Manpages - std_basic_stringbuf.3
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NAME
std::basic_stringbuf< _CharT, _Traits, _Alloc > - The actual work of input and output (for std::string).
SYNOPSIS
Inherits std::basic_streambuf< _CharT, _Traits >.
Public Types
typedef __string_type::size_type __size_type
typedef basic_streambuf*< char_type, traits_type > *__streambuf_type
typedef basic_string*< char_type, _Traits, _Alloc > *__string_type
typedef _Alloc allocator_type
typedef _CharT char_type
typedef traits_type::int_type int_type
typedef traits_type::off_type off_type
typedef traits_type::pos_type pos_type
typedef _Traits traits_type
Public Member Functions
basic_stringbuf ()
Starts with an empty string buffer.
basic_stringbuf (basic_stringbuf &&__rhs)
basic_stringbuf (const __string_type &__str, ios_base::openmode
__mode=*ios_base::in*|*ios_base::out*)
Starts with an existing string buffer.
basic_stringbuf (const basic_stringbuf &)=delete
basic_stringbuf (ios_base::openmode __mode)
Starts with an empty string buffer.
locale getloc () const
Locale access.
streamsize in_avail ()
Looking ahead into the stream.
basic_stringbuf & operator= (basic_stringbuf &&__rhs)
basic_stringbuf & operator= (const basic_stringbuf &)=delete
locale pubimbue (const locale &__loc)
Entry point for imbue().
int_type sbumpc ()
Getting the next character.
int_type sgetc ()
Getting the next character.
streamsize sgetn (char_type __s, *streamsize __n)
Entry point for xsgetn.
int_type snextc ()
Getting the next character.
int_type sputbackc (char_type __c)
Pushing characters back into the input stream.
int_type sputc (char_type __c)
Entry point for all single-character output functions.
streamsize sputn (const char_type __s, *streamsize __n)
Entry point for all single-character output functions.
__string_type str () const
Copying out the string buffer.
void str (const __string_type &__s)
Setting a new buffer.
int_type sungetc ()
Moving backwards in the input stream.
void swap (basic_stringbuf &__rhs) noexcept(_Noexcept_swap::value)
basic_streambuf * pubsetbuf (char_type __s, *streamsize __n)
Entry points for derived buffer functions.
pos_type pubseekoff (off_type __off, ios_base::seekdir __way,
ios_base::openmode __mode=*ios_base::in*|*ios_base::out*)
Alters the stream position.
pos_type pubseekpos (pos_type __sp, ios_base::openmode
__mode=*ios_base::in*|*ios_base::out*)
Alters the stream position.
int pubsync ()
Calls virtual sync function.
Protected Member Functions
void __safe_gbump (streamsize __n)
void __safe_pbump (streamsize __n)
void _M_pbump (char_type *__pbeg, char_type *__pend, off_type __off)
void _M_stringbuf_init (ios_base::openmode __mode)
void _M_sync (char_type *__base, __size_type __i, __size_type __o)
void _M_update_egptr ()
void gbump (int __n)
Moving the read position.
virtual void imbue (const locale &__loc)
Changes translations.
virtual int_type overflow (int_type __c=traits_type::eof())
Consumes data from the buffer; writes to the controlled sequence.
virtual int_type pbackfail (int_type __c=traits_type::eof())
Tries to back up the input sequence.
void pbump (int __n)
Moving the write position.
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 __sp, ios_base::openmode
__mode=*ios_base::in*|*ios_base::out*)
Alters the stream positions.
virtual __streambuf_type * setbuf (char_type __s, *streamsize
__n)
Manipulates the buffer.
void setg (char_type *__gbeg, char_type *__gnext, char_type *__gend)
Setting the three read area pointers.
void setp (char_type *__pbeg, char_type *__pend)
Setting the three write area pointers.
virtual streamsize showmanyc ()
Investigating the data available.
void swap (basic_streambuf &__sb)
virtual int sync ()
Synchronizes the buffer arrays with the controlled sequences.
virtual int_type uflow ()
Fetches more data from the controlled sequence.
virtual int_type underflow ()
Fetches more data from the controlled sequence.
virtual streamsize xsgetn (char_type __s, *streamsize __n)
Multiple character extraction.
virtual streamsize xsputn (const char_type __s, *streamsize __n)
Multiple character insertion.
char_type * eback () const
Access to the get area.
char_type * gptr () const
Access to the get area.
char_type * egptr () const
Access to the get area.
char_type * pbase () const
Access to the put area.
char_type * pptr () const
Access to the put area.
char_type * epptr () const
Access to the put area.
Protected Attributes
locale _M_buf_locale
Current locale setting.
char_type * _M_in_beg
Start of get area.
char_type * _M_in_cur
Current read area.
char_type * _M_in_end
End of get area.
ios_base::openmode _M_mode
Place to stash in || out || in | out settings for current stringbuf.
char_type * _M_out_beg
Start of put area.
char_type * _M_out_cur
Current put area.
char_type * _M_out_end
End of put area.
__string_type _M_string
Detailed Description
“template<typename _CharT, typename _Traits, typename _Alloc>
class std::basic_stringbuf< _CharT, _Traits, _Alloc >“The actual work of
input and output (for std::string).
Template Parameters
_CharT Type of character stream.
_Traits Traits for character type, defaults to char_traits<_CharT>.
_Alloc Allocator type, defaults to allocator<_CharT>.
This class associates either or both of its input and output sequences
with a sequence of characters, which can be initialized from, or made
available as, a std::basic_string
. (Paraphrased from [27.7.1]/1.)
For this class, open modes (of type ios_base::openmode
) have in
set
if the input sequence can be read, and out
set if the output sequence
can be written.
Definition at line 72 of file sstream.
Member Typedef Documentation
template<typename _CharT , typename _Traits , typename _Alloc >
typedef __string_type::size_type std::basic_stringbuf*< _CharT, _Traits, _Alloc >::__size_type Definition at line *96 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef basic_streambuf*<char_type, traits_type> *std::basic_stringbuf*< _CharT, _Traits, _Alloc >::*__streambuf_type Definition at line 94 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef basic_string*<char_type, _Traits, _Alloc> *std::basic_stringbuf*< _CharT, _Traits, _Alloc >::*__string_type Definition at line 95 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef _Alloc std::basic_stringbuf*< _CharT, _Traits, _Alloc >::allocator_type Definition at line *89 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef _CharT std::basic_stringbuf*< _CharT, _Traits, _Alloc >::char_type Definition at line *85 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef traits_type::int_type std::basic_stringbuf*< _CharT, _Traits, _Alloc >::int_type Definition at line *90 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef traits_type::off_type std::basic_stringbuf*< _CharT, _Traits, _Alloc >::off_type Definition at line *92 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef traits_type::pos_type std::basic_stringbuf*< _CharT, _Traits, _Alloc >::pos_type Definition at line *91 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
typedef _Traits std::basic_stringbuf*< _CharT, _Traits, _Alloc >::traits_type Definition at line *86 of file sstream.
Constructor & Destructor Documentation
template<typename _CharT , typename _Traits , typename _Alloc >
std::basic_stringbuf*< _CharT, _Traits, _Alloc >::*basic_stringbuf ()= [inline]= Starts with an empty string buffer. The default constructor initializes the parent class using its own default ctor.
Definition at line 114 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
std::basic_stringbuf*< _CharT, _Traits, _Alloc >::*basic_stringbuf (ios_base::openmode __mode)= [inline]=, = [explicit]= Starts with an empty string buffer.
Parameters
__mode Whether the buffer can read, or write, or both.
The default constructor initializes the parent class using its own default ctor.
Definition at line 126 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
std::basic_stringbuf*< _CharT, _Traits, _Alloc >::*basic_stringbuf
(const __string_type & __str, ios_base::openmode __mode =
ios_base::in*= | *ios_base::out)*
[inline]=, *= [explicit]=
Starts with an existing string buffer.
Parameters
/__str/* A string to copy as a starting buffer.
__mode Whether the buffer can read, or write, or both.*
This constructor initializes the parent class using its own default ctor.
Definition at line 139 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc >
std::basic_stringbuf< _CharT, _Traits, _Alloc >::basic_stringbuf (basic_stringbuf< _CharT, _Traits, _Alloc > && __rhs)*= [inline]= Definition at line *148 of file sstream.
Member Function Documentation
template<typename _CharT , typename _Traits > void
std::basic_streambuf< _CharT, _Traits >::__safe_gbump (streamsize __n)*= [inline]=, = [protected]=, = [inherited]= Definition at line *800 of file streambuf.
template<typename _CharT , typename _Traits > void
std::basic_streambuf< _CharT, _Traits >::__safe_pbump (streamsize __n)*= [inline]=, = [protected]=, = [inherited]= Definition at line *803 of file streambuf.
template<class _CharT , class _Traits , class _Alloc > void
std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_pbump (char_type * __pbeg, char_type * __pend, off_type __off)*= [protected]= Definition at line *276 of file sstream.tcc.
template<typename _CharT , typename _Traits , typename _Alloc > void
std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_stringbuf_init (ios_base::openmode __mode)*= [inline]=, = [protected]= Definition at line *326 of file sstream.
template<class _CharT , class _Traits , class _Alloc > void
std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_sync (char_type * __base, __size_type __i, __size_type __o)*= [protected]= Definition at line *245 of file sstream.tcc.
template<typename _CharT , typename _Traits , typename _Alloc > void
std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_update_egptr ()*= [inline]=, = [protected]= Definition at line *403 of file sstream.
template<typename _CharT , typename _Traits > char_type *
std::basic_streambuf< _CharT, _Traits >::eback () const*= [inline]=, = [protected]=, *= [inherited]= Access to the get area. These functions are only available to other protected functions, including derived classes.
- eback() returns the beginning pointer for the input sequence
- gptr() returns the next pointer for the input sequence
- egptr() returns the end pointer for the input sequence
Definition at line 487 of file streambuf.
template<typename _CharT , typename _Traits > char_type *
std::basic_streambuf< _CharT, _Traits >::egptr () const*= [inline]=, = [protected]=, *= [inherited]= Access to the get area. These functions are only available to other protected functions, including derived classes.
- eback() returns the beginning pointer for the input sequence
- gptr() returns the next pointer for the input sequence
- egptr() returns the end pointer for the input sequence
Definition at line 493 of file streambuf.
template<typename _CharT , typename _Traits > char_type *
std::basic_streambuf< _CharT, _Traits >::epptr () const*= [inline]=, = [protected]=, *= [inherited]= Access to the put area. These functions are only available to other protected functions, including derived classes.
- pbase() returns the beginning pointer for the output sequence
- pptr() returns the next pointer for the output sequence
- epptr() returns the end pointer for the output sequence
Definition at line 540 of file streambuf.
template<typename _CharT , typename _Traits > void
std::basic_streambuf< _CharT, _Traits >::gbump (int __n)*= [inline]=, = [protected]=, *= [inherited]= Moving the read position.
Parameters
/__n/* The delta by which to move.*
This just advances the read position without returning any data.
Definition at line 503 of file streambuf.
template<typename _CharT , typename _Traits > *locale
std::basic_streambuf< _CharT, _Traits >::getloc () const*= [inline]=*, *= [inherited]= Locale access.
Returns
The current locale in effect.
If pubimbue(loc) has been called, then the most recent =loc=* is returned. Otherwise the global locale in effect at the time of construction is returned. *
Definition at line 231 of file streambuf.
template<typename _CharT , typename _Traits > char_type *
std::basic_streambuf< _CharT, _Traits >::gptr () const*= [inline]=, = [protected]=, *= [inherited]= Access to the get area. These functions are only available to other protected functions, including derived classes.
- eback() returns the beginning pointer for the input sequence
- gptr() returns the next pointer for the input sequence
- egptr() returns the end pointer for the input sequence
Definition at line 490 of file streambuf.
template<typename _CharT , typename _Traits > virtual void
std::basic_streambuf< _CharT, _Traits >::imbue (const locale & __loc)*= [inline]=, = [protected]=, = [virtual]=, *= [inherited]= 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 > >, std::basic_filebuf< _CharT, std::char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.
Definition at line 581 of file streambuf.
template<typename _CharT , typename _Traits > *streamsize
std::basic_streambuf< _CharT, _Traits >::in_avail ()*= [inline]=*, *= [inherited]= Looking ahead into the stream.
Returns
The number of characters available.
If a read position is available, returns the number of characters available for reading before the buffer must be refilled. Otherwise returns the derived =showmanyc()=*. *
Definition at line 289 of file streambuf.
template<typename _CharT , typename _Traits , typename _Alloc >
basic_stringbuf & std::basic_stringbuf< _CharT, _Traits, _Alloc >::operator= (basic_stringbuf< _CharT, _Traits, _Alloc > && __rhs)*= [inline]= Definition at line *206 of file sstream.
template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::overflow (int_type __c = *=traits_type::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 definition of this function, see a good text such as Langer & Kreft, or [27.5.2.4.5]/3-7.
A functioning output streambuf can be created by overriding only this function (no buffer area will be used).
Note
Base class version does nothing, returns eof().
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 79 of file sstream.tcc.
References __gnu_debug::__base(), std::basic_string< _CharT, _Traits, _Alloc >::assign(), std::ios_base::in, std::max(), std::min(), std::ios_base::out, std::basic_string< _CharT, _Traits, _Alloc >::push_back(), and std::basic_string< _CharT, _Traits, _Alloc >::reserve().
template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::pbackfail (int_type __c = *=traits_type::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()
, andpptr()
are the same as forunderflow()
.*
Note
Base class version does nothing, returns eof().
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 45 of file sstream.tcc.
References std::ios_base::out.
template<typename _CharT , typename _Traits > char_type *
std::basic_streambuf< _CharT, _Traits >::pbase () const*= [inline]=, = [protected]=, *= [inherited]= Access to the put area. These functions are only available to other protected functions, including derived classes.
- pbase() returns the beginning pointer for the output sequence
- pptr() returns the next pointer for the output sequence
- epptr() returns the end pointer for the output sequence
Definition at line 534 of file streambuf.
template<typename _CharT , typename _Traits > void
std::basic_streambuf< _CharT, _Traits >::pbump (int __n)*= [inline]=, = [protected]=, *= [inherited]= Moving the write position.
Parameters
/__n/* The delta by which to move.*
This just advances the write position without returning any data.
Definition at line 550 of file streambuf.
template<typename _CharT , typename _Traits > char_type *
std::basic_streambuf< _CharT, _Traits >::pptr () const*= [inline]=, = [protected]=, *= [inherited]= Access to the put area. These functions are only available to other protected functions, including derived classes.
- pbase() returns the beginning pointer for the output sequence
- pptr() returns the next pointer for the output sequence
- epptr() returns the end pointer for the output sequence
Definition at line 537 of file streambuf.
template<typename _CharT , typename _Traits > *locale
std::basic_streambuf< _CharT, _Traits >::pubimbue (const locale & __loc)*= [inline]=*, *= [inherited]= Entry point for imbue().
Parameters
/__loc/* The new locale. *
Returns
The previous locale.
Calls the derived imbue(__loc).
Definition at line 214 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]=, *= [inherited]=
Alters the stream position.
Parameters
/__off/* Offset.
__way Value for ios_base::seekdir.
__mode Value for ios_base::openmode.*
Calls virtual seekoff function.
Definition at line 256 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]=, *= [inherited]=
Alters the stream position.
Parameters
/__sp/* Position
__mode Value for ios_base::openmode.*
Calls virtual seekpos function.
Definition at line 268 of file streambuf.
template<typename _CharT , typename _Traits > *basic_streambuf *
std::basic_streambuf< _CharT, _Traits >::pubsetbuf (char_type * __s,
streamsize __n)*= [inline]=*, = [inherited]=
Entry points for derived buffer functions. The public versions of
pubfoo
dispatch to the protected derived foo
member functions,
passing the arguments (if any) and returning the result unchanged. *
Definition at line 244 of file streambuf.
template<typename _CharT , typename _Traits > int
std::basic_streambuf< _CharT, _Traits >::pubsync ()*= [inline]=, *= [inherited]= Calls virtual sync function.
Definition at line 276 of file streambuf.
Referenced by std::wbuffer_convert< _Codecvt, _Elem, _Tr >::sync(), and std::basic_istream< _CharT, _Traits >::sync().
template<typename _CharT , typename _Traits > int_type
std::basic_streambuf< _CharT, _Traits >::sbumpc ()*= [inline]=, *= [inherited]= Getting the next character.
Returns
The next character, or eof.
If the input read position is available, returns that character and increments the read pointer, otherwise calls and returns =uflow()=*. *
Definition at line 321 of file streambuf.
Referenced by std::basic_istream< char >::getline().
template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::pos_type
std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff (off_type,
ios_base::seekdir, ios_base::openmode =
ios_base::in*= | *ios_base::out)*
[protected]=, *= [virtual]=
Alters the stream positions. Each derived class provides its own
appropriate behavior.
Note
Base class version does nothing, returns a =pos_type=* that represents an invalid stream position. *
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 167 of file sstream.tcc.
References std::ios_base::cur, std::ios_base::end, std::ios_base::in, and std::ios_base::out.
template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::pos_type
std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos (pos_type,
ios_base::openmode = ios_base::in*= | *ios_base::out)*
[protected]=,
*= [virtual]=
Alters the stream positions. Each derived class provides its own
appropriate behavior.
Note
Base class version does nothing, returns a =pos_type=* that represents an invalid stream position. *
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 215 of file sstream.tcc.
References std::ios_base::in, and std::ios_base::out.
template<typename _CharT , typename _Traits , typename _Alloc >
virtual __streambuf_type * std::basic_stringbuf< _CharT, _Traits, _Alloc >::setbuf (char_type * __s, streamsize __n)*= [inline]=, = [protected]=, *= [virtual]= Manipulates the buffer.
Parameters
/__s/* Pointer to a buffer area.
__n Size of __s. *
Returns
=this=* *
If no buffer has already been created, and both /__s/* and __n are
non-zero, then __s
is used as a buffer; see
https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
for more. *
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 368 of file sstream.
template<typename _CharT , typename _Traits > void
std::basic_streambuf< _CharT, _Traits >::setg (char_type * __gbeg, char_type * __gnext, char_type * __gend)*= [inline]=, = [protected]=, *= [inherited]= Setting the three read area pointers.
Parameters
/__gbeg/* A pointer.
__gnext A pointer.
__gend A pointer. *
Postcondition
/__gbeg/*
= *=eback()=*, */__gnext/* =
gptr()
, and __gend ==egptr()
*
Definition at line 514 of file streambuf.
template<typename _CharT , typename _Traits > void
std::basic_streambuf< _CharT, _Traits >::setp (char_type * __pbeg, char_type * __pend)*= [inline]=, = [protected]=, *= [inherited]= Setting the three write area pointers.
Parameters
/__pbeg/* A pointer.
__pend A pointer. *
Postcondition
/__pbeg/*
= *=pbase()=*, */__pbeg/* =
pptr()
, and __pend ==epptr()
*
Definition at line 560 of file streambuf.
template<typename _CharT , typename _Traits > int_type
std::basic_streambuf< _CharT, _Traits >::sgetc ()*= [inline]=, *= [inherited]= Getting the next character.
Returns
The next character, or eof.
If the input read position is available, returns that character, otherwise calls and returns =underflow()=*. Does not move the read position after fetching the character. *
Definition at line 343 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::sentry::sentry(), std::basic_istream< _CharT, _Traits >::get(), std::basic_istream< char >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), and std::basic_istream< char >::seekg().
template<typename _CharT , typename _Traits > *streamsize
std::basic_streambuf< _CharT, _Traits >::sgetn (char_type * __s, streamsize __n)*= [inline]=*, *= [inherited]= Entry point for xsgetn.
Parameters
/__s/* A buffer area.
__n A count.*
Returns xsgetn(__s,__n). The effect is to fill /__s/*[0] through __s[__n-1] with characters from the input sequence, if possible. *
Definition at line 362 of file streambuf.
template<typename _CharT , typename _Traits , typename _Alloc >
virtual streamsize std::basic_stringbuf< _CharT, _Traits, _Alloc >::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 from std::basic_streambuf< _CharT, _Traits >.
Definition at line 336 of file sstream.
template<typename _CharT , typename _Traits > int_type
std::basic_streambuf< _CharT, _Traits >::snextc ()*= [inline]=, *= [inherited]= Getting the next character.
Returns
The next character, or eof.
Calls =sbumpc()=*, and if that function returns traits::eof()
, so
does this function. Otherwise, sgetc()
. *
Definition at line 303 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::sentry::sentry(), std::basic_istream< _CharT, _Traits >::get(), std::basic_istream< char >::getline(), std::basic_istream< char >::putback(), and std::basic_istream< char >::seekg().
template<typename _CharT , typename _Traits > int_type
std::basic_streambuf< _CharT, _Traits >::sputbackc (char_type __c)*= [inline]=, *= [inherited]= Pushing characters back into the input stream.
Parameters
/__c/* The character to push back. *
Returns
The previous character, if possible.
Similar to sungetc(), but /__c/* is pushed onto the stream instead of the previous character. If successful, the next character fetched from the input stream will be __c. *
Definition at line 377 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]=, *= [inherited]= Entry point for all single-character output functions.
Parameters
/__c/* A character to output. *
Returns
/__c/*, if possible.*
One of two public output functions.
If a write position is available for the output sequence (i.e., the
buffer is not full), stores /__c/* in that position, increments the
position, and returns traits::to_int_type(__c)
. If a write position
is not available, returns overflow(__c)
. *
Definition at line 429 of file streambuf.
Referenced by 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]=*, *= [inherited]= Entry point for all single-character output functions.
Parameters
/__s/* A buffer read area.
__n A count.*
One of two public output functions.
Returns xsputn(__s,__n). The effect is to write /__s/*[0] through __s[__n-1] to the output sequence, if possible. *
Definition at line 455 of file streambuf.
template<typename _CharT , typename _Traits , typename _Alloc >
*__string_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::str () const*= [inline]= Copying out the string buffer.
Returns
A copy of one of the underlying sequences.
/If the buffer is only created in input mode, the underlying character sequence is equal to the input sequence; otherwise, it is equal to the output sequence./* [27.7.1.2]/1 *
Definition at line 242 of file sstream.
template<typename _CharT , typename _Traits , typename _Alloc > void
*std::basic_stringbuf< _CharT, _Traits, _Alloc >::str (const __string_type & __s)*= [inline]= Setting a new buffer.
Parameters
/__s/* The string to use as a new sequence.*
Deallocates any previous stored sequence, then copies /s/* to use as a new one. *
Definition at line 295 of file sstream.
template<typename _CharT , typename _Traits > int_type
std::basic_streambuf< _CharT, _Traits >::sungetc ()*= [inline]=, *= [inherited]= Moving backwards in the input stream.
Returns
The previous character, if possible.
If a putback position is available, this function decrements the input pointer and returns that character. Otherwise, calls and returns pbackfail(). The effect is to /unget/* the last character gotten. *
Definition at line 402 of file streambuf.
Referenced by std::basic_istream< _CharT, _Traits >::unget().
template<typename _CharT , typename _Traits > void
std::basic_streambuf< _CharT, _Traits >::swap (basic_streambuf< _CharT, _Traits > & __sb)*= [inline]=, = [protected]=, = [inherited]= Definition at line *817 of file streambuf.
template<typename _CharT , typename _Traits , typename _Alloc > void
std::basic_stringbuf< _CharT, _Traits, _Alloc >::swap (basic_stringbuf< _CharT, _Traits, _Alloc > & __rhs)*= [inline]=, = [noexcept]= Definition at line *219 of file sstream.
template<typename _CharT , typename _Traits > virtual int
std::basic_streambuf< _CharT, _Traits >::sync (void)*= [inline]=, = [protected]=, = [virtual]=, *= [inherited]= 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::wbuffer_convert< _Codecvt, _Elem, _Tr >, __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, _Traits >, std::basic_filebuf< _CharT, encoding_char_traits< _CharT > >, std::basic_filebuf< _CharT, std::char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.
Definition at line 632 of file streambuf.
template<typename _CharT , typename _Traits > virtual int_type
std::basic_streambuf< _CharT, _Traits >::uflow ()*= [inline]=, = [protected]=, = [virtual]=, *= [inherited]= Fetches more data from the controlled sequence.
Returns
The first character from the /pending sequence/*.*
Informally, this function does the same thing as =underflow()=*, and in
fact is required to call that function. It also returns the new
character, like underflow()
does. However, this function also moves
the read position forward by one. *
Reimplemented in __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >.
Definition at line 705 of file streambuf.
template<class _CharT , class _Traits , class _Alloc >
basic_stringbuf< _CharT, _Traits, _Alloc >::int_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::underflow*= [protected]=, *= [virtual]= Fetches more data from the controlled sequence.
Returns
The first character from the /pending sequence/*.*
Informally, this function is called when the input buffer is exhausted
(or does not exist, as buffering need not actually be done). If a buffer
exists, it is /refilled/*. In either case, the next available character
is returned, or traits::eof()
to indicate a null pending sequence.*
For a formal definition of the pending sequence, see a good text such as Langer & Kreft, or [27.5.2.4.3]/7-14.
A functioning input streambuf can be created by overriding only this function (no buffer area will be used). For an example, see https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html
Note
Base class version does nothing, returns eof().
Reimplemented from std::basic_streambuf< _CharT, _Traits >.
Definition at line 149 of file sstream.tcc.
References std::ios_base::in.
template<typename _CharT , typename _Traits > *streamsize
std::basic_streambuf< _CharT, _Traits >::xsgetn (char_type * __s, streamsize __n)*= [protected]=*, = [virtual]=, *= [inherited]= 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 > >, std::basic_filebuf< _CharT, std::char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.
Definition at line 45 of file streambuf.tcc.
References std::min().
template<typename _CharT , typename _Traits > *streamsize
std::basic_streambuf< _CharT, _Traits >::xsputn (const char_type * __s, streamsize __n)*= [protected]=*, = [virtual]=, *= [inherited]= 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 > >, std::basic_filebuf< _CharT, std::char_traits< _CharT > >, and std::basic_filebuf< char_type, traits_type >.
Definition at line 79 of file streambuf.tcc.
References std::min().
Member Data Documentation
template<typename _CharT , typename _Traits > *locale
std::basic_streambuf< _CharT, _Traits >::_M_buf_locale*= [protected]=*, *= [inherited]= Current locale setting.
Definition at line 197 of file streambuf.
Referenced by std::basic_filebuf< _CharT, _Traits >::basic_filebuf().
template<typename _CharT , typename _Traits > char_type*
std::basic_streambuf< _CharT, _Traits >::_M_in_beg*= [protected]=, *= [inherited]= Start of get area.
Definition at line 189 of file streambuf.
template<typename _CharT , typename _Traits > char_type*
std::basic_streambuf< _CharT, _Traits >::_M_in_cur*= [protected]=, *= [inherited]= Current read area.
Definition at line 190 of file streambuf.
template<typename _CharT , typename _Traits > char_type*
std::basic_streambuf< _CharT, _Traits >::_M_in_end*= [protected]=, *= [inherited]= End of get area.
Definition at line 191 of file streambuf.
template<typename _CharT , typename _Traits , typename _Alloc >
*ios_base::openmode std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_mode*= [protected]= Place to stash in || out || in | out settings for current stringbuf.
Definition at line 100 of file sstream.
template<typename _CharT , typename _Traits > char_type*
std::basic_streambuf< _CharT, _Traits >::_M_out_beg*= [protected]=, *= [inherited]= Start of put area.
Definition at line 192 of file streambuf.
template<typename _CharT , typename _Traits > char_type*
std::basic_streambuf< _CharT, _Traits >::_M_out_cur*= [protected]=, *= [inherited]= Current put area.
Definition at line 193 of file streambuf.
template<typename _CharT , typename _Traits > char_type*
std::basic_streambuf< _CharT, _Traits >::_M_out_end*= [protected]=, *= [inherited]= End of put area.
Definition at line 194 of file streambuf.
template<typename _CharT , typename _Traits , typename _Alloc >
__string_type std::basic_stringbuf< _CharT, _Traits, _Alloc >::_M_string*= [protected]= Definition at line *103 of file sstream.
Author
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