Public Types | |
|
typedef codecvt< char_type, char, __state_type > | __codecvt_type |
| typedef __basic_file< char > | __file_type |
|
typedef basic_filebuf < char_type, traits_type > | __filebuf_type |
| typedef traits_type::state_type | __state_type |
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typedef basic_streambuf < char_type, traits_type > | __streambuf_type |
| typedef _CharT | char_type |
| typedef traits_type::int_type | int_type |
| typedef traits_type::off_type | off_type |
| typedef traits_type::pos_type | pos_type |
| typedef _Traits | traits_type |
Public Member Functions | |
| basic_filebuf () | |
| virtual | ~basic_filebuf () |
| __filebuf_type * | close () |
| locale | getloc () const |
| streamsize | in_avail () |
| bool | is_open () const throw () |
| __filebuf_type * | open (const char *__s, ios_base::openmode __mode) |
| __filebuf_type * | open (const std::string &__s, ios_base::openmode __mode) |
| locale | pubimbue (const locale &__loc) |
| int_type | sbumpc () |
| int_type | sgetc () |
| streamsize | sgetn (char_type *__s, streamsize __n) |
| int_type | snextc () |
| int_type | sputbackc (char_type __c) |
| int_type | sputc (char_type __c) |
| streamsize | sputn (const char_type *__s, streamsize __n) |
| int_type | sungetc () |
| __streambuf_type * | pubsetbuf (char_type *__s, streamsize __n) |
| pos_type | pubseekoff (off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out) |
| pos_type | pubseekpos (pos_type __sp, ios_base::openmode __mode=ios_base::in|ios_base::out) |
| int | pubsync () |
Protected Member Functions | |
| void | __safe_gbump (streamsize __n) |
| void | __safe_pbump (streamsize __n) |
| void | _M_allocate_internal_buffer () |
| bool | _M_convert_to_external (char_type *, streamsize) |
| void | _M_create_pback () |
| void | _M_destroy_internal_buffer () throw () |
| void | _M_destroy_pback () throw () |
| int | _M_get_ext_pos (__state_type &__state) |
| pos_type | _M_seek (off_type __off, ios_base::seekdir __way, __state_type __state) |
| void | _M_set_buffer (streamsize __off) |
| bool | _M_terminate_output () |
| void | gbump (int __n) |
| virtual void | imbue (const locale &__loc) |
| virtual int_type | overflow (int_type __c=_Traits::eof()) |
| virtual int_type | pbackfail (int_type __c=_Traits::eof()) |
| void | pbump (int __n) |
| virtual pos_type | seekoff (off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out) |
| virtual pos_type | seekpos (pos_type __pos, ios_base::openmode __mode=ios_base::in|ios_base::out) |
| virtual __streambuf_type * | setbuf (char_type *__s, streamsize __n) |
| void | setg (char_type *__gbeg, char_type *__gnext, char_type *__gend) |
| void | setp (char_type *__pbeg, char_type *__pend) |
| virtual streamsize | showmanyc () |
| virtual int | sync () |
| virtual int_type | uflow () |
| virtual int_type | underflow () |
| virtual streamsize | xsgetn (char_type *__s, streamsize __n) |
| virtual streamsize | xsputn (const char_type *__s, streamsize __n) |
| char_type * | eback () const |
| char_type * | gptr () const |
| char_type * | egptr () const |
| char_type * | pbase () const |
| char_type * | pptr () const |
| char_type * | epptr () const |
Protected Attributes | |
| char_type * | _M_buf |
| bool | _M_buf_allocated |
| locale | _M_buf_locale |
| size_t | _M_buf_size |
| const __codecvt_type * | _M_codecvt |
| char * | _M_ext_buf |
| streamsize | _M_ext_buf_size |
| char * | _M_ext_end |
| const char * | _M_ext_next |
| __file_type | _M_file |
| char_type * | _M_in_beg |
| char_type * | _M_in_cur |
| char_type * | _M_in_end |
| __c_lock | _M_lock |
| ios_base::openmode | _M_mode |
| char_type * | _M_out_beg |
| char_type * | _M_out_cur |
| char_type * | _M_out_end |
| bool | _M_reading |
| __state_type | _M_state_beg |
| __state_type | _M_state_cur |
| __state_type | _M_state_last |
| bool | _M_writing |
| char_type | _M_pback |
| char_type * | _M_pback_cur_save |
| char_type * | _M_pback_end_save |
| bool | _M_pback_init |
Friends | |
| class | ios_base |
Detailed Description
template<typename _CharT, typename _Traits>
class std::basic_filebuf< _CharT, _Traits >
The actual work of input and output (for files).
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.
Constructor & Destructor Documentation
| std::basic_filebuf< _CharT, _Traits >::basic_filebuf | ( | ) |
Does not open any files.
The default constructor initializes the parent class using its own default ctor.
Definition at line 81 of file fstream.tcc.
References std::basic_streambuf< _CharT, _Traits >::_M_buf_locale.
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inlinevirtual |
Member Function Documentation
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inlineprotected |
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inlineprotected | |||||||||||||
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inlineprotected |
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.
| basic_filebuf< _CharT, _Traits >::__filebuf_type * std::basic_filebuf< _CharT, _Traits >::close | ( | ) |
Closes the currently associated file.
- Returns
thison 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 130 of file fstream.tcc.
Referenced by std::basic_ifstream< _CharT, _Traits >::close(), std::basic_ofstream< _CharT, _Traits >::close(), std::basic_fstream< _CharT, _Traits >::close(), and std::basic_filebuf< char_type, traits_type >::~basic_filebuf().
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inlineprotectedinherited |
Access to the get area.
These functions are only available to other protected functions, including derived classes.
- eback() returns the beginning pointer for the input sequence
- gptr() returns the next pointer for the input sequence
- egptr() returns the end pointer for the input sequence
Definition at line 461 of file streambuf.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_destroy_pback(), std::basic_streambuf< char, char_traits< char > >::sputbackc(), and std::basic_streambuf< char, char_traits< char > >::sungetc().
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inlineprotectedinherited |
Access to the get area.
These functions are only available to other protected functions, including derived classes.
- eback() returns the beginning pointer for the input sequence
- gptr() returns the next pointer for the input sequence
- egptr() returns the end pointer for the input sequence
Definition at line 467 of file streambuf.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), std::basic_streambuf< char, char_traits< char > >::in_avail(), std::basic_streambuf< char, char_traits< char > >::sbumpc(), std::basic_streambuf< char, char_traits< char > >::sgetc(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::showmanyc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().
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inlineprotectedinherited |
Access to the put area.
These functions are only available to other protected functions, including derived classes.
- pbase() returns the beginning pointer for the output sequence
- pptr() returns the next pointer for the output sequence
- epptr() returns the end pointer for the output sequence
Definition at line 514 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char > >::sputc().
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inlineprotectedinherited |
Moving the read position.
- Parameters
-
n The delta by which to move.
This just advances the read position without returning any data.
Definition at line 477 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char > >::sbumpc(), std::basic_streambuf< char, char_traits< char > >::sputbackc(), std::basic_streambuf< char, char_traits< char > >::sungetc(), and std::basic_streambuf< char, char_traits< char > >::uflow().
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inlineinherited |
Locale access.
- Returns
- The current locale in effect.
If pubimbue(loc) has been called, then the most recent loc is returned. Otherwise the global locale in effect at the time of construction is returned.
Definition at line 223 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char > >::pubimbue().
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inlineprotectedinherited |
Access to the get area.
These functions are only available to other protected functions, including derived classes.
- eback() returns the beginning pointer for the input sequence
- gptr() returns the next pointer for the input sequence
- egptr() returns the end pointer for the input sequence
Definition at line 464 of file streambuf.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), std::basic_filebuf< char_type, traits_type >::_M_destroy_pback(), std::basic_streambuf< char, char_traits< char > >::in_avail(), std::basic_streambuf< char, char_traits< char > >::sbumpc(), std::basic_streambuf< char, char_traits< char > >::sgetc(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::showmanyc(), std::basic_streambuf< char, char_traits< char > >::sputbackc(), std::basic_streambuf< char, char_traits< char > >::sungetc(), and std::basic_streambuf< char, char_traits< char > >::uflow().
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protectedvirtual |
Changes translations.
- Parameters
-
loc A new locale.
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.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 912 of file fstream.tcc.
References std::ios_base::cur.
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inlineinherited |
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().
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inline | |||||||||||||
Returns true if the external file is open.
Definition at line 224 of file fstream.
Referenced by std::basic_ifstream< _CharT, _Traits >::is_open(), std::basic_ofstream< _CharT, _Traits >::is_open(), and std::basic_fstream< _CharT, _Traits >::is_open().
| basic_filebuf< _CharT, _Traits >::__filebuf_type * std::basic_filebuf< _CharT, _Traits >::open | ( | const char * | __s, |
| ios_base::openmode | __mode | ||
| ) |
Opens an external file.
- Parameters
-
s The name of the file. mode The open mode flags.
- Returns
thison 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 96 of file fstream.tcc.
References std::ios_base::ate, std::ios_base::end, and std::basic_filebuf< _CharT, _Traits >::open().
Referenced by std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< char_type, traits_type >::open(), std::basic_ifstream< _CharT, _Traits >::open(), std::basic_ofstream< _CharT, _Traits >::open(), and std::basic_fstream< _CharT, _Traits >::open().
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inline |
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protectedvirtual |
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().
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 424 of file fstream.tcc.
References std::ios_base::cur, and std::ios_base::out.
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protectedvirtual |
Tries to back up the input sequence.
- Parameters
-
c The character to be inserted back into the sequence.
- Returns
- eof() on failure, some other value on success
- Postcondition
- The constraints of
gptr(),eback(), andpptr()are the same as forunderflow().
- Note
- Base class version does nothing, returns eof().
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 365 of file fstream.tcc.
References std::ios_base::cur, and std::ios_base::in.
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inlineprotectedinherited |
Access to the put area.
These functions are only available to other protected functions, including derived classes.
- pbase() returns the beginning pointer for the output sequence
- pptr() returns the next pointer for the output sequence
- epptr() returns the end pointer for the output sequence
Definition at line 508 of file streambuf.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().
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inlineprotectedinherited |
Moving the write position.
- Parameters
-
n The delta by which to move.
This just advances the write position without returning any data.
Definition at line 524 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char > >::sputc().
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inlineprotectedinherited |
Access to the put area.
These functions are only available to other protected functions, including derived classes.
- pbase() returns the beginning pointer for the output sequence
- pptr() returns the next pointer for the output sequence
- epptr() returns the end pointer for the output sequence
Definition at line 511 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char > >::sputc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().
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inlineinherited |
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inlineinherited |
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inlineinherited |
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inlineinherited |
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inlineinherited |
Entry points for derived buffer functions.
The public versions of pubfoo dispatch to the protected derived foo member functions, passing the arguments (if any) and returning the result unchanged.
Definition at line 250 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::sync().
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inlineinherited |
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 295 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), std::istreambuf_iterator< _CharT, _Traits >::operator++(), and std::basic_streambuf< char, char_traits< char > >::snextc().
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protectedvirtual |
Alters the stream positions.
Each derived class provides its own appropriate behavior.
- Note
- Base class version does nothing, returns a
pos_typethat represents an invalid stream position.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 715 of file fstream.tcc.
References std::ios_base::cur.
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protectedvirtual |
Alters the stream positions.
Each derived class provides its own appropriate behavior.
- Note
- Base class version does nothing, returns a
pos_typethat represents an invalid stream position.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 775 of file fstream.tcc.
References std::ios_base::beg.
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protectedvirtual |
Manipulates the buffer.
- Parameters
-
s Pointer to a buffer area. n Size of s.
- Returns
this
If no file has been opened, and both s and n are zero, then the stream becomes unbuffered. Otherwise, s is used as a buffer; see http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html for more.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 686 of file fstream.tcc.
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inlineprotectedinherited |
Setting the three read area pointers.
- Parameters
-
gbeg A pointer. gnext A pointer. gend A pointer.
Definition at line 488 of file streambuf.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), std::basic_filebuf< char_type, traits_type >::_M_destroy_pback(), and std::basic_filebuf< char_type, traits_type >::_M_set_buffer().
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inlineprotectedinherited |
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inlineinherited |
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 317 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::get(), std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), std::basic_istream< _CharT, _Traits >::sentry::sentry(), and std::basic_streambuf< char, char_traits< char > >::snextc().
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inlineinherited |
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protectedvirtual |
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. -
The standard adds that the morphemes of
showmanycare es-how-many-see, not show-manic.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 180 of file fstream.tcc.
References std::ios_base::binary, and std::ios_base::in.
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inlineinherited |
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 277 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::get(), std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), and std::basic_istream< _CharT, _Traits >::sentry::sentry().
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inlineinherited |
Pushing characters back into the input stream.
- Parameters
-
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 351 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::putback().
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inlineinherited |
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 403 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::get(), and std::ostreambuf_iterator< _CharT, _Traits >::operator=().
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inlineinherited |
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inlineinherited |
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 376 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::unget().
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protectedvirtual |
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 895 of file fstream.tcc.
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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 679 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char > >::sbumpc().
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protectedvirtual |
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 http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25.html
- Note
- Base class version does nothing, returns eof().
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 206 of file fstream.tcc.
References std::ios_base::in, and std::min().
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protectedvirtual |
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 551 of file fstream.tcc.
References std::ios_base::in.
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protectedvirtual |
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 639 of file fstream.tcc.
References std::min(), and std::ios_base::out.
Member Data Documentation
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protected |
Pointer to the beginning of internal buffer.
Definition at line 111 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_destroy_pback(), and std::basic_filebuf< char_type, traits_type >::_M_set_buffer().
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protectedinherited |
Current locale setting.
Definition at line 189 of file streambuf.
Referenced by std::basic_filebuf< _CharT, _Traits >::basic_filebuf(), std::basic_streambuf< char, char_traits< char > >::getloc(), and std::basic_streambuf< char, char_traits< char > >::pubimbue().
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protected |
Actual size of internal buffer. This number is equal to the size of the put area + 1 position, reserved for the overflow char of a full area.
Definition at line 118 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_set_buffer().
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protected |
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protected |
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protected |
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protected |
Place to stash in || out || in | out settings for current filebuf.
Definition at line 96 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_set_buffer().
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protected |
Necessary bits for putback buffer management.
- Note
- pbacks of over one character are not currently supported.
Definition at line 139 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback().
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protected |
Necessary bits for putback buffer management.
- Note
- pbacks of over one character are not currently supported.
Definition at line 140 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), and std::basic_filebuf< char_type, traits_type >::_M_destroy_pback().
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protected |
Necessary bits for putback buffer management.
- Note
- pbacks of over one character are not currently supported.
Definition at line 141 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), and std::basic_filebuf< char_type, traits_type >::_M_destroy_pback().
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protected |
Necessary bits for putback buffer management.
- Note
- pbacks of over one character are not currently supported.
Definition at line 142 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), and std::basic_filebuf< char_type, traits_type >::_M_destroy_pback().
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The documentation for this class was generated from the following files:
