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      1 // Iostreams base classes -*- C++ -*-
      2 
      3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
      4 // 2006, 2007, 2008, 2009
      5 // Free Software Foundation, Inc.
      6 //
      7 // This file is part of the GNU ISO C++ Library.  This library is free
      8 // software; you can redistribute it and/or modify it under the
      9 // terms of the GNU General Public License as published by the
     10 // Free Software Foundation; either version 3, or (at your option)
     11 // any later version.
     12 
     13 // This library is distributed in the hope that it will be useful,
     14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
     15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     16 // GNU General Public License for more details.
     17 
     18 // Under Section 7 of GPL version 3, you are granted additional
     19 // permissions described in the GCC Runtime Library Exception, version
     20 // 3.1, as published by the Free Software Foundation.
     21 
     22 // You should have received a copy of the GNU General Public License and
     23 // a copy of the GCC Runtime Library Exception along with this program;
     24 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     25 // <http://www.gnu.org/licenses/>.
     26 
     27 /** @file ios_base.h
     28  *  This is an internal header file, included by other library headers.
     29  *  You should not attempt to use it directly.
     30  */
     31 
     32 //
     33 // ISO C++ 14882: 27.4  Iostreams base classes
     34 //
     35 
     36 #ifndef _IOS_BASE_H
     37 #define _IOS_BASE_H 1
     38 
     39 #pragma GCC system_header
     40 
     41 #include <ext/atomicity.h>
     42 #include <bits/localefwd.h>
     43 #include <bits/locale_classes.h>
     44 
     45 #ifndef _GLIBCXX_STDIO_MACROS
     46 # include <cstdio>   // For SEEK_CUR, SEEK_END
     47 # define _IOS_BASE_SEEK_CUR SEEK_CUR
     48 # define _IOS_BASE_SEEK_END SEEK_END
     49 #else
     50 # define _IOS_BASE_SEEK_CUR 1
     51 # define _IOS_BASE_SEEK_END 2
     52 #endif
     53 
     54 _GLIBCXX_BEGIN_NAMESPACE(std)
     55 
     56   // The following definitions of bitmask types are enums, not ints,
     57   // as permitted (but not required) in the standard, in order to provide
     58   // better type safety in iostream calls.  A side effect is that
     59   // expressions involving them are no longer compile-time constants.
     60   enum _Ios_Fmtflags
     61     {
     62       _S_boolalpha 	= 1L << 0,
     63       _S_dec 		= 1L << 1,
     64       _S_fixed 		= 1L << 2,
     65       _S_hex 		= 1L << 3,
     66       _S_internal 	= 1L << 4,
     67       _S_left 		= 1L << 5,
     68       _S_oct 		= 1L << 6,
     69       _S_right 		= 1L << 7,
     70       _S_scientific 	= 1L << 8,
     71       _S_showbase 	= 1L << 9,
     72       _S_showpoint 	= 1L << 10,
     73       _S_showpos 	= 1L << 11,
     74       _S_skipws 	= 1L << 12,
     75       _S_unitbuf 	= 1L << 13,
     76       _S_uppercase 	= 1L << 14,
     77       _S_adjustfield 	= _S_left | _S_right | _S_internal,
     78       _S_basefield 	= _S_dec | _S_oct | _S_hex,
     79       _S_floatfield 	= _S_scientific | _S_fixed,
     80       _S_ios_fmtflags_end = 1L << 16
     81     };
     82 
     83   inline _Ios_Fmtflags
     84   operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
     85   { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); }
     86 
     87   inline _Ios_Fmtflags
     88   operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
     89   { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); }
     90 
     91   inline _Ios_Fmtflags
     92   operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
     93   { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); }
     94 
     95   inline _Ios_Fmtflags&
     96   operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
     97   { return __a = __a | __b; }
     98 
     99   inline _Ios_Fmtflags&
    100   operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
    101   { return __a = __a & __b; }
    102 
    103   inline _Ios_Fmtflags&
    104   operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
    105   { return __a = __a ^ __b; }
    106 
    107   inline _Ios_Fmtflags
    108   operator~(_Ios_Fmtflags __a)
    109   { return _Ios_Fmtflags(~static_cast<int>(__a)); }
    110 
    111 
    112   enum _Ios_Openmode
    113     {
    114       _S_app 		= 1L << 0,
    115       _S_ate 		= 1L << 1,
    116       _S_bin 		= 1L << 2,
    117       _S_in 		= 1L << 3,
    118       _S_out 		= 1L << 4,
    119       _S_trunc 		= 1L << 5,
    120       _S_ios_openmode_end = 1L << 16
    121     };
    122 
    123   inline _Ios_Openmode
    124   operator&(_Ios_Openmode __a, _Ios_Openmode __b)
    125   { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); }
    126 
    127   inline _Ios_Openmode
    128   operator|(_Ios_Openmode __a, _Ios_Openmode __b)
    129   { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); }
    130 
    131   inline _Ios_Openmode
    132   operator^(_Ios_Openmode __a, _Ios_Openmode __b)
    133   { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); }
    134 
    135   inline _Ios_Openmode&
    136   operator|=(_Ios_Openmode& __a, _Ios_Openmode __b)
    137   { return __a = __a | __b; }
    138 
    139   inline _Ios_Openmode&
    140   operator&=(_Ios_Openmode& __a, _Ios_Openmode __b)
    141   { return __a = __a & __b; }
    142 
    143   inline _Ios_Openmode&
    144   operator^=(_Ios_Openmode& __a, _Ios_Openmode __b)
    145   { return __a = __a ^ __b; }
    146 
    147   inline _Ios_Openmode
    148   operator~(_Ios_Openmode __a)
    149   { return _Ios_Openmode(~static_cast<int>(__a)); }
    150 
    151 
    152   enum _Ios_Iostate
    153     {
    154       _S_goodbit 		= 0,
    155       _S_badbit 		= 1L << 0,
    156       _S_eofbit 		= 1L << 1,
    157       _S_failbit		= 1L << 2,
    158       _S_ios_iostate_end = 1L << 16
    159     };
    160 
    161   inline _Ios_Iostate
    162   operator&(_Ios_Iostate __a, _Ios_Iostate __b)
    163   { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); }
    164 
    165   inline _Ios_Iostate
    166   operator|(_Ios_Iostate __a, _Ios_Iostate __b)
    167   { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); }
    168 
    169   inline _Ios_Iostate
    170   operator^(_Ios_Iostate __a, _Ios_Iostate __b)
    171   { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); }
    172 
    173   inline _Ios_Iostate&
    174   operator|=(_Ios_Iostate& __a, _Ios_Iostate __b)
    175   { return __a = __a | __b; }
    176 
    177   inline _Ios_Iostate&
    178   operator&=(_Ios_Iostate& __a, _Ios_Iostate __b)
    179   { return __a = __a & __b; }
    180 
    181   inline _Ios_Iostate&
    182   operator^=(_Ios_Iostate& __a, _Ios_Iostate __b)
    183   { return __a = __a ^ __b; }
    184 
    185   inline _Ios_Iostate
    186   operator~(_Ios_Iostate __a)
    187   { return _Ios_Iostate(~static_cast<int>(__a)); }
    188 
    189   enum _Ios_Seekdir
    190     {
    191       _S_beg = 0,
    192       _S_cur = _IOS_BASE_SEEK_CUR,
    193       _S_end = _IOS_BASE_SEEK_END,
    194       _S_ios_seekdir_end = 1L << 16
    195     };
    196 
    197   // 27.4.2  Class ios_base
    198   /**
    199    *  @brief  The base of the I/O class hierarchy.
    200    *  @ingroup io
    201    *
    202    *  This class defines everything that can be defined about I/O that does
    203    *  not depend on the type of characters being input or output.  Most
    204    *  people will only see @c ios_base when they need to specify the full
    205    *  name of the various I/O flags (e.g., the openmodes).
    206   */
    207   class ios_base
    208   {
    209   public:
    210 
    211     /**
    212      *  @brief These are thrown to indicate problems with io.
    213      *  @ingroup exceptions
    214      *
    215      *  27.4.2.1.1  Class ios_base::failure
    216      */
    217     class failure : public exception
    218     {
    219     public:
    220       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    221       // 48.  Use of non-existent exception constructor
    222       explicit
    223       failure(const string& __str) throw();
    224 
    225       // This declaration is not useless:
    226       // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html
    227       virtual
    228       ~failure() throw();
    229 
    230       virtual const char*
    231       what() const throw();
    232 
    233     private:
    234       string _M_msg;
    235     };
    236 
    237     // 27.4.2.1.2  Type ios_base::fmtflags
    238     /**
    239      *  @brief This is a bitmask type.
    240      *
    241      *  @c "_Ios_Fmtflags" is implementation-defined, but it is valid to
    242      *  perform bitwise operations on these values and expect the Right
    243      *  Thing to happen.  Defined objects of type fmtflags are:
    244      *  - boolalpha
    245      *  - dec
    246      *  - fixed
    247      *  - hex
    248      *  - internal
    249      *  - left
    250      *  - oct
    251      *  - right
    252      *  - scientific
    253      *  - showbase
    254      *  - showpoint
    255      *  - showpos
    256      *  - skipws
    257      *  - unitbuf
    258      *  - uppercase
    259      *  - adjustfield
    260      *  - basefield
    261      *  - floatfield
    262     */
    263     typedef _Ios_Fmtflags fmtflags;
    264 
    265     /// Insert/extract @c bool in alphabetic rather than numeric format.
    266     static const fmtflags boolalpha =   _S_boolalpha;
    267 
    268     /// Converts integer input or generates integer output in decimal base.
    269     static const fmtflags dec =         _S_dec;
    270 
    271     /// Generate floating-point output in fixed-point notation.
    272     static const fmtflags fixed =       _S_fixed;
    273 
    274     /// Converts integer input or generates integer output in hexadecimal base.
    275     static const fmtflags hex =         _S_hex;
    276 
    277     /// Adds fill characters at a designated internal point in certain
    278     /// generated output, or identical to @c right if no such point is
    279     /// designated.
    280     static const fmtflags internal =    _S_internal;
    281 
    282     /// Adds fill characters on the right (final positions) of certain
    283     /// generated output.  (I.e., the thing you print is flush left.)
    284     static const fmtflags left =        _S_left;
    285 
    286     /// Converts integer input or generates integer output in octal base.
    287     static const fmtflags oct =         _S_oct;
    288 
    289     /// Adds fill characters on the left (initial positions) of certain
    290     /// generated output.  (I.e., the thing you print is flush right.)
    291     static const fmtflags right =       _S_right;
    292 
    293     /// Generates floating-point output in scientific notation.
    294     static const fmtflags scientific =  _S_scientific;
    295 
    296     /// Generates a prefix indicating the numeric base of generated integer
    297     /// output.
    298     static const fmtflags showbase =    _S_showbase;
    299 
    300     /// Generates a decimal-point character unconditionally in generated
    301     /// floating-point output.
    302     static const fmtflags showpoint =   _S_showpoint;
    303 
    304     /// Generates a + sign in non-negative generated numeric output.
    305     static const fmtflags showpos =     _S_showpos;
    306 
    307     /// Skips leading white space before certain input operations.
    308     static const fmtflags skipws =      _S_skipws;
    309 
    310     /// Flushes output after each output operation.
    311     static const fmtflags unitbuf =     _S_unitbuf;
    312 
    313     /// Replaces certain lowercase letters with their uppercase equivalents
    314     /// in generated output.
    315     static const fmtflags uppercase =   _S_uppercase;
    316 
    317     /// A mask of left|right|internal.  Useful for the 2-arg form of @c setf.
    318     static const fmtflags adjustfield = _S_adjustfield;
    319 
    320     /// A mask of dec|oct|hex.  Useful for the 2-arg form of @c setf.
    321     static const fmtflags basefield =   _S_basefield;
    322 
    323     /// A mask of scientific|fixed.  Useful for the 2-arg form of @c setf.
    324     static const fmtflags floatfield =  _S_floatfield;
    325 
    326     // 27.4.2.1.3  Type ios_base::iostate
    327     /**
    328      *  @brief This is a bitmask type.
    329      *
    330      *  @c "_Ios_Iostate" is implementation-defined, but it is valid to
    331      *  perform bitwise operations on these values and expect the Right
    332      *  Thing to happen.  Defined objects of type iostate are:
    333      *  - badbit
    334      *  - eofbit
    335      *  - failbit
    336      *  - goodbit
    337     */
    338     typedef _Ios_Iostate iostate;
    339 
    340     /// Indicates a loss of integrity in an input or output sequence (such
    341     /// as an irrecoverable read error from a file).
    342     static const iostate badbit =	_S_badbit;
    343 
    344     /// Indicates that an input operation reached the end of an input sequence.
    345     static const iostate eofbit =	_S_eofbit;
    346 
    347     /// Indicates that an input operation failed to read the expected
    348     /// characters, or that an output operation failed to generate the
    349     /// desired characters.
    350     static const iostate failbit =	_S_failbit;
    351 
    352     /// Indicates all is well.
    353     static const iostate goodbit =	_S_goodbit;
    354 
    355     // 27.4.2.1.4  Type ios_base::openmode
    356     /**
    357      *  @brief This is a bitmask type.
    358      *
    359      *  @c "_Ios_Openmode" is implementation-defined, but it is valid to
    360      *  perform bitwise operations on these values and expect the Right
    361      *  Thing to happen.  Defined objects of type openmode are:
    362      *  - app
    363      *  - ate
    364      *  - binary
    365      *  - in
    366      *  - out
    367      *  - trunc
    368     */
    369     typedef _Ios_Openmode openmode;
    370 
    371     /// Seek to end before each write.
    372     static const openmode app =		_S_app;
    373 
    374     /// Open and seek to end immediately after opening.
    375     static const openmode ate =		_S_ate;
    376 
    377     /// Perform input and output in binary mode (as opposed to text mode).
    378     /// This is probably not what you think it is; see
    379     /// http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch27s02.html
    380     static const openmode binary =	_S_bin;
    381 
    382     /// Open for input.  Default for @c ifstream and fstream.
    383     static const openmode in =		_S_in;
    384 
    385     /// Open for output.  Default for @c ofstream and fstream.
    386     static const openmode out =		_S_out;
    387 
    388     /// Open for input.  Default for @c ofstream.
    389     static const openmode trunc =	_S_trunc;
    390 
    391     // 27.4.2.1.5  Type ios_base::seekdir
    392     /**
    393      *  @brief This is an enumerated type.
    394      *
    395      *  @c "_Ios_Seekdir" is implementation-defined.  Defined values
    396      *  of type seekdir are:
    397      *  - beg
    398      *  - cur, equivalent to @c SEEK_CUR in the C standard library.
    399      *  - end, equivalent to @c SEEK_END in the C standard library.
    400     */
    401     typedef _Ios_Seekdir seekdir;
    402 
    403     /// Request a seek relative to the beginning of the stream.
    404     static const seekdir beg =		_S_beg;
    405 
    406     /// Request a seek relative to the current position within the sequence.
    407     static const seekdir cur =		_S_cur;
    408 
    409     /// Request a seek relative to the current end of the sequence.
    410     static const seekdir end =		_S_end;
    411 
    412     // Annex D.6
    413     typedef int io_state;
    414     typedef int open_mode;
    415     typedef int seek_dir;
    416 
    417     typedef std::streampos streampos;
    418     typedef std::streamoff streamoff;
    419 
    420     // Callbacks;
    421     /**
    422      *  @brief  The set of events that may be passed to an event callback.
    423      *
    424      *  erase_event is used during ~ios() and copyfmt().  imbue_event is used
    425      *  during imbue().  copyfmt_event is used during copyfmt().
    426     */
    427     enum event
    428     {
    429       erase_event,
    430       imbue_event,
    431       copyfmt_event
    432     };
    433 
    434     /**
    435      *  @brief  The type of an event callback function.
    436      *  @param  event  One of the members of the event enum.
    437      *  @param  ios_base  Reference to the ios_base object.
    438      *  @param  int  The integer provided when the callback was registered.
    439      *
    440      *  Event callbacks are user defined functions that get called during
    441      *  several ios_base and basic_ios functions, specifically imbue(),
    442      *  copyfmt(), and ~ios().
    443     */
    444     typedef void (*event_callback) (event, ios_base&, int);
    445 
    446     /**
    447      *  @brief  Add the callback __fn with parameter __index.
    448      *  @param  __fn  The function to add.
    449      *  @param  __index  The integer to pass to the function when invoked.
    450      *
    451      *  Registers a function as an event callback with an integer parameter to
    452      *  be passed to the function when invoked.  Multiple copies of the
    453      *  function are allowed.  If there are multiple callbacks, they are
    454      *  invoked in the order they were registered.
    455     */
    456     void
    457     register_callback(event_callback __fn, int __index);
    458 
    459   protected:
    460     //@{
    461     /**
    462      *  ios_base data members (doc me)
    463     */
    464     streamsize		_M_precision;
    465     streamsize		_M_width;
    466     fmtflags		_M_flags;
    467     iostate		_M_exception;
    468     iostate		_M_streambuf_state;
    469     //@}
    470 
    471     // 27.4.2.6  Members for callbacks
    472     // 27.4.2.6  ios_base callbacks
    473     struct _Callback_list
    474     {
    475       // Data Members
    476       _Callback_list*		_M_next;
    477       ios_base::event_callback	_M_fn;
    478       int			_M_index;
    479       _Atomic_word		_M_refcount;  // 0 means one reference.
    480 
    481       _Callback_list(ios_base::event_callback __fn, int __index,
    482 		     _Callback_list* __cb)
    483       : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }
    484 
    485       void
    486       _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
    487 
    488       // 0 => OK to delete.
    489       int
    490       _M_remove_reference()
    491       { return __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1); }
    492     };
    493 
    494      _Callback_list*	_M_callbacks;
    495 
    496     void
    497     _M_call_callbacks(event __ev) throw();
    498 
    499     void
    500     _M_dispose_callbacks(void);
    501 
    502     // 27.4.2.5  Members for iword/pword storage
    503     struct _Words
    504     {
    505       void*	_M_pword;
    506       long	_M_iword;
    507       _Words() : _M_pword(0), _M_iword(0) { }
    508     };
    509 
    510     // Only for failed iword/pword calls.
    511     _Words		_M_word_zero;
    512 
    513     // Guaranteed storage.
    514     // The first 5 iword and pword slots are reserved for internal use.
    515     enum { _S_local_word_size = 8 };
    516     _Words		_M_local_word[_S_local_word_size];
    517 
    518     // Allocated storage.
    519     int			_M_word_size;
    520     _Words*		_M_word;
    521 
    522     _Words&
    523     _M_grow_words(int __index, bool __iword);
    524 
    525     // Members for locale and locale caching.
    526     locale		_M_ios_locale;
    527 
    528     void
    529     _M_init();
    530 
    531   public:
    532 
    533     // 27.4.2.1.6  Class ios_base::Init
    534     // Used to initialize standard streams. In theory, g++ could use
    535     // -finit-priority to order this stuff correctly without going
    536     // through these machinations.
    537     class Init
    538     {
    539       friend class ios_base;
    540     public:
    541       Init();
    542       ~Init();
    543 
    544     private:
    545       static _Atomic_word	_S_refcount;
    546       static bool		_S_synced_with_stdio;
    547     };
    548 
    549     // [27.4.2.2] fmtflags state functions
    550     /**
    551      *  @brief  Access to format flags.
    552      *  @return  The format control flags for both input and output.
    553     */
    554     fmtflags
    555     flags() const
    556     { return _M_flags; }
    557 
    558     /**
    559      *  @brief  Setting new format flags all at once.
    560      *  @param  fmtfl  The new flags to set.
    561      *  @return  The previous format control flags.
    562      *
    563      *  This function overwrites all the format flags with @a fmtfl.
    564     */
    565     fmtflags
    566     flags(fmtflags __fmtfl)
    567     {
    568       fmtflags __old = _M_flags;
    569       _M_flags = __fmtfl;
    570       return __old;
    571     }
    572 
    573     /**
    574      *  @brief  Setting new format flags.
    575      *  @param  fmtfl  Additional flags to set.
    576      *  @return  The previous format control flags.
    577      *
    578      *  This function sets additional flags in format control.  Flags that
    579      *  were previously set remain set.
    580     */
    581     fmtflags
    582     setf(fmtflags __fmtfl)
    583     {
    584       fmtflags __old = _M_flags;
    585       _M_flags |= __fmtfl;
    586       return __old;
    587     }
    588 
    589     /**
    590      *  @brief  Setting new format flags.
    591      *  @param  fmtfl  Additional flags to set.
    592      *  @param  mask  The flags mask for @a fmtfl.
    593      *  @return  The previous format control flags.
    594      *
    595      *  This function clears @a mask in the format flags, then sets
    596      *  @a fmtfl @c & @a mask.  An example mask is @c ios_base::adjustfield.
    597     */
    598     fmtflags
    599     setf(fmtflags __fmtfl, fmtflags __mask)
    600     {
    601       fmtflags __old = _M_flags;
    602       _M_flags &= ~__mask;
    603       _M_flags |= (__fmtfl & __mask);
    604       return __old;
    605     }
    606 
    607     /**
    608      *  @brief  Clearing format flags.
    609      *  @param  mask  The flags to unset.
    610      *
    611      *  This function clears @a mask in the format flags.
    612     */
    613     void
    614     unsetf(fmtflags __mask)
    615     { _M_flags &= ~__mask; }
    616 
    617     /**
    618      *  @brief  Flags access.
    619      *  @return  The precision to generate on certain output operations.
    620      *
    621      *  Be careful if you try to give a definition of "precision" here; see
    622      *  DR 189.
    623     */
    624     streamsize
    625     precision() const
    626     { return _M_precision; }
    627 
    628     /**
    629      *  @brief  Changing flags.
    630      *  @param  prec  The new precision value.
    631      *  @return  The previous value of precision().
    632     */
    633     streamsize
    634     precision(streamsize __prec)
    635     {
    636       streamsize __old = _M_precision;
    637       _M_precision = __prec;
    638       return __old;
    639     }
    640 
    641     /**
    642      *  @brief  Flags access.
    643      *  @return  The minimum field width to generate on output operations.
    644      *
    645      *  "Minimum field width" refers to the number of characters.
    646     */
    647     streamsize
    648     width() const
    649     { return _M_width; }
    650 
    651     /**
    652      *  @brief  Changing flags.
    653      *  @param  wide  The new width value.
    654      *  @return  The previous value of width().
    655     */
    656     streamsize
    657     width(streamsize __wide)
    658     {
    659       streamsize __old = _M_width;
    660       _M_width = __wide;
    661       return __old;
    662     }
    663 
    664     // [27.4.2.4] ios_base static members
    665     /**
    666      *  @brief  Interaction with the standard C I/O objects.
    667      *  @param  sync  Whether to synchronize or not.
    668      *  @return  True if the standard streams were previously synchronized.
    669      *
    670      *  The synchronization referred to is @e only that between the standard
    671      *  C facilities (e.g., stdout) and the standard C++ objects (e.g.,
    672      *  cout).  User-declared streams are unaffected.  See
    673      *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch28s02.html
    674     */
    675     static bool
    676     sync_with_stdio(bool __sync = true);
    677 
    678     // [27.4.2.3] ios_base locale functions
    679     /**
    680      *  @brief  Setting a new locale.
    681      *  @param  loc  The new locale.
    682      *  @return  The previous locale.
    683      *
    684      *  Sets the new locale for this stream, and then invokes each callback
    685      *  with imbue_event.
    686     */
    687     locale
    688     imbue(const locale& __loc);
    689 
    690     /**
    691      *  @brief  Locale access
    692      *  @return  A copy of the current locale.
    693      *
    694      *  If @c imbue(loc) has previously been called, then this function
    695      *  returns @c loc.  Otherwise, it returns a copy of @c std::locale(),
    696      *  the global C++ locale.
    697     */
    698     locale
    699     getloc() const
    700     { return _M_ios_locale; }
    701 
    702     /**
    703      *  @brief  Locale access
    704      *  @return  A reference to the current locale.
    705      *
    706      *  Like getloc above, but returns a reference instead of
    707      *  generating a copy.
    708     */
    709     const locale&
    710     _M_getloc() const
    711     { return _M_ios_locale; }
    712 
    713     // [27.4.2.5] ios_base storage functions
    714     /**
    715      *  @brief  Access to unique indices.
    716      *  @return  An integer different from all previous calls.
    717      *
    718      *  This function returns a unique integer every time it is called.  It
    719      *  can be used for any purpose, but is primarily intended to be a unique
    720      *  index for the iword and pword functions.  The expectation is that an
    721      *  application calls xalloc in order to obtain an index in the iword and
    722      *  pword arrays that can be used without fear of conflict.
    723      *
    724      *  The implementation maintains a static variable that is incremented and
    725      *  returned on each invocation.  xalloc is guaranteed to return an index
    726      *  that is safe to use in the iword and pword arrays.
    727     */
    728     static int
    729     xalloc() throw();
    730 
    731     /**
    732      *  @brief  Access to integer array.
    733      *  @param  __ix  Index into the array.
    734      *  @return  A reference to an integer associated with the index.
    735      *
    736      *  The iword function provides access to an array of integers that can be
    737      *  used for any purpose.  The array grows as required to hold the
    738      *  supplied index.  All integers in the array are initialized to 0.
    739      *
    740      *  The implementation reserves several indices.  You should use xalloc to
    741      *  obtain an index that is safe to use.  Also note that since the array
    742      *  can grow dynamically, it is not safe to hold onto the reference.
    743     */
    744     long&
    745     iword(int __ix)
    746     {
    747       _Words& __word = (__ix < _M_word_size)
    748 			? _M_word[__ix] : _M_grow_words(__ix, true);
    749       return __word._M_iword;
    750     }
    751 
    752     /**
    753      *  @brief  Access to void pointer array.
    754      *  @param  __ix  Index into the array.
    755      *  @return  A reference to a void* associated with the index.
    756      *
    757      *  The pword function provides access to an array of pointers that can be
    758      *  used for any purpose.  The array grows as required to hold the
    759      *  supplied index.  All pointers in the array are initialized to 0.
    760      *
    761      *  The implementation reserves several indices.  You should use xalloc to
    762      *  obtain an index that is safe to use.  Also note that since the array
    763      *  can grow dynamically, it is not safe to hold onto the reference.
    764     */
    765     void*&
    766     pword(int __ix)
    767     {
    768       _Words& __word = (__ix < _M_word_size)
    769 			? _M_word[__ix] : _M_grow_words(__ix, false);
    770       return __word._M_pword;
    771     }
    772 
    773     // Destructor
    774     /**
    775      *  Invokes each callback with erase_event.  Destroys local storage.
    776      *
    777      *  Note that the ios_base object for the standard streams never gets
    778      *  destroyed.  As a result, any callbacks registered with the standard
    779      *  streams will not get invoked with erase_event (unless copyfmt is
    780      *  used).
    781     */
    782     virtual ~ios_base();
    783 
    784   protected:
    785     ios_base();
    786 
    787   // _GLIBCXX_RESOLVE_LIB_DEFECTS
    788   // 50.  Copy constructor and assignment operator of ios_base
    789   private:
    790     ios_base(const ios_base&);
    791 
    792     ios_base&
    793     operator=(const ios_base&);
    794   };
    795 
    796   // [27.4.5.1] fmtflags manipulators
    797   /// Calls base.setf(ios_base::boolalpha).
    798   inline ios_base&
    799   boolalpha(ios_base& __base)
    800   {
    801     __base.setf(ios_base::boolalpha);
    802     return __base;
    803   }
    804 
    805   /// Calls base.unsetf(ios_base::boolalpha).
    806   inline ios_base&
    807   noboolalpha(ios_base& __base)
    808   {
    809     __base.unsetf(ios_base::boolalpha);
    810     return __base;
    811   }
    812 
    813   /// Calls base.setf(ios_base::showbase).
    814   inline ios_base&
    815   showbase(ios_base& __base)
    816   {
    817     __base.setf(ios_base::showbase);
    818     return __base;
    819   }
    820 
    821   /// Calls base.unsetf(ios_base::showbase).
    822   inline ios_base&
    823   noshowbase(ios_base& __base)
    824   {
    825     __base.unsetf(ios_base::showbase);
    826     return __base;
    827   }
    828 
    829   /// Calls base.setf(ios_base::showpoint).
    830   inline ios_base&
    831   showpoint(ios_base& __base)
    832   {
    833     __base.setf(ios_base::showpoint);
    834     return __base;
    835   }
    836 
    837   /// Calls base.unsetf(ios_base::showpoint).
    838   inline ios_base&
    839   noshowpoint(ios_base& __base)
    840   {
    841     __base.unsetf(ios_base::showpoint);
    842     return __base;
    843   }
    844 
    845   /// Calls base.setf(ios_base::showpos).
    846   inline ios_base&
    847   showpos(ios_base& __base)
    848   {
    849     __base.setf(ios_base::showpos);
    850     return __base;
    851   }
    852 
    853   /// Calls base.unsetf(ios_base::showpos).
    854   inline ios_base&
    855   noshowpos(ios_base& __base)
    856   {
    857     __base.unsetf(ios_base::showpos);
    858     return __base;
    859   }
    860 
    861   /// Calls base.setf(ios_base::skipws).
    862   inline ios_base&
    863   skipws(ios_base& __base)
    864   {
    865     __base.setf(ios_base::skipws);
    866     return __base;
    867   }
    868 
    869   /// Calls base.unsetf(ios_base::skipws).
    870   inline ios_base&
    871   noskipws(ios_base& __base)
    872   {
    873     __base.unsetf(ios_base::skipws);
    874     return __base;
    875   }
    876 
    877   /// Calls base.setf(ios_base::uppercase).
    878   inline ios_base&
    879   uppercase(ios_base& __base)
    880   {
    881     __base.setf(ios_base::uppercase);
    882     return __base;
    883   }
    884 
    885   /// Calls base.unsetf(ios_base::uppercase).
    886   inline ios_base&
    887   nouppercase(ios_base& __base)
    888   {
    889     __base.unsetf(ios_base::uppercase);
    890     return __base;
    891   }
    892 
    893   /// Calls base.setf(ios_base::unitbuf).
    894   inline ios_base&
    895   unitbuf(ios_base& __base)
    896   {
    897      __base.setf(ios_base::unitbuf);
    898      return __base;
    899   }
    900 
    901   /// Calls base.unsetf(ios_base::unitbuf).
    902   inline ios_base&
    903   nounitbuf(ios_base& __base)
    904   {
    905      __base.unsetf(ios_base::unitbuf);
    906      return __base;
    907   }
    908 
    909   // [27.4.5.2] adjustfield manipulators
    910   /// Calls base.setf(ios_base::internal, ios_base::adjustfield).
    911   inline ios_base&
    912   internal(ios_base& __base)
    913   {
    914      __base.setf(ios_base::internal, ios_base::adjustfield);
    915      return __base;
    916   }
    917 
    918   /// Calls base.setf(ios_base::left, ios_base::adjustfield).
    919   inline ios_base&
    920   left(ios_base& __base)
    921   {
    922     __base.setf(ios_base::left, ios_base::adjustfield);
    923     return __base;
    924   }
    925 
    926   /// Calls base.setf(ios_base::right, ios_base::adjustfield).
    927   inline ios_base&
    928   right(ios_base& __base)
    929   {
    930     __base.setf(ios_base::right, ios_base::adjustfield);
    931     return __base;
    932   }
    933 
    934   // [27.4.5.3] basefield manipulators
    935   /// Calls base.setf(ios_base::dec, ios_base::basefield).
    936   inline ios_base&
    937   dec(ios_base& __base)
    938   {
    939     __base.setf(ios_base::dec, ios_base::basefield);
    940     return __base;
    941   }
    942 
    943   /// Calls base.setf(ios_base::hex, ios_base::basefield).
    944   inline ios_base&
    945   hex(ios_base& __base)
    946   {
    947     __base.setf(ios_base::hex, ios_base::basefield);
    948     return __base;
    949   }
    950 
    951   /// Calls base.setf(ios_base::oct, ios_base::basefield).
    952   inline ios_base&
    953   oct(ios_base& __base)
    954   {
    955     __base.setf(ios_base::oct, ios_base::basefield);
    956     return __base;
    957   }
    958 
    959   // [27.4.5.4] floatfield manipulators
    960   /// Calls base.setf(ios_base::fixed, ios_base::floatfield).
    961   inline ios_base&
    962   fixed(ios_base& __base)
    963   {
    964     __base.setf(ios_base::fixed, ios_base::floatfield);
    965     return __base;
    966   }
    967 
    968   /// Calls base.setf(ios_base::scientific, ios_base::floatfield).
    969   inline ios_base&
    970   scientific(ios_base& __base)
    971   {
    972     __base.setf(ios_base::scientific, ios_base::floatfield);
    973     return __base;
    974   }
    975 
    976 _GLIBCXX_END_NAMESPACE
    977 
    978 #undef _IOS_BASE_SEEK_CUR
    979 #undef _IOS_BASE_SEEK_END
    980 
    981 #endif /* _IOS_BASE_H */
    982 
    983