SYNOPSIS

Inherited by std::basic_ios< _CharT, _Traits >.

Classes

class failure

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 199 of file ios_base.h.

Member Typedef Documentation

typedef void(* std::ios_base::event_callback)(\fBevent\fP __e, \fBios_base\fP &__b, int __i)

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 436 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 255 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 330 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 361 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 393 of file ios_base.h.

Member Enumeration Documentation

enum \fBstd::ios_base::event\fP

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 419 of file ios_base.h.

Constructor & Destructor Documentation

virtual std::ios_base::~ios_base ()\fC [virtual]\fP

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 \fBlocale\fP& std::ios_base::_M_getloc () const\fC [inline]\fP

Locale access.

Returns:

A reference to the current locale.

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

Definition at line 706 of file ios_base.h.

\fBfmtflags\fP std::ios_base::flags () const\fC [inline]\fP

Access to format flags.

Returns:

The format control flags for both input and output.

Definition at line 551 of file ios_base.h.

\fBfmtflags\fP std::ios_base::flags (\fBfmtflags\fP__fmtfl)\fC [inline]\fP

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 562 of file ios_base.h.

\fBlocale\fP std::ios_base::getloc () const\fC [inline]\fP

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 695 of file ios_base.h.

\fBlocale\fP std::ios_base::imbue (const \fBlocale\fP &__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.

long& std::ios_base::iword (int__ix)\fC [inline]\fP

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 741 of file ios_base.h.

\fBstreamsize\fP std::ios_base::precision () const\fC [inline]\fP

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 621 of file ios_base.h.

\fBstreamsize\fP std::ios_base::precision (\fBstreamsize\fP__prec)\fC [inline]\fP

Changing flags.

Parameters:

__prec The new precision value.

Returns:

The previous value of precision().

Definition at line 630 of file ios_base.h.

void*& std::ios_base::pword (int__ix)\fC [inline]\fP

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 762 of file ios_base.h.

void std::ios_base::register_callback (\fBevent_callback\fP__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.

\fBfmtflags\fP std::ios_base::setf (\fBfmtflags\fP__fmtfl)\fC [inline]\fP

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 578 of file ios_base.h.

Referenced by std::boolalpha(), 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().

\fBfmtflags\fP std::ios_base::setf (\fBfmtflags\fP__fmtfl, \fBfmtflags\fP__mask)\fC [inline]\fP

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 595 of file ios_base.h.

static bool std::ios_base::sync_with_stdio (bool__sync = \fCtrue\fP)\fC [static]\fP

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 (\fBfmtflags\fP__mask)\fC [inline]\fP

Clearing format flags.

Parameters:

__mask The flags to unset.

This function clears __mask in the format flags.

Definition at line 610 of file ios_base.h.

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

\fBstreamsize\fP std::ios_base::width () const\fC [inline]\fP

Flags access.

Returns:

The minimum field width to generate on output operations.

Minimum field width refers to the number of characters.

Definition at line 644 of file ios_base.h.

\fBstreamsize\fP std::ios_base::width (\fBstreamsize\fP__wide)\fC [inline]\fP

Changing flags.

Parameters:

__wide The new width value.

Returns:

The previous value of width().

Definition at line 653 of file ios_base.h.

static int std::ios_base::xalloc ()\fC [static]\fP

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 \fBfmtflags\fP std::ios_base::adjustfield\fC [static]\fP

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

Definition at line 310 of file ios_base.h.

Referenced by std::internal(), std::left(), and std::right().

const \fBopenmode\fP std::ios_base::app\fC [static]\fP

Seek to end before each write.

Definition at line 364 of file ios_base.h.

const \fBopenmode\fP std::ios_base::ate\fC [static]\fP

Open and seek to end immediately after opening.

Definition at line 367 of file ios_base.h.

const \fBiostate\fP std::ios_base::badbit\fC [static]\fP

Indicates a loss of integrity in an input or output sequence (such as an irrecoverable read error from a file).

Definition at line 334 of file ios_base.h.

Referenced by std::basic_ios< _CharT, _Traits >::bad(), and std::basic_ios< _CharT, _Traits >::fail().

const \fBfmtflags\fP std::ios_base::basefield\fC [static]\fP

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

Definition at line 313 of file ios_base.h.

Referenced by std::dec(), std::hex(), and std::oct().

const \fBseekdir\fP std::ios_base::beg\fC [static]\fP

Request a seek relative to the beginning of the stream.

Definition at line 396 of file ios_base.h.

const \fBopenmode\fP std::ios_base::binary\fC [static]\fP

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 372 of file ios_base.h.

const \fBfmtflags\fP std::ios_base::boolalpha\fC [static]\fP

Insert/extract bool in alphabetic rather than numeric format.

Definition at line 258 of file ios_base.h.

Referenced by std::boolalpha(), and std::noboolalpha().

const \fBseekdir\fP std::ios_base::cur\fC [static]\fP

Request a seek relative to the current position within the sequence.

Definition at line 399 of file ios_base.h.

const \fBfmtflags\fP std::ios_base::dec\fC [static]\fP

Converts integer input or generates integer output in decimal base.

Definition at line 261 of file ios_base.h.

Referenced by std::dec().

const \fBseekdir\fP std::ios_base::end\fC [static]\fP

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

Definition at line 402 of file ios_base.h.

const \fBiostate\fP std::ios_base::eofbit\fC [static]\fP

Indicates that an input operation reached the end of an input sequence.

Definition at line 337 of file ios_base.h.

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

const \fBiostate\fP std::ios_base::failbit\fC [static]\fP

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 342 of file ios_base.h.

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

const \fBfmtflags\fP std::ios_base::fixed\fC [static]\fP

Generate floating-point output in fixed-point notation.

Definition at line 264 of file ios_base.h.

Referenced by std::fixed().

const \fBfmtflags\fP std::ios_base::floatfield\fC [static]\fP

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

Definition at line 316 of file ios_base.h.

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

const \fBiostate\fP std::ios_base::goodbit\fC [static]\fP

Indicates all is well.

Definition at line 345 of file ios_base.h.

const \fBfmtflags\fP std::ios_base::hex\fC [static]\fP

Converts integer input or generates integer output in hexadecimal base.

Definition at line 267 of file ios_base.h.

Referenced by std::hex().

const \fBopenmode\fP std::ios_base::in\fC [static]\fP

Open for input. Default for ifstream and fstream.

Definition at line 375 of file ios_base.h.

const \fBfmtflags\fP std::ios_base::internal\fC [static]\fP

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 272 of file ios_base.h.

Referenced by std::internal().

const \fBfmtflags\fP std::ios_base::left\fC [static]\fP

Adds fill characters on the right (final positions) of certain generated output. (I.e., the thing you print is flush left.)

Definition at line 276 of file ios_base.h.

Referenced by std::left().

const \fBfmtflags\fP std::ios_base::oct\fC [static]\fP

Converts integer input or generates integer output in octal base.

Definition at line 279 of file ios_base.h.

Referenced by std::oct().

const \fBopenmode\fP std::ios_base::out\fC [static]\fP

Open for output. Default for ofstream and fstream.

Definition at line 378 of file ios_base.h.

const \fBfmtflags\fP std::ios_base::right\fC [static]\fP

Adds fill characters on the left (initial positions) of certain generated output. (I.e., the thing you print is flush right.)

Definition at line 283 of file ios_base.h.

Referenced by std::right().

const \fBfmtflags\fP std::ios_base::scientific\fC [static]\fP

Generates floating-point output in scientific notation.

Definition at line 286 of file ios_base.h.

Referenced by std::scientific().

const \fBfmtflags\fP std::ios_base::showbase\fC [static]\fP

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

Definition at line 290 of file ios_base.h.

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

const \fBfmtflags\fP std::ios_base::showpoint\fC [static]\fP

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

Definition at line 294 of file ios_base.h.

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

const \fBfmtflags\fP std::ios_base::showpos\fC [static]\fP

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

Definition at line 297 of file ios_base.h.

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

const \fBfmtflags\fP std::ios_base::skipws\fC [static]\fP

Skips leading white space before certain input operations.

Definition at line 300 of file ios_base.h.

Referenced by std::noskipws(), and std::skipws().

const \fBopenmode\fP std::ios_base::trunc\fC [static]\fP

Open for input. Default for ofstream.

Definition at line 381 of file ios_base.h.

const \fBfmtflags\fP std::ios_base::unitbuf\fC [static]\fP

Flushes output after each output operation.

Definition at line 303 of file ios_base.h.

Referenced by std::nounitbuf(), and std::unitbuf().

const \fBfmtflags\fP std::ios_base::uppercase\fC [static]\fP

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

Definition at line 307 of file ios_base.h.

Referenced by std::nouppercase(), and std::uppercase().

Author

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