libstdc++
std::basic_streambuf< _CharT, _Traits > Class Template Reference
Inheritance diagram for std::basic_streambuf< _CharT, _Traits >:

List of all members.

Public Types

Public Member Functions

Protected Member Functions

Friends


Detailed Description

template<typename _CharT, typename _Traits>
class std::basic_streambuf< _CharT, _Traits >

The actual work of input and output (interface).

This is a base class. Derived stream buffers each control a pair of character sequences: one for input, and one for output.

Section [27.5.1] of the standard describes the requirements and behavior of stream buffer classes. That section (three paragraphs) is reproduced here, for simplicity and accuracy.

  1. Stream buffers can impose various constraints on the sequences they control. Some constraints are:
    • The controlled input sequence can be not readable.
    • The controlled output sequence can be not writable.
    • The controlled sequences can be associated with the contents of other representations for character sequences, such as external files.
    • The controlled sequences can support operations directly to or from associated sequences.
    • The controlled sequences can impose limitations on how the program can read characters from a sequence, write characters to a sequence, put characters back into an input sequence, or alter the stream position.
    1. Each sequence is characterized by three pointers which, if non-null, all point into the same charT array object. The array object represents, at any moment, a (sub)sequence of characters from the sequence. Operations performed on a sequence alter the values stored in these pointers, perform reads and writes directly to or from associated sequences, and alter the stream position and conversion state as needed to maintain this subsequence relationship. The three pointers are:
      • the beginning pointer, or lowest element address in the array (called xbeg here);
      • the next pointer, or next element address that is a current candidate for reading or writing (called xnext here);
      • the end pointer, or first element address beyond the end of the array (called xend here).
    2. The following semantic constraints shall always apply for any set of three pointers for a sequence, using the pointer names given immediately above:
      • If xnext is not a null pointer, then xbeg and xend shall also be non-null pointers into the same charT array, as described above; otherwise, xbeg and xend shall also be null.
      • If xnext is not a null pointer and xnext < xend for an output sequence, then a write position is available. In this case, *xnext shall be assignable as the next element to write (to put, or to store a character value, into the sequence).
      • If xnext is not a null pointer and xbeg < xnext for an input sequence, then a putback position is available. In this case, xnext[-1] shall have a defined value and is the next (preceding) element to store a character that is put back into the input sequence.
      • If xnext is not a null pointer and xnext< xend for an input sequence, then a read position is available. In this case, *xnext shall have a defined value and is the next element to read (to get, or to obtain a character value, from the sequence).

Definition at line 117 of file streambuf.


Member Typedef Documentation

template<typename _CharT, typename _Traits>
typedef _CharT std::basic_streambuf< _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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >, and __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 126 of file streambuf.

template<typename _CharT, typename _Traits>
typedef traits_type::int_type std::basic_streambuf< _CharT, _Traits >::int_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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >, and __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 128 of file streambuf.

template<typename _CharT, typename _Traits>
typedef traits_type::off_type std::basic_streambuf< _CharT, _Traits >::off_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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >, and __gnu_cxx::stdio_filebuf< _CharT, _Traits >.

Definition at line 130 of file streambuf.

template<typename _CharT, typename _Traits>
typedef traits_type::pos_type std::basic_streambuf< _CharT, _Traits >::pos_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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >, __gnu_cxx::stdio_filebuf< _CharT, _Traits >, and __gnu_cxx::enc_filebuf< _CharT >.

Definition at line 129 of file streambuf.

template<typename _CharT, typename _Traits>
typedef _Traits std::basic_streambuf< _CharT, _Traits >::traits_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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >, __gnu_cxx::stdio_filebuf< _CharT, _Traits >, and __gnu_cxx::enc_filebuf< _CharT >.

Definition at line 127 of file streambuf.


Constructor & Destructor Documentation

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

Destructor deallocates no buffer space.

Definition at line 195 of file streambuf.

template<typename _CharT, typename _Traits>
std::basic_streambuf< _CharT, _Traits >::basic_streambuf ( ) [inline, protected]

Base constructor.

Only called from derived constructors, and sets up all the buffer data to zero, including the pointers described in the basic_streambuf class description. Note that, as a result,

  • the class starts with no read nor write positions available,
  • this is not an error

Definition at line 461 of file streambuf.


Member Function Documentation

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::eback ( ) const [inline, protected]

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 480 of file streambuf.

Referenced by std::basic_filebuf< char_type, traits_type >::_M_destroy_pback(), std::basic_streambuf< char_type, traits_type >::sputbackc(), and std::basic_streambuf< char_type, traits_type >::sungetc().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::egptr ( ) const [inline, protected]

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 486 of file streambuf.

Referenced by std::basic_filebuf< char_type, traits_type >::_M_create_pback(), std::basic_streambuf< char_type, traits_type >::in_avail(), std::basic_streambuf< char_type, traits_type >::sbumpc(), std::basic_streambuf< char_type, traits_type >::sgetc(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::showmanyc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::epptr ( ) const [inline, protected]

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 533 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sputc().

template<typename _CharT, typename _Traits>
void std::basic_streambuf< _CharT, _Traits >::gbump ( int  __n) [inline, protected]

Moving the read position.

Parameters:
__nThe delta by which to move.

This just advances the read position without returning any data.

Definition at line 496 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sbumpc(), std::basic_streambuf< char_type, traits_type >::sputbackc(), std::basic_streambuf< char_type, traits_type >::sungetc(), and std::basic_streambuf< char_type, traits_type >::uflow().

template<typename _CharT, typename _Traits>
locale std::basic_streambuf< _CharT, _Traits >::getloc ( ) const [inline]

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 224 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pubimbue().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::gptr ( ) const [inline, protected]
template<typename _CharT, typename _Traits>
virtual void std::basic_streambuf< _CharT, _Traits >::imbue ( const locale __loc) [inline, protected, virtual]

Changes translations.

Parameters:
__locA 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.

Definition at line 574 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pubimbue().

template<typename _CharT, typename _Traits>
streamsize std::basic_streambuf< _CharT, _Traits >::in_avail ( ) [inline]

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 282 of file streambuf.

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

Consumes data from the buffer; writes to the controlled sequence.

Parameters:
__cAn 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, and __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.

Definition at line 766 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sputc().

template<typename _CharT, typename _Traits>
virtual int_type std::basic_streambuf< _CharT, _Traits >::pbackfail ( int_type  __c = traits_type::eof()) [inline, protected, virtual]

Tries to back up the input sequence.

Parameters:
__cThe 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, and __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.

Definition at line 722 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sputbackc(), and std::basic_streambuf< char_type, traits_type >::sungetc().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::pbase ( ) const [inline, protected]

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 527 of file streambuf.

Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().

template<typename _CharT, typename _Traits>
void std::basic_streambuf< _CharT, _Traits >::pbump ( int  __n) [inline, protected]

Moving the write position.

Parameters:
__nThe delta by which to move.

This just advances the write position without returning any data.

Definition at line 543 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sputc().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::pptr ( ) const [inline, protected]

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 530 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sputc(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::str().

template<typename _CharT, typename _Traits>
locale std::basic_streambuf< _CharT, _Traits >::pubimbue ( const locale __loc) [inline]

Entry point for imbue().

Parameters:
__locThe new locale.
Returns:
The previous locale.

Calls the derived imbue(__loc).

Definition at line 207 of file streambuf.

template<typename _CharT, typename _Traits>
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]

Alters the stream position.

Parameters:
__offOffset.
__wayValue for ios_base::seekdir.
__modeValue for ios_base::openmode.

Calls virtual seekoff function.

Definition at line 249 of file streambuf.

template<typename _CharT, typename _Traits>
pos_type std::basic_streambuf< _CharT, _Traits >::pubseekpos ( pos_type  __sp,
ios_base::openmode  __mode = ios_base::in | ios_base::out 
) [inline]

Alters the stream position.

Parameters:
__spPosition
__modeValue for ios_base::openmode.

Calls virtual seekpos function.

Definition at line 261 of file streambuf.

template<typename _CharT, typename _Traits>
__streambuf_type* std::basic_streambuf< _CharT, _Traits >::pubsetbuf ( char_type __s,
streamsize  __n 
) [inline]

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 237 of file streambuf.

template<typename _CharT, typename _Traits>
int std::basic_streambuf< _CharT, _Traits >::pubsync ( ) [inline]

Calls virtual sync function.

Definition at line 269 of file streambuf.

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

template<typename _CharT, typename _Traits>
int_type std::basic_streambuf< _CharT, _Traits >::sbumpc ( ) [inline]

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 314 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_type, traits_type >::snextc().

template<typename _CharT, typename _Traits>
virtual pos_type std::basic_streambuf< _CharT, _Traits >::seekoff ( off_type  ,
ios_base::seekdir  ,
ios_base::openmode  = ios_base::in | ios_base::out 
) [inline, 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, and std::basic_stringbuf< _CharT, _Traits, _Alloc >.

Definition at line 600 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pubseekoff().

template<typename _CharT, typename _Traits>
virtual pos_type std::basic_streambuf< _CharT, _Traits >::seekpos ( pos_type  ,
ios_base::openmode  = ios_base::in | ios_base::out 
) [inline, 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, and std::basic_stringbuf< _CharT, _Traits, _Alloc >.

Definition at line 612 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pubseekpos().

template<typename _CharT, typename _Traits>
virtual basic_streambuf<char_type,_Traits>* std::basic_streambuf< _CharT, _Traits >::setbuf ( char_type ,
streamsize   
) [inline, protected, virtual]

Manipulates the buffer.

Each derived class provides its own appropriate behavior. See the next-to-last paragraph of http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html for more on this function.

Note:
Base class version does nothing, returns this.

Reimplemented in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, and std::basic_stringbuf< _CharT, _Traits, _Alloc >.

Definition at line 589 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pubsetbuf().

template<typename _CharT, typename _Traits>
void std::basic_streambuf< _CharT, _Traits >::setg ( char_type __gbeg,
char_type __gnext,
char_type __gend 
) [inline, protected]

Setting the three read area pointers.

Parameters:
__gbegA pointer.
__gnextA pointer.
__gendA pointer.
Postcondition:
__gbeg == eback(), __gnext == gptr(), and __gend == egptr()

Definition at line 507 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>
void std::basic_streambuf< _CharT, _Traits >::setp ( char_type __pbeg,
char_type __pend 
) [inline, protected]

Setting the three write area pointers.

Parameters:
__pbegA pointer.
__pendA pointer.
Postcondition:
__pbeg == pbase(), __pbeg == pptr(), and __pend == epptr()

Definition at line 553 of file streambuf.

Referenced by std::basic_filebuf< char_type, traits_type >::_M_set_buffer().

template<typename _CharT, typename _Traits>
int_type std::basic_streambuf< _CharT, _Traits >::sgetc ( ) [inline]

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 336 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_type, traits_type >::snextc().

template<typename _CharT, typename _Traits>
streamsize std::basic_streambuf< _CharT, _Traits >::sgetn ( char_type __s,
streamsize  __n 
) [inline]

Entry point for xsgetn.

Parameters:
__sA buffer area.
__nA 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 355 of file streambuf.

template<typename _CharT, typename _Traits>
virtual streamsize std::basic_streambuf< _CharT, _Traits >::showmanyc ( ) [inline, 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, and std::basic_stringbuf< _CharT, _Traits, _Alloc >.

Definition at line 647 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::in_avail().

template<typename _CharT, typename _Traits>
int_type std::basic_streambuf< _CharT, _Traits >::snextc ( ) [inline]

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 296 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>
int_type std::basic_streambuf< _CharT, _Traits >::sputbackc ( char_type  __c) [inline]

Pushing characters back into the input stream.

Parameters:
__cThe 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 370 of file streambuf.

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

template<typename _CharT, typename _Traits>
int_type std::basic_streambuf< _CharT, _Traits >::sputc ( char_type  __c) [inline]

Entry point for all single-character output functions.

Parameters:
__cA 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 422 of file streambuf.

Referenced by std::basic_istream< _CharT, _Traits >::get(), and std::ostreambuf_iterator< _CharT, _Traits >::operator=().

template<typename _CharT, typename _Traits>
streamsize std::basic_streambuf< _CharT, _Traits >::sputn ( const char_type __s,
streamsize  __n 
) [inline]

Entry point for all single-character output functions.

Parameters:
__sA buffer read area.
__nA 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 448 of file streambuf.

template<typename _CharT, typename _Traits>
int_type std::basic_streambuf< _CharT, _Traits >::sungetc ( ) [inline]

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 395 of file streambuf.

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

template<typename _CharT, typename _Traits>
virtual int std::basic_streambuf< _CharT, _Traits >::sync ( void  ) [inline, 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, and __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.

Definition at line 625 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pubsync().

template<typename _CharT, typename _Traits>
virtual int_type std::basic_streambuf< _CharT, _Traits >::uflow ( ) [inline, protected, virtual]

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 698 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sbumpc().

template<typename _CharT, typename _Traits>
virtual int_type std::basic_streambuf< _CharT, _Traits >::underflow ( ) [inline, 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< char_type, traits_type >, std::basic_stringbuf< _CharT, _Traits, _Alloc >, and __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.

Definition at line 685 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::sgetc(), and std::basic_streambuf< char_type, traits_type >::uflow().

template<typename _CharT , typename _Traits >
streamsize std::basic_streambuf< _CharT, _Traits >::xsgetn ( char_type __s,
streamsize  __n 
) [protected, virtual]

Multiple character extraction.

Parameters:
__sA buffer area.
__nMaximum 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.

Definition at line 47 of file streambuf.tcc.

References std::min().

Referenced by std::basic_streambuf< char_type, traits_type >::sgetn().

template<typename _CharT , typename _Traits >
streamsize std::basic_streambuf< _CharT, _Traits >::xsputn ( const char_type __s,
streamsize  __n 
) [protected, virtual]

Multiple character insertion.

Parameters:
__sA buffer area.
__nMaximum 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 in std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.

Definition at line 81 of file streambuf.tcc.

References std::min().

Referenced by std::basic_streambuf< char_type, traits_type >::sputn().


Member Data Documentation

template<typename _CharT, typename _Traits>
locale std::basic_streambuf< _CharT, _Traits >::_M_buf_locale [protected]
template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_in_beg [protected]

This is based on _IO_FILE, just reordered to be more consistent, and is intended to be the most minimal abstraction for an internal buffer.

  • get == input == read
  • put == output == write

Definition at line 182 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::eback(), and std::basic_streambuf< char_type, traits_type >::setg().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_in_cur [protected]

Entry point for imbue().

Parameters:
__locThe new locale.
Returns:
The previous locale.

Calls the derived imbue(__loc).

Definition at line 183 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::gbump(), std::basic_streambuf< char_type, traits_type >::gptr(), and std::basic_streambuf< char_type, traits_type >::setg().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_in_end [protected]

Entry point for imbue().

Parameters:
__locThe new locale.
Returns:
The previous locale.

Calls the derived imbue(__loc).

Definition at line 184 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::egptr(), and std::basic_streambuf< char_type, traits_type >::setg().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_out_beg [protected]

Entry point for imbue().

Parameters:
__locThe new locale.
Returns:
The previous locale.

Calls the derived imbue(__loc).

Definition at line 185 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pbase(), and std::basic_streambuf< char_type, traits_type >::setp().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_out_cur [protected]

Entry point for imbue().

Parameters:
__locThe new locale.
Returns:
The previous locale.

Calls the derived imbue(__loc).

Definition at line 186 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::pbump(), std::basic_streambuf< char_type, traits_type >::pptr(), and std::basic_streambuf< char_type, traits_type >::setp().

template<typename _CharT, typename _Traits>
char_type* std::basic_streambuf< _CharT, _Traits >::_M_out_end [protected]

Entry point for imbue().

Parameters:
__locThe new locale.
Returns:
The previous locale.

Calls the derived imbue(__loc).

Definition at line 187 of file streambuf.

Referenced by std::basic_streambuf< char_type, traits_type >::epptr(), and std::basic_streambuf< char_type, traits_type >::setp().


The documentation for this class was generated from the following files: