这个人不懒😄：

// -- C++ -- forwarding header.

// Copyright (C) 1997-2014 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 include/cstdio

• This is a Standard C++ Library file. You should @c #include this file
• in your programs, rather than any of the @a *.h implementation files.
• This is the C++ version of the Standard C Library header @c stdio.h,
• and its contents are (mostly) the same as that header, but are all
• contained in the namespace @c std (except for names which are defined
• as macros in C). */

// // ISO C++ 14882: 27.8.2 C Library files //

#pragma GCC system_header

#include <bits/c++config.h> #include <stdio.h>

#ifndef _GLIBCXX_CSTDIO #define _GLIBCXX_CSTDIO 1

#ifndef _GLIBCXX_HAVE_GETS extern "C" char* gets (char* __s) attribute((deprecated)); #endif

// Get rid of those macros defined in <stdio.h> in lieu of real functions. #undef clearerr #undef fclose #undef feof #undef ferror #undef fflush #undef fgetc #undef fgetpos #undef fgets #undef fopen #undef fprintf #undef fputc #undef fputs #undef fread #undef freopen #undef fscanf #undef fseek #undef fsetpos #undef ftell #undef fwrite #undef getc #undef getchar #if __cplusplus <= 201103L

undef gets

#endif #undef perror #undef printf #undef putc #undef putchar #undef puts #undef remove #undef rename #undef rewind #undef scanf #undef setbuf #undef setvbuf #undef sprintf #undef sscanf #undef tmpfile #undef tmpnam #undef ungetc #undef vfprintf #undef vprintf #undef vsprintf

namespace std { using ::FILE; using ::fpos_t;

using ::clearerr; using ::fclose; using ::feof; using ::ferror; using ::fflush; using ::fgetc; using ::fgetpos; using ::fgets; using ::fopen; using ::fprintf; using ::fputc; using ::fputs; using ::fread; using ::freopen; using ::fscanf; using ::fseek; using ::fsetpos; using ::ftell; using ::fwrite; using ::getc; using ::getchar; #if __cplusplus <= 201103L // LWG 2249 using ::gets; #endif using ::perror; using ::printf; using ::putc; using ::putchar; using ::puts; using ::remove; using ::rename; using ::rewind; using ::scanf; using ::setbuf; using ::setvbuf; using ::sprintf; using ::sscanf; using ::tmpfile; #if _GLIBCXX_USE_TMPNAM using ::tmpnam; #endif using ::ungetc; using ::vfprintf; using ::vprintf; using ::vsprintf; } // namespace

#if _GLIBCXX_USE_C99

#undef snprintf #undef vfscanf #undef vscanf #undef vsnprintf #undef vsscanf

namespace __gnu_cxx { #if _GLIBCXX_USE_C99_CHECK || _GLIBCXX_USE_C99_DYNAMIC extern "C" int (snprintf)(char * __restrict, std::size_t, const char * __restrict, ...) throw (); extern "C" int (vfscanf)(FILE * __restrict, const char * __restrict, __gnuc_va_list); extern "C" int (vscanf)(const char * __restrict, __gnuc_va_list); extern "C" int (vsnprintf)(char * __restrict, std::size_t, const char * __restrict, __gnuc_va_list) throw (); extern "C" int (vsscanf)(const char * __restrict, const char * __restrict, __gnuc_va_list) throw (); #endif

#if !_GLIBCXX_USE_C99_DYNAMIC using ::snprintf; using ::vfscanf; using ::vscanf; using ::vsnprintf; using ::vsscanf; #endif } // namespace __gnu_cxx

namespace std { using ::__gnu_cxx::snprintf; using ::__gnu_cxx::vfscanf; using ::__gnu_cxx::vscanf; using ::__gnu_cxx::vsnprintf; using ::__gnu_cxx::vsscanf; } // namespace std

#endif // _GLIBCXX_USE_C99

#endif

【and】

// Input streams -- C++ --

// Copyright (C) 1997-2014 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/.

// // ISO C++ 14882: 27.6.1 Input streams //

/** @file include/istream

• This is a Standard C++ Library header. */

#ifndef _GLIBCXX_ISTREAM #define _GLIBCXX_ISTREAM 1

#pragma GCC system_header

#include <ios> #include <ostream>

namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION

/**

• @brief Template class basic_istream.

• @ingroup io

• @tparam _CharT Type of character stream.

• @tparam _Traits Traits for character type, defaults to

• char_traits<_CharT>.
  

• This is the base class for all input streams. It provides text

• formatting of all builtin types, and communicates with any class

• derived from basic_streambuf to do the actual input. */ template<typename _CharT, typename _Traits> class basic_istream : virtual public basic_ios<_CharT, _Traits> { public: // Types (inherited from basic_ios (27.4.4)): typedef _CharT char_type; typedef typename _Traits::int_type int_type; typedef typename _Traits::pos_type pos_type; typedef typename _Traits::off_type off_type; typedef _Traits traits_type;

  // Non-standard Types: typedef basic_streambuf<_CharT, _Traits> __streambuf_type; typedef basic_ios<_CharT, _Traits> __ios_type; typedef basic_istream<_CharT, _Traits> __istream_type; typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > __num_get_type; typedef ctype<_CharT> __ctype_type;

protected:
  // Data Members:
  /**
   *  The number of characters extracted in the previous unformatted
   *  function; see gcount().
  */
  streamsize 		_M_gcount;

public:
  /**
   *  @brief  Base constructor.
   *
   *  This ctor is almost never called by the user directly, rather from
   *  derived classes' initialization lists, which pass a pointer to
   *  their own stream buffer.
  */
  explicit
  basic_istream(__streambuf_type* __sb)
  : _M_gcount(streamsize(0))
  { this->init(__sb); }

  /**
   *  @brief  Base destructor.
   *
   *  This does very little apart from providing a virtual base dtor.
  */
  virtual
  ~basic_istream()
  { _M_gcount = streamsize(0); }

  /// Safe prefix/suffix operations.
  class sentry;
  friend class sentry;

  //@{
  /**
   *  @brief  Interface for manipulators.
   *
   *  Manipulators such as @c std::ws and @c std::dec use these
   *  functions in constructs like
   *  <code>std::cin >> std::ws</code>.
   *  For more information, see the iomanip header.
  */
  __istream_type&
  operator>>(__istream_type& (*__pf)(__istream_type&))
  { return __pf(*this); }

  __istream_type&
  operator>>(__ios_type& (*__pf)(__ios_type&))
  {
__pf(*this);
return *this;
  }

  __istream_type&
  operator>>(ios_base& (*__pf)(ios_base&))
  {
__pf(*this);
return *this;
  }
  //@}

  //@{
  /**
   *  @name Extractors
   *
   *  All the @c operator>> functions (aka <em>formatted input
   *  functions</em>) have some common behavior.  Each starts by
   *  constructing a temporary object of type std::basic_istream::sentry
   *  with the second argument (noskipws) set to false.  This has several
   *  effects, concluding with the setting of a status flag; see the
   *  sentry documentation for more.
   *
   *  If the sentry status is good, the function tries to extract
   *  whatever data is appropriate for the type of the argument.
   *
   *  If an exception is thrown during extraction, ios_base::badbit
   *  will be turned on in the stream's error state without causing an
   *  ios_base::failure to be thrown.  The original exception will then
   *  be rethrown.
  */

  //@{
  /**
   *  @brief  Integer arithmetic extractors
   *  @param  __n A variable of builtin integral type.
   *  @return  @c *this if successful
   *
   *  These functions use the stream's current locale (specifically, the
   *  @c num_get facet) to parse the input data.
  */
  __istream_type&
  operator>>(bool& __n)
  { return _M_extract(__n); }

  __istream_type&
  operator>>(short& __n);

  __istream_type&
  operator>>(unsigned short& __n)
  { return _M_extract(__n); }

  __istream_type&
  operator>>(int& __n);

  __istream_type&
  operator>>(unsigned int& __n)
  { return _M_extract(__n); }

  __istream_type&
  operator>>(long& __n)
  { return _M_extract(__n); }

  __istream_type&
  operator>>(unsigned long& __n)
  { return _M_extract(__n); }

#ifdef _GLIBCXX_USE_LONG_LONG __istream_type& operator>>(long long& __n) { return _M_extract(__n); }

__istream_type&
  operator>>(unsigned long long& __n)
  { return _M_extract(__n); }

#endif //@}

//@{
  /**
   *  @brief  Floating point arithmetic extractors
   *  @param  __f A variable of builtin floating point type.
   *  @return  @c *this if successful
   *
   *  These functions use the stream's current locale (specifically, the
   *  @c num_get facet) to parse the input data.
  */
  __istream_type&
  operator>>(float& __f)
  { return _M_extract(__f); }

  __istream_type&
  operator>>(double& __f)
  { return _M_extract(__f); }

  __istream_type&
  operator>>(long double& __f)
  { return _M_extract(__f); }
  //@}

  /**
   *  @brief  Basic arithmetic extractors
   *  @param  __p A variable of pointer type.
   *  @return  @c *this if successful
   *
   *  These functions use the stream's current locale (specifically, the
   *  @c num_get facet) to parse the input data.
  */
  __istream_type&
  operator>>(void*& __p)
  { return _M_extract(__p); }

  /**
   *  @brief  Extracting into another streambuf.
   *  @param  __sb  A pointer to a streambuf
   *
   *  This function behaves like one of the basic arithmetic extractors,
   *  in that it also constructs a sentry object and has the same error
   *  handling behavior.
   *
   *  If @p __sb is NULL, the stream will set failbit in its error state.
   *
   *  Characters are extracted from this stream and inserted into the
   *  @p __sb streambuf until one of the following occurs:
   *
   *  - the input stream reaches end-of-file,
   *  - insertion into the output buffer fails (in this case, the
   *    character that would have been inserted is not extracted), or
   *  - an exception occurs (and in this case is caught)
   *
   *  If the function inserts no characters, failbit is set.
  */
  __istream_type&
  operator>>(__streambuf_type* __sb);
  //@}

  // [27.6.1.3] unformatted input
  /**
   *  @brief  Character counting
   *  @return  The number of characters extracted by the previous
   *           unformatted input function dispatched for this stream.
  */
  streamsize
  gcount() const
  { return _M_gcount; }

  //@{
  /**
   *  @name Unformatted Input Functions
   *
   *  All the unformatted input functions have some common behavior.
   *  Each starts by constructing a temporary object of type
   *  std::basic_istream::sentry with the second argument (noskipws)
   *  set to true.  This has several effects, concluding with the
   *  setting of a status flag; see the sentry documentation for more.
   *
   *  If the sentry status is good, the function tries to extract
   *  whatever data is appropriate for the type of the argument.
   *
   *  The number of characters extracted is stored for later retrieval
   *  by gcount().
   *
   *  If an exception is thrown during extraction, ios_base::badbit
   *  will be turned on in the stream's error state without causing an
   *  ios_base::failure to be thrown.  The original exception will then
   *  be rethrown.
  */

  /**
   *  @brief  Simple extraction.
   *  @return  A character, or eof().
   *
   *  Tries to extract a character.  If none are available, sets failbit
   *  and returns traits::eof().
  */
  int_type
  get();

  /**
   *  @brief  Simple extraction.
   *  @param  __c  The character in which to store data.
   *  @return  *this
   *
   *  Tries to extract a character and store it in @a __c.  If none are
   *  available, sets failbit and returns traits::eof().
   *
   *  @note  This function is not overloaded on signed char and
   *         unsigned char.
  */
  __istream_type&
  get(char_type& __c);

  /**
   *  @brief  Simple multiple-character extraction.
   *  @param  __s  Pointer to an array.
   *  @param  __n  Maximum number of characters to store in @a __s.
   *  @param  __delim  A "stop" character.
   *  @return  *this
   *
   *  Characters are extracted and stored into @a __s until one of the
   *  following happens:
   *
   *  - @c __n-1 characters are stored
   *  - the input sequence reaches EOF
   *  - the next character equals @a __delim, in which case the character
   *    is not extracted
   *
   * If no characters are stored, failbit is set in the stream's error
   * state.
   *
   * In any case, a null character is stored into the next location in
   * the array.
   *
   *  @note  This function is not overloaded on signed char and
   *         unsigned char.
  */
  __istream_type&
  get(char_type* __s, streamsize __n, char_type __delim);

  /**
   *  @brief  Simple multiple-character extraction.
   *  @param  __s  Pointer to an array.
   *  @param  __n  Maximum number of characters to store in @a s.
   *  @return  *this
   *
   *  Returns @c get(__s,__n,widen('\\n')).
  */
  __istream_type&
  get(char_type* __s, streamsize __n)
  { return this->get(__s, __n, this->widen('\n')); }

  /**
   *  @brief  Extraction into another streambuf.
   *  @param  __sb  A streambuf in which to store data.
   *  @param  __delim  A "stop" character.
   *  @return  *this
   *
   *  Characters are extracted and inserted into @a __sb until one of the
   *  following happens:
   *
   *  - the input sequence reaches EOF
   *  - insertion into the output buffer fails (in this case, the
   *    character that would have been inserted is not extracted)
   *  - the next character equals @a __delim (in this case, the character
   *    is not extracted)
   *  - an exception occurs (and in this case is caught)
   *
   * If no characters are stored, failbit is set in the stream's error
   * state.
  */
  __istream_type&
  get(__streambuf_type& __sb, char_type __delim);

  /**
   *  @brief  Extraction into another streambuf.
   *  @param  __sb  A streambuf in which to store data.
   *  @return  *this
   *
   *  Returns @c get(__sb,widen('\\n')).
  */
  __istream_type&
  get(__streambuf_type& __sb)
  { return this->get(__sb, this->widen('\n')); }

  /**
   *  @brief  String extraction.
   *  @param  __s  A character array in which to store the data.
   *  @param  __n  Maximum number of characters to extract.
   *  @param  __delim  A "stop" character.
   *  @return  *this
   *
   *  Extracts and stores characters into @a __s until one of the
   *  following happens.  Note that these criteria are required to be
   *  tested in the order listed here, to allow an input line to exactly
   *  fill the @a __s array without setting failbit.
   *
   *  -# the input sequence reaches end-of-file, in which case eofbit
   *     is set in the stream error state
   *  -# the next character equals @c __delim, in which case the character
   *     is extracted (and therefore counted in @c gcount()) but not stored
   *  -# @c __n-1 characters are stored, in which case failbit is set
   *     in the stream error state
   *
   *  If no characters are extracted, failbit is set.  (An empty line of
   *  input should therefore not cause failbit to be set.)
   *
   *  In any case, a null character is stored in the next location in
   *  the array.
  */
  __istream_type&
  getline(char_type* __s, streamsize __n, char_type __delim);

  /**
   *  @brief  String extraction.
   *  @param  __s  A character array in which to store the data.
   *  @param  __n  Maximum number of characters to extract.
   *  @return  *this
   *
   *  Returns @c getline(__s,__n,widen('\\n')).
  */
  __istream_type&
  getline(char_type* __s, streamsize __n)
  { return this->getline(__s, __n, this->widen('\n')); }

  /**
   *  @brief  Discarding characters
   *  @param  __n  Number of characters to discard.
   *  @param  __delim  A "stop" character.
   *  @return  *this
   *
   *  Extracts characters and throws them away until one of the
   *  following happens:
   *  - if @a __n @c != @c std::numeric_limits<int>::max(), @a __n
   *    characters are extracted
   *  - the input sequence reaches end-of-file
   *  - the next character equals @a __delim (in this case, the character
   *    is extracted); note that this condition will never occur if
   *    @a __delim equals @c traits::eof().
   *
   *  NB: Provide three overloads, instead of the single function
   *  (with defaults) mandated by the Standard: this leads to a
   *  better performing implementation, while still conforming to
   *  the Standard.
  */
  __istream_type&
  ignore(streamsize __n, int_type __delim);

  __istream_type&
  ignore(streamsize __n);

  __istream_type&
  ignore();

  /**
   *  @brief  Looking ahead in the stream
   *  @return  The next character, or eof().
   *
   *  If, after constructing the sentry object, @c good() is false,
   *  returns @c traits::eof().  Otherwise reads but does not extract
   *  the next input character.
  */
  int_type
  peek();

  /**
   *  @brief  Extraction without delimiters.
   *  @param  __s  A character array.
   *  @param  __n  Maximum number of characters to store.
   *  @return  *this
   *
   *  If the stream state is @c good(), extracts characters and stores
   *  them into @a __s until one of the following happens:
   *  - @a __n characters are stored
   *  - the input sequence reaches end-of-file, in which case the error
   *    state is set to @c failbit|eofbit.
   *
   *  @note  This function is not overloaded on signed char and
   *         unsigned char.
  */
  __istream_type&
  read(char_type* __s, streamsize __n);

  /**
   *  @brief  Extraction until the buffer is exhausted, but no more.
   *  @param  __s  A character array.
   *  @param  __n  Maximum number of characters to store.
   *  @return  The number of characters extracted.
   *
   *  Extracts characters and stores them into @a __s depending on the
   *  number of characters remaining in the streambuf's buffer,
   *  @c rdbuf()->in_avail(), called @c A here:
   *  - if @c A @c == @c -1, sets eofbit and extracts no characters
   *  - if @c A @c == @c 0, extracts no characters
   *  - if @c A @c > @c 0, extracts @c min(A,n)
   *
   *  The goal is to empty the current buffer, and to not request any
   *  more from the external input sequence controlled by the streambuf.
  */
  streamsize
  readsome(char_type* __s, streamsize __n);

  /**
   *  @brief  Unextracting a single character.
   *  @param  __c  The character to push back into the input stream.
   *  @return  *this
   *
   *  If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c).
   *
   *  If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in
   *  the error state.
   *
   *  @note  This function first clears eofbit.  Since no characters
   *         are extracted, the next call to @c gcount() will return 0,
   *         as required by DR 60.
  */
  __istream_type&
  putback(char_type __c);

  /**
   *  @brief  Unextracting the previous character.
   *  @return  *this
   *
   *  If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c).
   *
   *  If @c rdbuf() is null or if @c sungetc() fails, sets badbit in
   *  the error state.
   *
   *  @note  This function first clears eofbit.  Since no characters
   *         are extracted, the next call to @c gcount() will return 0,
   *         as required by DR 60.
  */
  __istream_type&
  unget();

  /**
   *  @brief  Synchronizing the stream buffer.
   *  @return  0 on success, -1 on failure
   *
   *  If @c rdbuf() is a null pointer, returns -1.
   *
   *  Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
   *  sets badbit and returns -1.
   *
   *  Otherwise, returns 0.
   *
   *  @note  This function does not count the number of characters
   *         extracted, if any, and therefore does not affect the next
   *         call to @c gcount().
  */
  int
  sync();

  /**
   *  @brief  Getting the current read position.
   *  @return  A file position object.
   *
   *  If @c fail() is not false, returns @c pos_type(-1) to indicate
   *  failure.  Otherwise returns @c rdbuf()->pubseekoff(0,cur,in).
   *
   *  @note  This function does not count the number of characters
   *         extracted, if any, and therefore does not affect the next
   *         call to @c gcount().  At variance with putback, unget and
   *         seekg, eofbit is not cleared first.
  */
  pos_type
  tellg();

  /**
   *  @brief  Changing the current read position.
   *  @param  __pos  A file position object.
   *  @return  *this
   *
   *  If @c fail() is not true, calls @c rdbuf()->pubseekpos(__pos).  If
   *  that function fails, sets failbit.
   *
   *  @note  This function first clears eofbit.  It does not count the
   *         number of characters extracted, if any, and therefore does
   *         not affect the next call to @c gcount().
  */
  __istream_type&
  seekg(pos_type);

  /**
   *  @brief  Changing the current read position.
   *  @param  __off  A file offset object.
   *  @param  __dir  The direction in which to seek.
   *  @return  *this
   *
   *  If @c fail() is not true, calls @c rdbuf()->pubseekoff(__off,__dir).
   *  If that function fails, sets failbit.
   *
   *  @note  This function first clears eofbit.  It does not count the
   *         number of characters extracted, if any, and therefore does
   *         not affect the next call to @c gcount().
  */
  __istream_type&
  seekg(off_type, ios_base::seekdir);
  //@}

protected:
  basic_istream()
  : _M_gcount(streamsize(0))
  { this->init(0); }

  template<typename _ValueT>
__istream_type&
_M_extract(_ValueT& __v);
};

/// Explicit specialization declarations, defined in src/istream.cc. template<> basic_istream<char>& basic_istream<char>:: getline(char_type* __s, streamsize __n, char_type __delim);

template<> basic_istream<char>& basic_istream<char>:: ignore(streamsize __n);

template<> basic_istream<char>& basic_istream<char>:: ignore(streamsize __n, int_type __delim);

#ifdef _GLIBCXX_USE_WCHAR_T template<> basic_istream<wchar_t>& basic_istream<wchar_t>:: getline(char_type* __s, streamsize __n, char_type __delim);

template<> basic_istream<wchar_t>& basic_istream<wchar_t>:: ignore(streamsize __n);

template<> basic_istream<wchar_t>& basic_istream<wchar_t>:: ignore(streamsize __n, int_type __delim); #endif

/**

• @brief Performs setup work for input streams.
• Objects of this class are created before all of the standard
• extractors are run. It is responsible for exception-safe
• prefix and suffix operations,</em> although only prefix actions
• are currently required by the standard. */ template<typename _CharT, typename _Traits> class basic_istream<_CharT, _Traits>::sentry { // Data Members. bool _M_ok;

public:
  /// Easy access to dependent types.
  typedef _Traits 					traits_type;
  typedef basic_streambuf<_CharT, _Traits> 		__streambuf_type;
  typedef basic_istream<_CharT, _Traits> 		__istream_type;
  typedef typename __istream_type::__ctype_type 	__ctype_type;
  typedef typename _Traits::int_type		__int_type;

  /**
   *  @brief  The constructor performs all the work.
   *  @param  __is  The input stream to guard.
   *  @param  __noskipws  Whether to consume whitespace or not.
   *
   *  If the stream state is good (@a __is.good() is true), then the
   *  following actions are performed, otherwise the sentry state
   *  is false (<em>not okay</em>) and failbit is set in the
   *  stream state.
   *
   *  The sentry's preparatory actions are:
   *
   *  -# if the stream is tied to an output stream, @c is.tie()->flush()
   *     is called to synchronize the output sequence
   *  -# if @a __noskipws is false, and @c ios_base::skipws is set in
   *     @c is.flags(), the sentry extracts and discards whitespace
   *     characters from the stream.  The currently imbued locale is
   *     used to determine whether each character is whitespace.
   *
   *  If the stream state is still good, then the sentry state becomes
   *  true (@a okay).
  */
  explicit
  sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false);

  /**
   *  @brief  Quick status checking.
   *  @return  The sentry state.
   *
   *  For ease of use, sentries may be converted to booleans.  The
   *  return value is that of the sentry state (true == okay).
  */

#if __cplusplus >= 201103L explicit #endif operator bool() const { return _M_ok; } };

//@{ /**

• @brief Character extractors
• @param __in An input stream.
• @param __c A character reference.
• @return in
• Behaves like one of the formatted arithmetic extractors described in
• std::basic_istream. After constructing a sentry object with good
• status, this function extracts a character (if one is available) and
• stores it in @a __c. Otherwise, sets failbit in the input stream. */ template<typename _CharT, typename _Traits> basic_istream<_CharT, _Traits>& operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c);

template<class _Traits> inline basic_istream<char, _Traits>& operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) { return (__in >> reinterpret_cast<char&>(__c)); }

template<class _Traits> inline basic_istream<char, _Traits>& operator>>(basic_istream<char, _Traits>& __in, signed char& __c) { return (__in >> reinterpret_cast<char&>(__c)); } //@}

//@{ /**

• @brief Character string extractors
• @param __in An input stream.
• @param __s A pointer to a character array.
• @return __in
• Behaves like one of the formatted arithmetic extractors described in
• std::basic_istream. After constructing a sentry object with good
• status, this function extracts up to @c n characters and stores them
• into the array starting at @a __s. @c n is defined as:
• • if @c width() is greater than zero, @c n is width() otherwise
• • @c n is the number of elements of the largest array of *
• • @c char_type that can store a terminating @c eos.</em>
• • [27.6.1.2.3]/6
• Characters are extracted and stored until one of the following happens:
• • @c n-1 characters are stored
• • EOF is reached
• • the next character is whitespace according to the current locale
• • the next character is a null byte (i.e., @c charT() )
• @c width(0) is then called for the input stream.
• If no characters are extracted, sets failbit. / template<typename _CharT, typename _Traits> basic_istream<_CharT, _Traits>& operator>>(basic_istream<_CharT, _Traits>& __in, _CharT __s);

// Explicit specialization declaration, defined in src/istream.cc. template<> basic_istream<char>& operator>>(basic_istream<char>& __in, char* __s);

template<class _Traits> inline basic_istream<char, _Traits>& operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) { return (__in >> reinterpret_cast<char*>(__s)); }

template<class _Traits> inline basic_istream<char, _Traits>& operator>>(basic_istream<char, _Traits>& __in, signed char* __s) { return (__in >> reinterpret_cast<char*>(__s)); } //@}

/**

• @brief Template class basic_iostream

• @ingroup io

• @tparam _CharT Type of character stream.

• @tparam _Traits Traits for character type, defaults to

• char_traits<_CharT>.
  

• This class multiply inherits from the input and output stream classes

• simply to provide a single interface. */ template<typename _CharT, typename _Traits> class basic_iostream : public basic_istream<_CharT, _Traits>, public basic_ostream<_CharT, _Traits> { public: // _GLIBCXX_RESOLVE_LIB_DEFECTS // 271. basic_iostream missing typedefs // Types (inherited): typedef _CharT char_type; typedef typename _Traits::int_type int_type; typedef typename _Traits::pos_type pos_type; typedef typename _Traits::off_type off_type; typedef _Traits traits_type;

  // Non-standard Types: typedef basic_istream<_CharT, _Traits> __istream_type; typedef basic_ostream<_CharT, _Traits> __ostream_type;

  /**

  • @brief Constructor does nothing.
  • Both of the parent classes are initialized with the same
  • streambuf pointer passed to this constructor. / explicit basic_iostream(basic_streambuf<_CharT, _Traits> __sb) : __istream_type(__sb), __ostream_type(__sb) { }

  /**

  • @brief Destructor does nothing. */ virtual ~basic_iostream() { }

protected:
  basic_iostream()
  : __istream_type(), __ostream_type() { }
};

/**

• @brief Quick and easy way to eat whitespace
• This manipulator extracts whitespace characters, stopping when the
• next character is non-whitespace, or when the input sequence is empty.
• If the sequence is empty, @c eofbit is set in the stream, but not
• @c failbit.
• The current locale is used to distinguish whitespace characters.
• Example:
• @code

• MyClass   mc;
  

• std::cin >> std::ws >> mc;
  

• @endcode
• will skip leading whitespace before calling operator>> on cin and your
• object. Note that the same effect can be achieved by creating a
• std::basic_istream::sentry inside your definition of operator>>. */ template<typename _CharT, typename _Traits> basic_istream<_CharT, _Traits>& ws(basic_istream<_CharT, _Traits>& __is);

#if __cplusplus >= 201103L // [27.7.1.6] Rvalue stream extraction /**

• @brief Generic extractor for rvalue stream
• @param __is An input stream.
• @param __x A reference to the extraction target.
• @return is
• This is just a forwarding function to allow extraction from
• rvalue streams since they won't bind to the extractor functions
• that take an lvalue reference. */ template<typename _CharT, typename _Traits, typename _Tp> inline basic_istream<_CharT, _Traits>& operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x) { return (__is >> __x); } #endif // C++11

_GLIBCXX_END_NAMESPACE_VERSION } // namespace

#include <bits/istream.tcc>

#endif /* _GLIBCXX_ISTREAM

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