// Iostreams base classes -*- C++ -*-
	
	// Copyright (C) 1997-2013 Free Software Foundation, Inc.
	//
	// This file is part of the GNU ISO C++ Library.  This library is free
	// software; you can redistribute it and/or modify it under the
	// terms of the GNU General Public License as published by the
	// Free Software Foundation; either version 3, or (at your option)
	// any later version.
	
	// This library is distributed in the hope that it will be useful,
	// but WITHOUT ANY WARRANTY; without even the implied warranty of
	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	// GNU General Public License for more details.
	
	// Under Section 7 of GPL version 3, you are granted additional
	// permissions described in the GCC Runtime Library Exception, version
	// 3.1, as published by the Free Software Foundation.
	
	// You should have received a copy of the GNU General Public License and
	// a copy of the GCC Runtime Library Exception along with this program;
	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
	// <http://www.gnu.org/licenses/>.
	
	/** @file bits/ios_base.h
	 *  This is an internal header file, included by other library headers.
	 *  Do not attempt to use it directly. @headername{ios}
	 */
	
	//
	// ISO C++ 14882: 27.4  Iostreams base classes
	//
	
	#ifndef _IOS_BASE_H
	#define _IOS_BASE_H 1
	
	#pragma GCC system_header
	
	#include <ext/atomicity.h>
	#include <bits/localefwd.h>
	#include <bits/locale_classes.h>
	
	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION
	
	  // The following definitions of bitmask types are enums, not ints,
	  // as permitted (but not required) in the standard, in order to provide
	  // better type safety in iostream calls.  A side effect is that
	  // expressions involving them are no longer compile-time constants.
	  enum _Ios_Fmtflags 
	    { 
	      _S_boolalpha 	= 1L << 0,
	      _S_dec 		= 1L << 1,
	      _S_fixed 		= 1L << 2,
	      _S_hex 		= 1L << 3,
	      _S_internal 	= 1L << 4,
	      _S_left 		= 1L << 5,
	      _S_oct 		= 1L << 6,
	      _S_right 		= 1L << 7,
	      _S_scientific 	= 1L << 8,
	      _S_showbase 	= 1L << 9,
	      _S_showpoint 	= 1L << 10,
	      _S_showpos 	= 1L << 11,
	      _S_skipws 	= 1L << 12,
	      _S_unitbuf 	= 1L << 13,
	      _S_uppercase 	= 1L << 14,
	      _S_adjustfield 	= _S_left | _S_right | _S_internal,
	      _S_basefield 	= _S_dec | _S_oct | _S_hex,
	      _S_floatfield 	= _S_scientific | _S_fixed,
	      _S_ios_fmtflags_end = 1L << 16 
	    };
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
	  operator&(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
	  { return _Ios_Fmtflags(static_cast<int>(__a) & static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
	  operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
	  { return _Ios_Fmtflags(static_cast<int>(__a) | static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
	  operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
	  { return _Ios_Fmtflags(static_cast<int>(__a) ^ static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Fmtflags
	  operator~(_Ios_Fmtflags __a)
	  { return _Ios_Fmtflags(~static_cast<int>(__a)); }
	
	  inline const _Ios_Fmtflags&
	  operator|=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
	  { return __a = __a | __b; }
	
	  inline const _Ios_Fmtflags&
	  operator&=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
	  { return __a = __a & __b; }
	
	  inline const _Ios_Fmtflags&
	  operator^=(_Ios_Fmtflags& __a, _Ios_Fmtflags __b)
	  { return __a = __a ^ __b; }
	
	
	  enum _Ios_Openmode 
	    { 
	      _S_app 		= 1L << 0,
	      _S_ate 		= 1L << 1,
	      _S_bin 		= 1L << 2,
	      _S_in 		= 1L << 3,
	      _S_out 		= 1L << 4,
	      _S_trunc 		= 1L << 5,
	      _S_ios_openmode_end = 1L << 16 
	    };
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
	  operator&(_Ios_Openmode __a, _Ios_Openmode __b)
	  { return _Ios_Openmode(static_cast<int>(__a) & static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
	  operator|(_Ios_Openmode __a, _Ios_Openmode __b)
	  { return _Ios_Openmode(static_cast<int>(__a) | static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
	  operator^(_Ios_Openmode __a, _Ios_Openmode __b)
	  { return _Ios_Openmode(static_cast<int>(__a) ^ static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Openmode
	  operator~(_Ios_Openmode __a)
	  { return _Ios_Openmode(~static_cast<int>(__a)); }
	
	  inline const _Ios_Openmode&
	  operator|=(_Ios_Openmode& __a, _Ios_Openmode __b)
	  { return __a = __a | __b; }
	
	  inline const _Ios_Openmode&
	  operator&=(_Ios_Openmode& __a, _Ios_Openmode __b)
	  { return __a = __a & __b; }
	
	  inline const _Ios_Openmode&
	  operator^=(_Ios_Openmode& __a, _Ios_Openmode __b)
	  { return __a = __a ^ __b; }
	
	
	  enum _Ios_Iostate
	    { 
	      _S_goodbit 		= 0,
	      _S_badbit 		= 1L << 0,
	      _S_eofbit 		= 1L << 1,
	      _S_failbit		= 1L << 2,
	      _S_ios_iostate_end = 1L << 16 
	    };
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
	  operator&(_Ios_Iostate __a, _Ios_Iostate __b)
	  { return _Ios_Iostate(static_cast<int>(__a) & static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
	  operator|(_Ios_Iostate __a, _Ios_Iostate __b)
	  { return _Ios_Iostate(static_cast<int>(__a) | static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
	  operator^(_Ios_Iostate __a, _Ios_Iostate __b)
	  { return _Ios_Iostate(static_cast<int>(__a) ^ static_cast<int>(__b)); }
	
	  inline _GLIBCXX_CONSTEXPR _Ios_Iostate
	  operator~(_Ios_Iostate __a)
	  { return _Ios_Iostate(~static_cast<int>(__a)); }
	
	  inline const _Ios_Iostate&
	  operator|=(_Ios_Iostate& __a, _Ios_Iostate __b)
	  { return __a = __a | __b; }
	
	  inline const _Ios_Iostate&
	  operator&=(_Ios_Iostate& __a, _Ios_Iostate __b)
	  { return __a = __a & __b; }
	
	  inline const  _Ios_Iostate&
	  operator^=(_Ios_Iostate& __a, _Ios_Iostate __b)
	  { return __a = __a ^ __b; }
	
	
	  enum _Ios_Seekdir 
	    { 
	      _S_beg = 0,
	      _S_cur = _GLIBCXX_STDIO_SEEK_CUR,
	      _S_end = _GLIBCXX_STDIO_SEEK_END,
	      _S_ios_seekdir_end = 1L << 16 
	    };
	
	  // 27.4.2  Class ios_base
	  /**
	   *  @brief  The base of the I/O class hierarchy.
	   *  @ingroup io
	   *
	   *  This class defines everything that can be defined about I/O that does
	   *  not depend on the type of characters being input or output.  Most
	   *  people will only see @c ios_base when they need to specify the full
	   *  name of the various I/O flags (e.g., the openmodes).
	  */
	  class ios_base
	  {
	  public:
	
	    /** 
	     *  @brief These are thrown to indicate problems with io.
	     *  @ingroup exceptions
	     *
	     *  27.4.2.1.1  Class ios_base::failure
	     */
	    class failure : public exception
	    {
	    public:
	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
	      // 48.  Use of non-existent exception constructor
	      explicit
	      failure(const string& __str) throw();
	
	      // This declaration is not useless:
	      // http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Vague-Linkage.html
	      virtual
	      ~failure() throw();
	
	      virtual const char*
	      what() const throw();
	
	    private:
	      string _M_msg;
	    };
	
	    // 27.4.2.1.2  Type ios_base::fmtflags
	    /**
	     *  @brief This is a bitmask type.
	     *
	     *  @c @a _Ios_Fmtflags is implementation-defined, but it is valid to
	     *  perform bitwise operations on these values and expect the Right
	     *  Thing to happen.  Defined objects of type fmtflags are:
	     *  - boolalpha
	     *  - dec
	     *  - fixed
	     *  - hex
	     *  - internal
	     *  - left
	     *  - oct
	     *  - right
	     *  - scientific
	     *  - showbase
	     *  - showpoint
	     *  - showpos
	     *  - skipws
	     *  - unitbuf
	     *  - uppercase
	     *  - adjustfield
	     *  - basefield
	     *  - floatfield
	    */
	    typedef _Ios_Fmtflags fmtflags;
	
	    /// Insert/extract @c bool in alphabetic rather than numeric format.
	    static const fmtflags boolalpha =   _S_boolalpha;
	
	    /// Converts integer input or generates integer output in decimal base.
	    static const fmtflags dec =         _S_dec;
	
	    /// Generate floating-point output in fixed-point notation.
	    static const fmtflags fixed =       _S_fixed;
	
	    /// Converts integer input or generates integer output in hexadecimal base.
	    static const fmtflags hex =         _S_hex;
	
	    /// Adds fill characters at a designated internal point in certain
	    /// generated output, or identical to @c right if no such point is
	    /// designated.
	    static const fmtflags internal =    _S_internal;
	
	    /// Adds fill characters on the right (final positions) of certain
	    /// generated output.  (I.e., the thing you print is flush left.)
	    static const fmtflags left =        _S_left;
	
	    /// Converts integer input or generates integer output in octal base.
	    static const fmtflags oct =         _S_oct;
	
	    /// Adds fill characters on the left (initial positions) of certain
	    /// generated output.  (I.e., the thing you print is flush right.)
	    static const fmtflags right =       _S_right;
	
	    /// Generates floating-point output in scientific notation.
	    static const fmtflags scientific =  _S_scientific;
	
	    /// Generates a prefix indicating the numeric base of generated integer
	    /// output.
	    static const fmtflags showbase =    _S_showbase;
	
	    /// Generates a decimal-point character unconditionally in generated
	    /// floating-point output.
	    static const fmtflags showpoint =   _S_showpoint;
	
	    /// Generates a + sign in non-negative generated numeric output.
	    static const fmtflags showpos =     _S_showpos;
	
	    /// Skips leading white space before certain input operations.
	    static const fmtflags skipws =      _S_skipws;
	
	    /// Flushes output after each output operation.
	    static const fmtflags unitbuf =     _S_unitbuf;
	
	    /// Replaces certain lowercase letters with their uppercase equivalents
	    /// in generated output.
	    static const fmtflags uppercase =   _S_uppercase;
	
	    /// A mask of left|right|internal.  Useful for the 2-arg form of @c setf.
	    static const fmtflags adjustfield = _S_adjustfield;
	
	    /// A mask of dec|oct|hex.  Useful for the 2-arg form of @c setf.
	    static const fmtflags basefield =   _S_basefield;
	
	    /// A mask of scientific|fixed.  Useful for the 2-arg form of @c setf.
	    static const fmtflags floatfield =  _S_floatfield;
	
	    // 27.4.2.1.3  Type ios_base::iostate
	    /**
	     *  @brief This is a bitmask type.
	     *
	     *  @c @a _Ios_Iostate is implementation-defined, but it is valid to
	     *  perform bitwise operations on these values and expect the Right
	     *  Thing to happen.  Defined objects of type iostate are:
	     *  - badbit
	     *  - eofbit
	     *  - failbit
	     *  - goodbit
	    */
	    typedef _Ios_Iostate iostate;
	
	    /// Indicates a loss of integrity in an input or output sequence (such
	    /// as an irrecoverable read error from a file).
	    static const iostate badbit =	_S_badbit;
	
	    /// Indicates that an input operation reached the end of an input sequence.
	    static const iostate eofbit =	_S_eofbit;
	
	    /// Indicates that an input operation failed to read the expected
	    /// characters, or that an output operation failed to generate the
	    /// desired characters.
	    static const iostate failbit =	_S_failbit;
	
	    /// Indicates all is well.
	    static const iostate goodbit =	_S_goodbit;
	
	    // 27.4.2.1.4  Type ios_base::openmode
	    /**
	     *  @brief This is a bitmask type.
	     *
	     *  @c @a _Ios_Openmode is implementation-defined, but it is valid to
	     *  perform bitwise operations on these values and expect the Right
	     *  Thing to happen.  Defined objects of type openmode are:
	     *  - app
	     *  - ate
	     *  - binary
	     *  - in
	     *  - out
	     *  - trunc
	    */
	    typedef _Ios_Openmode openmode;
	
	    /// Seek to end before each write.
	    static const openmode app =		_S_app;
	
	    /// Open and seek to end immediately after opening.
	    static const openmode ate =		_S_ate;
	
	    /// Perform input and output in binary mode (as opposed to text mode).
	    /// This is probably not what you think it is; see
	    /// http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch27s02.html
	    static const openmode binary =	_S_bin;
	
	    /// Open for input.  Default for @c ifstream and fstream.
	    static const openmode in =		_S_in;
	
	    /// Open for output.  Default for @c ofstream and fstream.
	    static const openmode out =		_S_out;
	
	    /// Open for input.  Default for @c ofstream.
	    static const openmode trunc =	_S_trunc;
	
	    // 27.4.2.1.5  Type ios_base::seekdir
	    /**
	     *  @brief This is an enumerated type.
	     *
	     *  @c @a _Ios_Seekdir is implementation-defined.  Defined values
	     *  of type seekdir are:
	     *  - beg
	     *  - cur, equivalent to @c SEEK_CUR in the C standard library.
	     *  - end, equivalent to @c SEEK_END in the C standard library.
	    */
	    typedef _Ios_Seekdir seekdir;
	
	    /// Request a seek relative to the beginning of the stream.
	    static const seekdir beg =		_S_beg;
	
	    /// Request a seek relative to the current position within the sequence.
	    static const seekdir cur =		_S_cur;
	
	    /// Request a seek relative to the current end of the sequence.
	    static const seekdir end =		_S_end;
	
	    // Annex D.6
	    typedef int io_state;
	    typedef int open_mode;
	    typedef int seek_dir;
	
	    typedef std::streampos streampos;
	    typedef std::streamoff streamoff;
	
	    // Callbacks;
	    /**
	     *  @brief  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().
	    */
	    enum event
	    {
	      erase_event,
	      imbue_event,
	      copyfmt_event
	    };
	
	    /**
	     *  @brief  The type of an event callback function.
	     *  @param  __e  One of the members of the event enum.
	     *  @param  __b  Reference to the ios_base object.
	     *  @param  __i  The integer provided when the callback was registered.
	     *
	     *  Event callbacks are user defined functions that get called during
	     *  several ios_base and basic_ios functions, specifically imbue(),
	     *  copyfmt(), and ~ios().
	    */
	    typedef void (*event_callback) (event __e, ios_base& __b, int __i);
	
	    /**
	     *  @brief  Add the callback __fn with parameter __index.
	     *  @param  __fn  The function to add.
	     *  @param  __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.
	    */
	    void
	    register_callback(event_callback __fn, int __index);
	
	  protected:
	    streamsize		_M_precision;
	    streamsize		_M_width;
	    fmtflags		_M_flags;
	    iostate		_M_exception;
	    iostate		_M_streambuf_state;
	
	    // 27.4.2.6  Members for callbacks
	    // 27.4.2.6  ios_base callbacks
	    struct _Callback_list
	    {
	      // Data Members
	      _Callback_list*		_M_next;
	      ios_base::event_callback	_M_fn;
	      int			_M_index;
	      _Atomic_word		_M_refcount;  // 0 means one reference.
	
	      _Callback_list(ios_base::event_callback __fn, int __index,
			     _Callback_list* __cb)
	      : _M_next(__cb), _M_fn(__fn), _M_index(__index), _M_refcount(0) { }
	
	      void
	      _M_add_reference() { __gnu_cxx::__atomic_add_dispatch(&_M_refcount, 1); }
	
	      // 0 => OK to delete.
	      int
	      _M_remove_reference() 
	      {
	        // Be race-detector-friendly.  For more info see bits/c++config.
	        _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_refcount);
	        int __res = __gnu_cxx::__exchange_and_add_dispatch(&_M_refcount, -1);
	        if (__res == 0)
	          {
	            _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_refcount);
	          }
	        return __res;
	      }
	    };
	
	     _Callback_list*	_M_callbacks;
	
	    void
	    _M_call_callbacks(event __ev) throw();
	
	    void
	    _M_dispose_callbacks(void) throw();
	
	    // 27.4.2.5  Members for iword/pword storage
	    struct _Words
	    {
	      void*	_M_pword;
	      long	_M_iword;
	      _Words() : _M_pword(0), _M_iword(0) { }
	    };
	
	    // Only for failed iword/pword calls.
	    _Words		_M_word_zero;
	
	    // Guaranteed storage.
	    // The first 5 iword and pword slots are reserved for internal use.
	    enum { _S_local_word_size = 8 };
	    _Words		_M_local_word[_S_local_word_size];
	
	    // Allocated storage.
	    int			_M_word_size;
	    _Words*		_M_word;
	
	    _Words&
	    _M_grow_words(int __index, bool __iword);
	
	    // Members for locale and locale caching.
	    locale		_M_ios_locale;
	
	    void
	    _M_init() throw();
	
	  public:
	
	    // 27.4.2.1.6  Class ios_base::Init
	    // Used to initialize standard streams. In theory, g++ could use
	    // -finit-priority to order this stuff correctly without going
	    // through these machinations.
	    class Init
	    {
	      friend class ios_base;
	    public:
	      Init();
	      ~Init();
	
	    private:
	      static _Atomic_word	_S_refcount;
	      static bool		_S_synced_with_stdio;
	    };
	
	    // [27.4.2.2] fmtflags state functions
	    /**
	     *  @brief  Access to format flags.
	     *  @return  The format control flags for both input and output.
	    */
	    fmtflags
	    flags() const
	    { return _M_flags; }
	
	    /**
	     *  @brief  Setting new format flags all at once.
	     *  @param  __fmtfl  The new flags to set.
	     *  @return  The previous format control flags.
	     *
	     *  This function overwrites all the format flags with @a __fmtfl.
	    */
	    fmtflags
	    flags(fmtflags __fmtfl)
	    {
	      fmtflags __old = _M_flags;
	      _M_flags = __fmtfl;
	      return __old;
	    }
	
	    /**
	     *  @brief  Setting new format flags.
	     *  @param  __fmtfl  Additional flags to set.
	     *  @return  The previous format control flags.
	     *
	     *  This function sets additional flags in format control.  Flags that
	     *  were previously set remain set.
	    */
	    fmtflags
	    setf(fmtflags __fmtfl)
	    {
	      fmtflags __old = _M_flags;
	      _M_flags |= __fmtfl;
	      return __old;
	    }
	
	    /**
	     *  @brief  Setting new format flags.
	     *  @param  __fmtfl  Additional flags to set.
	     *  @param  __mask  The flags mask for @a fmtfl.
	     *  @return  The previous format control flags.
	     *
	     *  This function clears @a mask in the format flags, then sets
	     *  @a fmtfl @c & @a mask.  An example mask is @c ios_base::adjustfield.
	    */
	    fmtflags
	    setf(fmtflags __fmtfl, fmtflags __mask)
	    {
	      fmtflags __old = _M_flags;
	      _M_flags &= ~__mask;
	      _M_flags |= (__fmtfl & __mask);
	      return __old;
	    }
	
	    /**
	     *  @brief  Clearing format flags.
	     *  @param  __mask  The flags to unset.
	     *
	     *  This function clears @a __mask in the format flags.
	    */
	    void
	    unsetf(fmtflags __mask)
	    { _M_flags &= ~__mask; }
	
	    /**
	     *  @brief  Flags access.
	     *  @return  The precision to generate on certain output operations.
	     *
	     *  Be careful if you try to give a definition of @a precision here; see
	     *  DR 189.
	    */
	    streamsize
	    precision() const
	    { return _M_precision; }
	
	    /**
	     *  @brief  Changing flags.
	     *  @param  __prec  The new precision value.
	     *  @return  The previous value of precision().
	    */
	    streamsize
	    precision(streamsize __prec)
	    {
	      streamsize __old = _M_precision;
	      _M_precision = __prec;
	      return __old;
	    }
	
	    /**
	     *  @brief  Flags access.
	     *  @return  The minimum field width to generate on output operations.
	     *
	     *  <em>Minimum field width</em> refers to the number of characters.
	    */
	    streamsize
	    width() const
	    { return _M_width; }
	
	    /**
	     *  @brief  Changing flags.
	     *  @param  __wide  The new width value.
	     *  @return  The previous value of width().
	    */
	    streamsize
	    width(streamsize __wide)
	    {
	      streamsize __old = _M_width;
	      _M_width = __wide;
	      return __old;
	    }
	
	    // [27.4.2.4] ios_base static members
	    /**
	     *  @brief  Interaction with the standard C I/O objects.
	     *  @param  __sync  Whether to synchronize or not.
	     *  @return  True if the standard streams were previously synchronized.
	     *
	     *  The synchronization referred to is @e only that between the standard
	     *  C facilities (e.g., stdout) and the standard C++ objects (e.g.,
	     *  cout).  User-declared streams are unaffected.  See
	     *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch28s02.html
	    */
	    static bool
	    sync_with_stdio(bool __sync = true);
	
	    // [27.4.2.3] ios_base locale functions
	    /**
	     *  @brief  Setting a new locale.
	     *  @param  __loc  The new locale.
	     *  @return  The previous locale.
	     *
	     *  Sets the new locale for this stream, and then invokes each callback
	     *  with imbue_event.
	    */
	    locale
	    imbue(const locale& __loc) throw();
	
	    /**
	     *  @brief  Locale access
	     *  @return  A copy of the current locale.
	     *
	     *  If @c imbue(loc) has previously been called, then this function
	     *  returns @c loc.  Otherwise, it returns a copy of @c std::locale(),
	     *  the global C++ locale.
	    */
	    locale
	    getloc() const
	    { return _M_ios_locale; }
	
	    /**
	     *  @brief  Locale access
	     *  @return  A reference to the current locale.
	     *
	     *  Like getloc above, but returns a reference instead of
	     *  generating a copy.
	    */
	    const locale&
	    _M_getloc() const
	    { return _M_ios_locale; }
	
	    // [27.4.2.5] ios_base storage functions
	    /**
	     *  @brief  Access to unique indices.
	     *  @return  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.
	    */
	    static int
	    xalloc() throw();
	
	    /**
	     *  @brief  Access to integer array.
	     *  @param  __ix  Index into the array.
	     *  @return  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.
	    */
	    long&
	    iword(int __ix)
	    {
	      _Words& __word = (__ix < _M_word_size)
				? _M_word[__ix] : _M_grow_words(__ix, true);
	      return __word._M_iword;
	    }
	
	    /**
	     *  @brief  Access to void pointer array.
	     *  @param  __ix  Index into the array.
	     *  @return  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.
	    */
	    void*&
	    pword(int __ix)
	    {
	      _Words& __word = (__ix < _M_word_size)
				? _M_word[__ix] : _M_grow_words(__ix, false);
	      return __word._M_pword;
	    }
	
	    // Destructor
	    /**
	     *  Invokes each callback with erase_event.  Destroys local storage.
	     *
	     *  Note that the ios_base object for the standard streams never gets
	     *  destroyed.  As a result, any callbacks registered with the standard
	     *  streams will not get invoked with erase_event (unless copyfmt is
	     *  used).
	    */
	    virtual ~ios_base();
	
	  protected:
	    ios_base() throw ();
	
	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
	  // 50.  Copy constructor and assignment operator of ios_base
	  private:
	    ios_base(const ios_base&);
	
	    ios_base&
	    operator=(const ios_base&);
	  };
	
	  // [27.4.5.1] fmtflags manipulators
	  /// Calls base.setf(ios_base::boolalpha).
	  inline ios_base&
	  boolalpha(ios_base& __base)
	  {
	    __base.setf(ios_base::boolalpha);
	    return __base;
	  }
	
	  /// Calls base.unsetf(ios_base::boolalpha).
	  inline ios_base&
	  noboolalpha(ios_base& __base)
	  {
	    __base.unsetf(ios_base::boolalpha);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::showbase).
	  inline ios_base&
	  showbase(ios_base& __base)
	  {
	    __base.setf(ios_base::showbase);
	    return __base;
	  }
	
	  /// Calls base.unsetf(ios_base::showbase).
	  inline ios_base&
	  noshowbase(ios_base& __base)
	  {
	    __base.unsetf(ios_base::showbase);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::showpoint).
	  inline ios_base&
	  showpoint(ios_base& __base)
	  {
	    __base.setf(ios_base::showpoint);
	    return __base;
	  }
	
	  /// Calls base.unsetf(ios_base::showpoint).
	  inline ios_base&
	  noshowpoint(ios_base& __base)
	  {
	    __base.unsetf(ios_base::showpoint);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::showpos).
	  inline ios_base&
	  showpos(ios_base& __base)
	  {
	    __base.setf(ios_base::showpos);
	    return __base;
	  }
	
	  /// Calls base.unsetf(ios_base::showpos).
	  inline ios_base&
	  noshowpos(ios_base& __base)
	  {
	    __base.unsetf(ios_base::showpos);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::skipws).
	  inline ios_base&
	  skipws(ios_base& __base)
	  {
	    __base.setf(ios_base::skipws);
	    return __base;
	  }
	
	  /// Calls base.unsetf(ios_base::skipws).
	  inline ios_base&
	  noskipws(ios_base& __base)
	  {
	    __base.unsetf(ios_base::skipws);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::uppercase).
	  inline ios_base&
	  uppercase(ios_base& __base)
	  {
	    __base.setf(ios_base::uppercase);
	    return __base;
	  }
	
	  /// Calls base.unsetf(ios_base::uppercase).
	  inline ios_base&
	  nouppercase(ios_base& __base)
	  {
	    __base.unsetf(ios_base::uppercase);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::unitbuf).
	  inline ios_base&
	  unitbuf(ios_base& __base)
	  {
	     __base.setf(ios_base::unitbuf);
	     return __base;
	  }
	
	  /// Calls base.unsetf(ios_base::unitbuf).
	  inline ios_base&
	  nounitbuf(ios_base& __base)
	  {
	     __base.unsetf(ios_base::unitbuf);
	     return __base;
	  }
	
	  // [27.4.5.2] adjustfield manipulators
	  /// Calls base.setf(ios_base::internal, ios_base::adjustfield).
	  inline ios_base&
	  internal(ios_base& __base)
	  {
	     __base.setf(ios_base::internal, ios_base::adjustfield);
	     return __base;
	  }
	
	  /// Calls base.setf(ios_base::left, ios_base::adjustfield).
	  inline ios_base&
	  left(ios_base& __base)
	  {
	    __base.setf(ios_base::left, ios_base::adjustfield);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::right, ios_base::adjustfield).
	  inline ios_base&
	  right(ios_base& __base)
	  {
	    __base.setf(ios_base::right, ios_base::adjustfield);
	    return __base;
	  }
	
	  // [27.4.5.3] basefield manipulators
	  /// Calls base.setf(ios_base::dec, ios_base::basefield).
	  inline ios_base&
	  dec(ios_base& __base)
	  {
	    __base.setf(ios_base::dec, ios_base::basefield);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::hex, ios_base::basefield).
	  inline ios_base&
	  hex(ios_base& __base)
	  {
	    __base.setf(ios_base::hex, ios_base::basefield);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::oct, ios_base::basefield).
	  inline ios_base&
	  oct(ios_base& __base)
	  {
	    __base.setf(ios_base::oct, ios_base::basefield);
	    return __base;
	  }
	
	  // [27.4.5.4] floatfield manipulators
	  /// Calls base.setf(ios_base::fixed, ios_base::floatfield).
	  inline ios_base&
	  fixed(ios_base& __base)
	  {
	    __base.setf(ios_base::fixed, ios_base::floatfield);
	    return __base;
	  }
	
	  /// Calls base.setf(ios_base::scientific, ios_base::floatfield).
	  inline ios_base&
	  scientific(ios_base& __base)
	  {
	    __base.setf(ios_base::scientific, ios_base::floatfield);
	    return __base;
	  }
	
	_GLIBCXX_END_NAMESPACE_VERSION
	} // namespace
	
	#endif /* _IOS_BASE_H */