libstdc++
std::ios_base Class Reference
Inheritance diagram for std::ios_base:

List of all members.

Classes

class  failure
 These are thrown to indicate problems with io.27.4.2.1.1 Class ios_base::failure. More...

Public Types

enum  event { erase_event, imbue_event, copyfmt_event }
typedef void(* event_callback )(event __e, ios_base &__b, int __i)
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

virtual ~ios_base ()
const locale_M_getloc () const
fmtflags flags () const
fmtflags flags (fmtflags __fmtfl)
locale getloc () const
locale imbue (const locale &__loc) throw ()
long & iword (int __ix)
streamsize precision () const
streamsize precision (streamsize __prec)
void *& pword (int __ix)
void register_callback (event_callback __fn, int __index)
fmtflags setf (fmtflags __fmtfl)
fmtflags setf (fmtflags __fmtfl, fmtflags __mask)
void unsetf (fmtflags __mask)
streamsize width () const
streamsize width (streamsize __wide)

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) throw ()
_Words & _M_grow_words (int __index, bool __iword)
void _M_init () throw ()

Protected Attributes

_Callback_list * _M_callbacks
iostate _M_exception
fmtflags _M_flags
locale _M_ios_locale
_Words _M_local_word [_S_local_word_size]
streamsize _M_precision
iostate _M_streambuf_state
streamsize _M_width
_Words * _M_word
int _M_word_size
_Words _M_word_zero

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 201 of file ios_base.h.


Member Typedef Documentation

typedef void(* std::ios_base::event_callback)(event __e, ios_base &__b, int __i)

The type of an event callback function.

Parameters:
__eOne of the members of the event enum.
__bReference to the ios_base object.
__iThe 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 438 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 257 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 332 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 363 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 395 of file ios_base.h.


Member Enumeration Documentation

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 421 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

fmtflags std::ios_base::flags ( fmtflags  __fmtfl)
inline

Setting new format flags all at once.

Parameters:
__fmtflThe new flags to set.
Returns:
The previous format control flags.

This function overwrites all the format flags with __fmtfl.

Definition at line 564 of file ios_base.h.

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 697 of file ios_base.h.

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

locale std::ios_base::imbue ( const locale __loc) throw ()

Setting a new locale.

Parameters:
__locThe 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 >.

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

long& std::ios_base::iword ( int  __ix)
inline

Access to integer array.

Parameters:
__ixIndex 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 743 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 623 of file ios_base.h.

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

streamsize std::ios_base::precision ( streamsize  __prec)
inline

Changing flags.

Parameters:
__precThe new precision value.
Returns:
The previous value of precision().

Definition at line 632 of file ios_base.h.

void*& std::ios_base::pword ( int  __ix)
inline

Access to void pointer array.

Parameters:
__ixIndex 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 764 of file ios_base.h.

void std::ios_base::register_callback ( event_callback  __fn,
int  __index 
)

Add the callback __fn with parameter __index.

Parameters:
__fnThe function to add.
__indexThe 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

Setting new format flags.

Parameters:
__fmtflAdditional 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 580 of file ios_base.h.

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

fmtflags std::ios_base::setf ( fmtflags  __fmtfl,
fmtflags  __mask 
)
inline

Setting new format flags.

Parameters:
__fmtflAdditional flags to set.
__maskThe 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 597 of file ios_base.h.

static bool std::ios_base::sync_with_stdio ( bool  __sync = true)
static

Interaction with the standard C I/O objects.

Parameters:
__syncWhether 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:
__maskThe flags to unset.

This function clears __mask in the format flags.

Definition at line 612 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 ( ) const
inline

Flags access.

Returns:
The minimum field width to generate on output operations.

Minimum field width refers to the number of characters.

Definition at line 646 of file ios_base.h.

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

streamsize std::ios_base::width ( streamsize  __wide)
inline

Changing flags.

Parameters:
__wideThe new width value.
Returns:
The previous value of width().

Definition at line 655 of file ios_base.h.

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

const fmtflags std::ios_base::adjustfield
static

A mask of left|right|internal. Useful for the 2-arg form of setf.

Definition at line 312 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

Seek to end before each write.

Definition at line 366 of file ios_base.h.

const openmode std::ios_base::ate
static

Open and seek to end immediately after opening.

Definition at line 369 of file ios_base.h.

Referenced by std::basic_filebuf< _CharT, _Traits >::open().

const fmtflags std::ios_base::basefield
static

A mask of dec|oct|hex. Useful for the 2-arg form of setf.

Definition at line 315 of file ios_base.h.

Referenced by std::dec(), std::num_get< _CharT, _InIter >::do_get(), std::hex(), std::oct(), 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 398 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 374 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 260 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 fmtflags std::ios_base::dec
static

Converts integer input or generates integer output in decimal base.

Definition at line 263 of file ios_base.h.

Referenced by std::dec().

const seekdir std::ios_base::end
static

Request a seek relative to the current end of the sequence.

Definition at line 404 of file ios_base.h.

Referenced by std::basic_filebuf< _CharT, _Traits >::open(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff().

const fmtflags std::ios_base::fixed
static

Generate floating-point output in fixed-point notation.

Definition at line 266 of file ios_base.h.

Referenced by std::fixed().

const fmtflags std::ios_base::floatfield
static

A mask of scientific|fixed. Useful for the 2-arg form of setf.

Definition at line 318 of file ios_base.h.

Referenced by std::fixed(), and std::scientific().

const fmtflags std::ios_base::hex
static

Converts integer input or generates integer output in hexadecimal base.

Definition at line 269 of file ios_base.h.

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

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 274 of file ios_base.h.

Referenced by std::internal().

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 278 of file ios_base.h.

Referenced by std::num_put< _CharT, _OutIter >::do_put(), and std::left().

const fmtflags std::ios_base::oct
static

Converts integer input or generates integer output in octal base.

Definition at line 281 of file ios_base.h.

Referenced by std::oct(), and std::basic_ostream< _CharT, _Traits >::operator<<().

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 285 of file ios_base.h.

Referenced by std::right().

const fmtflags std::ios_base::scientific
static

Generates floating-point output in scientific notation.

Definition at line 288 of file ios_base.h.

Referenced by std::scientific().

const fmtflags std::ios_base::showbase
static

Generates a prefix indicating the numeric base of generated integer output.

Definition at line 292 of file ios_base.h.

Referenced by std::noshowbase(), and std::showbase().

const fmtflags std::ios_base::showpoint
static

Generates a decimal-point character unconditionally in generated floating-point output.

Definition at line 296 of file ios_base.h.

Referenced by std::noshowpoint(), and std::showpoint().

const fmtflags std::ios_base::showpos
static

Generates a + sign in non-negative generated numeric output.

Definition at line 299 of file ios_base.h.

Referenced by std::noshowpos(), and std::showpos().

const fmtflags std::ios_base::skipws
static

Skips leading white space before certain input operations.

Definition at line 302 of file ios_base.h.

Referenced by std::noskipws(), std::basic_istream< _CharT, _Traits >::sentry::sentry(), and std::skipws().

const openmode std::ios_base::trunc
static

Open for input. Default for ofstream.

Definition at line 383 of file ios_base.h.

const fmtflags std::ios_base::unitbuf
static

Flushes output after each output operation.

Definition at line 305 of file ios_base.h.

Referenced by std::nounitbuf(), std::unitbuf(), and std::basic_ostream< _CharT, _Traits >::sentry::~sentry().

const fmtflags std::ios_base::uppercase
static

Replaces certain lowercase letters with their uppercase equivalents in generated output.

Definition at line 309 of file ios_base.h.

Referenced by std::num_put< _CharT, _OutIter >::do_put(), std::nouppercase(), and std::uppercase().


The documentation for this class was generated from the following file: