std::basic_filebuf<; _CharT, _Traits >(std::basic_filebuf< _CharT, _Traits >(3)
NAME
std::basic_filebuf< _CharT, _Traits > -
SYNOPSIS
Inherits std::basic_streambuf< _CharT, _Traits >.
Inherited by __gnu_cxx::stdio_filebuf< _CharT, _Traits >.
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
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 ()
basic_streambuf * 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 return traits_type::eof ()
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).
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 72 of file fstream.
Constructor & Destructor Documentation
template<typename _CharT , typename _Traits > 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 79 of file fstream.tcc.
References std::basic_streambuf< _CharT, _Traits >::_M_buf_locale.
template<typename _CharT, typename _Traits> virtual std::basic_filebuf<
_CharT, _Traits >::~basic_filebuf () [inline], [virtual]
The destructor closes the file first.
Definition at line 219 of file fstream.
Member Function Documentation
template<typename _CharT, typename _Traits> void std::basic_filebuf<
_CharT, _Traits >::_M_create_pback () [inline], [protected]
Initializes pback buffers, and moves normal buffers to safety.
Assumptions: _M_in_cur has already been moved back
Definition at line 177 of file fstream.
template<typename _CharT, typename _Traits> void std::basic_filebuf<
_CharT, _Traits >::_M_destroy_pback () [inline], [protected]
Deactivates pback buffer contents, and restores normal buffer.
Assumptions: The pback buffer has only moved forward.
Definition at line 194 of file fstream.
template<typename _CharT, typename _Traits> void std::basic_filebuf<
_CharT, _Traits >::_M_set_buffer (streamsize__off) [inline],
[protected]
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 395 of file fstream.
template<typename _CharT , typename _Traits > basic_filebuf< _CharT,
_Traits >::__filebuf_type * std::basic_filebuf< _CharT, _Traits
>::close ()
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 128 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::eback () const
[inline], [protected], [inherited]
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 482 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::egptr () const
[inline], [protected], [inherited]
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 488 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::epptr () const
[inline], [protected], [inherited]
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 535 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::sputc().
template<typename _CharT, typename _Traits = char_traits<_CharT>> void
std::basic_streambuf< _CharT, _Traits >::gbump (int__n) [inline],
[protected], [inherited]
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 498 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>> locale
std::basic_streambuf< _CharT, _Traits >::getloc () const [inline],
[inherited]
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 226 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::pubimbue().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::gptr () const
[inline], [protected], [inherited]
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 485 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().
template<typename _CharT , typename _Traits > void std::basic_filebuf<
_CharT, _Traits >::imbue (const locale &__loc) [protected], [virtual]
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 910 of file fstream.tcc.
References std::ios_base::cur.
template<typename _CharT, typename _Traits = char_traits<_CharT>>
streamsize std::basic_streambuf< _CharT, _Traits >::in_avail ()
[inline], [inherited]
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 284 of file streambuf.
template<typename _CharT, typename _Traits> bool std::basic_filebuf<
_CharT, _Traits >::is_open () const [inline]
Returns true if the external file is open.
Definition at line 227 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().
template<typename _CharT , typename _Traits > 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:
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 94 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().
template<typename _CharT, typename _Traits> __filebuf_type*
std::basic_filebuf< _CharT, _Traits >::open (const std::string &__s,
ios_base::openmode__mode) [inline]
Opens an external file.
Parameters:
__s The name of the file.
__mode The open mode flags.
Returns:
this on success, NULL on failure
Definition at line 280 of file fstream.
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::pbase () const
[inline], [protected], [inherited]
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 529 of file streambuf.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().
template<typename _CharT, typename _Traits = char_traits<_CharT>> void
std::basic_streambuf< _CharT, _Traits >::pbump (int__n) [inline],
[protected], [inherited]
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 545 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::sputc().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::pptr () const
[inline], [protected], [inherited]
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 532 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::sputc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().
template<typename _CharT, typename _Traits = char_traits<_CharT>> locale
std::basic_streambuf< _CharT, _Traits >::pubimbue (const locale &__loc)
[inline], [inherited]
Entry point for imbue().
Parameters:
__loc The new locale.
Returns:
The previous locale.
Calls the derived imbue(__loc).
Definition at line 209 of file streambuf.
template<typename _CharT, typename _Traits = char_traits<_CharT>> pos_type
std::basic_streambuf< _CharT, _Traits >::pubseekoff (off_type__off,
ios_base::seekdir__way, ios_base::openmode__mode = ios_base::in |
ios_base::out) [inline], [inherited]
Alters the stream position.
Parameters:
__off Offset.
__way Value for ios_base::seekdir.
__mode Value for ios_base::openmode.
Calls virtual seekoff function.
Definition at line 251 of file streambuf.
template<typename _CharT, typename _Traits = char_traits<_CharT>> pos_type
std::basic_streambuf< _CharT, _Traits >::pubseekpos (pos_type__sp,
ios_base::openmode__mode = ios_base::in | ios_base::out) [inline],
[inherited]
Alters the stream position.
Parameters:
__sp Position
__mode Value for ios_base::openmode.
Calls virtual seekpos function.
Definition at line 263 of file streambuf.
template<typename _CharT, typename _Traits = char_traits<_CharT>>
basic_streambuf* std::basic_streambuf< _CharT, _Traits >::pubsetbuf
(char_type *__s, streamsize__n) [inline], [inherited]
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 239 of file streambuf.
template<typename _CharT, typename _Traits = char_traits<_CharT>> int
std::basic_streambuf< _CharT, _Traits >::pubsync () [inline],
[inherited]
Calls virtual sync function.
Definition at line 271 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::sync().
template<typename _CharT, typename _Traits = char_traits<_CharT>> int_type
std::basic_streambuf< _CharT, _Traits >::sbumpc () [inline],
[inherited]
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 316 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().
template<typename _CharT , typename _Traits > basic_filebuf< _CharT,
_Traits >::pos_type std::basic_filebuf< _CharT, _Traits >::seekoff
(off_type, ios_base::seekdir, ios_base::openmode = ios_base::in |
ios_base::out) [protected], [virtual]
Alters the stream positions. Each derived class provides its own
appropriate behavior.
Note:
Base class version does nothing, returns a pos_type that represents
an invalid stream position.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 713 of file fstream.tcc.
References std::ios_base::cur.
template<typename _CharT , typename _Traits > basic_filebuf< _CharT,
_Traits >::pos_type std::basic_filebuf< _CharT, _Traits >::seekpos
(pos_type, ios_base::openmode = ios_base::in | ios_base::out)
[protected], [virtual]
Alters the stream positions. Each derived class provides its own
appropriate behavior.
Note:
Base class version does nothing, returns a pos_type that represents
an invalid stream position.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 773 of file fstream.tcc.
References std::ios_base::beg.
template<typename _CharT , typename _Traits > basic_filebuf< _CharT,
_Traits >::__streambuf_type * std::basic_filebuf< _CharT, _Traits
>::setbuf (char_type *__s, streamsize__n) [protected], [virtual]
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 684 of file fstream.tcc.
template<typename _CharT, typename _Traits = char_traits<_CharT>> void
std::basic_streambuf< _CharT, _Traits >::setg (char_type *__gbeg,
char_type *__gnext, char_type *__gend) [inline], [protected],
[inherited]
Setting the three read area pointers.
Parameters:
__gbeg A pointer.
__gnext A pointer.
__gend A pointer.
Postcondition:
__gbeg == eback(), __gnext == gptr(), and __gend == egptr()
Definition at line 509 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>> void
std::basic_streambuf< _CharT, _Traits >::setp (char_type *__pbeg,
char_type *__pend) [inline], [protected], [inherited]
Setting the three write area pointers.
Parameters:
__pbeg A pointer.
__pend A pointer.
Postcondition:
__pbeg == pbase(), __pbeg == pptr(), and __pend == epptr()
Definition at line 555 of file streambuf.
Referenced by std::basic_filebuf< char_type, traits_type
>::_M_set_buffer().
template<typename _CharT, typename _Traits = char_traits<_CharT>> int_type
std::basic_streambuf< _CharT, _Traits >::sgetc () [inline],
[inherited]
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 338 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
streamsize std::basic_streambuf< _CharT, _Traits >::sgetn (char_type
*__s, streamsize__n) [inline], [inherited]
Entry point for xsgetn.
Parameters:
__s A buffer area.
__n A count.
Returns xsgetn(__s,__n). The effect is to fill __s[0] through
__s[__n-1] with characters from the input sequence, if possible.
Definition at line 357 of file streambuf.
template<typename _CharT , typename _Traits > streamsize
std::basic_filebuf< _CharT, _Traits >::showmanyc () [protected],
[virtual]
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 showmanyc are es-how-many-
see, not show-manic.
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 178 of file fstream.tcc.
References std::ios_base::binary, and std::ios_base::in.
template<typename _CharT, typename _Traits = char_traits<_CharT>> int_type
std::basic_streambuf< _CharT, _Traits >::snextc () [inline],
[inherited]
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 298 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>> int_type
std::basic_streambuf< _CharT, _Traits >::sputbackc (char_type__c)
[inline], [inherited]
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 372 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::putback().
template<typename _CharT, typename _Traits = char_traits<_CharT>> int_type
std::basic_streambuf< _CharT, _Traits >::sputc (char_type__c) [inline],
[inherited]
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 424 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::get(), and
std::ostreambuf_iterator< _CharT, _Traits >::operator=().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
streamsize std::basic_streambuf< _CharT, _Traits >::sputn (const
char_type *__s, streamsize__n) [inline], [inherited]
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 450 of file streambuf.
template<typename _CharT, typename _Traits = char_traits<_CharT>> int_type
std::basic_streambuf< _CharT, _Traits >::sungetc () [inline],
[inherited]
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 397 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::unget().
template<typename _CharT , typename _Traits > int std::basic_filebuf<
_CharT, _Traits >::sync () [protected], [virtual]
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 893 of file fstream.tcc.
template<typename _CharT, typename _Traits = char_traits<_CharT>> virtual
int_type return std::basic_streambuf< _CharT, _Traits
>::traits_type::eof () [protected], [virtual], [inherited]
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(), and pptr() are the same as for
underflow().
Note:
Base class version does nothing, returns eof().
template<typename _CharT, typename _Traits = char_traits<_CharT>> virtual
int_type std::basic_streambuf< _CharT, _Traits >::uflow () [inline],
[protected], [virtual], [inherited]
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 700 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::sbumpc().
template<typename _CharT , typename _Traits > basic_filebuf< _CharT,
_Traits >::int_type std::basic_filebuf< _CharT, _Traits >::underflow ()
[protected], [virtual]
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 204 of file fstream.tcc.
References std::ios_base::in, and std::min().
template<typename _CharT , typename _Traits > streamsize
std::basic_filebuf< _CharT, _Traits >::xsgetn (char_type *__s,
streamsize__n) [protected], [virtual]
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 549 of file fstream.tcc.
References std::ios_base::in.
template<typename _CharT , typename _Traits > streamsize
std::basic_filebuf< _CharT, _Traits >::xsputn (const char_type *__s,
streamsize__n) [protected], [virtual]
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 637 of file fstream.tcc.
References std::min(), and std::ios_base::out.
Member Data Documentation
template<typename _CharT, typename _Traits> char_type* std::basic_filebuf<
_CharT, _Traits >::_M_buf [protected]
Pointer to the beginning of internal buffer.
Definition at line 114 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().
template<typename _CharT, typename _Traits = char_traits<_CharT>> locale
std::basic_streambuf< _CharT, _Traits >::_M_buf_locale [protected],
[inherited]
Current locale setting.
Definition at line 192 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().
template<typename _CharT, typename _Traits> size_t std::basic_filebuf<
_CharT, _Traits >::_M_buf_size [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 121 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type
>::_M_set_buffer().
template<typename _CharT, typename _Traits> char* std::basic_filebuf<
_CharT, _Traits >::_M_ext_buf [protected]
Buffer for external characters. Used for input when
codecvt::always_noconv() == false. When valid, this corresponds to
eback().
Definition at line 156 of file fstream.
template<typename _CharT, typename _Traits> streamsize std::basic_filebuf<
_CharT, _Traits >::_M_ext_buf_size [protected]
Size of buffer held by _M_ext_buf.
Definition at line 161 of file fstream.
template<typename _CharT, typename _Traits> const char* std::basic_filebuf<
_CharT, _Traits >::_M_ext_next [protected]
Pointers into the buffer held by _M_ext_buf that delimit a subsequence
of bytes that have been read but not yet converted. When valid,
_M_ext_next corresponds to egptr().
Definition at line 168 of file fstream.
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_in_beg
[protected], [inherited]
Start of get area.
Definition at line 184 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::eback(), and std::basic_streambuf< char, char_traits< char >
>::setg().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_in_cur
[protected], [inherited]
Current read area.
Definition at line 185 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::gbump(), std::basic_streambuf< char, char_traits< char > >::gptr(),
and std::basic_streambuf< char, char_traits< char > >::setg().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_in_end
[protected], [inherited]
End of get area.
Definition at line 186 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::egptr(), and std::basic_streambuf< char, char_traits< char >
>::setg().
template<typename _CharT, typename _Traits> ios_base::openmode
std::basic_filebuf< _CharT, _Traits >::_M_mode [protected]
Place to stash in || out || in | out settings for current filebuf.
Definition at line 99 of file fstream.
Referenced by std::basic_filebuf< char_type, traits_type
>::_M_set_buffer().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_out_beg
[protected], [inherited]
Start of put area.
Definition at line 187 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::pbase(), and std::basic_streambuf< char, char_traits< char >
>::setp().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_out_cur
[protected], [inherited]
Current put area.
Definition at line 188 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::pbump(), std::basic_streambuf< char, char_traits< char > >::pptr(),
and std::basic_streambuf< char, char_traits< char > >::setp().
template<typename _CharT, typename _Traits = char_traits<_CharT>>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_out_end
[protected], [inherited]
End of put area.
Definition at line 189 of file streambuf.
Referenced by std::basic_streambuf< char, char_traits< char >
>::epptr(), and std::basic_streambuf< char, char_traits< char >
>::setp().
template<typename _CharT, typename _Traits> char_type std::basic_filebuf<
_CharT, _Traits >::_M_pback [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().
template<typename _CharT, typename _Traits> char_type* std::basic_filebuf<
_CharT, _Traits >::_M_pback_cur_save [protected]
Necessary bits for putback buffer management.
Note:
pbacks of over one character are not currently supported.
Definition at line 143 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().
template<typename _CharT, typename _Traits> char_type* std::basic_filebuf<
_CharT, _Traits >::_M_pback_end_save [protected]
Necessary bits for putback buffer management.
Note:
pbacks of over one character are not currently supported.
Definition at line 144 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().
template<typename _CharT, typename _Traits> bool std::basic_filebuf<
_CharT, _Traits >::_M_pback_init [protected]
Necessary bits for putback buffer management.
Note:
pbacks of over one character are not currently supported.
Definition at line 145 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().
template<typename _CharT, typename _Traits> bool std::basic_filebuf<
_CharT, _Traits >::_M_reading [protected]
_M_reading == false && _M_writing == false for uncommitted mode;
_M_reading == true for read mode; _M_writing == true for write mode;
NB: _M_reading == true && _M_writing == true is unused.
Definition at line 133 of file fstream.
Author
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libstdc++ Wed Nostd::basic_filebuf< _CharT, _Traits >(3)
