std::basic_filebuf< _CharT, _Traits > Class Template Reference

The actual work of input and output (for files). More...

Inheritance diagram for std::basic_filebuf< _CharT, _Traits >:

std::basic_streambuf< _CharT, _Traits > __gnu_cxx::stdio_filebuf< _CharT, _Traits > List of all members.

Public Types

typedef _CharT char_type
typedef _Traits traits_type
typedef traits_type::int_type int_type
typedef traits_type::pos_type pos_type
typedef traits_type::off_type off_type
typedef basic_streambuf< char_type,
traits_type
__streambuf_type
typedef basic_filebuf< char_type,
traits_type
__filebuf_type
typedef __basic_file< char > __file_type
typedef traits_type::state_type __state_type
typedef codecvt< char_type,
char, __state_type
__codecvt_type

Public Member Functions

 basic_filebuf ()
 Does not open any files.

virtual ~basic_filebuf ()
 The destructor closes the file first.

bool is_open () const throw ()
 Returns true if the external file is open.

__filebuf_typeopen (const char *__s, ios_base::openmode __mode)
 Opens an external file.

__filebuf_typeclose () throw ()
 Closes the currently associated file.


Protected Member Functions

void _M_create_pback ()
void _M_destroy_pback () throw ()
void _M_allocate_internal_buffer ()
void _M_destroy_internal_buffer () throw ()
virtual streamsize showmanyc ()
 Investigating the data available.

virtual int_type underflow ()
 Fetches more data from the controlled sequence.

virtual int_type pbackfail (int_type __c=_Traits::eof())
 Tries to back up the input sequence.

virtual int_type overflow (int_type __c=_Traits::eof())
 Consumes data from the buffer; writes to the controlled sequence.

bool _M_convert_to_external (char_type *, streamsize)
virtual __streambuf_typesetbuf (char_type *__s, streamsize __n)
 Manipulates the buffer.

virtual pos_type seekoff (off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out)
 Alters the stream positions.

virtual pos_type seekpos (pos_type __pos, ios_base::openmode __mode=ios_base::in|ios_base::out)
 Alters the stream positions.

pos_type _M_seek (off_type __off, ios_base::seekdir __way, __state_type __state)
virtual int sync ()
 Synchronizes the buffer arrays with the controlled sequences.

virtual void imbue (const locale &__loc)
 Changes translations.

virtual streamsize xsgetn (char_type *__s, streamsize __n)
 Multiple character extraction.

virtual streamsize xsputn (const char_type *__s, streamsize __n)
 Multiple character insertion.

bool _M_terminate_output ()
void _M_set_buffer (streamsize __off)

Protected Attributes

__c_lock _M_lock
__file_type _M_file
ios_base::openmode _M_mode
__state_type _M_state_beg
__state_type _M_state_cur
__state_type _M_state_last
char_type_M_buf
size_t _M_buf_size
bool _M_buf_allocated
bool _M_reading
bool _M_writing
const __codecvt_type_M_codecvt
char * _M_ext_buf
streamsize _M_ext_buf_size
const char * _M_ext_next
char * _M_ext_end
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 sematics are described in terms of similar behavior in the Standard C Library's FILE streams.

Definition at line 69 of file fstream.


Member Typedef Documentation

template<typename _CharT, typename _Traits>
typedef codecvt<char_type, char, __state_type> std::basic_filebuf< _CharT, _Traits >::__codecvt_type
 

Definition at line 89 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::imbue().

template<typename _CharT, typename _Traits>
typedef __basic_file<char> std::basic_filebuf< _CharT, _Traits >::__file_type
 

Definition at line 87 of file fstream.

template<typename _CharT, typename _Traits>
typedef basic_filebuf<char_type, traits_type> std::basic_filebuf< _CharT, _Traits >::__filebuf_type
 

Definition at line 86 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::close(), and std::basic_filebuf< _CharT, _Traits >::open().

template<typename _CharT, typename _Traits>
typedef traits_type::state_type std::basic_filebuf< _CharT, _Traits >::__state_type
 

Definition at line 88 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), and std::basic_filebuf< _CharT, _Traits >::seekoff().

template<typename _CharT, typename _Traits>
typedef basic_streambuf<char_type, traits_type> std::basic_filebuf< _CharT, _Traits >::__streambuf_type
 

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 85 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::basic_filebuf().

template<typename _CharT, typename _Traits>
typedef _CharT std::basic_filebuf< _CharT, _Traits >::char_type
 

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation.

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Reimplemented in __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 73 of file fstream.

template<typename _CharT, typename _Traits>
typedef traits_type::int_type std::basic_filebuf< _CharT, _Traits >::int_type
 

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Reimplemented in __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 75 of file fstream.

template<typename _CharT, typename _Traits>
typedef traits_type::off_type std::basic_filebuf< _CharT, _Traits >::off_type
 

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Reimplemented in __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 77 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::pbackfail(), std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::seekpos().

template<typename _CharT, typename _Traits>
typedef traits_type::pos_type std::basic_filebuf< _CharT, _Traits >::pos_type
 

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Reimplemented in __gnu_cxx::enc_filebuf< _CharT >, and __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 76 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::pbackfail(), std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::seekpos().

template<typename _CharT, typename _Traits>
typedef _Traits std::basic_filebuf< _CharT, _Traits >::traits_type
 

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Reimplemented in __gnu_cxx::enc_filebuf< _CharT >, and __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 74 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 76 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::__streambuf_type, and std::basic_filebuf< _CharT, _Traits >::_M_codecvt.

template<typename _CharT, typename _Traits>
virtual std::basic_filebuf< _CharT, _Traits >::~basic_filebuf  )  [inline, virtual]
 

The destructor closes the file first.

Definition at line 277 of file fstream.


Member Function Documentation

template<typename _CharT, typename _Traits>
void std::basic_filebuf< _CharT, _Traits >::_M_allocate_internal_buffer  )  [protected]
 

Definition at line 45 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::_M_buf_allocated, and std::basic_filebuf< _CharT, _Traits >::_M_buf_size.

Referenced by std::basic_filebuf< _CharT, _Traits >::open(), and __gnu_cxx::stdio_filebuf< _CharT, _Traits >::stdio_filebuf().

template<typename _CharT, typename _Traits>
bool std::basic_filebuf< _CharT, _Traits >::_M_convert_to_external char_type ,
streamsize 
[protected]
 

Referenced by std::basic_filebuf< _CharT, _Traits >::overflow().

template<typename _CharT, typename _Traits>
void std::basic_filebuf< _CharT, _Traits >::_M_create_pback  )  [inline, protected]
 

Definition at line 233 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::pbackfail().

template<typename _CharT, typename _Traits>
void std::basic_filebuf< _CharT, _Traits >::_M_destroy_internal_buffer  )  throw () [protected]
 

Definition at line 59 of file fstream.tcc.

template<typename _CharT, typename _Traits>
void std::basic_filebuf< _CharT, _Traits >::_M_destroy_pback  )  throw () [inline, protected]
 

Definition at line 252 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::seekoff(), std::basic_filebuf< _CharT, _Traits >::seekpos(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
basic_filebuf< _CharT, _Traits >::pos_type std::basic_filebuf< _CharT, _Traits >::_M_seek off_type  __off,
ios_base::seekdir  __way,
__state_type  __state
[protected]
 

Definition at line 724 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::__state_type, std::basic_filebuf< _CharT, _Traits >::_M_ext_buf, std::basic_filebuf< _CharT, _Traits >::_M_ext_end, std::basic_filebuf< _CharT, _Traits >::_M_ext_next, std::basic_filebuf< _CharT, _Traits >::_M_reading, std::basic_filebuf< _CharT, _Traits >::_M_set_buffer(), std::basic_filebuf< _CharT, _Traits >::_M_state_cur, std::basic_filebuf< _CharT, _Traits >::_M_terminate_output(), std::basic_filebuf< _CharT, _Traits >::_M_writing, std::basic_filebuf< _CharT, _Traits >::off_type, std::basic_filebuf< _CharT, _Traits >::pos_type, std::ios_base::seekdir, and std::__basic_file< char >::seekoff().

Referenced by std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::seekpos().

template<typename _CharT, typename _Traits>
void std::basic_filebuf< _CharT, _Traits >::_M_set_buffer streamsize  __off  )  [inline, protected]
 

Definition at line 451 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::overflow(), __gnu_cxx::stdio_filebuf< _CharT, _Traits >::stdio_filebuf(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
bool std::basic_filebuf< _CharT, _Traits >::_M_terminate_output  )  [protected]
 

Definition at line 744 of file fstream.tcc.

References std::__check_facet(), std::basic_filebuf< _CharT, _Traits >::_M_codecvt, std::basic_filebuf< _CharT, _Traits >::_M_state_cur, std::basic_filebuf< _CharT, _Traits >::_M_writing, std::basic_filebuf< _CharT, _Traits >::overflow(), std::basic_streambuf< _CharT, _Traits >::pbase(), std::basic_streambuf< _CharT, _Traits >::pptr(), std::streamsize, std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::unshift(), and std::__basic_file< char >::xsputn().

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), and std::basic_filebuf< _CharT, _Traits >::imbue().

template<typename _CharT, typename _Traits>
basic_filebuf< _CharT, _Traits >::__filebuf_type * std::basic_filebuf< _CharT, _Traits >::close  )  throw ()
 

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 125 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::__filebuf_type, and std::ios_base::openmode.

Referenced by std::basic_filebuf< _CharT, _Traits >::open(), and std::basic_filebuf< _CharT, enc_char_traits< _CharT > >::~basic_filebuf().

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 822 of file fstream.tcc.

References std::__check_facet(), std::basic_filebuf< _CharT, _Traits >::__codecvt_type, std::basic_filebuf< _CharT, _Traits >::_M_codecvt, std::basic_filebuf< _CharT, _Traits >::_M_ext_buf, std::basic_filebuf< _CharT, _Traits >::_M_ext_end, std::basic_filebuf< _CharT, _Traits >::_M_ext_next, std::basic_filebuf< _CharT, _Traits >::_M_reading, std::basic_filebuf< _CharT, _Traits >::_M_set_buffer(), std::basic_filebuf< _CharT, _Traits >::_M_state_beg, std::basic_filebuf< _CharT, _Traits >::_M_state_cur, std::basic_filebuf< _CharT, _Traits >::_M_state_last, std::basic_filebuf< _CharT, _Traits >::_M_terminate_output(), std::basic_filebuf< _CharT, _Traits >::_M_writing, std::basic_streambuf< _CharT, _Traits >::eback(), std::basic_filebuf< _CharT, _Traits >::is_open(), std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::length(), std::basic_filebuf< _CharT, _Traits >::off_type, std::basic_filebuf< _CharT, _Traits >::pos_type, std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::streamsize.

template<typename _CharT, typename _Traits>
bool std::basic_filebuf< _CharT, _Traits >::is_open  )  const throw () [inline]
 

Returns true if the external file is open.

Definition at line 285 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::seekoff(), std::basic_filebuf< _CharT, _Traits >::seekpos(), std::basic_filebuf< _CharT, _Traits >::setbuf(), std::basic_filebuf< _CharT, _Traits >::showmanyc(), and __gnu_cxx::stdio_filebuf< _CharT, _Traits >::stdio_filebuf().

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 gives the relation between openmode combinations and the equivalent fopen() flags, but the table has not been copied yet.]

Definition at line 91 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::__filebuf_type, std::basic_filebuf< _CharT, _Traits >::_M_allocate_internal_buffer(), std::basic_filebuf< _CharT, _Traits >::_M_mode, std::basic_filebuf< _CharT, _Traits >::_M_reading, std::basic_filebuf< _CharT, _Traits >::_M_set_buffer(), std::basic_filebuf< _CharT, _Traits >::_M_state_beg, std::basic_filebuf< _CharT, _Traits >::_M_state_cur, std::basic_filebuf< _CharT, _Traits >::_M_state_last, std::basic_filebuf< _CharT, _Traits >::_M_writing, std::basic_filebuf< _CharT, _Traits >::close(), std::basic_filebuf< _CharT, _Traits >::is_open(), std::basic_filebuf< _CharT, _Traits >::off_type, std::__basic_file< char >::open(), std::ios_base::openmode, std::basic_filebuf< _CharT, _Traits >::pos_type, and std::basic_filebuf< _CharT, _Traits >::seekoff().

template<typename _CharT, typename _Traits>
basic_filebuf< _CharT, _Traits >::int_type std::basic_filebuf< _CharT, _Traits >::overflow int_type  __c = _Traits::eof()  )  [protected, virtual]
 

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 definiton 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 380 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::_M_buf_size, std::basic_filebuf< _CharT, _Traits >::_M_convert_to_external(), std::basic_filebuf< _CharT, _Traits >::_M_mode, std::basic_filebuf< _CharT, _Traits >::_M_reading, std::basic_filebuf< _CharT, _Traits >::_M_set_buffer(), std::basic_filebuf< _CharT, _Traits >::_M_writing, std::basic_streambuf< _CharT, _Traits >::pbase(), std::basic_streambuf< _CharT, _Traits >::pbump(), and std::basic_streambuf< _CharT, _Traits >::pptr().

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_terminate_output(), and std::basic_filebuf< _CharT, _Traits >::sync().

template<typename _CharT, typename _Traits>
basic_filebuf< _CharT, _Traits >::int_type std::basic_filebuf< _CharT, _Traits >::pbackfail int_type  __i = _Traits::eof()  )  [protected, virtual]
 

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().

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 328 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::_M_create_pback(), std::basic_filebuf< _CharT, _Traits >::_M_mode, std::basic_filebuf< _CharT, _Traits >::_M_pback_init, std::basic_filebuf< _CharT, _Traits >::_M_reading, std::basic_filebuf< _CharT, _Traits >::_M_writing, std::basic_streambuf< _CharT, _Traits >::eback(), std::basic_streambuf< _CharT, _Traits >::gbump(), std::basic_streambuf< _CharT, _Traits >::gptr(), std::basic_filebuf< _CharT, _Traits >::off_type, std::basic_filebuf< _CharT, _Traits >::pos_type, std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
basic_filebuf< _CharT, _Traits >::pos_type std::basic_filebuf< _CharT, _Traits >::seekoff off_type  __off,
ios_base::seekdir  __way,
ios_base::openmode  __mode = 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 656 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::__state_type, std::basic_filebuf< _CharT, _Traits >::_M_codecvt, std::basic_filebuf< _CharT, _Traits >::_M_destroy_pback(), std::basic_filebuf< _CharT, _Traits >::_M_ext_buf, std::basic_filebuf< _CharT, _Traits >::_M_ext_end, std::basic_filebuf< _CharT, _Traits >::_M_ext_next, std::basic_filebuf< _CharT, _Traits >::_M_reading, std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::_M_state_beg, std::basic_filebuf< _CharT, _Traits >::_M_state_last, std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::always_noconv(), std::basic_streambuf< _CharT, _Traits >::eback(), std::basic_streambuf< _CharT, _Traits >::egptr(), std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::encoding(), std::basic_streambuf< _CharT, _Traits >::gptr(), std::basic_filebuf< _CharT, _Traits >::is_open(), std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::length(), std::basic_filebuf< _CharT, _Traits >::off_type, std::ios_base::openmode, std::basic_filebuf< _CharT, _Traits >::pos_type, and std::ios_base::seekdir.

Referenced by std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), and std::basic_filebuf< _CharT, _Traits >::pbackfail().

template<typename _CharT, typename _Traits>
basic_filebuf< _CharT, _Traits >::pos_type std::basic_filebuf< _CharT, _Traits >::seekpos pos_type  __pos,
ios_base::openmode  __mode = 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 709 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::_M_destroy_pback(), std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::is_open(), std::basic_filebuf< _CharT, _Traits >::off_type, std::ios_base::openmode, and std::basic_filebuf< _CharT, _Traits >::pos_type.

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++/27_io/howto.html#2 for more.

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 629 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::_M_buf_size, std::basic_filebuf< _CharT, _Traits >::is_open(), and std::streamsize.

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 160 of file fstream.tcc.

References std::__check_facet(), std::basic_filebuf< _CharT, _Traits >::_M_codecvt, std::basic_filebuf< _CharT, _Traits >::_M_mode, std::basic_streambuf< _CharT, _Traits >::egptr(), std::basic_streambuf< _CharT, _Traits >::gptr(), std::basic_filebuf< _CharT, _Traits >::is_open(), std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::max_length(), std::__basic_file< char >::showmanyc(), and std::streamsize.

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 805 of file fstream.tcc.

References std::basic_filebuf< _CharT, _Traits >::overflow(), std::basic_streambuf< _CharT, _Traits >::pbase(), and std::basic_streambuf< _CharT, _Traits >::pptr().

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 definiton 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++/27_io/howto.html#6

Note:
Base class version does nothing, returns eof().

Reimplemented from std::basic_streambuf< _CharT, _Traits >.

Definition at line 178 of file fstream.tcc.

References std::__check_facet(), __N, std::__throw_ios_failure(), std::basic_filebuf< _CharT, _Traits >::_M_buf_size, std::basic_filebuf< _CharT, _Traits >::_M_codecvt, std::basic_filebuf< _CharT, _Traits >::_M_destroy_pback(), std::basic_filebuf< _CharT, _Traits >::_M_ext_buf, std::basic_filebuf< _CharT, _Traits >::_M_ext_buf_size, std::basic_filebuf< _CharT, _Traits >::_M_ext_end, std::basic_filebuf< _CharT, _Traits >::_M_ext_next, std::basic_filebuf< _CharT, _Traits >::_M_mode, std::basic_filebuf< _CharT, _Traits >::_M_reading, std::basic_filebuf< _CharT, _Traits >::_M_set_buffer(), std::basic_filebuf< _CharT, _Traits >::_M_state_cur, std::basic_filebuf< _CharT, _Traits >::_M_state_last, std::basic_filebuf< _CharT, _Traits >::_M_writing, std::basic_streambuf< _CharT, _Traits >::eback(), std::basic_streambuf< _CharT, _Traits >::egptr(), std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::encoding(), std::basic_streambuf< _CharT, _Traits >::gptr(), std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::in(), std::__codecvt_abstract_base< _InternT, _ExternT, _StateT >::max_length(), std::min(), std::streamsize, and std::__basic_file< char >::xsgetn().

Referenced by std::basic_filebuf< _CharT, _Traits >::pbackfail().

template<typename _CharT, typename _Traits>
virtual 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 >.

template<typename _CharT, typename _Traits>
virtual 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 >.


Friends And Related Function Documentation

template<typename _CharT, typename _Traits>
friend class ios_base [friend]
 

Definition at line 92 of file fstream.


Member Data Documentation

template<typename _CharT, typename _Traits>
char_type* std::basic_filebuf< _CharT, _Traits >::_M_buf [protected]
 

Definition at line 151 of file fstream.

template<typename _CharT, typename _Traits>
bool std::basic_filebuf< _CharT, _Traits >::_M_buf_allocated [protected]
 

Definition at line 168 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_allocate_internal_buffer().

template<typename _CharT, typename _Traits>
size_t std::basic_filebuf< _CharT, _Traits >::_M_buf_size [protected]
 

Definition at line 160 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_allocate_internal_buffer(), std::basic_filebuf< _CharT, _Traits >::overflow(), std::basic_filebuf< _CharT, _Traits >::setbuf(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
const __codecvt_type* std::basic_filebuf< _CharT, _Traits >::_M_codecvt [protected]
 

Definition at line 197 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_terminate_output(), std::basic_filebuf< _CharT, _Traits >::basic_filebuf(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::seekoff(), std::basic_filebuf< _CharT, _Traits >::showmanyc(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
char* std::basic_filebuf< _CharT, _Traits >::_M_ext_buf [protected]
 

Definition at line 206 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
streamsize std::basic_filebuf< _CharT, _Traits >::_M_ext_buf_size [protected]
 

Definition at line 213 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
char* std::basic_filebuf< _CharT, _Traits >::_M_ext_end [protected]
 

Definition at line 223 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
const char* std::basic_filebuf< _CharT, _Traits >::_M_ext_next [protected]
 

Definition at line 222 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
__file_type std::basic_filebuf< _CharT, _Traits >::_M_file [protected]
 

Definition at line 110 of file fstream.

template<typename _CharT, typename _Traits>
__c_lock std::basic_filebuf< _CharT, _Traits >::_M_lock [protected]
 

Definition at line 102 of file fstream.

template<typename _CharT, typename _Traits>
ios_base::openmode std::basic_filebuf< _CharT, _Traits >::_M_mode [protected]
 

Definition at line 117 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::overflow(), std::basic_filebuf< _CharT, _Traits >::pbackfail(), std::basic_filebuf< _CharT, _Traits >::showmanyc(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
char_type std::basic_filebuf< _CharT, _Traits >::_M_pback [protected]
 

Definition at line 190 of file fstream.

template<typename _CharT, typename _Traits>
char_type* std::basic_filebuf< _CharT, _Traits >::_M_pback_cur_save [protected]
 

Definition at line 191 of file fstream.

template<typename _CharT, typename _Traits>
char_type* std::basic_filebuf< _CharT, _Traits >::_M_pback_end_save [protected]
 

Definition at line 192 of file fstream.

template<typename _CharT, typename _Traits>
bool std::basic_filebuf< _CharT, _Traits >::_M_pback_init [protected]
 

Definition at line 193 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::pbackfail().

template<typename _CharT, typename _Traits>
bool std::basic_filebuf< _CharT, _Traits >::_M_reading [protected]
 

Definition at line 179 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::overflow(), std::basic_filebuf< _CharT, _Traits >::pbackfail(), std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
__state_type std::basic_filebuf< _CharT, _Traits >::_M_state_beg [protected]
 

Definition at line 125 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), and std::basic_filebuf< _CharT, _Traits >::seekoff().

template<typename _CharT, typename _Traits>
__state_type std::basic_filebuf< _CharT, _Traits >::_M_state_cur [protected]
 

Definition at line 135 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::_M_terminate_output(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
__state_type std::basic_filebuf< _CharT, _Traits >::_M_state_last [protected]
 

Definition at line 144 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_filebuf< _CharT, _Traits >::underflow().

template<typename _CharT, typename _Traits>
bool std::basic_filebuf< _CharT, _Traits >::_M_writing [protected]
 

Definition at line 180 of file fstream.

Referenced by std::basic_filebuf< _CharT, _Traits >::_M_seek(), std::basic_filebuf< _CharT, _Traits >::_M_terminate_output(), std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT, _Traits >::open(), std::basic_filebuf< _CharT, _Traits >::overflow(), std::basic_filebuf< _CharT, _Traits >::pbackfail(), and std::basic_filebuf< _CharT, _Traits >::underflow().


The documentation for this class was generated from the following files:
Generated on Tue Jan 30 17:32:16 2007 for GNU C++ STL by doxygen 1.3.6