Provided by: libstdc++-10-doc_10.4.0-5ubuntu2_all 
NAME
std::basic_ios< _CharT, _Traits > - Template class basic_ios, virtual base class for all
stream classes.
SYNOPSIS
Inherits std::ios_base.
Inherited by std::basic_istream< _CharT, _Traits > [virtual], and std::basic_ostream<
_CharT, _Traits > [virtual].
Public Types
typedef int io_state _GLIBCXX_DEPRECATED_SUGGEST('std::iostate')
typedef int open_mode _GLIBCXX_DEPRECATED_SUGGEST('std::openmode')
typedef int seek_dir _GLIBCXX_DEPRECATED_SUGGEST('std::seekdir')
typedef std::streamoff streamoff _GLIBCXX_DEPRECATED_SUGGEST('std::streamoff')
typedef std::streampos streampos _GLIBCXX_DEPRECATED_SUGGEST('std::streampos')
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 _Ios_Iostate iostate
This is a bitmask type.
typedef _Ios_Openmode openmode
This is a bitmask type.
typedef _Ios_Seekdir seekdir
This is an enumerated type.
typedef _CharT char_type
typedef _Traits::int_type int_type
typedef _Traits::pos_type pos_type
typedef _Traits::off_type off_type
typedef _Traits traits_type
typedef ctype< _CharT > __ctype_type
typedef num_put< _CharT, ostreambuf_iterator< _CharT, _Traits > > __num_put_type
typedef num_get< _CharT, istreambuf_iterator< _CharT, _Traits > > __num_get_type
Public Member Functions
basic_ios (basic_streambuf< _CharT, _Traits > *__sb)
Constructor performs initialization.
virtual ~basic_ios ()
Empty.
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.
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.
locale getloc () const
Locale access.
bool good () const
Fast error checking.
locale imbue (const locale &__loc)
Moves to a new locale.
long & iword (int __ix)
Access to integer array.
char narrow (char_type __c, char __dfault) const
Squeezes characters.
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 () const
Accessing the underlying buffer.
basic_streambuf< _CharT, _Traits > * rdbuf (basic_streambuf< _CharT, _Traits > *__sb)
Changing 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.
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.
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
basic_ios ()
Empty.
basic_ios (const basic_ios &)=delete
void _M_cache_locale (const locale &__loc)
void _M_call_callbacks (event __ev) throw ()
void _M_dispose_callbacks (void) throw ()
_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)
basic_ios & operator= (const basic_ios &)=delete
void set_rdbuf (basic_streambuf< _CharT, _Traits > *__sb)
void swap (basic_ios &__rhs) noexcept
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
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_ios< _CharT, _Traits >" Template class basic_ios, virtual base class for
all stream classes.
Template Parameters
_CharT Type of character stream.
_Traits Traits for character type, defaults to char_traits<_CharT>.
Most of the member functions called dispatched on stream objects (e.g.,
std::cout.foo(bar);) are consolidated in this class.
Definition at line 67 of file basic_ios.h.
Member Typedef Documentation
template<typename _CharT , typename _Traits > typedef ctype<_CharT> std::basic_ios< _CharT,
_Traits >::__ctype_type
These are non-standard types.
Definition at line 87 of file basic_ios.h.
template<typename _CharT , typename _Traits > typedef num_get<_CharT,
istreambuf_iterator<_CharT, _Traits> > std::basic_ios< _CharT, _Traits >::__num_get_type
These are non-standard types.
Definition at line 91 of file basic_ios.h.
template<typename _CharT , typename _Traits > typedef num_put<_CharT,
ostreambuf_iterator<_CharT, _Traits> > std::basic_ios< _CharT, _Traits >::__num_put_type
These are non-standard types.
Definition at line 89 of file basic_ios.h.
template<typename _CharT , typename _Traits > typedef _CharT std::basic_ios< _CharT, _Traits
>::char_type
These are standard types. They permit a standardized way of referring to names of (or
names dependent on) the template parameters, which are specific to the implementation.
Definition at line 76 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 529 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 341 of file ios_base.h.
template<typename _CharT , typename _Traits > typedef _Traits::int_type std::basic_ios<
_CharT, _Traits >::int_type
These are standard types. They permit a standardized way of referring to names of (or
names dependent on) the template parameters, which are specific to the implementation.
Definition at line 77 of file basic_ios.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 416 of file ios_base.h.
template<typename _CharT , typename _Traits > typedef _Traits::off_type std::basic_ios<
_CharT, _Traits >::off_type
These are standard types. They permit a standardized way of referring to names of (or
names dependent on) the template parameters, which are specific to the implementation.
Definition at line 79 of file basic_ios.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 447 of file ios_base.h.
template<typename _CharT , typename _Traits > typedef _Traits::pos_type std::basic_ios<
_CharT, _Traits >::pos_type
These are standard types. They permit a standardized way of referring to names of (or
names dependent on) the template parameters, which are specific to the implementation.
Definition at line 78 of file basic_ios.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 479 of file ios_base.h.
template<typename _CharT , typename _Traits > typedef _Traits std::basic_ios< _CharT, _Traits
>::traits_type
These are standard types. They permit a standardized way of referring to names of (or
names dependent on) the template parameters, which are specific to the implementation.
Definition at line 80 of file basic_ios.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 512 of file ios_base.h.
Constructor & Destructor Documentation
template<typename _CharT , typename _Traits > std::basic_ios< _CharT, _Traits >::basic_ios
(basic_streambuf< _CharT, _Traits > * __sb) [inline], [explicit]
Constructor performs initialization. The parameter is passed by derived streams.
Definition at line 270 of file basic_ios.h.
References std::basic_ios< _CharT, _Traits >::init().
template<typename _CharT , typename _Traits > virtual std::basic_ios< _CharT, _Traits
>::~basic_ios () [inline], [virtual]
Empty. The destructor does nothing. More specifically, it does not destroy the streambuf
held by rdbuf().
Definition at line 282 of file basic_ios.h.
template<typename _CharT , typename _Traits > std::basic_ios< _CharT, _Traits >::basic_ios ()
[inline], [protected]
Empty. The default constructor does nothing and is not normally accessible to users.
Definition at line 460 of file basic_ios.h.
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 804 of file ios_base.h.
Referenced by std::money_get< _CharT, _InIter >::do_get(), 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::num_put< _CharT, _OutIter >::do_put(), std::time_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]
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.
References std::ios_base::badbit, and std::basic_ios< _CharT, _Traits >::rdstate().
template<typename _CharT , typename _Traits > void std::basic_ios< _CharT, _Traits >::clear
(iostate __state = goodbit)
[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< _CharT, _Traits >::exceptions(),
std::__detail::operator>>(), std::basic_istream< _CharT, _Traits >::seekg(),
std::basic_ios< _CharT, _Traits >::setstate(), and std::basic_istream< _CharT, _Traits
>::unget().
template<typename _CharT , typename _Traits > basic_ios< _CharT, _Traits > & std::basic_ios<
_CharT, _Traits >::copyfmt (const basic_ios< _CharT, _Traits > & __rhs)
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.
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(), std::tie(), and
std::ios_base::width().
template<typename _CharT , typename _Traits > bool std::basic_ios< _CharT, _Traits >::eof ()
const [inline]
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.
References std::ios_base::eofbit, and std::basic_ios< _CharT, _Traits >::rdstate().
template<typename _CharT , typename _Traits > iostate std::basic_ios< _CharT, _Traits
>::exceptions () const [inline]
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< _CharT, _Traits >::copyfmt().
template<typename _CharT , typename _Traits > void std::basic_ios< _CharT, _Traits
>::exceptions (iostate __except) [inline]
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.
References std::basic_ios< _CharT, _Traits >::clear().
template<typename _CharT , typename _Traits > bool std::basic_ios< _CharT, _Traits >::fail ()
const [inline]
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.
References std::ios_base::badbit, std::ios_base::failbit, and std::basic_ios< _CharT,
_Traits >::rdstate().
Referenced by std::basic_ios< _CharT, _Traits >::operator bool(), and std::basic_ios<
_CharT, _Traits >::operator!().
template<typename _CharT , typename _Traits > char_type std::basic_ios< _CharT, _Traits
>::fill () const [inline]
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.
References std::basic_ios< _CharT, _Traits >::widen().
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), and std::basic_ios< _CharT,
_Traits >::fill().
template<typename _CharT , typename _Traits > char_type std::basic_ios< _CharT, _Traits
>::fill (char_type __ch) [inline]
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.
References std::basic_ios< _CharT, _Traits >::fill().
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 649 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(), std::operator<<(),
std::operator>>(), and std::__detail::operator>>().
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 660 of file ios_base.h.
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 793 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _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]
Fast error checking.
Returns
True if no error flags are set.
A wrapper around rdstate.
Definition at line 180 of file basic_ios.h.
References std::basic_ios< _CharT, _Traits >::rdstate().
Referenced by std::basic_istream< _CharT, _Traits >::sentry::sentry(), std::basic_ostream<
_CharT, _Traits >::sentry::sentry(), and std::__detail::operator>>().
template<typename _CharT , typename _Traits > locale std::basic_ios< _CharT, _Traits >::imbue
(const locale & __loc)
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.
References std::ios_base::imbue().
template<typename _CharT , typename _Traits > void std::basic_ios< _CharT, _Traits >::init
(basic_streambuf< _CharT, _Traits > * __sb) [protected]
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< _CharT, _Traits >::basic_ios().
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 839 of file ios_base.h.
template<typename _CharT , typename _Traits > char std::basic_ios< _CharT, _Traits >::narrow
(char_type __c, char __dfault) const [inline]
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 > std::basic_ios< _CharT, _Traits >::operator bool
() const [inline], [explicit]
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.
References std::basic_ios< _CharT, _Traits >::fail().
template<typename _CharT , typename _Traits > bool std::basic_ios< _CharT, _Traits
>::operator! () const [inline]
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.
References std::basic_ios< _CharT, _Traits >::fail().
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 719 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _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 728 of file ios_base.h.
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 860 of file ios_base.h.
template<typename _CharT , typename _Traits > basic_streambuf<_CharT, _Traits>*
std::basic_ios< _CharT, _Traits >::rdbuf () const [inline]
Accessing the underlying buffer.
Returns
The current stream buffer.
This does not change the state of the stream.
Definition at line 321 of file basic_ios.h.
Referenced by std::basic_istream< char >::getline(), std::basic_istream< char >::tellg(),
and std::ws().
template<typename _CharT , typename _Traits > basic_streambuf< _CharT, _Traits > *
std::basic_ios< _CharT, _Traits >::rdbuf (basic_streambuf< _CharT, _Traits > * __sb)
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 > iostate std::basic_ios< _CharT, _Traits
>::rdstate () const [inline]
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< _CharT, _Traits >::bad(), std::basic_ios< _CharT, _Traits
>::eof(), std::basic_ios< _CharT, _Traits >::fail(), std::basic_ios< _CharT, _Traits
>::good(), std::basic_istream< _CharT, _Traits >::seekg(), std::basic_ios< _CharT, _Traits
>::setstate(), and std::basic_istream< _CharT, _Traits >::unget().
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.
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 676 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 693 of file ios_base.h.
template<typename _CharT , typename _Traits > void std::basic_ios< _CharT, _Traits >::setstate
(iostate __state) [inline]
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.
References std::basic_ios< _CharT, _Traits >::clear(), and std::basic_ios< _CharT, _Traits
>::rdstate().
Referenced by std::basic_ostream< _CharT, _Traits >::sentry::sentry(), and std::ws().
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_ostream<_CharT, _Traits>* std::basic_ios<
_CharT, _Traits >::tie () const [inline]
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_ostream< _CharT, _Traits >::sentry::sentry(), and std::basic_ios<
_CharT, _Traits >::copyfmt().
template<typename _CharT , typename _Traits > basic_ostream<_CharT, _Traits>* std::basic_ios<
_CharT, _Traits >::tie (basic_ostream< _CharT, _Traits > * __tiestr) [inline]
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.
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 708 of file ios_base.h.
template<typename _CharT , typename _Traits > char_type std::basic_ios< _CharT, _Traits
>::widen (char __c) const [inline]
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< _CharT, _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 742 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), 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 751 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
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 396 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put(), std::internal(), std::left(),
and std::right().
const openmode std::ios_base::app [static], [inherited]
Seek to end before each write.
Definition at line 450 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::overflow(), and std::basic_filebuf<
_CharT, _Traits >::xsputn().
const openmode std::ios_base::ate [static], [inherited]
Open and seek to end immediately after opening.
Definition at line 453 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::open().
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 420 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::bad(), std::basic_ios< _CharT, _Traits
>::fail(), std::basic_istream< char >::get(), and std::basic_istream< char >::read().
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 399 of file ios_base.h.
Referenced by std::dec(), std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT,
_OutIter >::do_put(), std::hex(), and std::oct().
const seekdir std::ios_base::beg [static], [inherited]
Request a seek relative to the beginning of the stream.
Definition at line 482 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::seekpos(), and
__gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >::seekpos().
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 458 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 344 of file ios_base.h.
Referenced by std::boolalpha(), std::num_get< _CharT, _InIter >::do_get(), std::num_put<
_CharT, _OutIter >::do_put(), and std::noboolalpha().
const seekdir std::ios_base::cur [static], [inherited]
Request a seek relative to the current position within the sequence.
Definition at line 485 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::imbue(), std::basic_filebuf< _CharT,
_Traits >::overflow(), std::basic_filebuf< _CharT, _Traits >::pbackfail(),
std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_stringbuf< _CharT,
_Traits, _Alloc >::seekoff().
const fmtflags std::ios_base::dec [static], [inherited]
Converts integer input or generates integer output in decimal base.
Definition at line 347 of file ios_base.h.
Referenced by std::dec().
const seekdir std::ios_base::end [static], [inherited]
Request a seek relative to the current end of the sequence.
Definition at line 488 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::open(), and 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 423 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< _CharT, _Traits >::eof(), std::time_get< _CharT, _InIter
>::get(), std::basic_istream< char >::getline(), std::basic_istream< _CharT, _Traits
>::seekg(), std::basic_istream< _CharT, _Traits >::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 428 of file ios_base.h.
Referenced by std::basic_ostream< _CharT, _Traits >::sentry::sentry(), 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< _CharT, _Traits >::fail(), std::time_get< _CharT,
_InIter >::get(), std::basic_istream< char >::getline(), and std::basic_istream< char
>::operator>>().
const fmtflags std::ios_base::fixed [static], [inherited]
Generate floating-point output in fixed-point notation.
Definition at line 350 of file ios_base.h.
Referenced by std::fixed(), and std::hexfloat().
const fmtflags std::ios_base::floatfield [static], [inherited]
A mask of scientific|fixed. Useful for the 2-arg form of setf.
Definition at line 402 of file ios_base.h.
Referenced by std::defaultfloat(), std::fixed(), std::hexfloat(), and std::scientific().
const iostate std::ios_base::goodbit [static], [inherited]
Indicates all is well.
Definition at line 431 of file ios_base.h.
Referenced by std::basic_istream< _CharT, _Traits >::sentry::sentry(), 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< _CharT, _Traits
>::flush(), std::basic_istream< _CharT, _Traits >::get(), std::time_get< _CharT, _InIter
>::get(), std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT,
_Traits >::ignore(), std::basic_ostream< _CharT, _Traits >::operator<<(),
std::operator>>(), std::basic_istream< _CharT, _Traits >::operator>>(),
std::basic_istream< char >::operator>>(), std::basic_istream< _CharT, _Traits >::peek(),
std::basic_istream< char >::peek(), std::basic_ostream< _CharT, _Traits >::put(),
std::basic_istream< _CharT, _Traits >::read(), std::basic_istream< _CharT, _Traits
>::readsome(), std::basic_istream< char >::readsome(), std::basic_istream< _CharT, _Traits
>::seekg(), std::basic_ostream< _CharT, _Traits >::seekp(), std::basic_istream< _CharT,
_Traits >::sync(), and std::basic_istream< _CharT, _Traits >::unget().
const fmtflags std::ios_base::hex [static], [inherited]
Converts integer input or generates integer output in hexadecimal base.
Definition at line 353 of file ios_base.h.
Referenced by std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter
>::do_put(), and std::hex().
const openmode std::ios_base::in [static], [inherited]
Open for input. Default for ifstream and fstream.
Definition at line 461 of file ios_base.h.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::overflow(),
std::basic_filebuf< _CharT, _Traits >::pbackfail(), std::basic_stringbuf< _CharT, _Traits,
_Alloc >::seekoff(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos(),
std::basic_filebuf< _CharT, _Traits >::showmanyc(), std::basic_filebuf< _CharT, _Traits
>::underflow(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::underflow(), and
std::basic_filebuf< _CharT, _Traits >::xsgetn().
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 358 of file ios_base.h.
Referenced by std::internal().
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 362 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put(), and std::left().
const fmtflags std::ios_base::oct [static], [inherited]
Converts integer input or generates integer output in octal base.
Definition at line 365 of file ios_base.h.
Referenced by std::oct().
const openmode std::ios_base::out [static], [inherited]
Open for output. Default for ofstream and fstream.
Definition at line 464 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::overflow(), std::basic_stringbuf<
_CharT, _Traits, _Alloc >::overflow(), std::basic_stringbuf< _CharT, _Traits, _Alloc
>::pbackfail(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(),
std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos(), and std::basic_filebuf<
_CharT, _Traits >::xsputn().
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 369 of file ios_base.h.
Referenced by std::right().
const fmtflags std::ios_base::scientific [static], [inherited]
Generates floating-point output in scientific notation.
Definition at line 372 of file ios_base.h.
Referenced by std::hexfloat(), and std::scientific().
const fmtflags std::ios_base::showbase [static], [inherited]
Generates a prefix indicating the numeric base of generated integer output.
Definition at line 376 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put(), std::noshowbase(), and
std::showbase().
const fmtflags std::ios_base::showpoint [static], [inherited]
Generates a decimal-point character unconditionally in generated floating-point output.
Definition at line 380 of file ios_base.h.
Referenced by std::noshowpoint(), and std::showpoint().
const fmtflags std::ios_base::showpos [static], [inherited]
Generates a + sign in non-negative generated numeric output.
Definition at line 383 of file ios_base.h.
Referenced by std::noshowpos(), and std::showpos().
const fmtflags std::ios_base::skipws [static], [inherited]
Skips leading white space before certain input operations.
Definition at line 386 of file ios_base.h.
Referenced by std::noskipws(), std::__detail::operator>>(), and std::skipws().
const openmode std::ios_base::trunc [static], [inherited]
Truncate an existing stream when opening. Default for ofstream.
Definition at line 467 of file ios_base.h.
const fmtflags std::ios_base::unitbuf [static], [inherited]
Flushes output after each output operation.
Definition at line 389 of file ios_base.h.
Referenced by std::nounitbuf(), and std::unitbuf().
const fmtflags std::ios_base::uppercase [static], [inherited]
Replaces certain lowercase letters with their uppercase equivalents in generated output.
Definition at line 393 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put(), std::nouppercase(), and
std::uppercase().
Author
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