Provided by: libstdc++-8-doc_8.4.0-1ubuntu1~18.04_all 
NAME
std::basic_ifstream< _CharT, _Traits > - Controlling input for files.
SYNOPSIS
Inherits std::basic_istream< _CharT, _Traits >.
Public Types
typedef ctype< _CharT > __ctype_type
typedef basic_filebuf< char_type, traits_type > __filebuf_type
typedef basic_ios< _CharT, _Traits > __ios_type
typedef basic_istream< char_type, traits_type > __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 } The set of events that may be
passed to an event callback. "
typedef void(* event_callback) (event __e, ios_base &__b, int __i)
The type of an event callback function.
typedef _Ios_Fmtflags fmtflags
This is a bitmask type.
typedef traits_type::int_type int_type
typedef int io_state
typedef _Ios_Iostate iostate
This is a bitmask type.
typedef traits_type::off_type off_type
typedef int open_mode
typedef _Ios_Openmode openmode
This is a bitmask type.
typedef traits_type::pos_type pos_type
typedef int seek_dir
typedef _Ios_Seekdir seekdir
This is an enumerated type.
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
basic_ifstream ()
Default constructor.
basic_ifstream (const char *__s, ios_base::openmode __mode=ios_base::in)
Create an input file stream.
basic_ifstream (const std::string &__s, ios_base::openmode __mode=ios_base::in)
Create an input file stream.
basic_ifstream (const basic_ifstream &)=delete
basic_ifstream (basic_ifstream &&__rhs)
~basic_ifstream ()
The destructor does nothing.
template<typename _ValueT > basic_istream< _CharT, _Traits > & _M_extract (_ValueT &__v)
const locale & _M_getloc () const
Locale access.
void _M_setstate (iostate __state)
bool bad () const
Fast error checking.
void clear (iostate __state=goodbit)
[Re]sets the error state.
void close ()
Close the file.
basic_ios & copyfmt (const basic_ios &__rhs)
Copies fields of __rhs into this.
bool eof () const
Fast error checking.
iostate exceptions () const
Throwing exceptions on errors.
void exceptions (iostate __except)
Throwing exceptions on errors.
bool fail () const
Fast error checking.
char_type fill () const
Retrieves the empty character.
char_type fill (char_type __ch)
Sets a new empty character.
fmtflags flags () const
Access to format flags.
fmtflags flags (fmtflags __fmtfl)
Setting new format flags all at once.
streamsize gcount () const
Character counting.
template<> basic_istream< char > & getline (char_type *__s, streamsize __n, char_type
__delim)
Explicit specialization declarations, defined in src/istream.cc.
template<> basic_istream< wchar_t > & getline (char_type *__s, streamsize __n, char_type
__delim)
locale getloc () const
Locale access.
bool good () const
Fast error checking.
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)
Moves to a new locale.
bool is_open ()
Wrapper to test for an open file.
bool is_open () const
long & iword (int __ix)
Access to integer array.
char narrow (char_type __c, char __dfault) const
Squeezes characters.
void open (const char *__s, ios_base::openmode __mode=ios_base::in)
Opens an external file.
void open (const std::string &__s, ios_base::openmode __mode=ios_base::in)
Opens an external file.
basic_ifstream & operator= (const basic_ifstream &)=delete
basic_ifstream & operator= (basic_ifstream &&__rhs)
__istream_type & operator>> (void *&__p)
Basic arithmetic extractors.
__istream_type & operator>> (__streambuf_type *__sb)
Extracting into another streambuf.
streamsize precision () const
Flags access.
streamsize precision (streamsize __prec)
Changing flags.
void *& pword (int __ix)
Access to void pointer array.
basic_streambuf< _CharT, _Traits > * rdbuf (basic_streambuf< _CharT, _Traits > *__sb)
Changing the underlying buffer.
__filebuf_type * rdbuf () const
Accessing the underlying buffer.
iostate rdstate () const
Returns the error state of the stream buffer.
void register_callback (event_callback __fn, int __index)
Add the callback __fn with parameter __index.
fmtflags setf (fmtflags __fmtfl)
Setting new format flags.
fmtflags setf (fmtflags __fmtfl, fmtflags __mask)
Setting new format flags.
void setstate (iostate __state)
Sets additional flags in the error state.
void swap (basic_ifstream &__rhs)
basic_ostream< _CharT, _Traits > * tie () const
Fetches the current tied stream.
basic_ostream< _CharT, _Traits > * tie (basic_ostream< _CharT, _Traits > *__tiestr)
Ties this stream to an output stream.
void unsetf (fmtflags __mask)
Clearing format flags.
char_type widen (char __c) const
Widens characters.
streamsize width () const
Flags access.
streamsize width (streamsize __wide)
Changing flags.
__istream_type & operator>> (__istream_type &(*__pf)(__istream_type &))
Interface for manipulators.
__istream_type & operator>> (__ios_type &(*__pf)(__ios_type &))
Interface for manipulators.
__istream_type & operator>> (ios_base &(*__pf)(ios_base &))
Interface for manipulators.
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) and the original
exception will be rethrown if badbit is set in the exceptions mask.
__istream_type & operator>> (bool &__n)
Integer arithmetic extractors.
__istream_type & operator>> (short &__n)
Integer arithmetic extractors.
__istream_type & operator>> (unsigned short &__n)
Integer arithmetic extractors.
__istream_type & operator>> (int &__n)
Integer arithmetic extractors.
__istream_type & operator>> (unsigned int &__n)
Integer arithmetic extractors.
__istream_type & operator>> (long &__n)
Integer arithmetic extractors.
__istream_type & operator>> (unsigned long &__n)
Integer arithmetic extractors.
__istream_type & operator>> (long long &__n)
Integer arithmetic extractors.
__istream_type & operator>> (unsigned long long &__n)
Integer arithmetic extractors.
__istream_type & operator>> (float &__f)
Floating point arithmetic extractors.
__istream_type & operator>> (double &__f)
Floating point arithmetic extractors.
__istream_type & operator>> (long double &__f)
Floating point arithmetic extractors.
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().
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) and the original
exception will be rethrown if badbit is set in the exceptions mask.
int_type get ()
Simple extraction.
__istream_type & get (char_type &__c)
Simple extraction.
__istream_type & get (char_type *__s, streamsize __n, char_type __delim)
Simple multiple-character extraction.
__istream_type & get (char_type *__s, streamsize __n)
Simple multiple-character extraction.
__istream_type & get (__streambuf_type &__sb, char_type __delim)
Extraction into another streambuf.
__istream_type & get (__streambuf_type &__sb)
Extraction into another streambuf.
__istream_type & getline (char_type *__s, streamsize __n, char_type __delim)
String extraction.
__istream_type & getline (char_type *__s, streamsize __n)
String extraction.
__istream_type & ignore (streamsize __n, int_type __delim)
Discarding characters.
__istream_type & ignore (streamsize __n)
Simple extraction.
__istream_type & ignore ()
Simple extraction.
int_type peek ()
Looking ahead in the stream.
__istream_type & read (char_type *__s, streamsize __n)
Extraction without delimiters.
streamsize readsome (char_type *__s, streamsize __n)
Extraction until the buffer is exhausted, but no more.
__istream_type & putback (char_type __c)
Unextracting a single character.
__istream_type & unget ()
Unextracting the previous character.
int sync ()
Synchronizing the stream buffer.
pos_type tellg ()
Getting the current read position.
__istream_type & seekg (pos_type)
Changing the current read position.
__istream_type & seekg (off_type, ios_base::seekdir)
Changing the current read position.
operator bool () const
The quick-and-easy status check.
bool operator! () const
The quick-and-easy status check.
Static Public Member Functions
static bool sync_with_stdio (bool __sync=true)
Interaction with the standard C I/O objects.
static int xalloc () throw ()
Access to unique indices.
Static Public Attributes
static const fmtflags adjustfield
A mask of left|right|internal. Useful for the 2-arg form of setf.
static const openmode app
Seek to end before each write.
static const openmode ate
Open and seek to end immediately after opening.
static const iostate badbit
Indicates a loss of integrity in an input or output sequence (such as an irrecoverable
read error from a file).
static const fmtflags basefield
A mask of dec|oct|hex. Useful for the 2-arg form of setf.
static const seekdir beg
Request a seek relative to the beginning of the stream.
static const openmode binary
Perform input and output in binary mode (as opposed to text mode). This is probably
not what you think it is; see
https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary.
static const fmtflags boolalpha
Insert/extract bool in alphabetic rather than numeric format.
static const seekdir cur
Request a seek relative to the current position within the sequence.
static const fmtflags dec
Converts integer input or generates integer output in decimal base.
static const seekdir end
Request a seek relative to the current end of the sequence.
static const iostate eofbit
Indicates that an input operation reached the end of an input sequence.
static const iostate failbit
Indicates that an input operation failed to read the expected characters, or that an
output operation failed to generate the desired characters.
static const fmtflags fixed
Generate floating-point output in fixed-point notation.
static const fmtflags floatfield
A mask of scientific|fixed. Useful for the 2-arg form of setf.
static const iostate goodbit
Indicates all is well.
static const fmtflags hex
Converts integer input or generates integer output in hexadecimal base.
static const openmode in
Open for input. Default for ifstream and fstream.
static const fmtflags internal
Adds fill characters at a designated internal point in certain generated output, or
identical to right if no such point is designated.
static const fmtflags left
Adds fill characters on the right (final positions) of certain generated output.
(I.e., the thing you print is flush left.)
static const fmtflags oct
Converts integer input or generates integer output in octal base.
static const openmode out
Open for output. Default for ofstream and fstream.
static const fmtflags right
Adds fill characters on the left (initial positions) of certain generated output.
(I.e., the thing you print is flush right.)
static const fmtflags scientific
Generates floating-point output in scientific notation.
static const fmtflags showbase
Generates a prefix indicating the numeric base of generated integer output.
static const fmtflags showpoint
Generates a decimal-point character unconditionally in generated floating-point
output.
static const fmtflags showpos
Generates a + sign in non-negative generated numeric output.
static const fmtflags skipws
Skips leading white space before certain input operations.
static const openmode trunc
Truncate an existing stream when opening. Default for ofstream.
static const fmtflags unitbuf
Flushes output after each output operation.
static const fmtflags uppercase
Replaces certain lowercase letters with their uppercase equivalents in generated
output.
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) throw ()
template<typename _ValueT > __istream_type & _M_extract (_ValueT &__v)
_Words & _M_grow_words (int __index, bool __iword)
void _M_init () throw ()
void _M_move (ios_base &) noexcept
void _M_swap (ios_base &__rhs) noexcept
void init (basic_streambuf< _CharT, _Traits > *__sb)
All setup is performed here.
void move (basic_ios &__rhs)
void move (basic_ios &&__rhs)
void set_rdbuf (basic_streambuf< _CharT, _Traits > *__sb)
void swap (basic_ios &__rhs) noexcept
void swap (basic_istream &__rhs)
Protected Attributes
_Callback_list * _M_callbacks
const __ctype_type * _M_ctype
iostate _M_exception
char_type _M_fill
bool _M_fill_init
fmtflags _M_flags
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
streamsize _M_precision
basic_streambuf< _CharT, _Traits > * _M_streambuf
iostate _M_streambuf_state
basic_ostream< _CharT, _Traits > * _M_tie
streamsize _M_width
_Words * _M_word
int _M_word_size
_Words _M_word_zero
Detailed Description
template<typename _CharT, typename _Traits>
class std::basic_ifstream< _CharT, _Traits >" Controlling input for files.
Template Parameters:
_CharT Type of character stream.
_Traits Traits for character type, defaults to char_traits<_CharT>.
This class supports reading from named files, using the inherited functions from
std::basic_istream. To control the associated sequence, an instance of std::basic_filebuf
is used, which this page refers to as sb.
Definition at line 476 of file fstream.
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 89 of file basic_ios.h.
typedef void(* std::ios_base::event_callback) (event __e, ios_base &__b, int __i) [inherited]
The type of an event callback function.
Parameters:
__e One of the members of the event enum.
__b Reference to the ios_base object.
__i 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 506 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 323 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 398 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 429 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 461 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 489 of file ios_base.h.
Constructor & Destructor Documentation
template<typename _CharT , typename _Traits > std::basic_ifstream< _CharT, _Traits
>::basic_ifstream () [inline]
Default constructor. Initializes sb using its default constructor, and passes &sb to the
base class initializer. Does not open any files (you haven't given it a filename to open).
Definition at line 502 of file fstream.
template<typename _CharT , typename _Traits > std::basic_ifstream< _CharT, _Traits
>::basic_ifstream (const char * __s, ios_base::openmode __mode = ios_base::in) [inline],
[explicit]
Create an input file stream.
Parameters:
__s Null terminated string specifying the filename.
__mode Open file in specified mode (see std::ios_base).
ios_base::in is automatically included in __mode.
Definition at line 513 of file fstream.
template<typename _CharT , typename _Traits > std::basic_ifstream< _CharT, _Traits
>::basic_ifstream (const std::string & __s, ios_base::openmode __mode = ios_base::in)
[inline], [explicit]
Create an input file stream.
Parameters:
__s std::string specifying the filename.
__mode Open file in specified mode (see std::ios_base).
ios_base::in is automatically included in __mode.
Definition at line 529 of file fstream.
template<typename _CharT , typename _Traits > std::basic_ifstream< _CharT, _Traits
>::~basic_ifstream () [inline]
The destructor does nothing. The file is closed by the filebuf object, not the formatting
stream.
Definition at line 566 of file fstream.
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 776 of file ios_base.h.
Referenced by std::time_get< _CharT, _InIter >::do_date_order(), std::time_get< _CharT,
_InIter >::do_get(), 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_put< _CharT, _OutIter
>::do_put(), std::num_put< _CharT, _OutIter >::do_put(), std::time_get< _CharT, _InIter
>::get(), 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 211 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 41 of file basic_ios.tcc.
Referenced by std::basic_ios< char, _Traits >::exceptions(), std::__detail::operator>>(),
std::basic_istream< char >::putback(), std::basic_ios< char, _Traits >::rdstate(),
std::basic_istream< char >::seekg(), std::basic_ios< char, _Traits >::setstate(), and
std::basic_istream< char >::unget().
template<typename _CharT , typename _Traits > void std::basic_ifstream< _CharT, _Traits
>::close () [inline]
Close the file. Calls std::basic_filebuf::close(). If that function fails, failbit is set
in the stream's error state.
Definition at line 678 of file fstream.
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 63 of file basic_ios.tcc.
Referenced by std::basic_ios< char, _Traits >::rdbuf().
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 190 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 222 of file basic_ios.h.
Referenced by std::basic_ios< char, _Traits >::copyfmt(), and std::basic_ios< char,
_Traits >::setstate().
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 257 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 201 of file basic_ios.h.
Referenced by std::basic_ios< char, _Traits >::operator bool(), std::basic_ios< char,
_Traits >::operator!(), and std::regex_traits< _CharType >::value().
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 370 of file basic_ios.h.
Referenced by std::basic_ios< char, _Traits >::copyfmt(), and std::basic_ios< char,
_Traits >::fill().
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 390 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 621 of file ios_base.h.
Referenced by std::basic_ios< char, _Traits >::copyfmt(), std::mersenne_twister_engine<
uint_fast32_t, 32, 624, 397, 31, 0x9908b0dfUL, 11, 0xffffffffUL, 7, 0x9d2c5680UL, 15,
0xefc60000UL, 18, 1812433253UL >::discard(), std::money_get< _CharT, _InIter >::do_get(),
std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter >::do_put(),
std::subtract_with_carry_engine< _UIntType, __w, __s, __r >::operator()(),
std::discard_block_engine< _RandomNumberEngine, __p, __r >::operator()(),
std::shuffle_order_engine< _RandomNumberEngine, __k >::operator()(), std::basic_ostream<
char >::operator<<(), std::operator<<(), std::__detail::operator>>(), std::operator>>(),
and std::linear_congruential_engine< _UIntType, __a, __c, __m >::seed().
fmtflags std::ios_base::flags (fmtflags __fmtfl) [inline], [inherited]
Setting new format flags all at once.
Parameters:
__fmtfl The new flags to set.
Returns:
The previous format control flags.
This function overwrites all the format flags with __fmtfl.
Definition at line 632 of file ios_base.h.
template<typename _CharT, typename _Traits> streamsize std::basic_istream< _CharT, _Traits
>::gcount () const [inline], [inherited]
Character counting.
Returns:
The number of characters extracted by the previous unformatted input function
dispatched for this stream.
Definition at line 269 of file istream.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits >::int_type
std::basic_istream< _CharT, _Traits >::get (void) [inherited]
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 244 of file istream.tcc.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::get (char_type & __c) [inherited]
Simple extraction.
Parameters:
__c The character in which to store data.
Returns:
*this
Tries to extract a character and store it in __c. If none are available, sets failbit and
returns traits::eof().
Note:
This function is not overloaded on signed char and unsigned char.
Definition at line 280 of file istream.tcc.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::get (char_type * __s, streamsize __n, char_type
__delim) [inherited]
Simple multiple-character extraction.
Parameters:
__s Pointer to an array.
__n Maximum number of characters to store in __s.
__delim A 'stop' character.
Returns:
*this
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 317 of file istream.tcc.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::get (char_type * __s, streamsize __n) [inline], [inherited]
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('\n')).
Definition at line 354 of file istream.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::get (__streambuf_type & __sb, char_type __delim)
[inherited]
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 364 of file istream.tcc.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::get (__streambuf_type & __sb) [inline], [inherited]
Extraction into another streambuf.
Parameters:
__sb A streambuf in which to store data.
Returns:
*this
Returns get(__sb,widen('\n')).
Definition at line 387 of file istream.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::getline (char_type * __s, streamsize __n, char_type
__delim) [inherited]
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 408 of file istream.tcc.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::getline (char_type * __s, streamsize __n) [inline], [inherited]
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('\n')).
Definition at line 427 of file istream.
template<> basic_istream< char > & std::basic_istream< char >::getline (char_type * __s,
streamsize __n, char_type __delim) [inherited]
Explicit specialization declarations, defined in src/istream.cc.
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 765 of file ios_base.h.
Referenced by std::basic_ios< char, _Traits >::copyfmt(), std::money_put< _CharT, _OutIter
>::do_put(), 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 180 of file basic_ios.h.
Referenced by std::__detail::operator>>(), std::basic_ostream< _CharT, _Traits
>::sentry::sentry(), and std::basic_istream< _CharT, _Traits >::sentry::sentry().
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::ignore (streamsize __n, int_type __delim)
[inherited]
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 563 of file istream.tcc.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::ignore (streamsize __n) [inherited]
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 501 of file istream.tcc.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::ignore (void) [inherited]
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 468 of file istream.tcc.
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
Definition at line 114 of file basic_ios.tcc.
Referenced by std::basic_ios< char, _Traits >::fill().
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 126 of file basic_ios.tcc.
Referenced by std::basic_ios< char, _Traits >::basic_ios().
template<typename _CharT , typename _Traits > bool std::basic_ifstream< _CharT, _Traits
>::is_open () [inline]
Wrapper to test for an open file.
Returns:
rdbuf()->is_open()
Definition at line 607 of file fstream.
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 811 of file ios_base.h.
template<typename _CharT, typename _Traits> char std::basic_ios< _CharT, _Traits >::narrow
(char_type __c, char __dfault) 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 430 of file basic_ios.h.
template<typename _CharT , typename _Traits > void std::basic_ifstream< _CharT, _Traits
>::open (const char * __s, ios_base::openmode __mode = ios_base::in) [inline]
Opens an external file.
Parameters:
__s The name of the file.
__mode The open mode flags.
Calls std::basic_filebuf::open(s,__mode|in). If that function fails, failbit is set in the
stream's error state.
Definition at line 625 of file fstream.
template<typename _CharT , typename _Traits > void std::basic_ifstream< _CharT, _Traits
>::open (const std::string & __s, ios_base::openmode __mode = ios_base::in) [inline]
Opens an external file.
Parameters:
__s The name of the file.
__mode The open mode flags.
Calls std::basic_filebuf::open(__s,__mode|in). If that function fails, failbit is set in
the stream's error state.
Definition at line 645 of file fstream.
template<typename _CharT, typename _Traits> std::basic_ios< _CharT, _Traits >::operator bool
() const [inline], [explicit], [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 117 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 125 of file basic_ios.h.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (__istream_type &(*)(__istream_type &) __pf) [inline], [inherited]
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 120 of file istream.
Referenced by std::ws().
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (__ios_type &(*)(__ios_type &) __pf) [inline], [inherited]
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 124 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (ios_base &(*)(ios_base &) __pf) [inline], [inherited]
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 131 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (bool & __n) [inline], [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 168 of file istream.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::operator>> (short & __n) [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 122 of file istream.tcc.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (unsigned short & __n) [inline], [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 175 of file istream.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::operator>> (int & __n) [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 167 of file istream.tcc.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (unsigned int & __n) [inline], [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 182 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (long & __n) [inline], [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 186 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (unsigned long & __n) [inline], [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 190 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (long long & __n) [inline], [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 195 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (unsigned long long & __n) [inline], [inherited]
Integer arithmetic extractors.
Parameters:
__n A variable of builtin integral type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 199 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (float & __f) [inline], [inherited]
Floating point arithmetic extractors.
Parameters:
__f A variable of builtin floating point type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 214 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (double & __f) [inline], [inherited]
Floating point arithmetic extractors.
Parameters:
__f A variable of builtin floating point type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 218 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (long double & __f) [inline], [inherited]
Floating point arithmetic extractors.
Parameters:
__f A variable of builtin floating point type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 222 of file istream.
template<typename _CharT, typename _Traits> __istream_type& std::basic_istream< _CharT,
_Traits >::operator>> (void *& __p) [inline], [inherited]
Basic arithmetic extractors.
Parameters:
__p A variable of pointer type.
Returns:
*this if successful
These functions use the stream's current locale (specifically, the num_get facet) to parse
the input data.
Definition at line 235 of file istream.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::operator>> (__streambuf_type * __sb) [inherited]
Extracting into another streambuf.
Parameters:
__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 212 of file istream.tcc.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits >::int_type
std::basic_istream< _CharT, _Traits >::peek (void) [inherited]
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 628 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 691 of file ios_base.h.
Referenced by std::basic_ios< char, _Traits >::copyfmt().
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 700 of file ios_base.h.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::putback (char_type __c) [inherited]
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:
This function first clears eofbit. Since no characters are extracted, the next call to
gcount() will return 0, as required by DR 60.
Definition at line 719 of file istream.tcc.
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.
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 832 of file ios_base.h.
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 53 of file basic_ios.tcc.
template<typename _CharT , typename _Traits > __filebuf_type* std::basic_ifstream< _CharT,
_Traits >::rdbuf () const [inline]
Accessing the underlying buffer.
Returns:
The current basic_filebuf buffer.
This hides both signatures of std::basic_ios::rdbuf().
Definition at line 599 of file fstream.
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 137 of file basic_ios.h.
Referenced by std::basic_ios< char, _Traits >::bad(), std::basic_ios< char, _Traits
>::eof(), std::basic_ios< char, _Traits >::fail(), std::basic_ios< char, _Traits
>::good(), std::basic_istream< char >::putback(), std::basic_istream< char >::seekg(),
std::basic_ios< char, _Traits >::setstate(), and std::basic_istream< char >::unget().
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::read (char_type * __s, streamsize __n) [inherited]
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 658 of file istream.tcc.
template<typename _CharT , typename _Traits > streamsize std::basic_istream< _CharT, _Traits
>::readsome (char_type * __s, streamsize __n) [inherited]
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 687 of file istream.tcc.
void std::ios_base::register_callback (event_callback __fn, int __index) [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) [inherited]
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 first clears eofbit. It does not count the number of characters
extracted, if any, and therefore does not affect the next call to gcount().
Definition at line 853 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)
[inherited]
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 first clears eofbit. It does not count the number of characters
extracted, if any, and therefore does not affect the next call to gcount().
Definition at line 892 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 648 of file ios_base.h.
Referenced by std::__detail::operator>>().
fmtflags std::ios_base::setf (fmtflags __fmtfl, fmtflags __mask) [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 665 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 157 of file basic_ios.h.
Referenced by std::operator<<(), std::basic_ostream< _CharT, _Traits >::sentry::sentry(),
and std::ws().
template<typename _CharT , typename _Traits > int std::basic_istream< _CharT, _Traits >::sync
(void) [inherited]
Synchronizing the stream buffer.
Returns:
0 on success, -1 on failure
If rdbuf() is a null pointer, returns -1.
Otherwise, calls rdbuf()->pubsync(), and if that returns -1, sets badbit and returns -1.
Otherwise, returns 0.
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 789 of file istream.tcc.
static bool std::ios_base::sync_with_stdio (bool __sync = true) [static], [inherited]
Interaction with the standard C I/O objects.
Parameters:
__sync Whether to synchronize or not.
Returns:
True if the standard streams were previously synchronized.
The synchronization referred to is only that between the standard C facilities (e.g.,
stdout) and the standard C++ objects (e.g., cout). User-declared streams are unaffected.
See
https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits >::pos_type
std::basic_istream< _CharT, _Traits >::tellg (void) [inherited]
Getting the current read position.
Returns:
A file position object.
If fail() is not false, returns pos_type(-1) to indicate failure. Otherwise returns
rdbuf()->pubseekoff(0,cur,in).
Note:
This function does not count the number of characters extracted, if any, and therefore
does not affect the next call to gcount(). At variance with putback, unget and seekg,
eofbit is not cleared first.
Definition at line 825 of file istream.tcc.
template<typename _CharT, typename _Traits> basic_ostream<_CharT, _Traits>* std::basic_ios<
_CharT, _Traits >::tie () const [inline], [inherited]
Fetches the current tied stream.
Returns:
A pointer to the tied stream, or NULL if the stream is not tied.
A stream may be tied (or synchronized) to a second output stream. When this stream
performs any I/O, the tied stream is first flushed. For example, std::cin is tied to
std::cout.
Definition at line 295 of file basic_ios.h.
Referenced by std::basic_ios< char, _Traits >::basic_ios(), std::basic_ios< char, _Traits
>::copyfmt(), and std::basic_ostream< _CharT, _Traits >::sentry::sentry().
template<typename _CharT, typename _Traits> basic_ostream<_CharT, _Traits>* std::basic_ios<
_CharT, _Traits >::tie (basic_ostream< _CharT, _Traits > * __tiestr) [inline],
[inherited]
Ties this stream to an output stream.
Parameters:
__tiestr The output stream.
Returns:
The previously tied output stream, or NULL if the stream was not tied.
This sets up a new tie; see tie() for more.
Definition at line 307 of file basic_ios.h.
template<typename _CharT , typename _Traits > basic_istream< _CharT, _Traits > &
std::basic_istream< _CharT, _Traits >::unget (void) [inherited]
Unextracting the previous character.
Returns:
*this
If rdbuf() is not null, calls rdbuf()->sungetc(c).
If rdbuf() is null or if sungetc() fails, sets badbit in the error state.
Note:
This function first clears eofbit. Since no characters are extracted, the next call to
gcount() will return 0, as required by DR 60.
Definition at line 754 of file istream.tcc.
Referenced by std::__detail::operator>>().
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 680 of file ios_base.h.
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 449 of file basic_ios.h.
Referenced by std::basic_ios< char, _Traits >::fill(), std::getline(), and
std::tr2::operator>>().
streamsize std::ios_base::width () const [inline], [inherited]
Flags access.
Returns:
The minimum field width to generate on output operations.
Minimum field width refers to the number of characters.
Definition at line 714 of file ios_base.h.
Referenced by std::basic_ios< char, _Traits >::copyfmt(), std::money_get< _CharT, _InIter
>::do_get(), and std::num_put< _CharT, _OutIter >::do_put().
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 723 of file ios_base.h.
static int std::ios_base::xalloc () [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
template<typename _CharT, typename _Traits> streamsize std::basic_istream< _CharT, _Traits
>::_M_gcount [protected], [inherited]
The number of characters extracted in the previous unformatted function; see gcount().
Definition at line 82 of file istream.
Referenced by std::basic_istream< char >::get(), std::basic_istream< char >::getline(),
std::basic_istream< char >::ignore(), std::basic_istream< char >::peek(),
std::basic_istream< char >::putback(), std::basic_istream< char >::read(),
std::basic_istream< char >::readsome(), and std::basic_istream< char >::unget().
const fmtflags std::ios_base::adjustfield [static], [inherited]
A mask of left|right|internal. Useful for the 2-arg form of setf.
Definition at line 378 of file ios_base.h.
Referenced by std::money_get< _CharT, _InIter >::do_get(), and std::num_put< _CharT,
_OutIter >::do_put().
const openmode std::ios_base::app [static], [inherited]
Seek to end before each write.
Definition at line 432 of file ios_base.h.
const openmode std::ios_base::ate [static], [inherited]
Open and seek to end immediately after opening.
Definition at line 435 of file ios_base.h.
const iostate std::ios_base::badbit [static], [inherited]
Indicates a loss of integrity in an input or output sequence (such as an irrecoverable
read error from a file).
Definition at line 402 of file ios_base.h.
Referenced by std::basic_ios< char, _Traits >::bad(), std::basic_ios< char, _Traits
>::fail(), and std::operator<<().
const fmtflags std::ios_base::basefield [static], [inherited]
A mask of dec|oct|hex. Useful for the 2-arg form of setf.
Definition at line 381 of file ios_base.h.
Referenced by std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter
>::do_put(), and std::basic_ostream< char >::operator<<().
const seekdir std::ios_base::beg [static], [inherited]
Request a seek relative to the beginning of the stream.
Definition at line 464 of file ios_base.h.
Referenced by __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >::sync().
const openmode std::ios_base::binary [static], [inherited]
Perform input and output in binary mode (as opposed to text mode). This is probably not
what you think it is; see
https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary.
Definition at line 440 of file ios_base.h.
const fmtflags std::ios_base::boolalpha [static], [inherited]
Insert/extract bool in alphabetic rather than numeric format.
Definition at line 326 of file ios_base.h.
Referenced by std::num_get< _CharT, _InIter >::do_get(), and std::num_put< _CharT,
_OutIter >::do_put().
const seekdir std::ios_base::cur [static], [inherited]
Request a seek relative to the current position within the sequence.
Definition at line 467 of file ios_base.h.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(), and
__gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >::sync().
const fmtflags std::ios_base::dec [static], [inherited]
Converts integer input or generates integer output in decimal base.
Definition at line 329 of file ios_base.h.
const seekdir std::ios_base::end [static], [inherited]
Request a seek relative to the current end of the sequence.
Definition at line 470 of file ios_base.h.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff().
const iostate std::ios_base::eofbit [static], [inherited]
Indicates that an input operation reached the end of an input sequence.
Definition at line 405 of file ios_base.h.
Referenced by std::time_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::basic_ios< char, _Traits >::eof(), std::time_get< _CharT, _InIter
>::get(), std::basic_istream< char >::putback(), std::basic_istream< char >::seekg(),
std::basic_istream< char >::unget(), and std::ws().
const iostate std::ios_base::failbit [static], [inherited]
Indicates that an input operation failed to read the expected characters, or that an
output operation failed to generate the desired characters.
Definition at line 410 of file ios_base.h.
Referenced by std::time_get< _CharT, _InIter >::do_date_order(), std::num_get< _CharT,
_InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get_monthname(), std::time_get<
_CharT, _InIter >::do_get_weekday(), std::time_get< _CharT, _InIter >::do_get_year(),
std::basic_ios< char, _Traits >::fail(), std::time_get< _CharT, _InIter >::get(), and
std::basic_ostream< _CharT, _Traits >::sentry::sentry().
const fmtflags std::ios_base::fixed [static], [inherited]
Generate floating-point output in fixed-point notation.
Definition at line 332 of file ios_base.h.
const fmtflags std::ios_base::floatfield [static], [inherited]
A mask of scientific|fixed. Useful for the 2-arg form of setf.
Definition at line 384 of file ios_base.h.
const iostate std::ios_base::goodbit [static], [inherited]
Indicates all is well.
Definition at line 413 of file ios_base.h.
Referenced by std::time_get< _CharT, _InIter >::do_date_order(), std::time_get< _CharT,
_InIter >::do_get(), std::num_get< _CharT, _InIter >::do_get(), std::time_get< _CharT,
_InIter >::do_get_monthname(), std::time_get< _CharT, _InIter >::do_get_weekday(),
std::time_get< _CharT, _InIter >::do_get_year(), std::basic_ostream< char >::flush(),
std::basic_istream< char >::get(), std::time_get< _CharT, _InIter >::get(),
std::basic_istream< char >::getline(), std::basic_istream< char >::ignore(),
std::basic_ostream< char >::operator<<(), std::basic_istream< char >::operator>>(),
std::operator>>(), std::basic_istream< char >::peek(), std::basic_ostream< char >::put(),
std::basic_istream< char >::putback(), std::basic_ios< char, _Traits >::rdstate(),
std::basic_istream< char >::read(), std::basic_istream< char >::readsome(),
std::basic_istream< char >::seekg(), std::basic_ostream< char >::seekp(),
std::basic_ostream< _CharT, _Traits >::sentry::sentry(), std::basic_istream< _CharT,
_Traits >::sentry::sentry(), std::basic_istream< char >::sync(), and std::basic_istream<
char >::unget().
const fmtflags std::ios_base::hex [static], [inherited]
Converts integer input or generates integer output in hexadecimal base.
Definition at line 335 of file ios_base.h.
Referenced by std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter
>::do_put(), and std::basic_ostream< char >::operator<<().
const openmode std::ios_base::in [static], [inherited]
Open for input. Default for ifstream and fstream.
Definition at line 443 of file ios_base.h.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(),
std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos(), __gnu_cxx::stdio_sync_filebuf<
_CharT, _Traits >::sync(), and std::basic_stringbuf< _CharT, _Traits, _Alloc
>::underflow().
const fmtflags std::ios_base::internal [static], [inherited]
Adds fill characters at a designated internal point in certain generated output, or
identical to right if no such point is designated.
Definition at line 340 of file ios_base.h.
Referenced by std::money_get< _CharT, _InIter >::do_get().
const fmtflags std::ios_base::left [static], [inherited]
Adds fill characters on the right (final positions) of certain generated output. (I.e.,
the thing you print is flush left.)
Definition at line 344 of file ios_base.h.
Referenced by std::money_get< _CharT, _InIter >::do_get(), and std::num_put< _CharT,
_OutIter >::do_put().
const fmtflags std::ios_base::oct [static], [inherited]
Converts integer input or generates integer output in octal base.
Definition at line 347 of file ios_base.h.
Referenced by std::basic_ostream< char >::operator<<().
const openmode std::ios_base::out [static], [inherited]
Open for output. Default for ofstream and fstream.
Definition at line 446 of file ios_base.h.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(),
std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos(), and
__gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >::sync().
const fmtflags std::ios_base::right [static], [inherited]
Adds fill characters on the left (initial positions) of certain generated output. (I.e.,
the thing you print is flush right.)
Definition at line 351 of file ios_base.h.
const fmtflags std::ios_base::scientific [static], [inherited]
Generates floating-point output in scientific notation.
Definition at line 354 of file ios_base.h.
const fmtflags std::ios_base::showbase [static], [inherited]
Generates a prefix indicating the numeric base of generated integer output.
Definition at line 358 of file ios_base.h.
Referenced by std::money_get< _CharT, _InIter >::do_get(), and std::num_put< _CharT,
_OutIter >::do_put().
const fmtflags std::ios_base::showpoint [static], [inherited]
Generates a decimal-point character unconditionally in generated floating-point output.
Definition at line 362 of file ios_base.h.
const fmtflags std::ios_base::showpos [static], [inherited]
Generates a + sign in non-negative generated numeric output.
Definition at line 365 of file ios_base.h.
const fmtflags std::ios_base::skipws [static], [inherited]
Skips leading white space before certain input operations.
Definition at line 368 of file ios_base.h.
const openmode std::ios_base::trunc [static], [inherited]
Truncate an existing stream when opening. Default for ofstream.
Definition at line 449 of file ios_base.h.
const fmtflags std::ios_base::unitbuf [static], [inherited]
Flushes output after each output operation.
Definition at line 371 of file ios_base.h.
const fmtflags std::ios_base::uppercase [static], [inherited]
Replaces certain lowercase letters with their uppercase equivalents in generated output.
Definition at line 375 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put().
Author
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