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      1 // Iostreams base classes -*- C++ -*-
      2 
      3 // Copyright (C) 1997-2013 Free Software Foundation, Inc.
      4 //
      5 // This file is part of the GNU ISO C++ Library.  This library is free
      6 // software; you can redistribute it and/or modify it under the
      7 // terms of the GNU General Public License as published by the
      8 // Free Software Foundation; either version 3, or (at your option)
      9 // any later version.
     10 
     11 // This library is distributed in the hope that it will be useful,
     12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
     13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     14 // GNU General Public License for more details.
     15 
     16 // Under Section 7 of GPL version 3, you are granted additional
     17 // permissions described in the GCC Runtime Library Exception, version
     18 // 3.1, as published by the Free Software Foundation.
     19 
     20 // You should have received a copy of the GNU General Public License and
     21 // a copy of the GCC Runtime Library Exception along with this program;
     22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     23 // <http://www.gnu.org/licenses/>.
     24 
     25 /** @file bits/ios_base.h
     26  *  This is an internal header file, included by other library headers.
     27  *  Do not attempt to use it directly. @headername{ios}
     28  */
     29 
     30 //
     31 // ISO C++ 14882: 27.4  Iostreams base classes
     32 //
     33 
     34 #ifndef _IOS_BASE_H
     35 #define _IOS_BASE_H 1
     36 
     37 #pragma GCC system_header
     38 
     39 #include <ext/atomicity.h>
     40 #include <bits/localefwd.h>
     41 #include <bits/locale_classes.h>
     42 
     43 namespace std _GLIBCXX_VISIBILITY(default)
     44 {
     45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     46 
     47   // The following definitions of bitmask types are enums, not ints,
     48   // as permitted (but not required) in the standard, in order to provide
     49   // better type safety in iostream calls.  A side effect is that
     50   // expressions involving them are no longer compile-time constants.
     51   enum _Ios_Fmtflags
     52     {
     53       _S_boolalpha 	= 1L << 0,
     54       _S_dec 		= 1L << 1,
     55       _S_fixed 		= 1L << 2,
     56       _S_hex 		= 1L << 3,
     57       _S_internal 	= 1L << 4,
     58       _S_left 		= 1L << 5,
     59       _S_oct 		= 1L << 6,
     60       _S_right 		= 1L << 7,
     61       _S_scientific 	= 1L << 8,
     62       _S_showbase 	= 1L << 9,
     63       _S_showpoint 	= 1L << 10,
     64       _S_showpos 	= 1L << 11,
     65       _S_skipws 	= 1L << 12,
     66       _S_unitbuf 	= 1L << 13,
     67       _S_uppercase 	= 1L << 14,
     68       _S_adjustfield 	= _S_left | _S_right | _S_internal,
     69       _S_basefield 	= _S_dec | _S_oct | _S_hex,
     70       _S_floatfield 	= _S_scientific | _S_fixed,
     71       _S_ios_fmtflags_end = 1L << 16
     72     };
     73 
     74   inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
     75   operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
     76   { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); }
     77 
     78   inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
     79   operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
     80   { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); }
     81 
     82   inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
     83   operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
     84   { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); }
     85 
     86   inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
     87   operator~(_Ios_Fmtflags __a)
     88   { return _Ios_Fmtflags(~static_cast<int>(__a)); }
     89 
     90   inline const _Ios_Fmtflags&
     91   operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
     92   { return __a = __a | __b; }
     93 
     94   inline const _Ios_Fmtflags&
     95   operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
     96   { return __a = __a & __b; }
     97 
     98   inline const _Ios_Fmtflags&
     99   operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
    100   { return __a = __a ^ __b; }
    101 
    102 
    103   enum _Ios_Openmode
    104     {
    105       _S_app 		= 1L << 0,
    106       _S_ate 		= 1L << 1,
    107       _S_bin 		= 1L << 2,
    108       _S_in 		= 1L << 3,
    109       _S_out 		= 1L << 4,
    110       _S_trunc 		= 1L << 5,
    111       _S_ios_openmode_end = 1L << 16
    112     };
    113 
    114   inline _GLIBCXX_CONSTEXPR _Ios_Openmode
    115   operator&(_Ios_Openmode __a, _Ios_Openmode __b)
    116   { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); }
    117 
    118   inline _GLIBCXX_CONSTEXPR _Ios_Openmode
    119   operator|(_Ios_Openmode __a, _Ios_Openmode __b)
    120   { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); }
    121 
    122   inline _GLIBCXX_CONSTEXPR _Ios_Openmode
    123   operator^(_Ios_Openmode __a, _Ios_Openmode __b)
    124   { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); }
    125 
    126   inline _GLIBCXX_CONSTEXPR _Ios_Openmode
    127   operator~(_Ios_Openmode __a)
    128   { return _Ios_Openmode(~static_cast<int>(__a)); }
    129 
    130   inline const _Ios_Openmode&
    131   operator|=(_Ios_Openmode& __a, _Ios_Openmode __b)
    132   { return __a = __a | __b; }
    133 
    134   inline const _Ios_Openmode&
    135   operator&=(_Ios_Openmode& __a, _Ios_Openmode __b)
    136   { return __a = __a & __b; }
    137 
    138   inline const _Ios_Openmode&
    139   operator^=(_Ios_Openmode& __a, _Ios_Openmode __b)
    140   { return __a = __a ^ __b; }
    141 
    142 
    143   enum _Ios_Iostate
    144     {
    145       _S_goodbit 		= 0,
    146       _S_badbit 		= 1L << 0,
    147       _S_eofbit 		= 1L << 1,
    148       _S_failbit		= 1L << 2,
    149       _S_ios_iostate_end = 1L << 16
    150     };
    151 
    152   inline _GLIBCXX_CONSTEXPR _Ios_Iostate
    153   operator&(_Ios_Iostate __a, _Ios_Iostate __b)
    154   { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); }
    155 
    156   inline _GLIBCXX_CONSTEXPR _Ios_Iostate
    157   operator|(_Ios_Iostate __a, _Ios_Iostate __b)
    158   { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); }
    159 
    160   inline _GLIBCXX_CONSTEXPR _Ios_Iostate
    161   operator^(_Ios_Iostate __a, _Ios_Iostate __b)
    162   { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); }
    163 
    164   inline _GLIBCXX_CONSTEXPR _Ios_Iostate
    165   operator~(_Ios_Iostate __a)
    166   { return _Ios_Iostate(~static_cast<int>(__a)); }
    167 
    168   inline const _Ios_Iostate&
    169   operator|=(_Ios_Iostate& __a, _Ios_Iostate __b)
    170   { return __a = __a | __b; }
    171 
    172   inline const _Ios_Iostate&
    173   operator&=(_Ios_Iostate& __a, _Ios_Iostate __b)
    174   { return __a = __a & __b; }
    175 
    176   inline const  _Ios_Iostate&
    177   operator^=(_Ios_Iostate& __a, _Ios_Iostate __b)
    178   { return __a = __a ^ __b; }
    179 
    180 
    181   enum _Ios_Seekdir
    182     {
    183       _S_beg = 0,
    184       _S_cur = _GLIBCXX_STDIO_SEEK_CUR,
    185       _S_end = _GLIBCXX_STDIO_SEEK_END,
    186       _S_ios_seekdir_end = 1L << 16
    187     };
    188 
    189   // 27.4.2  Class ios_base
    190   /**
    191    *  @brief  The base of the I/O class hierarchy.
    192    *  @ingroup io
    193    *
    194    *  This class defines everything that can be defined about I/O that does
    195    *  not depend on the type of characters being input or output.  Most
    196    *  people will only see @c ios_base when they need to specify the full
    197    *  name of the various I/O flags (e.g., the openmodes).
    198   */
    199   class ios_base
    200   {
    201   public:
    202 
    203     /**
    204      *  @brief These are thrown to indicate problems with io.
    205      *  @ingroup exceptions
    206      *
    207      *  27.4.2.1.1  Class ios_base::failure
    208      */
    209     class failure : public exception
    210     {
    211     public:
    212       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    213       // 48.  Use of non-existent exception constructor
    214       explicit
    215       failure(const string& __str) throw();
    216 
    217       // This declaration is not useless:
    218       // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html
    219       virtual
    220       ~failure() throw();
    221 
    222       virtual const char*
    223       what() const throw();
    224 
    225     private:
    226       string _M_msg;
    227     };
    228 
    229     // 27.4.2.1.2  Type ios_base::fmtflags
    230     /**
    231      *  @brief This is a bitmask type.
    232      *
    233      *  @c @a _Ios_Fmtflags is implementation-defined, but it is valid to
    234      *  perform bitwise operations on these values and expect the Right
    235      *  Thing to happen.  Defined objects of type fmtflags are:
    236      *  - boolalpha
    237      *  - dec
    238      *  - fixed
    239      *  - hex
    240      *  - internal
    241      *  - left
    242      *  - oct
    243      *  - right
    244      *  - scientific
    245      *  - showbase
    246      *  - showpoint
    247      *  - showpos
    248      *  - skipws
    249      *  - unitbuf
    250      *  - uppercase
    251      *  - adjustfield
    252      *  - basefield
    253      *  - floatfield
    254     */
    255     typedef _Ios_Fmtflags fmtflags;
    256 
    257     /// Insert/extract @c bool in alphabetic rather than numeric format.
    258     static const fmtflags boolalpha =   _S_boolalpha;
    259 
    260     /// Converts integer input or generates integer output in decimal base.
    261     static const fmtflags dec =         _S_dec;
    262 
    263     /// Generate floating-point output in fixed-point notation.
    264     static const fmtflags fixed =       _S_fixed;
    265 
    266     /// Converts integer input or generates integer output in hexadecimal base.
    267     static const fmtflags hex =         _S_hex;
    268 
    269     /// Adds fill characters at a designated internal point in certain
    270     /// generated output, or identical to @c right if no such point is
    271     /// designated.
    272     static const fmtflags internal =    _S_internal;
    273 
    274     /// Adds fill characters on the right (final positions) of certain
    275     /// generated output.  (I.e., the thing you print is flush left.)
    276     static const fmtflags left =        _S_left;
    277 
    278     /// Converts integer input or generates integer output in octal base.
    279     static const fmtflags oct =         _S_oct;
    280 
    281     /// Adds fill characters on the left (initial positions) of certain
    282     /// generated output.  (I.e., the thing you print is flush right.)
    283     static const fmtflags right =       _S_right;
    284 
    285     /// Generates floating-point output in scientific notation.
    286     static const fmtflags scientific =  _S_scientific;
    287 
    288     /// Generates a prefix indicating the numeric base of generated integer
    289     /// output.
    290     static const fmtflags showbase =    _S_showbase;
    291 
    292     /// Generates a decimal-point character unconditionally in generated
    293     /// floating-point output.
    294     static const fmtflags showpoint =   _S_showpoint;
    295 
    296     /// Generates a + sign in non-negative generated numeric output.
    297     static const fmtflags showpos =     _S_showpos;
    298 
    299     /// Skips leading white space before certain input operations.
    300     static const fmtflags skipws =      _S_skipws;
    301 
    302     /// Flushes output after each output operation.
    303     static const fmtflags unitbuf =     _S_unitbuf;
    304 
    305     /// Replaces certain lowercase letters with their uppercase equivalents
    306     /// in generated output.
    307     static const fmtflags uppercase =   _S_uppercase;
    308 
    309     /// A mask of left|right|internal.  Useful for the 2-arg form of @c setf.
    310     static const fmtflags adjustfield = _S_adjustfield;
    311 
    312     /// A mask of dec|oct|hex.  Useful for the 2-arg form of @c setf.
    313     static const fmtflags basefield =   _S_basefield;
    314 
    315     /// A mask of scientific|fixed.  Useful for the 2-arg form of @c setf.
    316     static const fmtflags floatfield =  _S_floatfield;
    317 
    318     // 27.4.2.1.3  Type ios_base::iostate
    319     /**
    320      *  @brief This is a bitmask type.
    321      *
    322      *  @c @a _Ios_Iostate is implementation-defined, but it is valid to
    323      *  perform bitwise operations on these values and expect the Right
    324      *  Thing to happen.  Defined objects of type iostate are:
    325      *  - badbit
    326      *  - eofbit
    327      *  - failbit
    328      *  - goodbit
    329     */
    330     typedef _Ios_Iostate iostate;
    331 
    332     /// Indicates a loss of integrity in an input or output sequence (such
    333     /// as an irrecoverable read error from a file).
    334     static const iostate badbit =	_S_badbit;
    335 
    336     /// Indicates that an input operation reached the end of an input sequence.
    337     static const iostate eofbit =	_S_eofbit;
    338 
    339     /// Indicates that an input operation failed to read the expected
    340     /// characters, or that an output operation failed to generate the
    341     /// desired characters.
    342     static const iostate failbit =	_S_failbit;
    343 
    344     /// Indicates all is well.
    345     static const iostate goodbit =	_S_goodbit;
    346 
    347     // 27.4.2.1.4  Type ios_base::openmode
    348     /**
    349      *  @brief This is a bitmask type.
    350      *
    351      *  @c @a _Ios_Openmode is implementation-defined, but it is valid to
    352      *  perform bitwise operations on these values and expect the Right
    353      *  Thing to happen.  Defined objects of type openmode are:
    354      *  - app
    355      *  - ate
    356      *  - binary
    357      *  - in
    358      *  - out
    359      *  - trunc
    360     */
    361     typedef _Ios_Openmode openmode;
    362 
    363     /// Seek to end before each write.
    364     static const openmode app =		_S_app;
    365 
    366     /// Open and seek to end immediately after opening.
    367     static const openmode ate =		_S_ate;
    368 
    369     /// Perform input and output in binary mode (as opposed to text mode).
    370     /// This is probably not what you think it is; see
    371     /// http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch27s02.html
    372     static const openmode binary =	_S_bin;
    373 
    374     /// Open for input.  Default for @c ifstream and fstream.
    375     static const openmode in =		_S_in;
    376 
    377     /// Open for output.  Default for @c ofstream and fstream.
    378     static const openmode out =		_S_out;
    379 
    380     /// Open for input.  Default for @c ofstream.
    381     static const openmode trunc =	_S_trunc;
    382 
    383     // 27.4.2.1.5  Type ios_base::seekdir
    384     /**
    385      *  @brief This is an enumerated type.
    386      *
    387      *  @c @a _Ios_Seekdir is implementation-defined.  Defined values
    388      *  of type seekdir are:
    389      *  - beg
    390      *  - cur, equivalent to @c SEEK_CUR in the C standard library.
    391      *  - end, equivalent to @c SEEK_END in the C standard library.
    392     */
    393     typedef _Ios_Seekdir seekdir;
    394 
    395     /// Request a seek relative to the beginning of the stream.
    396     static const seekdir beg =		_S_beg;
    397 
    398     /// Request a seek relative to the current position within the sequence.
    399     static const seekdir cur =		_S_cur;
    400 
    401     /// Request a seek relative to the current end of the sequence.
    402     static const seekdir end =		_S_end;
    403 
    404     // Annex D.6
    405     typedef int io_state;
    406     typedef int open_mode;
    407     typedef int seek_dir;
    408 
    409     typedef std::streampos streampos;
    410     typedef std::streamoff streamoff;
    411 
    412     // Callbacks;
    413     /**
    414      *  @brief  The set of events that may be passed to an event callback.
    415      *
    416      *  erase_event is used during ~ios() and copyfmt().  imbue_event is used
    417      *  during imbue().  copyfmt_event is used during copyfmt().
    418     */
    419     enum event
    420     {
    421       erase_event,
    422       imbue_event,
    423       copyfmt_event
    424     };
    425 
    426     /**
    427      *  @brief  The type of an event callback function.
    428      *  @param  __e  One of the members of the event enum.
    429      *  @param  __b  Reference to the ios_base object.
    430      *  @param  __i  The integer provided when the callback was registered.
    431      *
    432      *  Event callbacks are user defined functions that get called during
    433      *  several ios_base and basic_ios functions, specifically imbue(),
    434      *  copyfmt(), and ~ios().
    435     */
    436     typedef void (*event_callback) (event __e, ios_base& __b, int __i);
    437 
    438     /**
    439      *  @brief  Add the callback __fn with parameter __index.
    440      *  @param  __fn  The function to add.
    441      *  @param  __index  The integer to pass to the function when invoked.
    442      *
    443      *  Registers a function as an event callback with an integer parameter to
    444      *  be passed to the function when invoked.  Multiple copies of the
    445      *  function are allowed.  If there are multiple callbacks, they are
    446      *  invoked in the order they were registered.
    447     */
    448     void
    449     register_callback(event_callback __fn, int __index);
    450 
    451   protected:
    452     streamsize		_M_precision;
    453     streamsize		_M_width;
    454     fmtflags		_M_flags;
    455     iostate		_M_exception;
    456     iostate		_M_streambuf_state;
    457 
    458     // 27.4.2.6  Members for callbacks
    459     // 27.4.2.6  ios_base callbacks
    460     struct _Callback_list
    461     {
    462       // Data Members
    463       _Callback_list*		_M_next;
    464       ios_base::event_callback	_M_fn;
    465       int			_M_index;
    466       _Atomic_word		_M_refcount;  // 0 means one reference.
    467 
    468       _Callback_list(ios_base::event_callback __fn, int __index,
    469 		     _Callback_list* __cb)
    470       : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }
    471 
    472       void
    473       _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
    474 
    475       // 0 => OK to delete.
    476       int
    477       _M_remove_reference()
    478       {
    479         // Be race-detector-friendly.  For more info see bits/c++config.
    480         _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
    481         int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1);
    482         if (__res == 0)
    483           {
    484             _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
    485           }
    486         return __res;
    487       }
    488     };
    489 
    490      _Callback_list*	_M_callbacks;
    491 
    492     void
    493     _M_call_callbacks(event __ev) throw();
    494 
    495     void
    496     _M_dispose_callbacks(void) throw();
    497 
    498     // 27.4.2.5  Members for iword/pword storage
    499     struct _Words
    500     {
    501       void*	_M_pword;
    502       long	_M_iword;
    503       _Words() : _M_pword(0), _M_iword(0) { }
    504     };
    505 
    506     // Only for failed iword/pword calls.
    507     _Words		_M_word_zero;
    508 
    509     // Guaranteed storage.
    510     // The first 5 iword and pword slots are reserved for internal use.
    511     enum { _S_local_word_size = 8 };
    512     _Words		_M_local_word[_S_local_word_size];
    513 
    514     // Allocated storage.
    515     int			_M_word_size;
    516     _Words*		_M_word;
    517 
    518     _Words&
    519     _M_grow_words(int __index, bool __iword);
    520 
    521     // Members for locale and locale caching.
    522     locale		_M_ios_locale;
    523 
    524     void
    525     _M_init() throw();
    526 
    527   public:
    528 
    529     // 27.4.2.1.6  Class ios_base::Init
    530     // Used to initialize standard streams. In theory, g++ could use
    531     // -finit-priority to order this stuff correctly without going
    532     // through these machinations.
    533     class Init
    534     {
    535       friend class ios_base;
    536     public:
    537       Init();
    538       ~Init();
    539 
    540     private:
    541       static _Atomic_word	_S_refcount;
    542       static bool		_S_synced_with_stdio;
    543     };
    544 
    545     // [27.4.2.2] fmtflags state functions
    546     /**
    547      *  @brief  Access to format flags.
    548      *  @return  The format control flags for both input and output.
    549     */
    550     fmtflags
    551     flags() const
    552     { return _M_flags; }
    553 
    554     /**
    555      *  @brief  Setting new format flags all at once.
    556      *  @param  __fmtfl  The new flags to set.
    557      *  @return  The previous format control flags.
    558      *
    559      *  This function overwrites all the format flags with @a __fmtfl.
    560     */
    561     fmtflags
    562     flags(fmtflags __fmtfl)
    563     {
    564       fmtflags __old = _M_flags;
    565       _M_flags = __fmtfl;
    566       return __old;
    567     }
    568 
    569     /**
    570      *  @brief  Setting new format flags.
    571      *  @param  __fmtfl  Additional flags to set.
    572      *  @return  The previous format control flags.
    573      *
    574      *  This function sets additional flags in format control.  Flags that
    575      *  were previously set remain set.
    576     */
    577     fmtflags
    578     setf(fmtflags __fmtfl)
    579     {
    580       fmtflags __old = _M_flags;
    581       _M_flags |= __fmtfl;
    582       return __old;
    583     }
    584 
    585     /**
    586      *  @brief  Setting new format flags.
    587      *  @param  __fmtfl  Additional flags to set.
    588      *  @param  __mask  The flags mask for @a fmtfl.
    589      *  @return  The previous format control flags.
    590      *
    591      *  This function clears @a mask in the format flags, then sets
    592      *  @a fmtfl @c & @a mask.  An example mask is @c ios_base::adjustfield.
    593     */
    594     fmtflags
    595     setf(fmtflags __fmtfl, fmtflags __mask)
    596     {
    597       fmtflags __old = _M_flags;
    598       _M_flags &= ~__mask;
    599       _M_flags |= (__fmtfl & __mask);
    600       return __old;
    601     }
    602 
    603     /**
    604      *  @brief  Clearing format flags.
    605      *  @param  __mask  The flags to unset.
    606      *
    607      *  This function clears @a __mask in the format flags.
    608     */
    609     void
    610     unsetf(fmtflags __mask)
    611     { _M_flags &= ~__mask; }
    612 
    613     /**
    614      *  @brief  Flags access.
    615      *  @return  The precision to generate on certain output operations.
    616      *
    617      *  Be careful if you try to give a definition of @a precision here; see
    618      *  DR 189.
    619     */
    620     streamsize
    621     precision() const
    622     { return _M_precision; }
    623 
    624     /**
    625      *  @brief  Changing flags.
    626      *  @param  __prec  The new precision value.
    627      *  @return  The previous value of precision().
    628     */
    629     streamsize
    630     precision(streamsize __prec)
    631     {
    632       streamsize __old = _M_precision;
    633       _M_precision = __prec;
    634       return __old;
    635     }
    636 
    637     /**
    638      *  @brief  Flags access.
    639      *  @return  The minimum field width to generate on output operations.
    640      *
    641      *  <em>Minimum field width</em> refers to the number of characters.
    642     */
    643     streamsize
    644     width() const
    645     { return _M_width; }
    646 
    647     /**
    648      *  @brief  Changing flags.
    649      *  @param  __wide  The new width value.
    650      *  @return  The previous value of width().
    651     */
    652     streamsize
    653     width(streamsize __wide)
    654     {
    655       streamsize __old = _M_width;
    656       _M_width = __wide;
    657       return __old;
    658     }
    659 
    660     // [27.4.2.4] ios_base static members
    661     /**
    662      *  @brief  Interaction with the standard C I/O objects.
    663      *  @param  __sync  Whether to synchronize or not.
    664      *  @return  True if the standard streams were previously synchronized.
    665      *
    666      *  The synchronization referred to is @e only that between the standard
    667      *  C facilities (e.g., stdout) and the standard C++ objects (e.g.,
    668      *  cout).  User-declared streams are unaffected.  See
    669      *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch28s02.html
    670     */
    671     static bool
    672     sync_with_stdio(bool __sync = true);
    673 
    674     // [27.4.2.3] ios_base locale functions
    675     /**
    676      *  @brief  Setting a new locale.
    677      *  @param  __loc  The new locale.
    678      *  @return  The previous locale.
    679      *
    680      *  Sets the new locale for this stream, and then invokes each callback
    681      *  with imbue_event.
    682     */
    683     locale
    684     imbue(const locale& __loc) throw();
    685 
    686     /**
    687      *  @brief  Locale access
    688      *  @return  A copy of the current locale.
    689      *
    690      *  If @c imbue(loc) has previously been called, then this function
    691      *  returns @c loc.  Otherwise, it returns a copy of @c std::locale(),
    692      *  the global C++ locale.
    693     */
    694     locale
    695     getloc() const
    696     { return _M_ios_locale; }
    697 
    698     /**
    699      *  @brief  Locale access
    700      *  @return  A reference to the current locale.
    701      *
    702      *  Like getloc above, but returns a reference instead of
    703      *  generating a copy.
    704     */
    705     const locale&
    706     _M_getloc() const
    707     { return _M_ios_locale; }
    708 
    709     // [27.4.2.5] ios_base storage functions
    710     /**
    711      *  @brief  Access to unique indices.
    712      *  @return  An integer different from all previous calls.
    713      *
    714      *  This function returns a unique integer every time it is called.  It
    715      *  can be used for any purpose, but is primarily intended to be a unique
    716      *  index for the iword and pword functions.  The expectation is that an
    717      *  application calls xalloc in order to obtain an index in the iword and
    718      *  pword arrays that can be used without fear of conflict.
    719      *
    720      *  The implementation maintains a static variable that is incremented and
    721      *  returned on each invocation.  xalloc is guaranteed to return an index
    722      *  that is safe to use in the iword and pword arrays.
    723     */
    724     static int
    725     xalloc() throw();
    726 
    727     /**
    728      *  @brief  Access to integer array.
    729      *  @param  __ix  Index into the array.
    730      *  @return  A reference to an integer associated with the index.
    731      *
    732      *  The iword function provides access to an array of integers that can be
    733      *  used for any purpose.  The array grows as required to hold the
    734      *  supplied index.  All integers in the array are initialized to 0.
    735      *
    736      *  The implementation reserves several indices.  You should use xalloc to
    737      *  obtain an index that is safe to use.  Also note that since the array
    738      *  can grow dynamically, it is not safe to hold onto the reference.
    739     */
    740     long&
    741     iword(int __ix)
    742     {
    743       _Words& __word = (__ix < _M_word_size)
    744 			? _M_word[__ix] : _M_grow_words(__ix, true);
    745       return __word._M_iword;
    746     }
    747 
    748     /**
    749      *  @brief  Access to void pointer array.
    750      *  @param  __ix  Index into the array.
    751      *  @return  A reference to a void* associated with the index.
    752      *
    753      *  The pword function provides access to an array of pointers that can be
    754      *  used for any purpose.  The array grows as required to hold the
    755      *  supplied index.  All pointers in the array are initialized to 0.
    756      *
    757      *  The implementation reserves several indices.  You should use xalloc to
    758      *  obtain an index that is safe to use.  Also note that since the array
    759      *  can grow dynamically, it is not safe to hold onto the reference.
    760     */
    761     void*&
    762     pword(int __ix)
    763     {
    764       _Words& __word = (__ix < _M_word_size)
    765 			? _M_word[__ix] : _M_grow_words(__ix, false);
    766       return __word._M_pword;
    767     }
    768 
    769     // Destructor
    770     /**
    771      *  Invokes each callback with erase_event.  Destroys local storage.
    772      *
    773      *  Note that the ios_base object for the standard streams never gets
    774      *  destroyed.  As a result, any callbacks registered with the standard
    775      *  streams will not get invoked with erase_event (unless copyfmt is
    776      *  used).
    777     */
    778     virtual ~ios_base();
    779 
    780   protected:
    781     ios_base() throw ();
    782 
    783   // _GLIBCXX_RESOLVE_LIB_DEFECTS
    784   // 50.  Copy constructor and assignment operator of ios_base
    785   private:
    786     ios_base(const ios_base&);
    787 
    788     ios_base&
    789     operator=(const ios_base&);
    790   };
    791 
    792   // [27.4.5.1] fmtflags manipulators
    793   /// Calls base.setf(ios_base::boolalpha).
    794   inline ios_base&
    795   boolalpha(ios_base& __base)
    796   {
    797     __base.setf(ios_base::boolalpha);
    798     return __base;
    799   }
    800 
    801   /// Calls base.unsetf(ios_base::boolalpha).
    802   inline ios_base&
    803   noboolalpha(ios_base& __base)
    804   {
    805     __base.unsetf(ios_base::boolalpha);
    806     return __base;
    807   }
    808 
    809   /// Calls base.setf(ios_base::showbase).
    810   inline ios_base&
    811   showbase(ios_base& __base)
    812   {
    813     __base.setf(ios_base::showbase);
    814     return __base;
    815   }
    816 
    817   /// Calls base.unsetf(ios_base::showbase).
    818   inline ios_base&
    819   noshowbase(ios_base& __base)
    820   {
    821     __base.unsetf(ios_base::showbase);
    822     return __base;
    823   }
    824 
    825   /// Calls base.setf(ios_base::showpoint).
    826   inline ios_base&
    827   showpoint(ios_base& __base)
    828   {
    829     __base.setf(ios_base::showpoint);
    830     return __base;
    831   }
    832 
    833   /// Calls base.unsetf(ios_base::showpoint).
    834   inline ios_base&
    835   noshowpoint(ios_base& __base)
    836   {
    837     __base.unsetf(ios_base::showpoint);
    838     return __base;
    839   }
    840 
    841   /// Calls base.setf(ios_base::showpos).
    842   inline ios_base&
    843   showpos(ios_base& __base)
    844   {
    845     __base.setf(ios_base::showpos);
    846     return __base;
    847   }
    848 
    849   /// Calls base.unsetf(ios_base::showpos).
    850   inline ios_base&
    851   noshowpos(ios_base& __base)
    852   {
    853     __base.unsetf(ios_base::showpos);
    854     return __base;
    855   }
    856 
    857   /// Calls base.setf(ios_base::skipws).
    858   inline ios_base&
    859   skipws(ios_base& __base)
    860   {
    861     __base.setf(ios_base::skipws);
    862     return __base;
    863   }
    864 
    865   /// Calls base.unsetf(ios_base::skipws).
    866   inline ios_base&
    867   noskipws(ios_base& __base)
    868   {
    869     __base.unsetf(ios_base::skipws);
    870     return __base;
    871   }
    872 
    873   /// Calls base.setf(ios_base::uppercase).
    874   inline ios_base&
    875   uppercase(ios_base& __base)
    876   {
    877     __base.setf(ios_base::uppercase);
    878     return __base;
    879   }
    880 
    881   /// Calls base.unsetf(ios_base::uppercase).
    882   inline ios_base&
    883   nouppercase(ios_base& __base)
    884   {
    885     __base.unsetf(ios_base::uppercase);
    886     return __base;
    887   }
    888 
    889   /// Calls base.setf(ios_base::unitbuf).
    890   inline ios_base&
    891   unitbuf(ios_base& __base)
    892   {
    893      __base.setf(ios_base::unitbuf);
    894      return __base;
    895   }
    896 
    897   /// Calls base.unsetf(ios_base::unitbuf).
    898   inline ios_base&
    899   nounitbuf(ios_base& __base)
    900   {
    901      __base.unsetf(ios_base::unitbuf);
    902      return __base;
    903   }
    904 
    905   // [27.4.5.2] adjustfield manipulators
    906   /// Calls base.setf(ios_base::internal, ios_base::adjustfield).
    907   inline ios_base&
    908   internal(ios_base& __base)
    909   {
    910      __base.setf(ios_base::internal, ios_base::adjustfield);
    911      return __base;
    912   }
    913 
    914   /// Calls base.setf(ios_base::left, ios_base::adjustfield).
    915   inline ios_base&
    916   left(ios_base& __base)
    917   {
    918     __base.setf(ios_base::left, ios_base::adjustfield);
    919     return __base;
    920   }
    921 
    922   /// Calls base.setf(ios_base::right, ios_base::adjustfield).
    923   inline ios_base&
    924   right(ios_base& __base)
    925   {
    926     __base.setf(ios_base::right, ios_base::adjustfield);
    927     return __base;
    928   }
    929 
    930   // [27.4.5.3] basefield manipulators
    931   /// Calls base.setf(ios_base::dec, ios_base::basefield).
    932   inline ios_base&
    933   dec(ios_base& __base)
    934   {
    935     __base.setf(ios_base::dec, ios_base::basefield);
    936     return __base;
    937   }
    938 
    939   /// Calls base.setf(ios_base::hex, ios_base::basefield).
    940   inline ios_base&
    941   hex(ios_base& __base)
    942   {
    943     __base.setf(ios_base::hex, ios_base::basefield);
    944     return __base;
    945   }
    946 
    947   /// Calls base.setf(ios_base::oct, ios_base::basefield).
    948   inline ios_base&
    949   oct(ios_base& __base)
    950   {
    951     __base.setf(ios_base::oct, ios_base::basefield);
    952     return __base;
    953   }
    954 
    955   // [27.4.5.4] floatfield manipulators
    956   /// Calls base.setf(ios_base::fixed, ios_base::floatfield).
    957   inline ios_base&
    958   fixed(ios_base& __base)
    959   {
    960     __base.setf(ios_base::fixed, ios_base::floatfield);
    961     return __base;
    962   }
    963 
    964   /// Calls base.setf(ios_base::scientific, ios_base::floatfield).
    965   inline ios_base&
    966   scientific(ios_base& __base)
    967   {
    968     __base.setf(ios_base::scientific, ios_base::floatfield);
    969     return __base;
    970   }
    971 
    972 _GLIBCXX_END_NAMESPACE_VERSION
    973 } // namespace
    974 
    975 #endif /* _IOS_BASE_H */
    976