std::basic_istream< _CharT, _Traits >(3cxx)

NAME¶

std::basic_istream< _CharT, _Traits > -

SYNOPSIS¶

Inherits std::basic_ios< _CharT, _Traits >.

Inherited by std::basic_ifstream< _CharT, _Traits >, std::basic_iostream< _CharT, _Traits >, and std::basic_istringstream< _CharT, _Traits, _Alloc >.

Classes¶

class sentry
Performs setup work for input streams.

Public Types¶

typedef ctype< _CharT > __ctype_type
typedef basic_ios< _CharT,
_Traits > __ios_type"
typedef basic_istream< _CharT,
_Traits > __istream_type"
typedef num_get< _CharT,
istreambuf_iterator< _CharT,
_Traits > > __num_get_type"
typedef basic_streambuf
< _CharT, _Traits > __streambuf_type"
typedef _CharT char_type
enum event { erase_event, imbue_event, copyfmt_event }
typedef void(* event_callback )(event, ios_base &, int)
typedef _Ios_Fmtflags fmtflags
typedef _Traits::int_type int_type
typedef int io_state
typedef _Ios_Iostate iostate
typedef _Traits::off_type off_type
typedef int open_mode
typedef _Ios_Openmode openmode
typedef _Traits::pos_type pos_type
typedef int seek_dir
typedef _Ios_Seekdir seekdir
typedef std::streamoff streamoff
typedef std::streampos streampos
typedef _Traits traits_type

typedef num_put< _CharT,
ostreambuf_iterator< _CharT,
_Traits > > __num_put_type"

Public Member Functions¶

const locale & _M_getloc () const
void _M_setstate (iostate __state)
bool bad () const
basic_istream (__streambuf_type *__sb)
void clear (iostate __state=goodbit)
basic_ios & copyfmt (const basic_ios &__rhs)
bool eof () const
iostate exceptions () const
void exceptions (iostate __except)
bool fail () const
char_type fill () const
char_type fill (char_type __ch)
fmtflags flags () const
fmtflags flags (fmtflags __fmtfl)
streamsize gcount () const
template<> basic_istream< char > & getline (char_type *__s, streamsize __n, char_type __delim)
template<> basic_istream< wchar_t > & getline (char_type *__s, streamsize __n, char_type __delim)
locale getloc () const
bool good () const
template<> basic_istream< char > & ignore (streamsize __n)
template<> basic_istream< char > & ignore (streamsize __n, int_type __delim)
template<> basic_istream< wchar_t > & ignore (streamsize __n)
template<> basic_istream< wchar_t > & ignore (streamsize __n, int_type __delim)
locale imbue (const locale &__loc)
long & iword (int __ix)
char narrow (char_type __c, char __dfault) const
streamsize precision () const
streamsize precision (streamsize __prec)
void *& pword (int __ix)
basic_streambuf< _CharT,
_Traits > * rdbuf () const "
basic_streambuf< _CharT,
_Traits > * rdbuf (basic_streambuf< _CharT, _Traits > *__sb)"
iostate rdstate () const
void register_callback (event_callback __fn, int __index)
fmtflags setf (fmtflags __fmtfl)
fmtflags setf (fmtflags __fmtfl, fmtflags __mask)
void setstate (iostate __state)
basic_ostream< _CharT, _Traits > * tie () const
basic_ostream< _CharT, _Traits > * tie (basic_ostream< _CharT, _Traits > *__tiestr)
void unsetf (fmtflags __mask)
char_type widen (char __c) const
streamsize width () const
streamsize width (streamsize __wide)
virtual ~basic_istream ()

__istream_type & operator>> (__istream_type &(*__pf)(__istream_type &))
__istream_type & operator>> (__ios_type &(*__pf)(__ios_type &))
__istream_type & operator>> (ios_base &(*__pf)(ios_base &))

Arithmetic Extractors
All the operator>> functions (aka formatted input functions) have some common behavior. Each starts by constructing a temporary object of type std::basic_istream::sentry with the second argument (noskipws) set to false. This has several effects, concluding with the setting of a status flag; see the sentry documentation for more.

If the sentry status is good, the function tries to extract whatever data is appropriate for the type of the argument.

If an exception is thrown during extraction, ios_base::badbit will be turned on in the stream's error state without causing an ios_base::failure to be thrown. The original exception will then be rethrown.

__istream_type & operator>> (bool &__n)
__istream_type & operator>> (short &__n)
__istream_type & operator>> (unsigned short &__n)
__istream_type & operator>> (int &__n)
__istream_type & operator>> (unsigned int &__n)
__istream_type & operator>> (long &__n)
__istream_type & operator>> (unsigned long &__n)
__istream_type & operator>> (long long &__n)
__istream_type & operator>> (unsigned long long &__n)
__istream_type & operator>> (float &__f)
__istream_type & operator>> (double &__f)
__istream_type & operator>> (long double &__f)
__istream_type & operator>> (void *&__p)
__istream_type & operator>> (__streambuf_type *__sb)

Unformatted Input Functions
All the unformatted input functions have some common behavior. Each starts by constructing a temporary object of type std::basic_istream::sentry with the second argument (noskipws) set to true. This has several effects, concluding with the setting of a status flag; see the sentry documentation for more.

If the sentry status is good, the function tries to extract whatever data is appropriate for the type of the argument.

The number of characters extracted is stored for later retrieval by gcount().

int_type get ()
__istream_type & get (char_type &__c)
__istream_type & get (char_type *__s, streamsize __n, char_type __delim)
__istream_type & get (char_type *__s, streamsize __n)
__istream_type & get (__streambuf_type &__sb, char_type __delim)
__istream_type & get (__streambuf_type &__sb)
__istream_type & getline (char_type *__s, streamsize __n, char_type __delim)
__istream_type & getline (char_type *__s, streamsize __n)
__istream_type & ignore ()
__istream_type & ignore (streamsize __n)
__istream_type & ignore (streamsize __n, int_type __delim)
int_type peek ()
__istream_type & read (char_type *__s, streamsize __n)
streamsize readsome (char_type *__s, streamsize __n)
__istream_type & putback (char_type __c)
__istream_type & unget ()
int sync ()
pos_type tellg ()
__istream_type & seekg (pos_type)
__istream_type & seekg (off_type, ios_base::seekdir)

operator void * () const
bool operator! () const

Static Public Member Functions¶

static bool sync_with_stdio (bool __sync=true)
static int xalloc () throw ()

Static Public Attributes¶

static const fmtflags adjustfield
static const openmode app
static const openmode ate
static const iostate badbit
static const fmtflags basefield
static const seekdir beg
static const openmode binary
static const fmtflags boolalpha
static const seekdir cur
static const fmtflags dec
static const seekdir end
static const iostate eofbit
static const iostate failbit
static const fmtflags fixed
static const fmtflags floatfield
static const iostate goodbit
static const fmtflags hex
static const openmode in
static const fmtflags internal
static const fmtflags left
static const fmtflags oct
static const openmode out
static const fmtflags right
static const fmtflags scientific
static const fmtflags showbase
static const fmtflags showpoint
static const fmtflags showpos
static const fmtflags skipws
static const openmode trunc
static const fmtflags unitbuf
static const fmtflags uppercase

Protected Types¶

enum { _S_local_word_size }

Protected Member Functions¶

void _M_cache_locale (const locale &__loc)
void _M_call_callbacks (event __ev) throw ()
void _M_dispose_callbacks (void)
template<typename _ValueT > __istream_type & _M_extract (_ValueT &__v)
_Words & _M_grow_words (int __index, bool __iword)
void _M_init ()
void init (basic_streambuf< _CharT, _Traits > *__sb)

Protected Attributes¶

_Callback_list * _M_callbacks
const __ctype_type * _M_ctype
char_type _M_fill
bool _M_fill_init
streamsize _M_gcount
locale _M_ios_locale
_Words _M_local_word [_S_local_word_size]
const __num_get_type * _M_num_get
const __num_put_type * _M_num_put
basic_streambuf< _CharT,
_Traits > * _M_streambuf"
basic_ostream< _CharT, _Traits > * _M_tie
_Words * _M_word
int _M_word_size
_Words _M_word_zero

streamsize _M_precision
streamsize _M_width
fmtflags _M_flags
iostate _M_exception
iostate _M_streambuf_state

Friends¶

class sentry

Detailed Description¶

template<typename _CharT, typename _Traits>class std::basic_istream< _CharT, _Traits >¶

Controlling input.

This is the base class for all input streams. It provides text formatting of all builtin types, and communicates with any class derived from basic_streambuf to do the actual input.

Definition at line 55 of file istream.

Member Typedef Documentation¶

template<typename _CharT, typename _Traits> typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > std::basic_ios< _CharT, _Traits >::__num_put_type [inherited]¶

These are non-standard types.

Definition at line 84 of file basic_ios.h.

typedef void(* std::ios_base::event_callback)(event, ios_base &, int) [inherited]¶

The type of an event callback function. Parameters:

event One of the members of the event enum.
ios_base Reference to the ios_base object.
int The integer provided when the callback was registered.

Event callbacks are user defined functions that get called during several ios_base and basic_ios functions, specifically imbue(), copyfmt(), and ~ios().

Definition at line 444 of file ios_base.h.

typedef _Ios_Fmtflags std::ios_base::fmtflags [inherited]¶

This is a bitmask type. '_Ios_Fmtflags' is implementation-defined, but it is valid to perform bitwise operations on these values and expect the Right Thing to happen. Defined objects of type fmtflags are:

boolalpha
dec
fixed
hex
internal
left
oct
right
scientific
showbase
showpoint
showpos
skipws
unitbuf
uppercase
adjustfield
basefield
floatfield

Definition at line 263 of file ios_base.h.

typedef _Ios_Iostate std::ios_base::iostate [inherited]¶

This is a bitmask type. '_Ios_Iostate' is implementation-defined, but it is valid to perform bitwise operations on these values and expect the Right Thing to happen. Defined objects of type iostate are:

badbit
eofbit
failbit
goodbit

Definition at line 338 of file ios_base.h.

typedef _Ios_Openmode std::ios_base::openmode [inherited]¶

This is a bitmask type. '_Ios_Openmode' is implementation-defined, but it is valid to perform bitwise operations on these values and expect the Right Thing to happen. Defined objects of type openmode are:

app
ate
binary
in
out
trunc

Definition at line 369 of file ios_base.h.

typedef _Ios_Seekdir std::ios_base::seekdir [inherited]¶

This is an enumerated type. '_Ios_Seekdir' is implementation-defined. Defined values of type seekdir are:

beg
cur, equivalent to SEEK_CUR in the C standard library.
end, equivalent to SEEK_END in the C standard library.

Definition at line 401 of file ios_base.h.

Member Enumeration Documentation¶

enum std::ios_base::event [inherited]¶

The set of events that may be passed to an event callback. erase_event is used during ~ios() and copyfmt(). imbue_event is used during imbue(). copyfmt_event is used during copyfmt().

Definition at line 427 of file ios_base.h.

Constructor & Destructor Documentation¶

template<typename _CharT, typename _Traits> std::basic_istream< _CharT, _Traits >::basic_istream (__streambuf_type *__sb) [inline], [explicit]¶

Base constructor. This ctor is almost never called by the user directly, rather from derived classes' initialization lists, which pass a pointer to their own stream buffer.

Definition at line 91 of file istream.

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

Base destructor. This does very little apart from providing a virtual base dtor.

Definition at line 101 of file istream.

Member Function Documentation¶

const locale& std::ios_base::_M_getloc () const [inline], [inherited]¶

Locale access. Returns:

A reference to the current locale.

Like getloc above, but returns a reference instead of generating a copy.

Definition at line 710 of file ios_base.h.

Referenced by std::money_get< _CharT, _InIter >::do_get(), std::num_get< _CharT, _InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get_date(), std::time_get< _CharT, _InIter >::do_get_monthname(), std::time_get< _CharT, _InIter >::do_get_time(), std::time_get< _CharT, _InIter >::do_get_weekday(), std::time_get< _CharT, _InIter >::do_get_year(), std::time_put< _CharT, _OutIter >::do_put(), std::num_put< _CharT, _OutIter >::do_put(), and std::time_put< _CharT, _OutIter >::put().

template<typename _CharT, typename _Traits> bool std::basic_ios< _CharT, _Traits >::bad () const [inline], [inherited]¶

Fast error checking. Returns:

True if the badbit is set.

Note that other iostate flags may also be set.

Definition at line 201 of file basic_ios.h.

template<typename _CharT , typename _Traits > void std::basic_ios< _CharT, _Traits >::clear (iostate__state = goodbit) [inherited]¶

[Re]sets the error state. Parameters:

state The new state flag(s) to set.

See std::ios_base::iostate for the possible bit values. Most users will not need to pass an argument.

Definition at line 40 of file basic_ios.tcc.

template<typename _CharT , typename _Traits > basic_ios< _CharT, _Traits > & std::basic_ios< _CharT, _Traits >::copyfmt (const basic_ios< _CharT, _Traits > &__rhs) [inherited]¶

Copies fields of __rhs into this. Parameters:

__rhs The source values for the copies.

Returns:

Reference to this object.

All fields of __rhs are copied into this object except that rdbuf() and rdstate() remain unchanged. All values in the pword and iword arrays are copied. Before copying, each callback is invoked with erase_event. After copying, each (new) callback is invoked with copyfmt_event. The final step is to copy exceptions().

Definition at line 62 of file basic_ios.tcc.

References std::basic_ios< _CharT, _Traits >::exceptions(), std::basic_ios< _CharT, _Traits >::fill(), std::ios_base::flags(), std::ios_base::getloc(), std::ios_base::precision(), std::basic_ios< _CharT, _Traits >::tie(), and std::ios_base::width().

template<typename _CharT, typename _Traits> bool std::basic_ios< _CharT, _Traits >::eof () const [inline], [inherited]¶

Fast error checking. Returns:

True if the eofbit is set.

Note that other iostate flags may also be set.

Definition at line 180 of file basic_ios.h.

template<typename _CharT, typename _Traits> iostate std::basic_ios< _CharT, _Traits >::exceptions () const [inline], [inherited]¶

Throwing exceptions on errors. Returns:

The current exceptions mask.

This changes nothing in the stream. See the one-argument version of exceptions(iostate) for the meaning of the return value.

Definition at line 212 of file basic_ios.h.

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

template<typename _CharT, typename _Traits> void std::basic_ios< _CharT, _Traits >::exceptions (iostate__except) [inline], [inherited]¶

Throwing exceptions on errors. Parameters:

except The new exceptions mask.

By default, error flags are set silently. You can set an exceptions mask for each stream; if a bit in the mask becomes set in the error flags, then an exception of type std::ios_base::failure is thrown.

If the error flag is already set when the exceptions mask is added, the exception is immediately thrown. Try running the following under GCC 3.1 or later:

#include <iostream>
#include <fstream>
#include <exception>
int main()
{


    std::set_terminate (__gnu_cxx::__verbose_terminate_handler);


    std::ifstream f ('/etc/motd');


    std::cerr << 'Setting badbit0;


    f.setstate (std::ios_base::badbit);


    std::cerr << 'Setting exception mask0;


    f.exceptions (std::ios_base::badbit);
}

Definition at line 247 of file basic_ios.h.

template<typename _CharT, typename _Traits> bool std::basic_ios< _CharT, _Traits >::fail () const [inline], [inherited]¶

Fast error checking. Returns:

True if either the badbit or the failbit is set.

Checking the badbit in fail() is historical practice. Note that other iostate flags may also be set.

Definition at line 191 of file basic_ios.h.

template<typename _CharT, typename _Traits> char_type std::basic_ios< _CharT, _Traits >::fill () const [inline], [inherited]¶

Retrieves the 'empty' character. Returns:

The current fill character.

It defaults to a space (' ') in the current locale.

Definition at line 360 of file basic_ios.h.

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

template<typename _CharT, typename _Traits> char_type std::basic_ios< _CharT, _Traits >::fill (char_type__ch) [inline], [inherited]¶

Sets a new 'empty' character. Parameters:

ch The new character.

Returns:

The previous fill character.

The fill character is used to fill out space when P+ characters have been requested (e.g., via setw), Q characters are actually used, and Q<P. It defaults to a space (' ') in the current locale.

Definition at line 380 of file basic_ios.h.

fmtflags std::ios_base::flags () const [inline], [inherited]¶

Access to format flags. Returns:

The format control flags for both input and output.

Definition at line 555 of file ios_base.h.

Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter >::do_put(), and std::operator<<().

fmtflags std::ios_base::flags (fmtflags__fmtfl) [inline], [inherited]¶

Setting new format flags all at once. Parameters:

fmtfl The new flags to set.

Characters are extracted and stored into s until one of the following happens:

n-1 characters are stored
the input sequence reaches EOF
the next character equals delim, in which case the character is not extracted

If no characters are stored, failbit is set in the stream's error state.

In any case, a null character is stored into the next location in the array.

Note:

This function is not overloaded on signed char and unsigned char.

Definition at line 259 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sgetc(), and std::basic_streambuf< _CharT, _Traits >::snextc().

template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT, _Traits >::get (char_type *s, streamsizen) [inline]¶

Simple multiple-character extraction. Parameters:

s Pointer to an array.
n Maximum number of characters to store in s.

Returns:

*this

Returns get(s,n,widen('

Definition at line 332 of file istream.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::get (__streambuf_type &__sb, char_type__delim)¶

Extraction into another streambuf. Parameters:

sb A streambuf in which to store data.
delim A 'stop' character.

Returns:

*this

Characters are extracted and inserted into sb until one of the following happens:

the input sequence reaches EOF
insertion into the output buffer fails (in this case, the character that would have been inserted is not extracted)
the next character equals delim (in this case, the character is not extracted)
an exception occurs (and in this case is caught)

If no characters are stored, failbit is set in the stream's error state.

Definition at line 306 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sgetc(), std::basic_streambuf< _CharT, _Traits >::snextc(), and std::basic_streambuf< _CharT, _Traits >::sputc().

template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT, _Traits >::get (__streambuf_type &__sb) [inline]¶

Extraction into another streambuf. Parameters:

sb A streambuf in which to store data.

Returns:

*this

Returns get(sb,widen('

Definition at line 365 of file istream.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::getline (char_type *s, streamsizen, char_type__delim)¶

String extraction. Parameters:

s A character array in which to store the data.
n Maximum number of characters to extract.
delim A 'stop' character.

Returns:

*this

Extracts and stores characters into s until one of the following happens. Note that these criteria are required to be tested in the order listed here, to allow an input line to exactly fill the s array without setting failbit.

1.: the input sequence reaches end-of-file, in which case eofbit is set in the stream error state
2.: the next character equals delim, in which case the character is extracted (and therefore counted in gcount()) but not stored
3.: n-1 characters are stored, in which case failbit is set in the stream error state

If no characters are extracted, failbit is set. (An empty line of input should therefore not cause failbit to be set.)

In any case, a null character is stored in the next location in the array.

Definition at line 350 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sbumpc(), std::basic_streambuf< _CharT, _Traits >::sgetc(), and std::basic_streambuf< _CharT, _Traits >::snextc().

template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT, _Traits >::getline (char_type *s, streamsizen) [inline]¶

String extraction. Parameters:

s A character array in which to store the data.
n Maximum number of characters to extract.

Returns:

*this

Returns getline(s,n,widen('

Definition at line 405 of file istream.

Referenced by std::basic_istream< char >::getline().

locale std::ios_base::getloc () const [inline], [inherited]¶

Locale access. Returns:

A copy of the current locale.

If imbue(loc) has previously been called, then this function returns loc. Otherwise, it returns a copy of std::locale(), the global C++ locale.

Definition at line 699 of file ios_base.h.

Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), std::money_put< _CharT, _OutIter >::do_put(), std::operator>>(), and std::ws().

template<typename _CharT, typename _Traits> bool std::basic_ios< _CharT, _Traits >::good () const [inline], [inherited]¶

Fast error checking. Returns:

True if no error flags are set.

A wrapper around rdstate.

Definition at line 170 of file basic_ios.h.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::ignore (void)¶

Discarding characters. Parameters:

n Number of characters to discard.
delim A 'stop' character.

Returns:

*this

Extracts characters and throws them away until one of the following happens:

if n != std::numeric_limits<int>::max(), n characters are extracted
the input sequence reaches end-of-file
the next character equals delim (in this case, the character is extracted); note that this condition will never occur if delim equals traits::eof().

NB: Provide three overloads, instead of the single function (with defaults) mandated by the Standard: this leads to a better performing implementation, while still conforming to the Standard.

Definition at line 410 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sbumpc().

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::ignore (streamsize__n)¶

Simple extraction. Returns:

A character, or eof().

Tries to extract a character. If none are available, sets failbit and returns traits::eof().

Definition at line 443 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sgetc(), and std::basic_streambuf< _CharT, _Traits >::snextc().

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::ignore (streamsize__n, int_type__delim)¶

Simple extraction. Returns:

A character, or eof().

Tries to extract a character. If none are available, sets failbit and returns traits::eof().

Definition at line 505 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sbumpc(), std::basic_streambuf< _CharT, _Traits >::sgetc(), and std::basic_streambuf< _CharT, _Traits >::snextc().

template<typename _CharT , typename _Traits > locale std::basic_ios< _CharT, _Traits >::imbue (const locale &__loc) [inherited]¶

Moves to a new locale. Parameters:

loc The new locale.

Returns:

The previous locale.

Calls ios_base::imbue(loc), and if a stream buffer is associated with this stream, calls that buffer's pubimbue(loc).

Additional l10n notes are at http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html

Reimplemented from std::ios_base.

Definition at line 113 of file basic_ios.tcc.

Referenced by std::operator<<().

template<typename _CharT, typename _Traits> void std::basic_ios< _CharT, _Traits >::init (basic_streambuf< _CharT, _Traits > *__sb) [protected], [inherited]¶

All setup is performed here. This is called from the public constructor. It is not virtual and cannot be redefined.

Definition at line 125 of file basic_ios.tcc.

long& std::ios_base::iword (int__ix) [inline], [inherited]¶

Access to integer array. Parameters:

__ix Index into the array.

Returns:

A reference to an integer associated with the index.

The iword function provides access to an array of integers that can be used for any purpose. The array grows as required to hold the supplied index. All integers in the array are initialized to 0.

The implementation reserves several indices. You should use xalloc to obtain an index that is safe to use. Also note that since the array can grow dynamically, it is not safe to hold onto the reference.

Definition at line 745 of file ios_base.h.

template<typename _CharT, typename _Traits> char std::basic_ios< _CharT, _Traits >::narrow (char_typec, chardfault) const [inline], [inherited]¶

Squeezes characters. Parameters:

c The character to narrow.
dfault The character to narrow.

Returns:

The narrowed character.

Maps a character of char_type to a character of char, if possible.

Returns the result of

std::use_facet<ctype<char_type> >(getloc()).narrow(c,dfault)

Additional l10n notes are at http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html

Definition at line 420 of file basic_ios.h.

template<typename _CharT, typename _Traits> std::basic_ios< _CharT, _Traits >::operator void * () const [inline], [inherited]¶

The quick-and-easy status check. This allows you to write constructs such as 'if (!a_stream) ...' and 'while (a_stream) ...'

Definition at line 111 of file basic_ios.h.

template<typename _CharT, typename _Traits> bool std::basic_ios< _CharT, _Traits >::operator! () const [inline], [inherited]¶

The quick-and-easy status check. This allows you to write constructs such as 'if (!a_stream) ...' and 'while (a_stream) ...'

Definition at line 115 of file basic_ios.h.

template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT, _Traits >::operator>> (__istream_type &(*)(__istream_type &)__pf) [inline]¶

Interface for manipulators. Manipulators such as std::ws and std::dec use these functions in constructs like 'std::cin >> std::ws'. For more information, see the iomanip header.

Definition at line 119 of file istream.

template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT, _Traits >::operator>> (__ios_type &(*)(__ios_type &)__pf) [inline]¶

sb A pointer to a streambuf

This function behaves like one of the basic arithmetic extractors, in that it also constructs a sentry object and has the same error handling behavior.

If sb is NULL, the stream will set failbit in its error state.

Characters are extracted from this stream and inserted into the sb streambuf until one of the following occurs:

the input stream reaches end-of-file,
insertion into the output buffer fails (in this case, the character that would have been inserted is not extracted), or
an exception occurs (and in this case is caught)

If the function inserts no characters, failbit is set.

Definition at line 154 of file istream.tcc.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits >::int_type std::basic_istream< _CharT, _Traits >::peek (void)¶

Looking ahead in the stream. Returns:

The next character, or eof().

If, after constructing the sentry object, good() is false, returns traits::eof(). Otherwise reads but does not extract the next input character.

Definition at line 570 of file istream.tcc.

streamsize std::ios_base::precision () const [inline], [inherited]¶

Flags access. Returns:

The precision to generate on certain output operations.

Be careful if you try to give a definition of 'precision' here; see DR 189.

Definition at line 625 of file ios_base.h.

Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), and std::operator<<().

streamsize std::ios_base::precision (streamsize__prec) [inline], [inherited]¶

Changing flags. Parameters:

prec The new precision value.

Returns:

The previous value of precision().

Definition at line 634 of file ios_base.h.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::putback (char_type__c)¶

Unextracting a single character. Parameters:

c The character to push back into the input stream.

Returns:

*this

If rdbuf() is not null, calls rdbuf()->sputbackc(c).

If rdbuf() is null or if sputbackc() fails, sets badbit in the error state.

Note:

Since no characters are extracted, the next call to gcount() will return 0, as required by DR 60.

Definition at line 661 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sputbackc().

Referenced by std::operator>>().

void*& std::ios_base::pword (int__ix) [inline], [inherited]¶

Access to void pointer array. Parameters:

__ix Index into the array.

Returns:

A reference to a void* associated with the index.

The pword function provides access to an array of pointers that can be used for any purpose. The array grows as required to hold the supplied index. All pointers in the array are initialized to 0.

Definition at line 766 of file ios_base.h.

template<typename _CharT, typename _Traits> basic_streambuf<_CharT, _Traits>* std::basic_ios< _CharT, _Traits >::rdbuf () const [inline], [inherited]¶

Accessing the underlying buffer. Returns:

The current stream buffer.

This does not change the state of the stream.

Reimplemented in std::basic_fstream< _CharT, _Traits >, std::basic_ofstream< _CharT, _Traits >, std::basic_stringstream< _CharT, _Traits, _Alloc >, std::basic_ifstream< _CharT, _Traits >, std::basic_ostringstream< _CharT, _Traits, _Alloc >, and std::basic_istringstream< _CharT, _Traits, _Alloc >.

Definition at line 311 of file basic_ios.h.

Referenced by std::getline(), std::operator>>(), and std::ws().

template<typename _CharT, typename _Traits> basic_streambuf< _CharT, _Traits > * std::basic_ios< _CharT, _Traits >::rdbuf (basic_streambuf< _CharT, _Traits > *__sb) [inherited]¶

Changing the underlying buffer. Parameters:

sb The new stream buffer.

Returns:

The previous stream buffer.

Associates a new buffer with the current stream, and clears the error state.

Due to historical accidents which the LWG refuses to correct, the I/O library suffers from a design error: this function is hidden in derived classes by overrides of the zero-argument rdbuf(), which is non-virtual for hysterical raisins. As a result, you must use explicit qualifications to access this function via any derived class. For example:

std::fstream     foo;         // or some other derived type
std::streambuf*  p = .....;
foo.ios::rdbuf(p);            // ios == basic_ios<char>

Definition at line 52 of file basic_ios.tcc.

template<typename _CharT, typename _Traits> iostate std::basic_ios< _CharT, _Traits >::rdstate () const [inline], [inherited]¶

Returns the error state of the stream buffer. Returns:

A bit pattern (well, isn't everything?)

See std::ios_base::iostate for the possible bit values. Most users will call one of the interpreting wrappers, e.g., good().

Definition at line 127 of file basic_ios.h.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::read (char_type *s, streamsizen)¶

Extraction without delimiters. Parameters:

s A character array.
n Maximum number of characters to store.

Returns:

*this

If the stream state is good(), extracts characters and stores them into s until one of the following happens:

n characters are stored
the input sequence reaches end-of-file, in which case the error state is set to failbit|eofbit.

Note:

This function is not overloaded on signed char and unsigned char.

Definition at line 600 of file istream.tcc.

template<typename _CharT , typename _Traits > streamsize std::basic_istream< _CharT, _Traits >::readsome (char_type *s, streamsizen)¶

Extraction until the buffer is exhausted, but no more. Parameters:

s A character array.
n Maximum number of characters to store.

Returns:

The number of characters extracted.

Extracts characters and stores them into s depending on the number of characters remaining in the streambuf's buffer, rdbuf()->in_avail(), called A here:

if A == -1, sets eofbit and extracts no characters
if A == 0, extracts no characters
if A > 0, extracts min(A,n)

The goal is to empty the current buffer, and to not request any more from the external input sequence controlled by the streambuf.

Definition at line 629 of file istream.tcc.

References std::min().

void std::ios_base::register_callback (event_callbackfn, intindex) [inherited]¶

Add the callback __fn with parameter __index. Parameters:

__fn The function to add.
__index The integer to pass to the function when invoked.

Registers a function as an event callback with an integer parameter to be passed to the function when invoked. Multiple copies of the function are allowed. If there are multiple callbacks, they are invoked in the order they were registered.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::seekg (pos_type__pos)¶

Changing the current read position. Parameters:

pos A file position object.

Returns:

*this

If fail() is not true, calls rdbuf()->pubseekpos(pos). If that function fails, sets failbit.

Note:

This function does not count the number of characters extracted, if any, and therefore does not affect the next call to gcount().

Definition at line 787 of file istream.tcc.

template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > & std::basic_istream< _CharT, _Traits >::seekg (off_type__off, ios_base::seekdir__dir)¶

Changing the current read position. Parameters:

off A file offset object.
dir The direction in which to seek.

Returns:

*this

If fail() is not true, calls rdbuf()->pubseekoff(off,dir). If that function fails, sets failbit.

Note:

This function does not count the number of characters extracted, if any, and therefore does not affect the next call to gcount().

Definition at line 820 of file istream.tcc.

fmtflags std::ios_base::setf (fmtflags__fmtfl) [inline], [inherited]¶

Setting new format flags. Parameters:

fmtfl Additional flags to set.

Returns:

The previous format control flags.

This function sets additional flags in format control. Flags that were previously set remain set.

Definition at line 582 of file ios_base.h.

Referenced by std::boolalpha(), std::dec(), std::fixed(), std::hex(), std::internal(), std::left(), std::oct(), std::right(), std::scientific(), std::showbase(), std::showpoint(), std::showpos(), std::skipws(), std::unitbuf(), and std::uppercase().

fmtflags std::ios_base::setf (fmtflagsfmtfl, fmtflagsmask) [inline], [inherited]¶

Setting new format flags. Parameters:

fmtfl Additional flags to set.
mask The flags mask for fmtfl.

Returns:

The previous format control flags.

This function clears mask in the format flags, then sets fmtfl & mask. An example mask is ios_base::adjustfield.

Definition at line 599 of file ios_base.h.

template<typename _CharT, typename _Traits> void std::basic_ios< _CharT, _Traits >::setstate (iostate__state) [inline], [inherited]¶

Sets additional flags in the error state. Parameters:

state The additional state flag(s) to set.

See std::ios_base::iostate for the possible bit values.

Definition at line 147 of file basic_ios.h.

Referenced by std::getline(), std::operator<<(), std::operator>>(), and std::ws().

template<typename _CharT , typename _Traits > int std::basic_istream< _CharT, _Traits >::sync (void)¶

Synchronizing the stream buffer. Returns:

0 on success, -1 on failure

If rdbuf() is a null pointer, returns -1.

Definition at line 694 of file istream.tcc.

References std::basic_streambuf< _CharT, _Traits >::sungetc().

void std::ios_base::unsetf (fmtflags__mask) [inline], [inherited]¶

Clearing format flags. Parameters:

mask The flags to unset.

This function clears mask in the format flags.

Definition at line 614 of file ios_base.h.

Referenced by std::noboolalpha(), std::noshowbase(), std::noshowpoint(), std::noshowpos(), std::noskipws(), std::nounitbuf(), and std::nouppercase().

template<typename _CharT, typename _Traits> char_type std::basic_ios< _CharT, _Traits >::widen (char__c) const [inline], [inherited]¶

Widens characters. Parameters:

c The character to widen.

Returns:

The widened character.

Maps a character of char to a character of char_type.

Returns the result of

std::use_facet<ctype<char_type> >(getloc()).widen(c)

Additional l10n notes are at http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html

Definition at line 439 of file basic_ios.h.

Referenced by std::endl(), std::getline(), and std::operator>>().

streamsize std::ios_base::width () const [inline], [inherited]¶

Flags access. Returns:

The minimum field width to generate on output operations.

Definition at line 648 of file ios_base.h.

Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), std::num_put< _CharT, _OutIter >::do_put(), and std::operator>>().

streamsize std::ios_base::width (streamsize__wide) [inline], [inherited]¶

Changing flags. Parameters:

wide The new width value.

Returns:

The previous value of width().

Definition at line 657 of file ios_base.h.

static int std::ios_base::xalloc () throw () [static], [inherited]¶

Access to unique indices. Returns:

An integer different from all previous calls.

This function returns a unique integer every time it is called. It can be used for any purpose, but is primarily intended to be a unique index for the iword and pword functions. The expectation is that an application calls xalloc in order to obtain an index in the iword and pword arrays that can be used without fear of conflict.

The implementation maintains a static variable that is incremented and returned on each invocation. xalloc is guaranteed to return an index that is safe to use in the iword and pword arrays.

Member Data Documentation¶