std::ios_base(3)std::ios_base(3)NAMEstd::ios_base-
The base of the I/O class hierarchy.
This class defines everything that can be defined about I/O that does
not depend on the type of characters being input or output. Most people
will only see ios_base when they need to specify the full name of the
various I/O flags (e.g., the openmodes).
SYNOPSIS
Inherited by std::basic_ios< char, _Traits >, and std::basic_ios<
_CharT, _Traits >.
Classes
class failure
These are thrown to indicate problems with io.
27.4.2.1.1 Class ios_base::failure. "
Public Types
enum event { erase_event, imbue_event, copyfmt_event }
typedef void(* event_callback )(event, ios_base &, int)
typedef _Ios_Fmtflags fmtflags
typedef int io_state
typedef _Ios_Iostate iostate
typedef int open_mode
typedef _Ios_Openmode openmode
typedef int seek_dir
typedef _Ios_Seekdir seekdir
typedef std::streamoff streamoff
typedef std::streampos streampos
Public Member Functions
const locale & _M_getloc () const
fmtflags flags (fmtflags __fmtfl)
fmtflags flags () const
locale getloc () const
locale imbue (const locale &__loc)
long & iword (int __ix)
streamsize precision (streamsize __prec)
streamsize precision () const
void *& pword (int __ix)
void register_callback (event_callback __fn, int __index)
fmtflags setf (fmtflags __fmtfl, fmtflags __mask)
fmtflags setf (fmtflags __fmtfl)
void unsetf (fmtflags __mask)
streamsize width (streamsize __wide)
streamsize width () const
virtual ~ios_base ()
Static Public Member Functions
static bool sync_with_stdio (bool __sync=true)
static int xalloc () throw ()
Static Public Attributes
static const fmtflags adjustfield
static const openmode app
static const openmode ate
static const iostate badbit
static const fmtflags basefield
static const seekdir beg
static const openmode binary
static const fmtflags boolalpha
static const seekdir cur
static const fmtflags dec
static const seekdir end
static const iostate eofbit
static const iostate failbit
static const fmtflags fixed
static const fmtflags floatfield
static const iostate goodbit
static const fmtflags hex
static const openmode in
static const fmtflags internal
static const fmtflags left
static const fmtflags oct
static const openmode out
static const fmtflags right
static const fmtflags scientific
static const fmtflags showbase
static const fmtflags showpoint
static const fmtflags showpos
static const fmtflags skipws
static const openmode trunc
static const fmtflags unitbuf
static const fmtflags uppercase
Protected Types
enum { _S_local_word_size }
Protected Member Functions
void _M_call_callbacks (event __ev) throw ()
void _M_dispose_callbacks (void)
_Words & _M_grow_words (int __index, bool __iword)
void _M_init ()
Protected Attributes
_Callback_list * _M_callbacks
locale _M_ios_locale
_Words _M_local_word [_S_local_word_size]
_Words * _M_word
int _M_word_size
_Words _M_word_zero
iostate _M_exception
fmtflags _M_flags
streamsize _M_precision
iostate _M_streambuf_state
streamsize _M_width
Detailed Description
The base of the I/O class hierarchy.
This class defines everything that can be defined about I/O that does
not depend on the type of characters being input or output. Most people
will only see ios_base when they need to specify the full name of the
various I/O flags (e.g., the openmodes).
Definition at line 207 of file ios_base.h.
Member Typedef Documentation
typedef void(* std::ios_base::event_callback)(event, ios_base &, int)
The type of an event callback function. Parameters:
event One of the members of the event enum.
ios_base Reference to the ios_base object.
int The integer provided when the callback was registered.
Event callbacks are user defined functions that get called during
several ios_base and basic_ios functions, specifically imbue(),
copyfmt(), and ~ios().
Definition at line 444 of file ios_base.h.
typedef _Ios_Fmtflags std::ios_base::fmtflags
This is a bitmask type. '_Ios_Fmtflags' is implementation-defined, but
it is valid to perform bitwise operations on these values and expect
the Right Thing to happen. Defined objects of type fmtflags are:
· boolalpha
· dec
· fixed
· hex
· internal
· left
· oct
· right
· scientific
· showbase
· showpoint
· showpos
· skipws
· unitbuf
· uppercase
· adjustfield
· basefield
· floatfield
Definition at line 263 of file ios_base.h.
typedef _Ios_Iostate std::ios_base::iostate
This is a bitmask type. '_Ios_Iostate' is implementation-defined, but
it is valid to perform bitwise operations on these values and expect
the Right Thing to happen. Defined objects of type iostate are:
· badbit
· eofbit
· failbit
· goodbit
Definition at line 338 of file ios_base.h.
typedef _Ios_Openmode std::ios_base::openmode
This is a bitmask type. '_Ios_Openmode' is implementation-defined, but
it is valid to perform bitwise operations on these values and expect
the Right Thing to happen. Defined objects of type openmode are:
· app
· ate
· binary
· in
· out
· trunc
Definition at line 369 of file ios_base.h.
typedef _Ios_Seekdir std::ios_base::seekdir
This is an enumerated type. '_Ios_Seekdir' is implementation-defined.
Defined values of type seekdir are:
· beg
· cur, equivalent to SEEK_CUR in the C standard library.
· end, equivalent to SEEK_END in the C standard library.
Definition at line 401 of file ios_base.h.
Member Enumeration Documentation
enum std::ios_base::event
The set of events that may be passed to an event callback. erase_event
is used during ~ios() and copyfmt(). imbue_event is used during
imbue(). copyfmt_event is used during copyfmt().
Definition at line 427 of file ios_base.h.
Constructor & Destructor Documentation
virtual std::ios_base::~ios_base () [virtual] Invokes each callback with
erase_event. Destroys local storage.
Note that the ios_base object for the standard streams never gets
destroyed. As a result, any callbacks registered with the standard
streams will not get invoked with erase_event (unless copyfmt is used).
Member Function Documentation
const locale& std::ios_base::_M_getloc () const [inline]
Locale access. Returns:
A reference to the current locale.
Like getloc above, but returns a reference instead of generating a
copy.
Definition at line 710 of file ios_base.h.
Referenced by std::money_get< _CharT, _InIter >::do_get(),
std::num_get< _CharT, _InIter >::do_get(), std::time_get< _CharT,
_InIter >::do_get_date(), std::time_get< _CharT, _InIter
>::do_get_monthname(), std::time_get< _CharT, _InIter >::do_get_time(),
std::time_get< _CharT, _InIter >::do_get_weekday(), std::time_get<
_CharT, _InIter >::do_get_year(), std::time_put< _CharT, _OutIter
>::do_put(), std::num_put< _CharT, _OutIter >::do_put(), and
std::time_put< _CharT, _OutIter >::put().
fmtflags std::ios_base::flags (fmtflags __fmtfl) [inline]
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 566 of file ios_base.h.
fmtflags std::ios_base::flags () const [inline]
Access to format flags. Returns:
The format control flags for both input and output.
Definition at line 555 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(),
std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT,
_OutIter >::do_put(), std::basic_ostream< _CharT, _Traits
>::operator<<(), and std::operator<<().
locale std::ios_base::getloc () const [inline]
Locale access. Returns:
A copy of the current locale.
If imbue(loc) has previously been called, then this function returns
loc. Otherwise, it returns a copy of std::locale(), the global C++
locale.
Definition at line 699 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(),
std::money_put< _CharT, _OutIter >::do_put(), std::basic_ios< _CharT,
_Traits >::imbue(), std::operator>>(), and std::ws().
locale std::ios_base::imbue (const locale & __loc)
Setting a new locale. Parameters:
loc The new locale.
Returns:
The previous locale.
Sets the new locale for this stream, and then invokes each callback
with imbue_event.
Reimplemented in std::basic_ios< _CharT, _Traits >, and std::basic_ios<
char, _Traits >.
long& std::ios_base::iword (int __ix) [inline]
Access to integer array. Parameters:
__ix Index into the array.
Returns:
A reference to an integer associated with the index.
The iword function provides access to an array of integers that can be
used for any purpose. The array grows as required to hold the supplied
index. All integers in the array are initialized to 0.
The implementation reserves several indices. You should use xalloc to
obtain an index that is safe to use. Also note that since the array can
grow dynamically, it is not safe to hold onto the reference.
Definition at line 745 of file ios_base.h.
streamsize std::ios_base::precision (streamsize __prec) [inline]
Changing flags. Parameters:
prec The new precision value.
Returns:
The previous value of precision().
Definition at line 634 of file ios_base.h.
streamsize std::ios_base::precision () const [inline]
Flags access. Returns:
The precision to generate on certain output operations.
Be careful if you try to give a definition of 'precision' here; see DR
189.
Definition at line 625 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), and
std::operator<<().
void*& std::ios_base::pword (int __ix) [inline]
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 766 of file ios_base.h.
void std::ios_base::register_callback (event_callback __fn, int __index)
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, fmtflags __mask) [inline]
Setting new format flags. Parameters:
fmtfl Additional flags to set.
mask The flags mask for fmtfl.
Returns:
The previous format control flags.
This function clears mask in the format flags, then sets fmtfl & mask.
An example mask is ios_base::adjustfield.
Definition at line 599 of file ios_base.h.
fmtflags std::ios_base::setf (fmtflags __fmtfl) [inline]
Setting new format flags. Parameters:
fmtfl Additional flags to set.
Returns:
The previous format control flags.
This function sets additional flags in format control. Flags that were
previously set remain set.
Definition at line 582 of file ios_base.h.
Referenced by std::boolalpha(), std::dec(), std::fixed(), std::hex(),
std::internal(), std::left(), std::oct(), std::right(),
std::scientific(), std::showbase(), std::showpoint(), std::showpos(),
std::skipws(), std::unitbuf(), and std::uppercase().
static bool std::ios_base::sync_with_stdio (bool __sync = true) [static]
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
http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch28s02.html
void std::ios_base::unsetf (fmtflags __mask) [inline]
Clearing format flags. Parameters:
mask The flags to unset.
This function clears mask in the format flags.
Definition at line 614 of file ios_base.h.
Referenced by std::noboolalpha(), std::noshowbase(),
std::noshowpoint(), std::noshowpos(), std::noskipws(),
std::nounitbuf(), and std::nouppercase().
streamsize std::ios_base::width (streamsize __wide) [inline]
Changing flags. Parameters:
wide The new width value.
Returns:
The previous value of width().
Definition at line 657 of file ios_base.h.
streamsize std::ios_base::width () const [inline]
Flags access. Returns:
The minimum field width to generate on output operations.
Definition at line 648 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(),
std::num_put< _CharT, _OutIter >::do_put(), and std::operator>>().
static int std::ios_base::xalloc () throw () [static]
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
iostate std::ios_base::_M_exception [protected] ios_base data members (doc
me)
Definition at line 467 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::init().
fmtflags std::ios_base::_M_flags [protected] ios_base data members (doc me)
Definition at line 466 of file ios_base.h.
streamsize std::ios_base::_M_precision [protected] ios_base data members
(doc me)
Definition at line 464 of file ios_base.h.
iostate std::ios_base::_M_streambuf_state [protected] ios_base data members
(doc me)
Definition at line 468 of file ios_base.h.
Referenced by std::basic_ios< _CharT, _Traits >::init().
streamsize std::ios_base::_M_width [protected] ios_base data members (doc
me)
Definition at line 465 of file ios_base.h.
const fmtflags std::ios_base::adjustfield [static]
A mask of left|right|internal. Useful for the 2-arg form of setf.
Definition at line 318 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put().
const openmode std::ios_base::app [static]
Seek to end before each write.
Definition at line 372 of file ios_base.h.
const openmode std::ios_base::ate [static]
Open and seek to end immediately after opening.
Definition at line 375 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::open().
const iostate std::ios_base::badbit [static]
Indicates a loss of integrity in an input or output sequence (such as
an irrecoverable read error from a file).
Definition at line 342 of file ios_base.h.
Referenced by std::basic_ostream< _CharT, _Traits >::flush(),
std::basic_istream< _CharT, _Traits >::get(), std::basic_istream<
_CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits
>::ignore(), std::basic_ios< _CharT, _Traits >::init(),
std::operator<<(), std::basic_ostream< _CharT, _Traits >::operator<<(),
std::operator>>(), std::basic_istream< _CharT, _Traits >::peek(),
std::basic_ostream< _CharT, _Traits >::put(), std::basic_istream<
_CharT, _Traits >::putback(), std::basic_istream< _CharT, _Traits
>::read(), std::basic_istream< _CharT, _Traits >::readsome(),
std::basic_istream< _CharT, _Traits >::seekg(), std::basic_ostream<
_CharT, _Traits >::seekp(), std::basic_istream< _CharT, _Traits
>::sync(), std::basic_istream< _CharT, _Traits >::tellg(),
std::basic_ostream< _CharT, _Traits >::tellp(), std::basic_istream<
_CharT, _Traits >::unget(), and std::basic_ostream< _CharT, _Traits
>::write().
const fmtflags std::ios_base::basefield [static]
A mask of dec|oct|hex. Useful for the 2-arg form of setf.
Definition at line 321 of file ios_base.h.
Referenced by std::num_get< _CharT, _InIter >::do_get(), and
std::basic_ostream< _CharT, _Traits >::operator<<().
const seekdir std::ios_base::beg [static]
Request a seek relative to the beginning of the stream.
Definition at line 404 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::seekpos().
const openmode std::ios_base::binary [static]
Perform input and output in binary mode (as opposed to text mode). This
is probably not what you think it is; see
http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch27s02.html.
Definition at line 380 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::showmanyc().
const fmtflags std::ios_base::boolalpha [static]
Insert/extract bool in alphabetic rather than numeric format.
Definition at line 266 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]
Request a seek relative to the current position within the sequence.
Definition at line 407 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::imbue(),
std::basic_filebuf< _CharT, _Traits >::pbackfail(),
std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(),
std::basic_filebuf< _CharT, _Traits >::seekoff(), std::basic_istream<
_CharT, _Traits >::tellg(), and std::basic_ostream< _CharT, _Traits
>::tellp().
const fmtflags std::ios_base::dec [static]
Converts integer input or generates integer output in decimal base.
Definition at line 269 of file ios_base.h.
const seekdir std::ios_base::end [static]
Request a seek relative to the current end of the sequence.
Definition at line 410 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]
Indicates that an input operation reached the end of an input sequence.
Definition at line 345 of file ios_base.h.
Referenced by 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_istream< _CharT, _Traits
>::get(), std::basic_istream< _CharT, _Traits >::getline(),
std::basic_istream< _CharT, _Traits >::ignore(), std::operator>>(),
std::basic_istream< _CharT, _Traits >::operator>>(),
std::basic_istream< _CharT, _Traits >::peek(), std::basic_istream<
_CharT, _Traits >::read(), std::basic_istream< _CharT, _Traits
>::readsome(), and std::ws().
const iostate std::ios_base::failbit [static]
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 350 of file ios_base.h.
Referenced by 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_istream< _CharT, _Traits >::get(), std::basic_istream<
_CharT, _Traits >::getline(), std::basic_ostream< _CharT, _Traits
>::operator<<(), std::basic_istream< _CharT, _Traits >::operator>>(),
std::operator>>(), std::basic_istream< _CharT, _Traits >::read(),
std::basic_istream< _CharT, _Traits >::seekg(), and std::basic_ostream<
_CharT, _Traits >::seekp().
const fmtflags std::ios_base::fixed [static]
Generate floating-point output in fixed-point notation.
Definition at line 272 of file ios_base.h.
const fmtflags std::ios_base::floatfield [static]
A mask of scientific|fixed. Useful for the 2-arg form of setf.
Definition at line 324 of file ios_base.h.
const iostate std::ios_base::goodbit [static]
Indicates all is well.
Definition at line 353 of file ios_base.h.
Referenced by std::num_get< _CharT, _InIter >::do_get(), std::time_get<
_CharT, _InIter >::do_get_monthname(), std::time_get< _CharT, _InIter
>::do_get_weekday(), std::basic_ostream< _CharT, _Traits >::flush(),
std::basic_istream< _CharT, _Traits >::get(), std::basic_istream<
_CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits
>::ignore(), std::basic_ios< _CharT, _Traits >::init(),
std::basic_ostream< _CharT, _Traits >::operator<<(), std::operator>>(),
std::basic_istream< _CharT, _Traits >::operator>>(),
std::basic_istream< _CharT, _Traits >::peek(), std::basic_ostream<
_CharT, _Traits >::put(), std::basic_istream< _CharT, _Traits
>::putback(), std::basic_istream< _CharT, _Traits >::read(),
std::basic_istream< _CharT, _Traits >::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]
Converts integer input or generates integer output in hexadecimal base.
Definition at line 275 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< _CharT, _Traits
>::operator<<().
const openmode std::ios_base::in [static]
Open for input. Default for ifstream and fstream.
Definition at line 383 of file ios_base.h.
Referenced by std::basic_filebuf< _CharT, _Traits >::pbackfail(),
std::basic_istream< _CharT, _Traits >::seekg(), std::basic_stringbuf<
_CharT, _Traits, _Alloc >::seekoff(), std::basic_stringbuf< _CharT,
_Traits, _Alloc >::seekpos(), std::basic_filebuf< _CharT, _Traits
>::showmanyc(), std::basic_istream< _CharT, _Traits >::tellg(),
std::basic_stringbuf< _CharT, _Traits, _Alloc >::underflow(),
std::basic_filebuf< _CharT, _Traits >::underflow(), and
std::basic_filebuf< _CharT, _Traits >::xsgetn().
const fmtflags std::ios_base::internal [static]
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 280 of file ios_base.h.
const fmtflags std::ios_base::left [static]
Adds fill characters on the right (final positions) of certain
generated output. (I.e., the thing you print is flush left.).
Definition at line 284 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put().
const fmtflags std::ios_base::oct [static]
Converts integer input or generates integer output in octal base.
Definition at line 287 of file ios_base.h.
Referenced by std::basic_ostream< _CharT, _Traits >::operator<<().
const openmode std::ios_base::out [static]
Open for output. Default for ofstream and fstream.
Definition at line 386 of file ios_base.h.
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc
>::overflow(), std::basic_filebuf< _CharT, _Traits >::overflow(),
std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(),
std::basic_ostream< _CharT, _Traits >::seekp(), std::basic_stringbuf<
_CharT, _Traits, _Alloc >::seekpos(), std::basic_ostream< _CharT,
_Traits >::tellp(), and std::basic_filebuf< _CharT, _Traits
>::xsputn().
const fmtflags std::ios_base::right [static]
Adds fill characters on the left (initial positions) of certain
generated output. (I.e., the thing you print is flush right.).
Definition at line 291 of file ios_base.h.
const fmtflags std::ios_base::scientific [static]
Generates floating-point output in scientific notation.
Definition at line 294 of file ios_base.h.
const fmtflags std::ios_base::showbase [static]
Generates a prefix indicating the numeric base of generated integer
output.
Definition at line 298 of file ios_base.h.
const fmtflags std::ios_base::showpoint [static]
Generates a decimal-point character unconditionally in generated
floating-point output.
Definition at line 302 of file ios_base.h.
const fmtflags std::ios_base::showpos [static]
Generates a + sign in non-negative generated numeric output.
Definition at line 305 of file ios_base.h.
const fmtflags std::ios_base::skipws [static]
Skips leading white space before certain input operations.
Definition at line 308 of file ios_base.h.
const openmode std::ios_base::trunc [static]
Open for input. Default for ofstream.
Definition at line 389 of file ios_base.h.
const fmtflags std::ios_base::unitbuf [static]
Flushes output after each output operation.
Definition at line 311 of file ios_base.h.
const fmtflags std::ios_base::uppercase [static]
Replaces certain lowercase letters with their uppercase equivalents in
generated output.
Definition at line 315 of file ios_base.h.
Referenced by std::num_put< _CharT, _OutIter >::do_put().
Author
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libstdc++ 22 Nov 2013 std::ios_base(3)
