekoff (off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out) |
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| virtual pos_type | seekpos (pos_type __pos, ios_base::openmode __mode=ios_base::in|ios_base::out) |
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| virtual __streambuf_type * | setbuf (char_type *__s, streamsize __n) |
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| void | setg (char_type *__gbeg, char_type *__gnext, char_type *__gend) |
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| void | setp (char_type *__pbeg, char_type *__pend) |
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| virtual streamsize | showmanyc () |
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void | swap (basic_streambuf &__sb) |
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| virtual int | sync () |
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| virtual int_type | uflow () |
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| virtual int_type | underflow () |
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| virtual streamsize | xsgetn (char_type *__s, streamsize __n) |
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| virtual streamsize | xsputn (const char_type *__s, streamsize __n) |
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| char_type * | eback () const |
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| char_type * | gptr () const |
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| char_type * | egptr () const |
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| char_type * | pbase () const |
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| char_type * | pptr () const |
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| char_type * | epptr () const |
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template<typename _CharT, typename _Traits>
class std::basic_filebuf< _CharT, _Traits >
The actual work of input and output (for files).
- Template Parameters
-
| _CharT | Type of character stream. |
| _Traits | Traits for character type, defaults to char_traits<_CharT>. |
This class associates both its input and output sequence with an external disk file, and maintains a joint file position for both sequences. Many of its semantics are described in terms of similar behavior in the Standard C Library's FILE streams.
Requirements on traits_type, specific to this class:
- traits_type::pos_type must be fpos<traits_type::state_type>
- traits_type::off_type must be streamoff
- traits_type::state_type must be Assignable and DefaultConstructible,
- traits_type::state_type() must be the initial state for codecvt.
Definition at line 80 of file fstream.
template<typename _CharT, typename _Traits>
This function sets the pointers of the internal buffer, both get and put areas. Typically:
__off == egptr() - eback() upon underflow/uflow (read mode); __off == 0 upon overflow (write mode); __off == -1 upon open, setbuf, seekoff/pos (uncommitted mode).
NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size reflects the actual allocated memory and the last cell is reserved for the overflow char of a full put area.
Definition at line 443 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::close().
template<typename _CharT , typename _Traits >
Closes the currently associated file.
- Returns
this on success, NULL on failure
If no file is currently open, this function immediately fails.
If a put buffer area exists, overflow(eof) is called to flush all the characters. The file is then closed.
If any operations fail, this function also fails.
Definition at line 213 of file fstream.tcc.
template<typename _CharT, typename _Traits>
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inlineprotectedvirtualinherited |
Changes translations.
- Parameters
-
Translations done during I/O which depend on the current locale are changed by this call. The standard adds, Between invocations of this function a class derived from streambuf can safely cache results of calls to locale functions and to members of facets so obtained.
- Note
- Base class version does nothing.
Definition at line 583 of file streambuf.
template<typename _CharT, typename _Traits>
Looking ahead into the stream.
- Returns
- The number of characters available.
If a read position is available, returns the number of characters available for reading before the buffer must be refilled. Otherwise returns the derived showmanyc().
Definition at line 291 of file streambuf.
template<typename _CharT , typename _Traits >
Opens an external file.
- Parameters
-
| __s | The name of the file. |
| __mode | The open mode flags. |
- Returns
this on success, NULL on failure
If a file is already open, this function immediately fails. Otherwise it tries to open the file named __s using the flags given in __mode.
Table 92, adapted here, gives the relation between openmode combinations and the equivalent fopen() flags. (NB: lines app, in|out|app, in|app, binary|app, binary|in|out|app, and binary|in|app per DR 596)
+---------------------------------------------------------+
| ios_base Flag combination stdio equivalent |
|binary in out trunc app |
+---------------------------------------------------------+
| + w |
| + + a |
| + a |
| + + w |
| + r |
| + + r+ |
| + + + w+ |
| + + + a+ |
| + + a+ |
+---------------------------------------------------------+
| + + wb |
| + + + ab |
| + + ab |
| + + + wb |
| + + rb |
| + + + r+b |
| + + + + w+b |
| + + + + a+b |
| + + + a+b |
+---------------------------------------------------------+
Definition at line 179 of file fstream.tcc.
Referenced by std::basic_filebuf< char_type, traits_type >::open().
template<typename _CharT, typename _Traits>
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inlineprotectedvirtualinherited |
Consumes data from the buffer; writes to the controlled sequence.
- Parameters
-
| __c | An additional character to consume. |
- Returns
- eof() to indicate failure, something else (usually __c, or not_eof())
Informally, this function is called when the output buffer is full (or does not exist, as buffering need not actually be done). If a buffer exists, it is consumed, with some effect on the controlled sequence. (Typically, the buffer is written out to the sequence verbatim.) In either case, the character c is also written out, if __c is not eof().
For a formal definition of this function, see a good text such as Langer & Kreft, or [27.5.2.4.5]/3-7.
A functioning output streambuf can be created by overriding only this function (no buffer area will be used).
- Note
- Base class version does nothing, returns eof().
Definition at line 775 of file streambuf.
template<typename _CharT, typename _Traits>
Getting the next character.
- Returns
- The next character, or eof.
If the input read position is available, returns that character and increments the read pointer, otherwise calls and returns uflow().
Definition at line 323 of file streambuf.
template<typename _CharT, typename _Traits>
Getting the next character.
- Returns
- The next character, or eof.
If the input read position is available, returns that character, otherwise calls and returns underflow(). Does not move the read position after fetching the character.
Definition at line 345 of file streambuf.
template<typename _CharT , typename _Traits >
Investigating the data available.
- Returns
- An estimate of the number of characters available in the input sequence, or -1.
If it returns a positive value, then successive calls to underflow() will not return traits::eof() until at least that number of characters have been supplied. If showmanyc() returns -1, then calls to underflow() or uflow() will fail. [27.5.2.4.3]/1
- Note
- Base class version does nothing, returns zero.
-
The standard adds that the intention is not only that the calls [to underflow or uflow] will not return
eof() but that they will return immediately.
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The standard adds that the morphemes of
showmanyc are es-how-many-see, not show-manic.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 263 of file fstream.tcc.
template<typename _CharT, typename _Traits>
Getting the next character.
- Returns
- The next character, or eof.
Calls sbumpc(), and if that function returns traits::eof(), so does this function. Otherwise, sgetc().
Definition at line 305 of file streambuf.
template<typename _CharT, typename _Traits>
Pushing characters back into the input stream.
- Parameters
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| __c | The character to push back. |
- Returns
- The previous character, if possible.
Similar to sungetc(), but __c is pushed onto the stream instead of the previous character. If successful, the next character fetched from the input stream will be __c.
Definition at line 379 of file streambuf.
template<typename _CharT, typename _Traits>
Entry point for all single-character output functions.
- Parameters
-
| __c | A character to output. |
- Returns
- __c, if possible.
One of two public output functions.
If a write position is available for the output sequence (i.e., the buffer is not full), stores __c in that position, increments the position, and returns traits::to_int_type(__c). If a write position is not available, returns overflow(__c).
Definition at line 431 of file streambuf.
Referenced by std::ostreambuf_iterator< _CharT, _Traits >::operator=().
template<typename _CharT, typename _Traits>
Entry point for all single-character output functions.
- Parameters
-
| __s | A buffer read area. |
| __n | A count. |
One of two public output functions.
Returns xsputn(__s,__n). The effect is to write __s[0] through __s[__n-1] to the output sequence, if possible.
Definition at line 457 of file streambuf.
template<typename _CharT, typename _Traits>
Moving backwards in the input stream.
- Returns
- The previous character, if possible.
If a putback position is available, this function decrements the input pointer and returns that character. Otherwise, calls and returns pbackfail(). The effect is to unget the last character gotten.
Definition at line 404 of file streambuf.
template<typename _CharT , typename _Traits >
Synchronizes the buffer arrays with the controlled sequences.
- Returns
- -1 on failure.
Each derived class provides its own appropriate behavior, including the definition of failure.
- Note
- Base class version does nothing, returns zero.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 978 of file fstream.tcc.
template<typename _CharT, typename _Traits>
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inlineprotectedvirtualinherited |
Fetches more data from the controlled sequence.
- Returns
- The first character from the pending sequence.
Informally, this function does the same thing as underflow(), and in fact is required to call that function. It also returns the new character, like underflow() does. However, this function also moves the read position forward by one.
Reimplemented in __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.
Definition at line 707 of file streambuf.
template<typename _CharT , typename _Traits >
Fetches more data from the controlled sequence.
- Returns
- The first character from the pending sequence.
Informally, this function is called when the input buffer is exhausted (or does not exist, as buffering need not actually be done). If a buffer exists, it is refilled. In either case, the next available character is returned, or traits::eof() to indicate a null pending sequence.
For a formal definition of the pending sequence, see a good text such as Langer & Kreft, or [27.5.2.4.3]/7-14.
A functioning input streambuf can be created by overriding only this function (no buffer area will be used). For an example, see https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html
- Note
- Base class version does nothing, returns eof().
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 289 of file fstream.tcc.
template<typename _CharT , typename _Traits >
Multiple character extraction.
- Parameters
-
| __s | A buffer area. |
| __n | Maximum number of characters to assign. |
- Returns
- The number of characters assigned.
Fills __s[0] through __s[__n-1] with characters from the input sequence, as if by sbumpc(). Stops when either __n characters have been copied, or when traits::eof() would be copied.
It is expected that derived classes provide a more efficient implementation by overriding this definition.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 635 of file fstream.tcc.
template<typename _CharT , typename _Traits >
Multiple character insertion.
- Parameters
-
| __s | A buffer area. |
| __n | Maximum number of characters to write. |
- Returns
- The number of characters written.
Writes __s[0] through __s[__n-1] to the output sequence, as if by sputc(). Stops when either n characters have been copied, or when sputc() would return traits::eof().
It is expected that derived classes provide a more efficient implementation by overriding this definition.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 721 of file fstream.tcc.
template<typename _CharT, typename _Traits>
1.8.15