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被禁言 刘宇航
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cmath库代码

// -*- C++ -*- 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/cmath
 *  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 math.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: 26.5  C library
//

#pragma GCC system_header

#include <bits/c++config.h>
#include <bits/cpp_type_traits.h>
#include <ext/type_traits.h>
#include <math.h>

#ifndef _GLIBCXX_CMATH
#define _GLIBCXX_CMATH 1

// Get rid of those macros defined in <math.h> in lieu of real functions.
#undef abs
#undef div
#undef acos
#undef asin
#undef atan
#undef atan2
#undef ceil
#undef cos
#undef cosh
#undef exp
#undef fabs
#undef floor
#undef fmod
#undef frexp
#undef ldexp
#undef log
#undef log10
#undef modf
#undef pow
#undef sin
#undef sinh
#undef sqrt
#undef tan
#undef tanh

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR double
  abs(double __x)
  { return __builtin_fabs(__x); }
#endif

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  abs(float __x)
  { return __builtin_fabsf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  abs(long double __x)
  { return __builtin_fabsl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    abs(_Tp __x)
    { return __builtin_fabs(__x); }

  using ::acos;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  acos(float __x)
  { return __builtin_acosf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  acos(long double __x)
  { return __builtin_acosl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    acos(_Tp __x)
    { return __builtin_acos(__x); }

  using ::asin;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  asin(float __x)
  { return __builtin_asinf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  asin(long double __x)
  { return __builtin_asinl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    asin(_Tp __x)
    { return __builtin_asin(__x); }

  using ::atan;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  atan(float __x)
  { return __builtin_atanf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  atan(long double __x)
  { return __builtin_atanl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    atan(_Tp __x)
    { return __builtin_atan(__x); }

  using ::atan2;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  atan2(float __y, float __x)
  { return __builtin_atan2f(__y, __x); }

  inline _GLIBCXX_CONSTEXPR long double
  atan2(long double __y, long double __x)
  { return __builtin_atan2l(__y, __x); }
#endif

  template<typename _Tp, typename _Up>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    atan2(_Tp __y, _Up __x)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return atan2(__type(__y), __type(__x));
    }

  using ::ceil;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  ceil(float __x)
  { return __builtin_ceilf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  ceil(long double __x)
  { return __builtin_ceill(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    ceil(_Tp __x)
    { return __builtin_ceil(__x); }

  using ::cos;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  cos(float __x)
  { return __builtin_cosf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  cos(long double __x)
  { return __builtin_cosl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    cos(_Tp __x)
    { return __builtin_cos(__x); }

  using ::cosh;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  cosh(float __x)
  { return __builtin_coshf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  cosh(long double __x)
  { return __builtin_coshl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    cosh(_Tp __x)
    { return __builtin_cosh(__x); }

  using ::exp;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  exp(float __x)
  { return __builtin_expf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  exp(long double __x)
  { return __builtin_expl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    exp(_Tp __x)
    { return __builtin_exp(__x); }

  using ::fabs;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  fabs(float __x)
  { return __builtin_fabsf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  fabs(long double __x)
  { return __builtin_fabsl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    fabs(_Tp __x)
    { return __builtin_fabs(__x); }

  using ::floor;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  floor(float __x)
  { return __builtin_floorf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  floor(long double __x)
  { return __builtin_floorl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    floor(_Tp __x)
    { return __builtin_floor(__x); }

  using ::fmod;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  fmod(float __x, float __y)
  { return __builtin_fmodf(__x, __y); }

  inline _GLIBCXX_CONSTEXPR long double
  fmod(long double __x, long double __y)
  { return __builtin_fmodl(__x, __y); }
#endif

  template<typename _Tp, typename _Up>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fmod(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fmod(__type(__x), __type(__y));
    }

  using ::frexp;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline float
  frexp(float __x, int* __exp)
  { return __builtin_frexpf(__x, __exp); }

  inline long double
  frexp(long double __x, int* __exp)
  { return __builtin_frexpl(__x, __exp); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    frexp(_Tp __x, int* __exp)
    { return __builtin_frexp(__x, __exp); }

  using ::ldexp;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  ldexp(float __x, int __exp)
  { return __builtin_ldexpf(__x, __exp); }

  inline _GLIBCXX_CONSTEXPR long double
  ldexp(long double __x, int __exp)
  { return __builtin_ldexpl(__x, __exp); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    ldexp(_Tp __x, int __exp)
    { return __builtin_ldexp(__x, __exp); }

  using ::log;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  log(float __x)
  { return __builtin_logf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  log(long double __x)
  { return __builtin_logl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    log(_Tp __x)
    { return __builtin_log(__x); }

  using ::log10;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  log10(float __x)
  { return __builtin_log10f(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  log10(long double __x)
  { return __builtin_log10l(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    log10(_Tp __x)
    { return __builtin_log10(__x); }

  using ::modf;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline float
  modf(float __x, float* __iptr)
  { return __builtin_modff(__x, __iptr); }

  inline long double
  modf(long double __x, long double* __iptr)
  { return __builtin_modfl(__x, __iptr); }
#endif

  using ::pow;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  pow(float __x, float __y)
  { return __builtin_powf(__x, __y); }

  inline _GLIBCXX_CONSTEXPR long double
  pow(long double __x, long double __y)
  { return __builtin_powl(__x, __y); }

#if __cplusplus < 201103L
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // DR 550. What should the return type of pow(float,int) be?
  inline double
  pow(double __x, int __i)
  { return __builtin_powi(__x, __i); }

  inline float
  pow(float __x, int __n)
  { return __builtin_powif(__x, __n); }

  inline long double
  pow(long double __x, int __n)
  { return __builtin_powil(__x, __n); }
#endif
#endif

  template<typename _Tp, typename _Up>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    pow(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return pow(__type(__x), __type(__y));
    }

  using ::sin;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  sin(float __x)
  { return __builtin_sinf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  sin(long double __x)
  { return __builtin_sinl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    sin(_Tp __x)
    { return __builtin_sin(__x); }

  using ::sinh;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  sinh(float __x)
  { return __builtin_sinhf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  sinh(long double __x)
  { return __builtin_sinhl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    sinh(_Tp __x)
    { return __builtin_sinh(__x); }

  using ::sqrt;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  sqrt(float __x)
  { return __builtin_sqrtf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  sqrt(long double __x)
  { return __builtin_sqrtl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    sqrt(_Tp __x)
    { return __builtin_sqrt(__x); }

  using ::tan;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  tan(float __x)
  { return __builtin_tanf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  tan(long double __x)
  { return __builtin_tanl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    tan(_Tp __x)
    { return __builtin_tan(__x); }

  using ::tanh;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  tanh(float __x)
  { return __builtin_tanhf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  tanh(long double __x)
  { return __builtin_tanhl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    tanh(_Tp __x)
    { return __builtin_tanh(__x); }

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#if _GLIBCXX_USE_C99_MATH
#if !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC

// These are possible macros imported from C99-land.
#undef fpclassify
#undef isfinite
#undef isinf
#undef isnan
#undef isnormal
#undef signbit
#undef isgreater
#undef isgreaterequal
#undef isless
#undef islessequal
#undef islessgreater
#undef isunordered

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

#if __cplusplus >= 201103L
  constexpr int
  fpclassify(float __x)
  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
                FP_SUBNORMAL, FP_ZERO, __x); }

  constexpr int
  fpclassify(double __x)
  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
                FP_SUBNORMAL, FP_ZERO, __x); }

  constexpr int
  fpclassify(long double __x)
  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
                FP_SUBNORMAL, FP_ZERO, __x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              int>::__type
    fpclassify(_Tp __x)
    { return __x != 0 ? FP_NORMAL : FP_ZERO; }

  constexpr bool
  isfinite(float __x)
  { return __builtin_isfinite(__x); }

  constexpr bool
  isfinite(double __x)
  { return __builtin_isfinite(__x); }

  constexpr bool
  isfinite(long double __x)
  { return __builtin_isfinite(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isfinite(_Tp __x)
    { return true; }

  constexpr bool
  isinf(float __x)
  { return __builtin_isinf(__x); }

  constexpr bool
  isinf(double __x)
  { return __builtin_isinf(__x); }

  constexpr bool
  isinf(long double __x)
  { return __builtin_isinf(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isinf(_Tp __x)
    { return false; }

  constexpr bool
  isnan(float __x)
  { return __builtin_isnan(__x); }

  constexpr bool
  isnan(double __x)
  { return __builtin_isnan(__x); }

  constexpr bool
  isnan(long double __x)
  { return __builtin_isnan(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isnan(_Tp __x)
    { return false; }

  constexpr bool
  isnormal(float __x)
  { return __builtin_isnormal(__x); }

  constexpr bool
  isnormal(double __x)
  { return __builtin_isnormal(__x); }

  constexpr bool
  isnormal(long double __x)
  { return __builtin_isnormal(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isnormal(_Tp __x)
    { return __x != 0 ? true : false; }

  // The front-end doesn't provide a type generic builtin (libstdc++/58625).
  constexpr bool
  signbit(float __x)
  { return __builtin_signbitf(__x); }

  constexpr bool
  signbit(double __x)
  { return __builtin_signbit(__x); }

  constexpr bool
  signbit(long double __x)
  { return __builtin_signbitl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    signbit(_Tp __x)
    { return __x < 0 ? true : false; }

  constexpr bool
  isgreater(float __x, float __y)
  { return __builtin_isgreater(__x, __y); }

  constexpr bool
  isgreater(double __x, double __y)
  { return __builtin_isgreater(__x, __y); }

  constexpr bool
  isgreater(long double __x, long double __y)
  { return __builtin_isgreater(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
                && __is_arithmetic<_Up>::__value), bool>::__type
    isgreater(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isgreater(__type(__x), __type(__y));
    }

  constexpr bool
  isgreaterequal(float __x, float __y)
  { return __builtin_isgreaterequal(__x, __y); }

  constexpr bool
  isgreaterequal(double __x, double __y)
  { return __builtin_isgreaterequal(__x, __y); }

  constexpr bool
  isgreaterequal(long double __x, long double __y)
  { return __builtin_isgreaterequal(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
                && __is_arithmetic<_Up>::__value), bool>::__type
    isgreaterequal(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isgreaterequal(__type(__x), __type(__y));
    }

  constexpr bool
  isless(float __x, float __y)
  { return __builtin_isless(__x, __y); }

  constexpr bool
  isless(double __x, double __y)
  { return __builtin_isless(__x, __y); }

  constexpr bool
  isless(long double __x, long double __y)
  { return __builtin_isless(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
                && __is_arithmetic<_Up>::__value), bool>::__type
    isless(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isless(__type(__x), __type(__y));
    }

  constexpr bool
  islessequal(float __x, float __y)
  { return __builtin_islessequal(__x, __y); }

  constexpr bool
  islessequal(double __x, double __y)
  { return __builtin_islessequal(__x, __y); }

  constexpr bool
  islessequal(long double __x, long double __y)
  { return __builtin_islessequal(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
                && __is_arithmetic<_Up>::__value), bool>::__type
    islessequal(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_islessequal(__type(__x), __type(__y));
    }

  constexpr bool
  islessgreater(float __x, float __y)
  { return __builtin_islessgreater(__x, __y); }

  constexpr bool
  islessgreater(double __x, double __y)
  { return __builtin_islessgreater(__x, __y); }

  constexpr bool
  islessgreater(long double __x, long double __y)
  { return __builtin_islessgreater(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
                && __is_arithmetic<_Up>::__value), bool>::__type
    islessgreater(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_islessgreater(__type(__x), __type(__y));
    }

  constexpr bool
  isunordered(float __x, float __y)
  { return __builtin_isunordered(__x, __y); }

  constexpr bool
  isunordered(double __x, double __y)
  { return __builtin_isunordered(__x, __y); }

  constexpr bool
  isunordered(long double __x, long double __y)
  { return __builtin_isunordered(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
                && __is_arithmetic<_Up>::__value), bool>::__type
    isunordered(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isunordered(__type(__x), __type(__y));
    }

#else

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    fpclassify(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
                  FP_SUBNORMAL, FP_ZERO, __type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isfinite(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isfinite(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isinf(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isinf(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isnan(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isnan(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isnormal(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isnormal(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    signbit(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_signbit(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isgreater(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isgreater(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isgreaterequal(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isgreaterequal(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isless(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isless(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    islessequal(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_islessequal(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    islessgreater(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_islessgreater(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
                       int>::__type
    isunordered(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isunordered(__type(__f1), __type(__f2));
    }

#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif /* _GLIBCXX_USE_C99_FP_MACROS_DYNAMIC */
#endif

#if __cplusplus >= 201103L

#ifdef _GLIBCXX_USE_C99_MATH_TR1

#undef acosh
#undef acoshf
#undef acoshl
#undef asinh
#undef asinhf
#undef asinhl
#undef atanh
#undef atanhf
#undef atanhl
#undef cbrt
#undef cbrtf
#undef cbrtl
#undef copysign
#undef copysignf
#undef copysignl
#undef erf
#undef erff
#undef erfl
#undef erfc
#undef erfcf
#undef erfcl
#undef exp2
#undef exp2f
#undef exp2l
#undef expm1
#undef expm1f
#undef expm1l
#undef fdim
#undef fdimf
#undef fdiml
#undef fma
#undef fmaf
#undef fmal
#undef fmax
#undef fmaxf
#undef fmaxl
#undef fmin
#undef fminf
#undef fminl
#undef hypot
#undef hypotf
#undef hypotl
#undef ilogb
#undef ilogbf
#undef ilogbl
#undef lgamma
#undef lgammaf
#undef lgammal
#undef llrint
#undef llrintf
#undef llrintl
#undef llround
#undef llroundf
#undef llroundl
#undef log1p
#undef log1pf
#undef log1pl
#undef log2
#undef log2f
#undef log2l
#undef logb
#undef logbf
#undef logbl
#undef lrint
#undef lrintf
#undef lrintl
#undef lround
#undef lroundf
#undef lroundl
#undef nan
#undef nanf
#undef nanl
#undef nearbyint
#undef nearbyintf
#undef nearbyintl
#undef nextafter
#undef nextafterf
#undef nextafterl
#undef nexttoward
#undef nexttowardf
#undef nexttowardl
#undef remainder
#undef remainderf
#undef remainderl
#undef remquo
#undef remquof
#undef remquol
#undef rint
#undef rintf
#undef rintl
#undef round
#undef roundf
#undef roundl
#undef scalbln
#undef scalblnf
#undef scalblnl
#undef scalbn
#undef scalbnf
#undef scalbnl
#undef tgamma
#undef tgammaf
#undef tgammal
#undef trunc
#undef truncf
#undef truncl

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // types
  using ::double_t;
  using ::float_t;

  // functions
  using ::acosh;
  using ::acoshf;
  using ::acoshl;

  using ::asinh;
  using ::asinhf;
  using ::asinhl;

  using ::atanh;
  using ::atanhf;
  using ::atanhl;

  using ::cbrt;
  using ::cbrtf;
  using ::cbrtl;

  using ::copysign;
  using ::copysignf;
  using ::copysignl;

  using ::erf;
  using ::erff;
  using ::erfl;

  using ::erfc;
  using ::erfcf;
  using ::erfcl;

  using ::exp2;
  using ::exp2f;
  using ::exp2l;

  using ::expm1;
  using ::expm1f;
  using ::expm1l;

  using ::fdim;
  using ::fdimf;
  using ::fdiml;

  using ::fma;
  using ::fmaf;
  using ::fmal;

  using ::fmax;
  using ::fmaxf;
  using ::fmaxl;

  using ::fmin;
  using ::fminf;
  using ::fminl;

  using ::hypot;
  using ::hypotf;
  using ::hypotl;

  using ::ilogb;
  using ::ilogbf;
  using ::ilogbl;

  using ::lgamma;
  using ::lgammaf;
  using ::lgammal;

  using ::llrint;
  using ::llrintf;
  using ::llrintl;

  using ::llround;
  using ::llroundf;
  using ::llroundl;

  using ::log1p;
  using ::log1pf;
  using ::log1pl;

  using ::log2;
  using ::log2f;
  using ::log2l;

  using ::logb;
  using ::logbf;
  using ::logbl;

  using ::lrint;
  using ::lrintf;
  using ::lrintl;

  using ::lround;
  using ::lroundf;
  using ::lroundl;

  using ::nan;
  using ::nanf;
  using ::nanl;

  using ::nearbyint;
  using ::nearbyintf;
  using ::nearbyintl;

  using ::nextafter;
  using ::nextafterf;
  using ::nextafterl;

  using ::nexttoward;
  using ::nexttowardf;
  using ::nexttowardl;

  using ::remainder;
  using ::remainderf;
  using ::remainderl;

  using ::remquo;
  using ::remquof;
  using ::remquol;

  using ::rint;
  using ::rintf;
  using ::rintl;

  using ::round;
  using ::roundf;
  using ::roundl;

  using ::scalbln;
  using ::scalblnf;
  using ::scalblnl;

  using ::scalbn;
  using ::scalbnf;
  using ::scalbnl;

  using ::tgamma;
  using ::tgammaf;
  using ::tgammal;

  using ::trunc;
  using ::truncf;
  using ::truncl;

  /// Additional overloads.
  constexpr float
  acosh(float __x)
  { return __builtin_acoshf(__x); }

  constexpr long double
  acosh(long double __x)
  { return __builtin_acoshl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    acosh(_Tp __x)
    { return __builtin_acosh(__x); }

  constexpr float
  asinh(float __x)
  { return __builtin_asinhf(__x); }

  constexpr long double
  asinh(long double __x)
  { return __builtin_asinhl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    asinh(_Tp __x)
    { return __builtin_asinh(__x); }

  constexpr float
  atanh(float __x)
  { return __builtin_atanhf(__x); }

  constexpr long double
  atanh(long double __x)
  { return __builtin_atanhl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    atanh(_Tp __x)
    { return __builtin_atanh(__x); }

  constexpr float
  cbrt(float __x)
  { return __builtin_cbrtf(__x); }

  constexpr long double
  cbrt(long double __x)
  { return __builtin_cbrtl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    cbrt(_Tp __x)
    { return __builtin_cbrt(__x); }

  constexpr float
  copysign(float __x, float __y)
  { return __builtin_copysignf(__x, __y); }

  constexpr long double
  copysign(long double __x, long double __y)
  { return __builtin_copysignl(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    copysign(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return copysign(__type(__x), __type(__y));
    }

  constexpr float
  erf(float __x)
  { return __builtin_erff(__x); }

  constexpr long double
  erf(long double __x)
  { return __builtin_erfl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    erf(_Tp __x)
    { return __builtin_erf(__x); }

  constexpr float
  erfc(float __x)
  { return __builtin_erfcf(__x); }

  constexpr long double
  erfc(long double __x)
  { return __builtin_erfcl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    erfc(_Tp __x)
    { return __builtin_erfc(__x); }

  constexpr float
  exp2(float __x)
  { return __builtin_exp2f(__x); }

  constexpr long double
  exp2(long double __x)
  { return __builtin_exp2l(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    exp2(_Tp __x)
    { return __builtin_exp2(__x); }

  constexpr float
  expm1(float __x)
  { return __builtin_expm1f(__x); }

  constexpr long double
  expm1(long double __x)
  { return __builtin_expm1l(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    expm1(_Tp __x)
    { return __builtin_expm1(__x); }

  constexpr float
  fdim(float __x, float __y)
  { return __builtin_fdimf(__x, __y); }

  constexpr long double
  fdim(long double __x, long double __y)
  { return __builtin_fdiml(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fdim(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fdim(__type(__x), __type(__y));
    }

  constexpr float
  fma(float __x, float __y, float __z)
  { return __builtin_fmaf(__x, __y, __z); }

  constexpr long double
  fma(long double __x, long double __y, long double __z)
  { return __builtin_fmal(__x, __y, __z); }

  template<typename _Tp, typename _Up, typename _Vp>
    constexpr typename __gnu_cxx::__promote_3<_Tp, _Up, _Vp>::__type
    fma(_Tp __x, _Up __y, _Vp __z)
    {
      typedef typename __gnu_cxx::__promote_3<_Tp, _Up, _Vp>::__type __type;
      return fma(__type(__x), __type(__y), __type(__z));
    }

  constexpr float
  fmax(float __x, float __y)
  { return __builtin_fmaxf(__x, __y); }

  constexpr long double
  fmax(long double __x, long double __y)
  { return __builtin_fmaxl(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fmax(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fmax(__type(__x), __type(__y));
    }

  constexpr float
  fmin(float __x, float __y)
  { return __builtin_fminf(__x, __y); }

  constexpr long double
  fmin(long double __x, long double __y)
  { return __builtin_fminl(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fmin(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fmin(__type(__x), __type(__y));
    }

  constexpr float
  hypot(float __x, float __y)
  { return __builtin_hypotf(__x, __y); }

  constexpr long double
  hypot(long double __x, long double __y)
  { return __builtin_hypotl(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    hypot(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return hypot(__type(__x), __type(__y));
    }

  constexpr int
  ilogb(float __x)
  { return __builtin_ilogbf(__x); }

  constexpr int
  ilogb(long double __x)
  { return __builtin_ilogbl(__x); }

  template<typename _Tp>
    constexpr
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    int>::__type
    ilogb(_Tp __x)
    { return __builtin_ilogb(__x); }

  constexpr float
  lgamma(float __x)
  { return __builtin_lgammaf(__x); }

  constexpr long double
  lgamma(long double __x)
  { return __builtin_lgammal(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    lgamma(_Tp __x)
    { return __builtin_lgamma(__x); }

  constexpr long long
  llrint(float __x)
  { return __builtin_llrintf(__x); }

  constexpr long long
  llrint(long double __x)
  { return __builtin_llrintl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long long>::__type
    llrint(_Tp __x)
    { return __builtin_llrint(__x); }

  constexpr long long
  llround(float __x)
  { return __builtin_llroundf(__x); }

  constexpr long long
  llround(long double __x)
  { return __builtin_llroundl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long long>::__type
    llround(_Tp __x)
    { return __builtin_llround(__x); }

  constexpr float
  log1p(float __x)
  { return __builtin_log1pf(__x); }

  constexpr long double
  log1p(long double __x)
  { return __builtin_log1pl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    log1p(_Tp __x)
    { return __builtin_log1p(__x); }

  // DR 568.
  constexpr float
  log2(float __x)
  { return __builtin_log2f(__x); }

  constexpr long double
  log2(long double __x)
  { return __builtin_log2l(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    log2(_Tp __x)
    { return __builtin_log2(__x); }

  constexpr float
  logb(float __x)
  { return __builtin_logbf(__x); }

  constexpr long double
  logb(long double __x)
  { return __builtin_logbl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    logb(_Tp __x)
    { return __builtin_logb(__x); }

  constexpr long
  lrint(float __x)
  { return __builtin_lrintf(__x); }

  constexpr long
  lrint(long double __x)
  { return __builtin_lrintl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long>::__type
    lrint(_Tp __x)
    { return __builtin_lrint(__x); }

  constexpr long
  lround(float __x)
  { return __builtin_lroundf(__x); }

  constexpr long
  lround(long double __x)
  { return __builtin_lroundl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long>::__type
    lround(_Tp __x)
    { return __builtin_lround(__x); }

  constexpr float
  nearbyint(float __x)
  { return __builtin_nearbyintf(__x); }

  constexpr long double
  nearbyint(long double __x)
  { return __builtin_nearbyintl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    nearbyint(_Tp __x)
    { return __builtin_nearbyint(__x); }

  constexpr float
  nextafter(float __x, float __y)
  { return __builtin_nextafterf(__x, __y); }

  constexpr long double
  nextafter(long double __x, long double __y)
  { return __builtin_nextafterl(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    nextafter(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return nextafter(__type(__x), __type(__y));
    }

  constexpr float
  nexttoward(float __x, long double __y)
  { return __builtin_nexttowardf(__x, __y); }

  constexpr long double
  nexttoward(long double __x, long double __y)
  { return __builtin_nexttowardl(__x, __y); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    nexttoward(_Tp __x, long double __y)
    { return __builtin_nexttoward(__x, __y); }

  constexpr float
  remainder(float __x, float __y)
  { return __builtin_remainderf(__x, __y); }

  constexpr long double
  remainder(long double __x, long double __y)
  { return __builtin_remainderl(__x, __y); }

  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    remainder(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return remainder(__type(__x), __type(__y));
    }

  inline float
  remquo(float __x, float __y, int* __pquo)
  { return __builtin_remquof(__x, __y, __pquo); }

  inline long double
  remquo(long double __x, long double __y, int* __pquo)
  { return __builtin_remquol(__x, __y, __pquo); }

  template<typename _Tp, typename _Up>
    inline typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    remquo(_Tp __x, _Up __y, int* __pquo)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return remquo(__type(__x), __type(__y), __pquo);
    }

  constexpr float
  rint(float __x)
  { return __builtin_rintf(__x); }

  constexpr long double
  rint(long double __x)
  { return __builtin_rintl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    rint(_Tp __x)
    { return __builtin_rint(__x); }

  constexpr float
  round(float __x)
  { return __builtin_roundf(__x); }

  constexpr long double
  round(long double __x)
  { return __builtin_roundl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    round(_Tp __x)
    { return __builtin_round(__x); }

  constexpr float
  scalbln(float __x, long __ex)
  { return __builtin_scalblnf(__x, __ex); }

  constexpr long double
  scalbln(long double __x, long __ex)
  { return __builtin_scalblnl(__x, __ex); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    scalbln(_Tp __x, long __ex)
    { return __builtin_scalbln(__x, __ex); }

  constexpr float
  scalbn(float __x, int __ex)
  { return __builtin_scalbnf(__x, __ex); }

  constexpr long double
  scalbn(long double __x, int __ex)
  { return __builtin_scalbnl(__x, __ex); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    scalbn(_Tp __x, int __ex)
    { return __builtin_scalbn(__x, __ex); }

  constexpr float
  tgamma(float __x)
  { return __builtin_tgammaf(__x); }

  constexpr long double
  tgamma(long double __x)
  { return __builtin_tgammal(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    tgamma(_Tp __x)
    { return __builtin_tgamma(__x); }

  constexpr float
  trunc(float __x)
  { return __builtin_truncf(__x); }

  constexpr long double
  trunc(long double __x)
  { return __builtin_truncl(__x); }

  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    trunc(_Tp __x)
    { return __builtin_trunc(__x); }

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif // _GLIBCXX_USE_C99_MATH_TR1

#endif // C++11

#endif

 


0
0
孟昭旭
孟昭旭
初级光能
初级光能
// 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(&apos;\\n&apos;)).
      */
      __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(&apos;\\n&apos;)).
      */
      __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(&apos;\\n&apos;)).
      */
      __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 <em>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 <em>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 */

istream

0
孟昭旭
孟昭旭
初级光能
初级光能
#undef abs
#undef div
#undef acos
#undef asin
#undef atan
#undef atan2
#undef ceil
#undef cos
#undef cosh
#undef exp
#undef fabs
#undef floor
#undef fmod
#undef frexp
#undef ldexp
#undef log
#undef log10
#undef modf
#undef pow
#undef sin
#undef sinh
#undef sqrt
#undef tan
#undef tanh

这一块应该是cmath的所有函数

#undef sin
#undef sinh
#undef sqrt
#undef tan
#undef tanh

这一块还好理解((反)三角函数)

#undef acos
#undef asin
#undef atan
#undef atan2
#undef ceil
#undef cos
#undef cosh

这些到底是啥呀????!!!!

(A)三角函数?

我要回答