basic_ios Class Template Reference

#include <basic_ios.h>

Inheritance diagram for basic_ios:

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Collaboration diagram for basic_ios:

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List of all members.

Detailed Description

template<typename CharT, typename Traits>
class std::basic_ios< CharT, Traits >

Most of the member functions called dispatched on stream objects (e.g., std::cout.foo(bar);) are consolidated in this class.

Definition at line 56 of file basic_ios.h.

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Static Protected Attributes


Member Typedef Documentation

typedef CharT char_type
 

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation. Definition at line 65 of file basic_ios.h.

Referenced by basic_ios::basic_ios(), basic_ios::fill(), and basic_ios::narrow().

typedef void(* event_callback)(event, ios_base &, int) [inherited]
 

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 392 of file ios_base.h.

typedef IosFmtflags fmtflags [inherited]
 

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 210 of file ios_base.h.

Referenced by num_put::do_put(), ios_base::flags(), ios_base::setf(), and ios_base::unsetf().

typedef Traits::int_type int_type
 

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation. Definition at line 66 of file basic_ios.h.

typedef IosIostate iostate [inherited]
 

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 285 of file ios_base.h.

Referenced by money_get::do_get(), num_get::do_get(), time_get::do_get_date(), time_get::do_get_monthname(), time_get::do_get_time(), time_get::do_get_weekday(), time_get::do_get_year(), money_get::get(), num_get< CharT, istreambuf_iterator< CharT, Traits > >::get(), time_get::get_date(), time_get::get_monthname(), time_get::get_time(), time_get::get_weekday(), time_get::get_year(), std::getline(), and std::operator>>().

typedef Traits::off_type off_type
 

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation. Definition at line 68 of file basic_ios.h.

typedef IosOpenmode openmode [inherited]
 

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 316 of file ios_base.h.

Referenced by stdio_filebuf::stdio_filebuf().

typedef Traits::pos_type pos_type
 

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation. Definition at line 67 of file basic_ios.h.

typedef IosSeekdir seekdir [inherited]
 

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 349 of file ios_base.h.

typedef Traits traits_type
 

These are standard types. They permit a standardized way of referring to names of (or names dependant on) the template parameters, which are specific to the implementation. Definition at line 69 of file basic_ios.h.


Member Enumeration Documentation

enum 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 375 of file ios_base.h.


Constructor & Destructor Documentation

basic_ios basic_streambuf< CharT, Traits > *  sb  )  [inline, explicit]
 

Constructor performs initialization.

The parameter is passed by derived streams. Definition at line 256 of file basic_ios.h.

References basic_ios::init().

virtual ~basic_ios  )  [inline, virtual]
 

Empty.

The destructor does nothing. More specifically, it does not destroy the streambuf held by rdbuf(). Definition at line 268 of file basic_ios.h.

basic_ios  )  [inline, protected]
 

Empty.

The default constructor does nothing and is not normally accessible to users. Definition at line 444 of file basic_ios.h.

References basic_ios::char_type.


Member Function Documentation

bool 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 197 of file basic_ios.h.

References basic_ios::rdstate().

void 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 39 of file basic_ios.tcc.

References basic_ios::exceptions(), basic_ios::rdbuf(), and basic_ios::rdstate().

Referenced by basic_ios::exceptions(), basic_ios::rdbuf(), and basic_ios::setstate().

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 61 of file basic_ios.tcc.

References basic_ios::exceptions(), basic_ios::fill(), ios_base::flags(), ios_base::getloc(), ios_base::precision(), basic_ios::tie(), and ios_base::width().

bool 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 176 of file basic_ios.h.

References basic_ios::rdstate().

void 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 flage 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 badbit\n";
      f.setstate (std::ios_base::badbit);

      std::cerr << "Setting exception mask\n";
      f.exceptions (std::ios_base::badbit);
  }
Definition at line 243 of file basic_ios.h.

References basic_ios::clear().

iostate 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 208 of file basic_ios.h.

Referenced by basic_ios::clear(), and basic_ios::copyfmt().

bool 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 187 of file basic_ios.h.

References basic_ios::rdstate().

Referenced by basic_ios::operator void *(), and basic_ios::operator!().

char_type 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 376 of file basic_ios.h.

References basic_ios::char_type, and basic_ios::fill().

char_type fill  )  const [inline]
 

Retreives the "empty" character.

Returns:
The current fill character.
It defaults to a space (' ') in the current locale. Definition at line 356 of file basic_ios.h.

References basic_ios::widen().

Referenced by basic_ios::copyfmt(), and basic_ios::fill().

fmtflags 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 515 of file ios_base.h.

References ios_base::fmtflags.

fmtflags flags  )  const [inline, inherited]
 

Access to format flags.

Returns:
The format control flags for both input and output.
Definition at line 505 of file ios_base.h.

Referenced by basic_ios::copyfmt(), num_get::do_get(), and num_put::do_put().

locale 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 647 of file ios_base.h.

Referenced by basic_ios::copyfmt(), and money_put::do_put().

bool good  )  const [inline]
 

Fast error checking.

Returns:
True if no error flags are set.
A wrapper around rdstate. Definition at line 166 of file basic_ios.h.

References basic_ios::rdstate().

locale 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++/22_locale/howto.html

Reimplemented from ios_base.

Definition at line 122 of file basic_ios.tcc.

References basic_ios::rdbuf().

void 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 134 of file basic_ios.tcc.

Referenced by basic_ios::basic_ios().

long& 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 691 of file ios_base.h.

const locale& 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 657 of file ios_base.h.

char narrow char_type  c,
char  __dfault
const
 

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++/22_locale/howto.html Definition at line 111 of file basic_ios.tcc.

References basic_ios::char_type.

operator void *  )  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 107 of file basic_ios.h.

References basic_ios::fail().

bool 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 111 of file basic_ios.h.

References basic_ios::fail().

streamsize precision streamsize  __prec  )  [inline, inherited]
 

Changing flags.

Parameters:
prec The new precision value.
Returns:
The previous value of precision().
Definition at line 583 of file ios_base.h.

References std::streamsize.

streamsize precision  )  const [inline, inherited]
 

Flags access.

Returns:
The precision to generate on certain output operations.
Definition at line 575 of file ios_base.h.

Referenced by basic_ios::copyfmt().

void*& 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 712 of file ios_base.h.

basic_streambuf< 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 51 of file basic_ios.tcc.

References basic_ios::clear().

basic_streambuf<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 307 of file basic_ios.h.

Referenced by basic_ios::clear(), and basic_ios::imbue().

iostate 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 123 of file basic_ios.h.

Referenced by basic_ios::bad(), basic_ios::clear(), basic_ios::eof(), basic_ios::fail(), and basic_ios::good().

void 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 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 548 of file ios_base.h.

References ios_base::fmtflags.

fmtflags 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 531 of file ios_base.h.

References ios_base::fmtflags.

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().

void 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 143 of file basic_ios.h.

References basic_ios::clear().

bool 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 http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#8 for more.

basic_ostream<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 293 of file basic_ios.h.

basic_ostream<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 281 of file basic_ios.h.

Referenced by basic_ios::copyfmt().

void 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 563 of file ios_base.h.

References ios_base::fmtflags.

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

CharT widen char  c  )  const
 

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++/22_locale/howto.html Definition at line 116 of file basic_ios.tcc.

Referenced by basic_ios::fill().

streamsize width streamsize  __wide  )  [inline, inherited]
 

Changing flags.

Parameters:
wide The new width value.
Returns:
The previous value of width().
Definition at line 605 of file ios_base.h.

References std::streamsize.

streamsize 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 597 of file ios_base.h.

Referenced by basic_ios::copyfmt(), and num_put::do_put().

int xalloc  )  throw () [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 adjustfield [static, inherited]
 

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

Definition at line 265 of file ios_base.h.

const openmode app [static, inherited]
 

Seek to end before each write.

Definition at line 319 of file ios_base.h.

const openmode ate [static, inherited]
 

Open and seek to end immediately after opening.

Definition at line 322 of file ios_base.h.

const iostate 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 289 of file ios_base.h.

const fmtflags basefield [static, inherited]
 

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

Definition at line 268 of file ios_base.h.

const seekdir beg [static, inherited]
 

Request a seek relative to the beginning of the stream.

Definition at line 352 of file ios_base.h.

const openmode 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 http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#3 and http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#7 for more.

Definition at line 328 of file ios_base.h.

const fmtflags boolalpha [static, inherited]
 

Insert/extract bool in alphabetic rather than numeric format.

Definition at line 213 of file ios_base.h.

const seekdir cur [static, inherited]
 

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

Definition at line 355 of file ios_base.h.

const fmtflags dec [static, inherited]
 

Converts integer input or generates integer output in decimal base.

Definition at line 216 of file ios_base.h.

const seekdir end [static, inherited]
 

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

Definition at line 358 of file ios_base.h.

const iostate eofbit [static, inherited]
 

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

Definition at line 292 of file ios_base.h.

const iostate 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 297 of file ios_base.h.

const fmtflags fixed [static, inherited]
 

Generate floating-point output in fixed-point notation.

Definition at line 219 of file ios_base.h.

const fmtflags floatfield [static, inherited]
 

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

Definition at line 271 of file ios_base.h.

const iostate goodbit [static, inherited]
 

Indicates all is well.

Definition at line 300 of file ios_base.h.

const fmtflags hex [static, inherited]
 

Converts integer input or generates integer output in hexadecimal base.

Definition at line 222 of file ios_base.h.

const openmode in [static, inherited]
 

Open for input. Default for ifstream and fstream.

Definition at line 331 of file ios_base.h.

const fmtflags 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 227 of file ios_base.h.

const fmtflags 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 231 of file ios_base.h.

const fmtflags oct [static, inherited]
 

Converts integer input or generates integer output in octal base.

Definition at line 234 of file ios_base.h.

const openmode out [static, inherited]
 

Open for output. Default for ofstream and fstream.

Definition at line 334 of file ios_base.h.

const fmtflags 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 238 of file ios_base.h.

const fmtflags scientific [static, inherited]
 

Generates floating-point output in scientific notation.

Definition at line 241 of file ios_base.h.

const fmtflags showbase [static, inherited]
 

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

Definition at line 245 of file ios_base.h.

const fmtflags showpoint [static, inherited]
 

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

Definition at line 249 of file ios_base.h.

const fmtflags showpos [static, inherited]
 

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

Definition at line 252 of file ios_base.h.

const fmtflags skipws [static, inherited]
 

Skips leading white space before certain input operations.

Definition at line 255 of file ios_base.h.

const openmode trunc [static, inherited]
 

Open for input. Default for ofstream.

Definition at line 337 of file ios_base.h.

const fmtflags unitbuf [static, inherited]
 

Flushes output after each output operation.

Definition at line 258 of file ios_base.h.

const fmtflags uppercase [static, inherited]
 

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

Definition at line 262 of file ios_base.h.


The documentation for this class was generated from the following files:
Generated on Sun Sep 12 15:50:11 2004 for libstdc++ source by doxygen 1.3.8