std::ios_base

std::ios_base Class Reference

The very top of the I/O class hierarchy. More...

#include <ios_base.h>

Inheritance diagram for std::ios_base:

[legend]Collaboration diagram for std::ios_base:


Public Types
typedef IosFmtflags	fmtflags
	This is a bitmask type.
typedef IosIostate	iostate
	This is a bitmask type.
typedef IosOpenmode	openmode
	This is a bitmask type.
typedef IosSeekdir	seekdir
	This is an enumerated type.
typedef void(*	event_callback )(event, ios_base &, int)
	The type of an event callback function.
enum	event
	The set of events that may be passed to an event callback. More...
Public Member Functions
void	register_callback (event_callback __fn, int index)
	Add the callback __fn with parameter index.
fmtflags	flags () const
	Access to format flags.
fmtflags	flags (fmtflags __fmtfl)
	Setting new format flags all at once.
fmtflags	setf (fmtflags __fmtfl)
	Setting new format flags.
fmtflags	setf (fmtflags __fmtfl, fmtflags __mask)
	Setting new format flags.
void	unsetf (fmtflags __mask)
	Clearing format flags.
streamsize	precision () const
	Flags access.
streamsize	precision (streamsize __prec)
	Changing flags.
streamsize	width () const
	Flags access.
streamsize	width (streamsize __wide)
	Changing flags.
locale	imbue (const locale &__loc)
	Setting a new locale.
locale	getloc () const
	Locale access.
const locale &	M_getloc () const
	Locale access.
long &	iword (int __ix)
	Access to integer array.
void *&	pword (int __ix)
	Access to void pointer array.
virtual	~ios_base ()
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	boolalpha
	Insert/extract `bool` in alphabetic rather than numeric format.
static const fmtflags	dec
	Converts integer input or generates integer output in decimal base.
static const fmtflags	fixed
	Generate floating-point output in fixed-point notation.
static const fmtflags	hex
	Converts integer input or generates integer output in hexadecimal base.
static const fmtflags	internal
	designated.
static const fmtflags	left
	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 fmtflags	right
	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
	output.
static const fmtflags	showpoint
	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 fmtflags	unitbuf
	Flushes output after each output operation.
static const fmtflags	uppercase
	in generated output.
static const fmtflags	adjustfield
	A mask of left\|right\|internal. Useful for the 2-arg form of `setf`.
static const fmtflags	basefield
	A mask of dec\|oct\|hex. Useful for the 2-arg form of `setf`.
static const fmtflags	floatfield
	A mask of scientific\|fixed. Useful for the 2-arg form of `setf`.
static const iostate	badbit
	as an irrecoverable read error from a file).
static const iostate	eofbit
	Indicates that an input operation reached the end of an input sequence.
static const iostate	failbit
	desired characters.
static const iostate	goodbit
	Indicates all is well.
static const openmode	app
	Seek to end before each write.
static const openmode	ate
	Open and seek to end immediately after opening.
static const openmode	binary
	http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#7 for more.
static const openmode	in
	Open for input. Default for `ifstream` and fstream.
static const openmode	out
	Open for output. Default for `ofstream` and fstream.
static const openmode	trunc
	Open for input. Default for `ofstream`.
static const seekdir	beg
	Request a seek relative to the beginning of the stream.
static const seekdir	cur
	Request a seek relative to the current position within the sequence.
static const seekdir	end
	Request a seek relative to the current end of the sequence.
Classes
class	failure
	These are thrown to indicate problems. Doc me. More...

Detailed Description

The very top 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, 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 437 of file ios_base.h.

typedef IosFmtflags std::ios_base::fmtflags

This is a bitmask type.
"IosFmtflags" 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 253 of file ios_base.h.

typedef IosIostate std::ios_base::iostate

This is a bitmask type.
"IosIostate" 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 328 of file ios_base.h.

typedef IosOpenmode std::ios_base::openmode

This is a bitmask type.
"IosOpenmode" 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 359 of file ios_base.h.

typedef IosSeekdir std::ios_base::seekdir

This is an enumerated type.
"IosSeekdir" is implementation-defined. Defined values of type seekdir are:

beg
cur, equivalent to SEEKCUR in the C standard library.
end, equivalent to SEEKEND in the C standard library.

Definition at line 392 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 420 of file ios_base.h.

Constructor & Destructor Documentation

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).
Definition at line 126 of file ios.cc.

Member Function Documentation

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 560 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 550 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<<(), std::basic_ostream< char >::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 692 of file ios_base.h.
Referenced by std::basic_ios< CharT, Traits >::copyfmt(), and std::money_put< CharT, OutIter >::do_put().

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 >.
Definition at line 53 of file ios_locale.cc.
Referenced by std::basic_ios< CharT, Traits >::imbue().

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 736 of file ios_base.h.

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 702 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 628 of file ios_base.h.

streamsize std::ios_base::precision ( ) const [inline]

Flags access.

Returns:
The precision to generate on certain output operations.

Definition at line 620 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 757 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.
Definition at line 148 of file ios.cc.

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 593 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 576 of file ios_base.h.
Referenced by std::boolalpha().

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++/27_io/howto.html#8 for more.
Definition at line 148 of file ios_init.cc.
References std::cerr, std::cin, std::clog, std::cout, in, and out.

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 608 of file ios_base.h.

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 650 of file ios_base.h.

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 642 of file ios_base.h.
Referenced by std::basic_ios< CharT, Traits >::copyfmt(), and std::num_put< CharT, OutIter >::do_put().

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.
Definition at line 139 of file ios.cc.

Member Data Documentation

const ios_base::fmtflags std::ios_base::adjustfield [static]

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

Definition at line 89 of file ios.cc.
Referenced by std::internal(), std::left(), and std::right().

const ios_base::openmode std::ios_base::app [static]

Seek to end before each write.

Definition at line 98 of file ios.cc.

const ios_base::openmode std::ios_base::ate [static]

Open and seek to end immediately after opening.

Definition at line 99 of file ios.cc.
Referenced by std::basic_filebuf< CharT, Traits >::open().

const ios_base::fmtflags std::ios_base::basefield [static]

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

Definition at line 90 of file ios.cc.
Referenced by std::dec(), std::hex(), std::oct(), std::basic_ostream< CharT, Traits >::operator<<(), and std::basic_ostream< char >::operator<<().

const ios_base::seekdir std::ios_base::beg [static]

Request a seek relative to the beginning of the stream.

Definition at line 105 of file ios.cc.
Referenced by std::basic_filebuf< CharT, Traits >::seekpos().

const ios_base::openmode std::ios_base::binary [static]

http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#7 for more.

Definition at line 100 of file ios.cc.

const ios_base::fmtflags std::ios_base::boolalpha [static]

Insert/extract bool in alphabetic rather than numeric format.

Definition at line 74 of file ios.cc.
Referenced by std::boolalpha(), std::num_get< CharT, InIter >::do_get(), std::num_put< CharT, OutIter >::do_put(), and std::noboolalpha().

const ios_base::seekdir std::ios_base::cur [static]

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

Definition at line 106 of file ios.cc.
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 ios_base::fmtflags std::ios_base::dec [static]

Converts integer input or generates integer output in decimal base.

Definition at line 75 of file ios.cc.
Referenced by std::dec().

const ios_base::seekdir std::ios_base::end [static]

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

Definition at line 107 of file ios.cc.
Referenced by std::basic_filebuf< CharT, Traits >::open(), and std::basic_stringbuf< CharT, Traits, Alloc >::seekoff().

const ios_base::iostate std::ios_base::eofbit [static]

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

Definition at line 94 of file ios.cc.
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_ios< char, Traits >::eof(), std::basic_istream< CharT, Traits >::get(), std::getline(), std::basic_istream< CharT, Traits >::getline(), std::basic_istream< CharT, Traits >::ignore(), std::operator>>(), std::basic_istream< CharT, Traits >::peek(), std::basic_istream< CharT, Traits >::read(), std::basic_istream< CharT, Traits >::readsome(), and std::ws().

const ios_base::fmtflags std::ios_base::fixed [static]

Generate floating-point output in fixed-point notation.

Definition at line 76 of file ios.cc.
Referenced by std::fixed().

const ios_base::fmtflags std::ios_base::floatfield [static]

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

Definition at line 91 of file ios.cc.
Referenced by std::fixed(), and std::scientific().

const ios_base::fmtflags std::ios_base::hex [static]

Converts integer input or generates integer output in hexadecimal base.

Definition at line 77 of file ios.cc.
Referenced by std::hex(), std::basic_ostream< CharT, Traits >::operator<<(), and std::basic_ostream< char >::operator<<().

const ios_base::openmode std::ios_base::in [static]

Open for input. Default for ifstream and fstream.

Definition at line 101 of file ios.cc.
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(), sync_with_stdio(), std::basic_istream< CharT, Traits >::tellg(), std::basic_stringbuf< CharT, Traits, Alloc >::underflow(), and std::basic_filebuf< CharT, Traits >::underflow().

const ios_base::fmtflags std::ios_base::internal [static]

designated.

Definition at line 78 of file ios.cc.
Referenced by std::internal().

const ios_base::fmtflags std::ios_base::left [static]

generated output. (I.e., the thing you print is flush left.)

Definition at line 79 of file ios.cc.
Referenced by std::left().

const ios_base::fmtflags std::ios_base::oct [static]

Converts integer input or generates integer output in octal base.

Definition at line 80 of file ios.cc.
Referenced by std::oct(), std::basic_ostream< CharT, Traits >::operator<<(), and std::basic_ostream< char >::operator<<().

const ios_base::openmode std::ios_base::out [static]

Open for output. Default for ofstream and fstream.

Definition at line 102 of file ios.cc.
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(), sync_with_stdio(), and std::basic_ostream< CharT, Traits >::tellp().

const ios_base::fmtflags std::ios_base::right [static]

generated output. (I.e., the thing you print is flush right.)

Definition at line 81 of file ios.cc.
Referenced by std::right().

const ios_base::fmtflags std::ios_base::scientific [static]

Generates floating-point output in scientific notation.

Definition at line 82 of file ios.cc.
Referenced by std::scientific().

const ios_base::fmtflags std::ios_base::showbase [static]

output.

Definition at line 83 of file ios.cc.
Referenced by std::noshowbase(), and std::showbase().

const ios_base::fmtflags std::ios_base::showpoint [static]

floating-point output.

Definition at line 84 of file ios.cc.
Referenced by std::noshowpoint(), and std::showpoint().

const ios_base::fmtflags std::ios_base::showpos [static]

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

Definition at line 85 of file ios.cc.
Referenced by std::noshowpos(), and std::showpos().

const ios_base::fmtflags std::ios_base::skipws [static]

Skips leading white space before certain input operations.

Definition at line 86 of file ios.cc.
Referenced by std::noskipws(), and std::skipws().

const ios_base::openmode std::ios_base::trunc [static]

Open for input. Default for ofstream.

Definition at line 103 of file ios.cc.

const ios_base::fmtflags std::ios_base::unitbuf [static]

Flushes output after each output operation.

Definition at line 87 of file ios.cc.
Referenced by std::nounitbuf(), and std::unitbuf().

const ios_base::fmtflags std::ios_base::uppercase [static]

in generated output.

Definition at line 88 of file ios.cc.
Referenced by std::nouppercase(), and std::uppercase().

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

Generated on Fri May 6 01:12:39 2005 for libstdc++-v3 Source by

1.4.2

std::ios_base Class Reference

Public Types

Public Member Functions

Static Public Member Functions