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

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

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

Public Member Functions
virtual	~basic_streambuf ()
locale	getloc () const
streamsize	in_avail ()
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
	basic_streambuf ()
void	__safe_gbump (streamsize __n)
void	__safe_pbump (streamsize __n)
void	gbump (int __n)
virtual void	imbue (const locale &__loc)
void	pbump (int __n)
virtual pos_type	seekoff (off_type, ios_base::seekdir, ios_base::openmode=ios_base::in|ios_base::out)
virtual pos_type	seekpos (pos_type, ios_base::openmode=ios_base::in|ios_base::out)
virtual basic_streambuf < char_type, _Traits > *	setbuf (char_type *, streamsize)
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
locale	_M_buf_locale
char_type *	_M_in_beg
char_type *	_M_in_cur
char_type *	_M_in_end
char_type *	_M_out_beg
char_type *	_M_out_cur
char_type *	_M_out_end
virtual	int_type

Friends
template<bool _IsMove, typename _CharT2 >
__gnu_cxx::__enable_if < __is_char< _CharT2 > ::__value, _CharT2 * >::__type	__copy_move_a2 (istreambuf_iterator< _CharT2 >, istreambuf_iterator< _CharT2 >, _CharT2 *)
streamsize	__copy_streambufs_eof (basic_streambuf *, basic_streambuf *, bool &)
class	basic_ios< char_type, traits_type >
class	basic_istream< char_type, traits_type >
class	basic_ostream< char_type, traits_type >
template<typename _CharT2 >
__gnu_cxx::__enable_if < __is_char< _CharT2 > ::__value, istreambuf_iterator < _CharT2 > >::__type	find (istreambuf_iterator< _CharT2 >, istreambuf_iterator< _CharT2 >, const _CharT2 &)
template<typename _CharT2 , typename _Traits2 , typename _Alloc >
basic_istream< _CharT2, _Traits2 > &	getline (basic_istream< _CharT2, _Traits2 > &, basic_string< _CharT2, _Traits2, _Alloc > &, _CharT2)
class	istreambuf_iterator< char_type, traits_type >
template<typename _CharT2 , typename _Traits2 >
basic_istream< _CharT2, _Traits2 > &	operator>> (basic_istream< _CharT2, _Traits2 > &, _CharT2 *)
template<typename _CharT2 , typename _Traits2 , typename _Alloc >
basic_istream< _CharT2, _Traits2 > &	operator>> (basic_istream< _CharT2, _Traits2 > &, basic_string< _CharT2, _Traits2, _Alloc > &)
class	ostreambuf_iterator< char_type, traits_type >

Detailed Description

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

The actual work of input and output (interface).

Template Parameters

_CharT	Type of character stream.
_Traits	Traits for character type, defaults to char_traits<_CharT>.

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.
2. 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).
3. 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 80 of file iosfwd.

Member Typedef Documentation

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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

This is a non-standard type.

Definition at line 138 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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 dependent on) the template parameters, which are specific to the implementation.

Definition at line 129 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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 dependent on) the template parameters, which are specific to the implementation.

Definition at line 131 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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 dependent on) the template parameters, which are specific to the implementation.

Definition at line 133 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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 dependent on) the template parameters, which are specific to the implementation.

Definition at line 132 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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 dependent on) the template parameters, which are specific to the implementation.

Definition at line 130 of file streambuf.

Constructor & Destructor Documentation

template<typename _CharT, typename _Traits = char_traits<_CharT>>

virtual std::basic_streambuf< _CharT, _Traits >::~basic_streambuf ( )

inlinevirtual

Destructor deallocates no buffer space.

Definition at line 197 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>

std::basic_streambuf< _CharT, _Traits >::basic_streambuf ( )

inlineprotected

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 463 of file streambuf.

Member Function Documentation

template<typename _CharT, typename _Traits = char_traits<_CharT>>

char_type* std::basic_streambuf< _CharT, _Traits >::eback ( ) const

inlineprotected

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

inlineprotected

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

inlineprotected

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 )

inlineprotected

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

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

inlineprotected

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 = char_traits<_CharT>>

virtual void std::basic_streambuf< _CharT, _Traits >::imbue ( const locale &  __loc )

inlineprotectedvirtual

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 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 576 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubimbue().

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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 284 of file streambuf.

template<typename _CharT, typename _Traits = char_traits<_CharT>>

char_type* std::basic_streambuf< _CharT, _Traits >::pbase ( ) const

inlineprotected

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 )

inlineprotected

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

inlineprotected

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

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

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

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

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

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

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 = char_traits<_CharT>>

virtual pos_type std::basic_streambuf< _CharT, _Traits >::seekoff ( off_type  , ios_base::seekdir  , ios_base::openmode  = ios_base::in | ios_base::out  )

inlineprotectedvirtual

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 602 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubseekoff().

template<typename _CharT, typename _Traits = char_traits<_CharT>>

virtual pos_type std::basic_streambuf< _CharT, _Traits >::seekpos ( pos_type  , ios_base::openmode  = ios_base::in | ios_base::out  )

inlineprotectedvirtual

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 614 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubseekpos().

template<typename _CharT, typename _Traits = char_traits<_CharT>>

virtual basic_streambuf<char_type,_Traits>* std::basic_streambuf< _CharT, _Traits >::setbuf ( char_type *  , streamsize    )

inlineprotectedvirtual

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 591 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubsetbuf().

template<typename _CharT, typename _Traits = char_traits<_CharT>>

void std::basic_streambuf< _CharT, _Traits >::setg ( char_type *  __gbeg, char_type *  __gnext, char_type *  __gend  )

inlineprotected

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  )

inlineprotected

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

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

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 = char_traits<_CharT>>

virtual streamsize std::basic_streambuf< _CharT, _Traits >::showmanyc ( )

inlineprotectedvirtual

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 649 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::in_avail().

template<typename _CharT, typename _Traits = char_traits<_CharT>>

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 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

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

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

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

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 = char_traits<_CharT>>

virtual int std::basic_streambuf< _CharT, _Traits >::sync ( void  )

inlineprotectedvirtual

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 627 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::pubsync().

template<typename _CharT, typename _Traits = char_traits<_CharT>>

virtual int_type return std::basic_streambuf< _CharT, _Traits >::traits_type::eof ( )

protectedvirtual

Tries to back up the input sequence.

Parameters

__c	The character to be inserted back into the sequence.

Returns

eof() on failure, some other value on success

Postcondition

The constraints of gptr(), eback(), 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 ( )

inlineprotectedvirtual

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 = char_traits<_CharT>>

virtual int_type std::basic_streambuf< _CharT, _Traits >::underflow ( )

inlineprotectedvirtual

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 687 of file streambuf.

Referenced by std::basic_streambuf< char, char_traits< char > >::sgetc(), and std::basic_streambuf< char, char_traits< char > >::uflow().

template<typename _CharT , typename _Traits >

streamsize std::basic_streambuf< _CharT, _Traits >::xsgetn ( char_type *  __s, streamsize  __n  )

protectedvirtual

Multiple character extraction.

Parameters

__s	A buffer area.
__n	Maximum number of characters to assign.

Returns

The number of characters assigned.

Fills __s[0] through __s[__n-1] with characters from the input sequence, as if by sbumpc(). Stops when either __n characters have been copied, or when traits::eof() would be copied.

It is expected that derived classes provide a more efficient implementation by overriding this definition.

Reimplemented 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 46 of file streambuf.tcc.

References std::min().

Referenced by std::basic_streambuf< char, char_traits< char > >::sgetn().

template<typename _CharT , typename _Traits >

streamsize std::basic_streambuf< _CharT, _Traits >::xsputn ( const char_type *  __s, streamsize  __n  )

protectedvirtual

Multiple character insertion.

Parameters

__s	A buffer area.
__n	Maximum number of characters to write.

Returns

The number of characters written.

Writes __s[0] through __s[__n-1] to the output sequence, as if by sputc(). Stops when either n characters have been copied, or when sputc() would return traits::eof().

It is expected that derived classes provide a more efficient implementation by overriding this definition.

Reimplemented 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 80 of file streambuf.tcc.

References std::min().

Referenced by std::basic_streambuf< char, char_traits< char > >::sputn().

Member Data Documentation

template<typename _CharT, typename _Traits = char_traits<_CharT>>

locale std::basic_streambuf< _CharT, _Traits >::_M_buf_locale

protected

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 = char_traits<_CharT>>

char_type* std::basic_streambuf< _CharT, _Traits >::_M_in_beg

protected

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

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

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 = char_traits<_CharT>>

char_type* std::basic_streambuf< _CharT, _Traits >::_M_out_beg

protected

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

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

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_traits<_CharT>>

virtual std::basic_streambuf< _CharT, _Traits >::int_type

protected

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

Parameters

__c	An additional character to consume.

Returns

eof() to indicate failure, something else (usually __c, or not_eof())

Informally, this function is called when the output buffer is full (or does not exist, as buffering need not actually be done). If a buffer exists, it is consumed, with some effect on the controlled sequence. (Typically, the buffer is written out to the sequence verbatim.) In either case, the character c is also written out, if __c is not eof().

For a formal definition of this function, see a good text such as Langer & Kreft, or [27.5.2.4.5]/3-7.

A functioning output streambuf can be created by overriding only this function (no buffer area will be used).

Note

Base class version does nothing, returns eof().

Definition at line 769 of file streambuf.

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

• iosfwd
• streambuf
• streambuf.tcc