1// <functional> -*- C++ -*-
2
3// Copyright (C) 2001-2015 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/*
26 * Copyright (c) 1997
27 * Silicon Graphics Computer Systems, Inc.
28 *
29 * Permission to use, copy, modify, distribute and sell this software
30 * and its documentation for any purpose is hereby granted without fee,
31 * provided that the above copyright notice appear in all copies and
32 * that both that copyright notice and this permission notice appear
33 * in supporting documentation.  Silicon Graphics makes no
34 * representations about the suitability of this software for any
35 * purpose.  It is provided "as is" without express or implied warranty.
36 *
37 */
38
39/** @file include/functional
40 *  This is a Standard C++ Library header.
41 */
42
43#ifndef _GLIBCXX_FUNCTIONAL
44#define _GLIBCXX_FUNCTIONAL 1
45
46#pragma GCC system_header
47
48#include <bits/c++config.h>
49#include <bits/stl_function.h>
50
51#if __cplusplus >= 201103L
52
53#include <typeinfo>
54#include <new>
55#include <tuple>
56#include <type_traits>
57#include <bits/functexcept.h>
58#include <bits/functional_hash.h>
59
60namespace std _GLIBCXX_VISIBILITY(default)
61{
62_GLIBCXX_BEGIN_NAMESPACE_VERSION
63
64  template<typename _MemberPointer>
65    class _Mem_fn;
66  template<typename _Tp, typename _Class>
67    _Mem_fn<_Tp _Class::*>
68    mem_fn(_Tp _Class::*) noexcept;
69
70  /// If we have found a result_type, extract it.
71  template<typename _Functor, typename = __void_t<>>
72    struct _Maybe_get_result_type
73    { };
74
75  template<typename _Functor>
76    struct _Maybe_get_result_type<_Functor,
77				  __void_t<typename _Functor::result_type>>
78    { typedef typename _Functor::result_type result_type; };
79
80  /**
81   *  Base class for any function object that has a weak result type, as
82   *  defined in 20.8.2 [func.require] of C++11.
83  */
84  template<typename _Functor>
85    struct _Weak_result_type_impl
86    : _Maybe_get_result_type<_Functor>
87    { };
88
89  /// Retrieve the result type for a function type.
90  template<typename _Res, typename... _ArgTypes>
91    struct _Weak_result_type_impl<_Res(_ArgTypes...)>
92    { typedef _Res result_type; };
93
94  template<typename _Res, typename... _ArgTypes>
95    struct _Weak_result_type_impl<_Res(_ArgTypes......)>
96    { typedef _Res result_type; };
97
98  template<typename _Res, typename... _ArgTypes>
99    struct _Weak_result_type_impl<_Res(_ArgTypes...) const>
100    { typedef _Res result_type; };
101
102  template<typename _Res, typename... _ArgTypes>
103    struct _Weak_result_type_impl<_Res(_ArgTypes......) const>
104    { typedef _Res result_type; };
105
106  template<typename _Res, typename... _ArgTypes>
107    struct _Weak_result_type_impl<_Res(_ArgTypes...) volatile>
108    { typedef _Res result_type; };
109
110  template<typename _Res, typename... _ArgTypes>
111    struct _Weak_result_type_impl<_Res(_ArgTypes......) volatile>
112    { typedef _Res result_type; };
113
114  template<typename _Res, typename... _ArgTypes>
115    struct _Weak_result_type_impl<_Res(_ArgTypes...) const volatile>
116    { typedef _Res result_type; };
117
118  template<typename _Res, typename... _ArgTypes>
119    struct _Weak_result_type_impl<_Res(_ArgTypes......) const volatile>
120    { typedef _Res result_type; };
121
122  /// Retrieve the result type for a function reference.
123  template<typename _Res, typename... _ArgTypes>
124    struct _Weak_result_type_impl<_Res(&)(_ArgTypes...)>
125    { typedef _Res result_type; };
126
127  template<typename _Res, typename... _ArgTypes>
128    struct _Weak_result_type_impl<_Res(&)(_ArgTypes......)>
129    { typedef _Res result_type; };
130
131  /// Retrieve the result type for a function pointer.
132  template<typename _Res, typename... _ArgTypes>
133    struct _Weak_result_type_impl<_Res(*)(_ArgTypes...)>
134    { typedef _Res result_type; };
135
136  template<typename _Res, typename... _ArgTypes>
137    struct _Weak_result_type_impl<_Res(*)(_ArgTypes......)>
138    { typedef _Res result_type; };
139
140  /// Retrieve result type for a member function pointer.
141  template<typename _Res, typename _Class, typename... _ArgTypes>
142    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)>
143    { typedef _Res result_type; };
144
145  template<typename _Res, typename _Class, typename... _ArgTypes>
146    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)>
147    { typedef _Res result_type; };
148
149  /// Retrieve result type for a const member function pointer.
150  template<typename _Res, typename _Class, typename... _ArgTypes>
151    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) const>
152    { typedef _Res result_type; };
153
154  template<typename _Res, typename _Class, typename... _ArgTypes>
155    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) const>
156    { typedef _Res result_type; };
157
158  /// Retrieve result type for a volatile member function pointer.
159  template<typename _Res, typename _Class, typename... _ArgTypes>
160    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) volatile>
161    { typedef _Res result_type; };
162
163  template<typename _Res, typename _Class, typename... _ArgTypes>
164    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) volatile>
165    { typedef _Res result_type; };
166
167  /// Retrieve result type for a const volatile member function pointer.
168  template<typename _Res, typename _Class, typename... _ArgTypes>
169    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)
170				  const volatile>
171    { typedef _Res result_type; };
172
173  template<typename _Res, typename _Class, typename... _ArgTypes>
174    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)
175				  const volatile>
176    { typedef _Res result_type; };
177
178  /**
179   *  Strip top-level cv-qualifiers from the function object and let
180   *  _Weak_result_type_impl perform the real work.
181  */
182  template<typename _Functor>
183    struct _Weak_result_type
184    : _Weak_result_type_impl<typename remove_cv<_Functor>::type>
185    { };
186
187  /**
188   * Invoke a function object, which may be either a member pointer or a
189   * function object. The first parameter will tell which.
190   */
191  template<typename _Functor, typename... _Args>
192    inline
193    typename enable_if<
194	     (!is_member_pointer<_Functor>::value
195	      && !is_function<_Functor>::value
196	      && !is_function<typename remove_pointer<_Functor>::type>::value),
197	     typename result_of<_Functor&(_Args&&...)>::type
198	   >::type
199    __invoke(_Functor& __f, _Args&&... __args)
200    {
201      return __f(std::forward<_Args>(__args)...);
202    }
203
204  template<typename _Functor, typename... _Args>
205    inline
206    typename enable_if<
207             (is_member_pointer<_Functor>::value
208              && !is_function<_Functor>::value
209              && !is_function<typename remove_pointer<_Functor>::type>::value),
210             typename result_of<_Functor(_Args&&...)>::type
211           >::type
212    __invoke(_Functor& __f, _Args&&... __args)
213    {
214      return std::mem_fn(__f)(std::forward<_Args>(__args)...);
215    }
216
217  // To pick up function references (that will become function pointers)
218  template<typename _Functor, typename... _Args>
219    inline
220    typename enable_if<
221	     (is_pointer<_Functor>::value
222	      && is_function<typename remove_pointer<_Functor>::type>::value),
223	     typename result_of<_Functor(_Args&&...)>::type
224	   >::type
225    __invoke(_Functor __f, _Args&&... __args)
226    {
227      return __f(std::forward<_Args>(__args)...);
228    }
229
230  /**
231   *  Knowing which of unary_function and binary_function _Tp derives
232   *  from, derives from the same and ensures that reference_wrapper
233   *  will have a weak result type. See cases below.
234   */
235  template<bool _Unary, bool _Binary, typename _Tp>
236    struct _Reference_wrapper_base_impl;
237
238  // None of the nested argument types.
239  template<typename _Tp>
240    struct _Reference_wrapper_base_impl<false, false, _Tp>
241    : _Weak_result_type<_Tp>
242    { };
243
244  // Nested argument_type only.
245  template<typename _Tp>
246    struct _Reference_wrapper_base_impl<true, false, _Tp>
247    : _Weak_result_type<_Tp>
248    {
249      typedef typename _Tp::argument_type argument_type;
250    };
251
252  // Nested first_argument_type and second_argument_type only.
253  template<typename _Tp>
254    struct _Reference_wrapper_base_impl<false, true, _Tp>
255    : _Weak_result_type<_Tp>
256    {
257      typedef typename _Tp::first_argument_type first_argument_type;
258      typedef typename _Tp::second_argument_type second_argument_type;
259    };
260
261  // All the nested argument types.
262   template<typename _Tp>
263    struct _Reference_wrapper_base_impl<true, true, _Tp>
264    : _Weak_result_type<_Tp>
265    {
266      typedef typename _Tp::argument_type argument_type;
267      typedef typename _Tp::first_argument_type first_argument_type;
268      typedef typename _Tp::second_argument_type second_argument_type;
269    };
270
271  _GLIBCXX_HAS_NESTED_TYPE(argument_type)
272  _GLIBCXX_HAS_NESTED_TYPE(first_argument_type)
273  _GLIBCXX_HAS_NESTED_TYPE(second_argument_type)
274
275  /**
276   *  Derives from unary_function or binary_function when it
277   *  can. Specializations handle all of the easy cases. The primary
278   *  template determines what to do with a class type, which may
279   *  derive from both unary_function and binary_function.
280  */
281  template<typename _Tp>
282    struct _Reference_wrapper_base
283    : _Reference_wrapper_base_impl<
284      __has_argument_type<_Tp>::value,
285      __has_first_argument_type<_Tp>::value
286      && __has_second_argument_type<_Tp>::value,
287      _Tp>
288    { };
289
290  // - a function type (unary)
291  template<typename _Res, typename _T1>
292    struct _Reference_wrapper_base<_Res(_T1)>
293    : unary_function<_T1, _Res>
294    { };
295
296  template<typename _Res, typename _T1>
297    struct _Reference_wrapper_base<_Res(_T1) const>
298    : unary_function<_T1, _Res>
299    { };
300
301  template<typename _Res, typename _T1>
302    struct _Reference_wrapper_base<_Res(_T1) volatile>
303    : unary_function<_T1, _Res>
304    { };
305
306  template<typename _Res, typename _T1>
307    struct _Reference_wrapper_base<_Res(_T1) const volatile>
308    : unary_function<_T1, _Res>
309    { };
310
311  // - a function type (binary)
312  template<typename _Res, typename _T1, typename _T2>
313    struct _Reference_wrapper_base<_Res(_T1, _T2)>
314    : binary_function<_T1, _T2, _Res>
315    { };
316
317  template<typename _Res, typename _T1, typename _T2>
318    struct _Reference_wrapper_base<_Res(_T1, _T2) const>
319    : binary_function<_T1, _T2, _Res>
320    { };
321
322  template<typename _Res, typename _T1, typename _T2>
323    struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
324    : binary_function<_T1, _T2, _Res>
325    { };
326
327  template<typename _Res, typename _T1, typename _T2>
328    struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
329    : binary_function<_T1, _T2, _Res>
330    { };
331
332  // - a function pointer type (unary)
333  template<typename _Res, typename _T1>
334    struct _Reference_wrapper_base<_Res(*)(_T1)>
335    : unary_function<_T1, _Res>
336    { };
337
338  // - a function pointer type (binary)
339  template<typename _Res, typename _T1, typename _T2>
340    struct _Reference_wrapper_base<_Res(*)(_T1, _T2)>
341    : binary_function<_T1, _T2, _Res>
342    { };
343
344  // - a pointer to member function type (unary, no qualifiers)
345  template<typename _Res, typename _T1>
346    struct _Reference_wrapper_base<_Res (_T1::*)()>
347    : unary_function<_T1*, _Res>
348    { };
349
350  // - a pointer to member function type (binary, no qualifiers)
351  template<typename _Res, typename _T1, typename _T2>
352    struct _Reference_wrapper_base<_Res (_T1::*)(_T2)>
353    : binary_function<_T1*, _T2, _Res>
354    { };
355
356  // - a pointer to member function type (unary, const)
357  template<typename _Res, typename _T1>
358    struct _Reference_wrapper_base<_Res (_T1::*)() const>
359    : unary_function<const _T1*, _Res>
360    { };
361
362  // - a pointer to member function type (binary, const)
363  template<typename _Res, typename _T1, typename _T2>
364    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const>
365    : binary_function<const _T1*, _T2, _Res>
366    { };
367
368  // - a pointer to member function type (unary, volatile)
369  template<typename _Res, typename _T1>
370    struct _Reference_wrapper_base<_Res (_T1::*)() volatile>
371    : unary_function<volatile _T1*, _Res>
372    { };
373
374  // - a pointer to member function type (binary, volatile)
375  template<typename _Res, typename _T1, typename _T2>
376    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) volatile>
377    : binary_function<volatile _T1*, _T2, _Res>
378    { };
379
380  // - a pointer to member function type (unary, const volatile)
381  template<typename _Res, typename _T1>
382    struct _Reference_wrapper_base<_Res (_T1::*)() const volatile>
383    : unary_function<const volatile _T1*, _Res>
384    { };
385
386  // - a pointer to member function type (binary, const volatile)
387  template<typename _Res, typename _T1, typename _T2>
388    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const volatile>
389    : binary_function<const volatile _T1*, _T2, _Res>
390    { };
391
392  /**
393   *  @brief Primary class template for reference_wrapper.
394   *  @ingroup functors
395   *  @{
396   */
397  template<typename _Tp>
398    class reference_wrapper
399    : public _Reference_wrapper_base<typename remove_cv<_Tp>::type>
400    {
401      _Tp* _M_data;
402
403    public:
404      typedef _Tp type;
405
406      reference_wrapper(_Tp& __indata) noexcept
407      : _M_data(std::__addressof(__indata))
408      { }
409
410      reference_wrapper(_Tp&&) = delete;
411
412      reference_wrapper(const reference_wrapper&) = default;
413
414      reference_wrapper&
415      operator=(const reference_wrapper&) = default;
416
417      operator _Tp&() const noexcept
418      { return this->get(); }
419
420      _Tp&
421      get() const noexcept
422      { return *_M_data; }
423
424      template<typename... _Args>
425	typename result_of<_Tp&(_Args&&...)>::type
426	operator()(_Args&&... __args) const
427	{
428	  return __invoke(get(), std::forward<_Args>(__args)...);
429	}
430    };
431
432
433  /// Denotes a reference should be taken to a variable.
434  template<typename _Tp>
435    inline reference_wrapper<_Tp>
436    ref(_Tp& __t) noexcept
437    { return reference_wrapper<_Tp>(__t); }
438
439  /// Denotes a const reference should be taken to a variable.
440  template<typename _Tp>
441    inline reference_wrapper<const _Tp>
442    cref(const _Tp& __t) noexcept
443    { return reference_wrapper<const _Tp>(__t); }
444
445  template<typename _Tp>
446    void ref(const _Tp&&) = delete;
447
448  template<typename _Tp>
449    void cref(const _Tp&&) = delete;
450
451  /// std::ref overload to prevent wrapping a reference_wrapper
452  template<typename _Tp>
453    inline reference_wrapper<_Tp>
454    ref(reference_wrapper<_Tp> __t) noexcept
455    { return std::ref(__t.get()); }
456
457  /// std::cref overload to prevent wrapping a reference_wrapper
458  template<typename _Tp>
459    inline reference_wrapper<const _Tp>
460    cref(reference_wrapper<_Tp> __t) noexcept
461    { return std::cref(__t.get()); }
462
463  // @} group functors
464
465  template<typename... _Types>
466    struct _Pack : integral_constant<size_t, sizeof...(_Types)>
467    { };
468
469  template<typename _From, typename _To, bool = _From::value == _To::value>
470    struct _AllConvertible : false_type
471    { };
472
473  template<typename... _From, typename... _To>
474    struct _AllConvertible<_Pack<_From...>, _Pack<_To...>, true>
475    : __and_<is_convertible<_From, _To>...>
476    { };
477
478  template<typename _Tp1, typename _Tp2>
479    using _NotSame = __not_<is_same<typename std::decay<_Tp1>::type,
480				    typename std::decay<_Tp2>::type>>;
481
482  /**
483   * Derives from @c unary_function or @c binary_function, or perhaps
484   * nothing, depending on the number of arguments provided. The
485   * primary template is the basis case, which derives nothing.
486   */
487  template<typename _Res, typename... _ArgTypes>
488    struct _Maybe_unary_or_binary_function { };
489
490  /// Derives from @c unary_function, as appropriate.
491  template<typename _Res, typename _T1>
492    struct _Maybe_unary_or_binary_function<_Res, _T1>
493    : std::unary_function<_T1, _Res> { };
494
495  /// Derives from @c binary_function, as appropriate.
496  template<typename _Res, typename _T1, typename _T2>
497    struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
498    : std::binary_function<_T1, _T2, _Res> { };
499
500  template<typename _Signature>
501    struct _Mem_fn_traits;
502
503  template<typename _Res, typename _Class, typename... _ArgTypes>
504    struct _Mem_fn_traits_base
505    {
506      using __result_type = _Res;
507      using __class_type =  _Class;
508      using __arg_types = _Pack<_ArgTypes...>;
509      using __maybe_type
510	= _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>;
511      using __arity = integral_constant<size_t, sizeof...(_ArgTypes)>;
512    };
513
514#define _GLIBCXX_MEM_FN_TRAITS2(_CV, _REF, _LVAL, _RVAL)		\
515  template<typename _Res, typename _Class, typename... _ArgTypes>	\
516    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes...) _CV _REF>	\
517    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>		\
518    {									\
519      using __pmf_type  = _Res (_Class::*)(_ArgTypes...) _CV _REF;	\
520      using __lvalue = _LVAL;						\
521      using __rvalue = _RVAL;						\
522      using __vararg = false_type;					\
523    };									\
524  template<typename _Res, typename _Class, typename... _ArgTypes>	\
525    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes... ...) _CV _REF>	\
526    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>		\
527    {									\
528      using __pmf_type  = _Res (_Class::*)(_ArgTypes... ...) _CV _REF;	\
529      using __lvalue = _LVAL;						\
530      using __rvalue = _RVAL;						\
531      using __vararg = true_type;					\
532    };
533
534#define _GLIBCXX_MEM_FN_TRAITS(_REF, _LVAL, _RVAL)		\
535  _GLIBCXX_MEM_FN_TRAITS2(		, _REF, _LVAL, _RVAL)	\
536  _GLIBCXX_MEM_FN_TRAITS2(const		, _REF, _LVAL, _RVAL)	\
537  _GLIBCXX_MEM_FN_TRAITS2(volatile	, _REF, _LVAL, _RVAL)	\
538  _GLIBCXX_MEM_FN_TRAITS2(const volatile, _REF, _LVAL, _RVAL)
539
540_GLIBCXX_MEM_FN_TRAITS( , true_type, true_type)
541_GLIBCXX_MEM_FN_TRAITS(&, true_type, false_type)
542_GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
543
544#undef _GLIBCXX_MEM_FN_TRAITS
545#undef _GLIBCXX_MEM_FN_TRAITS2
546
547  template<typename _MemFunPtr,
548	   bool __is_mem_fn = is_member_function_pointer<_MemFunPtr>::value>
549    class _Mem_fn_base
550    : public _Mem_fn_traits<_MemFunPtr>::__maybe_type
551    {
552      using _Traits = _Mem_fn_traits<_MemFunPtr>;
553
554      using _Class = typename _Traits::__class_type;
555      using _ArgTypes = typename _Traits::__arg_types;
556      using _Pmf = typename _Traits::__pmf_type;
557
558      using _Arity = typename _Traits::__arity;
559      using _Varargs = typename _Traits::__vararg;
560
561      template<typename _Func, typename... _BoundArgs>
562	friend struct _Bind_check_arity;
563
564      // for varargs functions we just check the number of arguments,
565      // otherwise we also check they are convertible.
566      template<typename _Args>
567	using _CheckArgs = typename conditional<_Varargs::value,
568	  __bool_constant<(_Args::value >= _ArgTypes::value)>,
569	  _AllConvertible<_Args, _ArgTypes>
570	>::type;
571
572    public:
573      using result_type = typename _Traits::__result_type;
574
575      explicit _Mem_fn_base(_Pmf __pmf) : _M_pmf(__pmf) { }
576
577      // Handle objects
578      template<typename... _Args, typename _Req
579               = _Require<typename _Traits::__lvalue,
580                          _CheckArgs<_Pack<_Args...>>>>
581	result_type
582	operator()(_Class& __object, _Args&&... __args) const
583	{ return (__object.*_M_pmf)(std::forward<_Args>(__args)...); }
584
585      template<typename... _Args, typename _Req
586               = _Require<typename _Traits::__rvalue,
587                          _CheckArgs<_Pack<_Args...>>>>
588	result_type
589	operator()(_Class&& __object, _Args&&... __args) const
590	{
591	  return (std::move(__object).*_M_pmf)(std::forward<_Args>(__args)...);
592	}
593
594      // Handle pointers
595      template<typename... _Args, typename _Req
596               = _Require<typename _Traits::__lvalue,
597                          _CheckArgs<_Pack<_Args...>>>>
598	result_type
599	operator()(_Class* __object, _Args&&... __args) const
600	{ return (__object->*_M_pmf)(std::forward<_Args>(__args)...); }
601
602      // Handle smart pointers, references and pointers to derived
603      template<typename _Tp, typename... _Args, typename _Req
604               = _Require<_NotSame<_Class, _Tp>, _NotSame<_Class*, _Tp>,
605                          _CheckArgs<_Pack<_Args...>>>>
606	result_type
607	operator()(_Tp&& __object, _Args&&... __args) const
608	{
609	  return _M_call(std::forward<_Tp>(__object), &__object,
610	      std::forward<_Args>(__args)...);
611	}
612
613      // Handle reference wrappers
614      template<typename _Tp, typename... _Args, typename _Req
615               = _Require<is_base_of<_Class, _Tp>, typename _Traits::__lvalue,
616                          _CheckArgs<_Pack<_Args...>>>>
617	result_type
618	operator()(reference_wrapper<_Tp> __ref, _Args&&... __args) const
619	{ return operator()(__ref.get(), std::forward<_Args>(__args)...); }
620
621    private:
622      template<typename _Tp, typename... _Args>
623	result_type
624	_M_call(_Tp&& __object, const volatile _Class *,
625		_Args&&... __args) const
626	{
627	  return (std::forward<_Tp>(__object).*_M_pmf)
628	    (std::forward<_Args>(__args)...);
629	}
630
631      template<typename _Tp, typename... _Args>
632	result_type
633	_M_call(_Tp&& __ptr, const volatile void *, _Args&&... __args) const
634	{ return ((*__ptr).*_M_pmf)(std::forward<_Args>(__args)...); }
635
636      _Pmf _M_pmf;
637    };
638
639  // Partial specialization for member object pointers.
640  template<typename _Res, typename _Class>
641    class _Mem_fn_base<_Res _Class::*, false>
642    {
643      using __pm_type = _Res _Class::*;
644
645      // This bit of genius is due to Peter Dimov, improved slightly by
646      // Douglas Gregor.
647      // Made less elegant to support perfect forwarding and noexcept.
648      template<typename _Tp>
649	auto
650	_M_call(_Tp&& __object, const _Class *) const noexcept
651	-> decltype(std::forward<_Tp>(__object).*std::declval<__pm_type&>())
652	{ return std::forward<_Tp>(__object).*_M_pm; }
653
654      template<typename _Tp, typename _Up>
655	auto
656	_M_call(_Tp&& __object, _Up * const *) const noexcept
657	-> decltype((*std::forward<_Tp>(__object)).*std::declval<__pm_type&>())
658	{ return (*std::forward<_Tp>(__object)).*_M_pm; }
659
660      template<typename _Tp>
661	auto
662	_M_call(_Tp&& __ptr, const volatile void*) const
663	noexcept(noexcept((*__ptr).*std::declval<__pm_type&>()))
664	-> decltype((*__ptr).*std::declval<__pm_type&>())
665	{ return (*__ptr).*_M_pm; }
666
667      using _Arity = integral_constant<size_t, 0>;
668      using _Varargs = false_type;
669
670      template<typename _Func, typename... _BoundArgs>
671	friend struct _Bind_check_arity;
672
673    public:
674      explicit
675      _Mem_fn_base(_Res _Class::*__pm) noexcept : _M_pm(__pm) { }
676
677      // Handle objects
678      _Res&
679      operator()(_Class& __object) const noexcept
680      { return __object.*_M_pm; }
681
682      const _Res&
683      operator()(const _Class& __object) const noexcept
684      { return __object.*_M_pm; }
685
686      _Res&&
687      operator()(_Class&& __object) const noexcept
688      { return std::forward<_Class>(__object).*_M_pm; }
689
690      const _Res&&
691      operator()(const _Class&& __object) const noexcept
692      { return std::forward<const _Class>(__object).*_M_pm; }
693
694      // Handle pointers
695      _Res&
696      operator()(_Class* __object) const noexcept
697      { return __object->*_M_pm; }
698
699      const _Res&
700      operator()(const _Class* __object) const noexcept
701      { return __object->*_M_pm; }
702
703      // Handle smart pointers and derived
704      template<typename _Tp, typename _Req = _Require<_NotSame<_Class*, _Tp>>>
705	auto
706	operator()(_Tp&& __unknown) const
707	noexcept(noexcept(std::declval<_Mem_fn_base*>()->_M_call
708			  (std::forward<_Tp>(__unknown), &__unknown)))
709	-> decltype(this->_M_call(std::forward<_Tp>(__unknown), &__unknown))
710	{ return _M_call(std::forward<_Tp>(__unknown), &__unknown); }
711
712      template<typename _Tp, typename _Req = _Require<is_base_of<_Class, _Tp>>>
713	auto
714	operator()(reference_wrapper<_Tp> __ref) const
715	noexcept(noexcept(std::declval<_Mem_fn_base&>()(__ref.get())))
716	-> decltype((*this)(__ref.get()))
717	{ return (*this)(__ref.get()); }
718
719    private:
720      _Res _Class::*_M_pm;
721    };
722
723  template<typename _Res, typename _Class>
724    struct _Mem_fn<_Res _Class::*>
725    : _Mem_fn_base<_Res _Class::*>
726    {
727      using _Mem_fn_base<_Res _Class::*>::_Mem_fn_base;
728    };
729
730  // _GLIBCXX_RESOLVE_LIB_DEFECTS
731  // 2048.  Unnecessary mem_fn overloads
732  /**
733   *  @brief Returns a function object that forwards to the member
734   *  pointer @a pm.
735   *  @ingroup functors
736   */
737  template<typename _Tp, typename _Class>
738    inline _Mem_fn<_Tp _Class::*>
739    mem_fn(_Tp _Class::* __pm) noexcept
740    {
741      return _Mem_fn<_Tp _Class::*>(__pm);
742    }
743
744  /**
745   *  @brief Determines if the given type _Tp is a function object
746   *  should be treated as a subexpression when evaluating calls to
747   *  function objects returned by bind(). [TR1 3.6.1]
748   *  @ingroup binders
749   */
750  template<typename _Tp>
751    struct is_bind_expression
752    : public false_type { };
753
754  /**
755   *  @brief Determines if the given type _Tp is a placeholder in a
756   *  bind() expression and, if so, which placeholder it is. [TR1 3.6.2]
757   *  @ingroup binders
758   */
759  template<typename _Tp>
760    struct is_placeholder
761    : public integral_constant<int, 0>
762    { };
763
764  /** @brief The type of placeholder objects defined by libstdc++.
765   *  @ingroup binders
766   */
767  template<int _Num> struct _Placeholder { };
768
769  _GLIBCXX_END_NAMESPACE_VERSION
770
771  /** @namespace std::placeholders
772   *  @brief ISO C++11 entities sub-namespace for functional.
773   *  @ingroup binders
774   */
775  namespace placeholders
776  {
777  _GLIBCXX_BEGIN_NAMESPACE_VERSION
778  /* Define a large number of placeholders. There is no way to
779   * simplify this with variadic templates, because we're introducing
780   * unique names for each.
781   */
782    extern const _Placeholder<1> _1;
783    extern const _Placeholder<2> _2;
784    extern const _Placeholder<3> _3;
785    extern const _Placeholder<4> _4;
786    extern const _Placeholder<5> _5;
787    extern const _Placeholder<6> _6;
788    extern const _Placeholder<7> _7;
789    extern const _Placeholder<8> _8;
790    extern const _Placeholder<9> _9;
791    extern const _Placeholder<10> _10;
792    extern const _Placeholder<11> _11;
793    extern const _Placeholder<12> _12;
794    extern const _Placeholder<13> _13;
795    extern const _Placeholder<14> _14;
796    extern const _Placeholder<15> _15;
797    extern const _Placeholder<16> _16;
798    extern const _Placeholder<17> _17;
799    extern const _Placeholder<18> _18;
800    extern const _Placeholder<19> _19;
801    extern const _Placeholder<20> _20;
802    extern const _Placeholder<21> _21;
803    extern const _Placeholder<22> _22;
804    extern const _Placeholder<23> _23;
805    extern const _Placeholder<24> _24;
806    extern const _Placeholder<25> _25;
807    extern const _Placeholder<26> _26;
808    extern const _Placeholder<27> _27;
809    extern const _Placeholder<28> _28;
810    extern const _Placeholder<29> _29;
811  _GLIBCXX_END_NAMESPACE_VERSION
812  }
813
814  _GLIBCXX_BEGIN_NAMESPACE_VERSION
815
816  /**
817   *  Partial specialization of is_placeholder that provides the placeholder
818   *  number for the placeholder objects defined by libstdc++.
819   *  @ingroup binders
820   */
821  template<int _Num>
822    struct is_placeholder<_Placeholder<_Num> >
823    : public integral_constant<int, _Num>
824    { };
825
826  template<int _Num>
827    struct is_placeholder<const _Placeholder<_Num> >
828    : public integral_constant<int, _Num>
829    { };
830
831  /**
832   * Used by _Safe_tuple_element to indicate that there is no tuple
833   * element at this position.
834   */
835  struct _No_tuple_element;
836
837  /**
838   * Implementation helper for _Safe_tuple_element. This primary
839   * template handles the case where it is safe to use @c
840   * tuple_element.
841   */
842  template<std::size_t __i, typename _Tuple, bool _IsSafe>
843    struct _Safe_tuple_element_impl
844    : tuple_element<__i, _Tuple> { };
845
846  /**
847   * Implementation helper for _Safe_tuple_element. This partial
848   * specialization handles the case where it is not safe to use @c
849   * tuple_element. We just return @c _No_tuple_element.
850   */
851  template<std::size_t __i, typename _Tuple>
852    struct _Safe_tuple_element_impl<__i, _Tuple, false>
853    {
854      typedef _No_tuple_element type;
855    };
856
857  /**
858   * Like tuple_element, but returns @c _No_tuple_element when
859   * tuple_element would return an error.
860   */
861 template<std::size_t __i, typename _Tuple>
862   struct _Safe_tuple_element
863   : _Safe_tuple_element_impl<__i, _Tuple,
864			      (__i < tuple_size<_Tuple>::value)>
865   { };
866
867  /**
868   *  Maps an argument to bind() into an actual argument to the bound
869   *  function object [TR1 3.6.3/5]. Only the first parameter should
870   *  be specified: the rest are used to determine among the various
871   *  implementations. Note that, although this class is a function
872   *  object, it isn't entirely normal because it takes only two
873   *  parameters regardless of the number of parameters passed to the
874   *  bind expression. The first parameter is the bound argument and
875   *  the second parameter is a tuple containing references to the
876   *  rest of the arguments.
877   */
878  template<typename _Arg,
879	   bool _IsBindExp = is_bind_expression<_Arg>::value,
880	   bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
881    class _Mu;
882
883  /**
884   *  If the argument is reference_wrapper<_Tp>, returns the
885   *  underlying reference. [TR1 3.6.3/5 bullet 1]
886   */
887  template<typename _Tp>
888    class _Mu<reference_wrapper<_Tp>, false, false>
889    {
890    public:
891      typedef _Tp& result_type;
892
893      /* Note: This won't actually work for const volatile
894       * reference_wrappers, because reference_wrapper::get() is const
895       * but not volatile-qualified. This might be a defect in the TR.
896       */
897      template<typename _CVRef, typename _Tuple>
898	result_type
899	operator()(_CVRef& __arg, _Tuple&) const volatile
900	{ return __arg.get(); }
901    };
902
903  /**
904   *  If the argument is a bind expression, we invoke the underlying
905   *  function object with the same cv-qualifiers as we are given and
906   *  pass along all of our arguments (unwrapped). [TR1 3.6.3/5 bullet 2]
907   */
908  template<typename _Arg>
909    class _Mu<_Arg, true, false>
910    {
911    public:
912      template<typename _CVArg, typename... _Args>
913	auto
914	operator()(_CVArg& __arg,
915		   tuple<_Args...>& __tuple) const volatile
916	-> decltype(__arg(declval<_Args>()...))
917	{
918	  // Construct an index tuple and forward to __call
919	  typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
920	    _Indexes;
921	  return this->__call(__arg, __tuple, _Indexes());
922	}
923
924    private:
925      // Invokes the underlying function object __arg by unpacking all
926      // of the arguments in the tuple.
927      template<typename _CVArg, typename... _Args, std::size_t... _Indexes>
928	auto
929	__call(_CVArg& __arg, tuple<_Args...>& __tuple,
930	       const _Index_tuple<_Indexes...>&) const volatile
931	-> decltype(__arg(declval<_Args>()...))
932	{
933	  return __arg(std::forward<_Args>(std::get<_Indexes>(__tuple))...);
934	}
935    };
936
937  /**
938   *  If the argument is a placeholder for the Nth argument, returns
939   *  a reference to the Nth argument to the bind function object.
940   *  [TR1 3.6.3/5 bullet 3]
941   */
942  template<typename _Arg>
943    class _Mu<_Arg, false, true>
944    {
945    public:
946      template<typename _Signature> class result;
947
948      template<typename _CVMu, typename _CVArg, typename _Tuple>
949	class result<_CVMu(_CVArg, _Tuple)>
950	{
951	  // Add a reference, if it hasn't already been done for us.
952	  // This allows us to be a little bit sloppy in constructing
953	  // the tuple that we pass to result_of<...>.
954	  typedef typename _Safe_tuple_element<(is_placeholder<_Arg>::value
955						- 1), _Tuple>::type
956	    __base_type;
957
958	public:
959	  typedef typename add_rvalue_reference<__base_type>::type type;
960	};
961
962      template<typename _Tuple>
963	typename result<_Mu(_Arg, _Tuple)>::type
964	operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
965	{
966	  return std::forward<typename result<_Mu(_Arg, _Tuple)>::type>(
967	      ::std::get<(is_placeholder<_Arg>::value - 1)>(__tuple));
968	}
969    };
970
971  /**
972   *  If the argument is just a value, returns a reference to that
973   *  value. The cv-qualifiers on the reference are the same as the
974   *  cv-qualifiers on the _Mu object. [TR1 3.6.3/5 bullet 4]
975   */
976  template<typename _Arg>
977    class _Mu<_Arg, false, false>
978    {
979    public:
980      template<typename _Signature> struct result;
981
982      template<typename _CVMu, typename _CVArg, typename _Tuple>
983	struct result<_CVMu(_CVArg, _Tuple)>
984	{
985	  typedef typename add_lvalue_reference<_CVArg>::type type;
986	};
987
988      // Pick up the cv-qualifiers of the argument
989      template<typename _CVArg, typename _Tuple>
990	_CVArg&&
991	operator()(_CVArg&& __arg, _Tuple&) const volatile
992	{ return std::forward<_CVArg>(__arg); }
993    };
994
995  /**
996   *  Maps member pointers into instances of _Mem_fn but leaves all
997   *  other function objects untouched. Used by std::bind(). The
998   *  primary template handles the non-member-pointer case.
999   */
1000  template<typename _Tp>
1001    struct _Maybe_wrap_member_pointer
1002    {
1003      typedef _Tp type;
1004
1005      static const _Tp&
1006      __do_wrap(const _Tp& __x)
1007      { return __x; }
1008
1009      static _Tp&&
1010      __do_wrap(_Tp&& __x)
1011      { return static_cast<_Tp&&>(__x); }
1012    };
1013
1014  /**
1015   *  Maps member pointers into instances of _Mem_fn but leaves all
1016   *  other function objects untouched. Used by std::bind(). This
1017   *  partial specialization handles the member pointer case.
1018   */
1019  template<typename _Tp, typename _Class>
1020    struct _Maybe_wrap_member_pointer<_Tp _Class::*>
1021    {
1022      typedef _Mem_fn<_Tp _Class::*> type;
1023
1024      static type
1025      __do_wrap(_Tp _Class::* __pm)
1026      { return type(__pm); }
1027    };
1028
1029  // Specialization needed to prevent "forming reference to void" errors when
1030  // bind<void>() is called, because argument deduction instantiates
1031  // _Maybe_wrap_member_pointer<void> outside the immediate context where
1032  // SFINAE applies.
1033  template<>
1034    struct _Maybe_wrap_member_pointer<void>
1035    {
1036      typedef void type;
1037    };
1038
1039  // std::get<I> for volatile-qualified tuples
1040  template<std::size_t _Ind, typename... _Tp>
1041    inline auto
1042    __volget(volatile tuple<_Tp...>& __tuple)
1043    -> __tuple_element_t<_Ind, tuple<_Tp...>> volatile&
1044    { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
1045
1046  // std::get<I> for const-volatile-qualified tuples
1047  template<std::size_t _Ind, typename... _Tp>
1048    inline auto
1049    __volget(const volatile tuple<_Tp...>& __tuple)
1050    -> __tuple_element_t<_Ind, tuple<_Tp...>> const volatile&
1051    { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
1052
1053  /// Type of the function object returned from bind().
1054  template<typename _Signature>
1055    struct _Bind;
1056
1057   template<typename _Functor, typename... _Bound_args>
1058    class _Bind<_Functor(_Bound_args...)>
1059    : public _Weak_result_type<_Functor>
1060    {
1061      typedef _Bind __self_type;
1062      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1063	_Bound_indexes;
1064
1065      _Functor _M_f;
1066      tuple<_Bound_args...> _M_bound_args;
1067
1068      // Call unqualified
1069      template<typename _Result, typename... _Args, std::size_t... _Indexes>
1070	_Result
1071	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
1072	{
1073	  return _M_f(_Mu<_Bound_args>()
1074		      (std::get<_Indexes>(_M_bound_args), __args)...);
1075	}
1076
1077      // Call as const
1078      template<typename _Result, typename... _Args, std::size_t... _Indexes>
1079	_Result
1080	__call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
1081	{
1082	  return _M_f(_Mu<_Bound_args>()
1083		      (std::get<_Indexes>(_M_bound_args), __args)...);
1084	}
1085
1086      // Call as volatile
1087      template<typename _Result, typename... _Args, std::size_t... _Indexes>
1088	_Result
1089	__call_v(tuple<_Args...>&& __args,
1090		 _Index_tuple<_Indexes...>) volatile
1091	{
1092	  return _M_f(_Mu<_Bound_args>()
1093		      (__volget<_Indexes>(_M_bound_args), __args)...);
1094	}
1095
1096      // Call as const volatile
1097      template<typename _Result, typename... _Args, std::size_t... _Indexes>
1098	_Result
1099	__call_c_v(tuple<_Args...>&& __args,
1100		   _Index_tuple<_Indexes...>) const volatile
1101	{
1102	  return _M_f(_Mu<_Bound_args>()
1103		      (__volget<_Indexes>(_M_bound_args), __args)...);
1104	}
1105
1106     public:
1107      template<typename... _Args>
1108	explicit _Bind(const _Functor& __f, _Args&&... __args)
1109	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1110	{ }
1111
1112      template<typename... _Args>
1113	explicit _Bind(_Functor&& __f, _Args&&... __args)
1114	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1115	{ }
1116
1117      _Bind(const _Bind&) = default;
1118
1119      _Bind(_Bind&& __b)
1120      : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1121      { }
1122
1123      // Call unqualified
1124      template<typename... _Args, typename _Result
1125	= decltype( std::declval<_Functor&>()(
1126	      _Mu<_Bound_args>()( std::declval<_Bound_args&>(),
1127				  std::declval<tuple<_Args...>&>() )... ) )>
1128	_Result
1129	operator()(_Args&&... __args)
1130	{
1131	  return this->__call<_Result>(
1132	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1133	      _Bound_indexes());
1134	}
1135
1136      // Call as const
1137      template<typename... _Args, typename _Result
1138	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
1139		       typename add_const<_Functor>::type&>::type>()(
1140	      _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
1141				  std::declval<tuple<_Args...>&>() )... ) )>
1142	_Result
1143	operator()(_Args&&... __args) const
1144	{
1145	  return this->__call_c<_Result>(
1146	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1147	      _Bound_indexes());
1148	}
1149
1150      // Call as volatile
1151      template<typename... _Args, typename _Result
1152	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
1153                       typename add_volatile<_Functor>::type&>::type>()(
1154	      _Mu<_Bound_args>()( std::declval<volatile _Bound_args&>(),
1155				  std::declval<tuple<_Args...>&>() )... ) )>
1156	_Result
1157	operator()(_Args&&... __args) volatile
1158	{
1159	  return this->__call_v<_Result>(
1160	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1161	      _Bound_indexes());
1162	}
1163
1164      // Call as const volatile
1165      template<typename... _Args, typename _Result
1166	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
1167                       typename add_cv<_Functor>::type&>::type>()(
1168	      _Mu<_Bound_args>()( std::declval<const volatile _Bound_args&>(),
1169				  std::declval<tuple<_Args...>&>() )... ) )>
1170	_Result
1171	operator()(_Args&&... __args) const volatile
1172	{
1173	  return this->__call_c_v<_Result>(
1174	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1175	      _Bound_indexes());
1176	}
1177    };
1178
1179  /// Type of the function object returned from bind<R>().
1180  template<typename _Result, typename _Signature>
1181    struct _Bind_result;
1182
1183  template<typename _Result, typename _Functor, typename... _Bound_args>
1184    class _Bind_result<_Result, _Functor(_Bound_args...)>
1185    {
1186      typedef _Bind_result __self_type;
1187      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1188	_Bound_indexes;
1189
1190      _Functor _M_f;
1191      tuple<_Bound_args...> _M_bound_args;
1192
1193      // sfinae types
1194      template<typename _Res>
1195	struct __enable_if_void : enable_if<is_void<_Res>::value, int> { };
1196      template<typename _Res>
1197	struct __disable_if_void : enable_if<!is_void<_Res>::value, int> { };
1198
1199      // Call unqualified
1200      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1201	_Result
1202	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1203	    typename __disable_if_void<_Res>::type = 0)
1204	{
1205	  return _M_f(_Mu<_Bound_args>()
1206		      (std::get<_Indexes>(_M_bound_args), __args)...);
1207	}
1208
1209      // Call unqualified, return void
1210      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1211	void
1212	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1213	    typename __enable_if_void<_Res>::type = 0)
1214	{
1215	  _M_f(_Mu<_Bound_args>()
1216	       (std::get<_Indexes>(_M_bound_args), __args)...);
1217	}
1218
1219      // Call as const
1220      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1221	_Result
1222	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1223	    typename __disable_if_void<_Res>::type = 0) const
1224	{
1225	  return _M_f(_Mu<_Bound_args>()
1226		      (std::get<_Indexes>(_M_bound_args), __args)...);
1227	}
1228
1229      // Call as const, return void
1230      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1231	void
1232	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1233	    typename __enable_if_void<_Res>::type = 0) const
1234	{
1235	  _M_f(_Mu<_Bound_args>()
1236	       (std::get<_Indexes>(_M_bound_args),  __args)...);
1237	}
1238
1239      // Call as volatile
1240      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1241	_Result
1242	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1243	    typename __disable_if_void<_Res>::type = 0) volatile
1244	{
1245	  return _M_f(_Mu<_Bound_args>()
1246		      (__volget<_Indexes>(_M_bound_args), __args)...);
1247	}
1248
1249      // Call as volatile, return void
1250      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1251	void
1252	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1253	    typename __enable_if_void<_Res>::type = 0) volatile
1254	{
1255	  _M_f(_Mu<_Bound_args>()
1256	       (__volget<_Indexes>(_M_bound_args), __args)...);
1257	}
1258
1259      // Call as const volatile
1260      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1261	_Result
1262	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1263	    typename __disable_if_void<_Res>::type = 0) const volatile
1264	{
1265	  return _M_f(_Mu<_Bound_args>()
1266		      (__volget<_Indexes>(_M_bound_args), __args)...);
1267	}
1268
1269      // Call as const volatile, return void
1270      template<typename _Res, typename... _Args, std::size_t... _Indexes>
1271	void
1272	__call(tuple<_Args...>&& __args,
1273	       _Index_tuple<_Indexes...>,
1274	    typename __enable_if_void<_Res>::type = 0) const volatile
1275	{
1276	  _M_f(_Mu<_Bound_args>()
1277	       (__volget<_Indexes>(_M_bound_args), __args)...);
1278	}
1279
1280    public:
1281      typedef _Result result_type;
1282
1283      template<typename... _Args>
1284	explicit _Bind_result(const _Functor& __f, _Args&&... __args)
1285	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1286	{ }
1287
1288      template<typename... _Args>
1289	explicit _Bind_result(_Functor&& __f, _Args&&... __args)
1290	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1291	{ }
1292
1293      _Bind_result(const _Bind_result&) = default;
1294
1295      _Bind_result(_Bind_result&& __b)
1296      : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1297      { }
1298
1299      // Call unqualified
1300      template<typename... _Args>
1301	result_type
1302	operator()(_Args&&... __args)
1303	{
1304	  return this->__call<_Result>(
1305	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1306	      _Bound_indexes());
1307	}
1308
1309      // Call as const
1310      template<typename... _Args>
1311	result_type
1312	operator()(_Args&&... __args) const
1313	{
1314	  return this->__call<_Result>(
1315	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1316	      _Bound_indexes());
1317	}
1318
1319      // Call as volatile
1320      template<typename... _Args>
1321	result_type
1322	operator()(_Args&&... __args) volatile
1323	{
1324	  return this->__call<_Result>(
1325	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1326	      _Bound_indexes());
1327	}
1328
1329      // Call as const volatile
1330      template<typename... _Args>
1331	result_type
1332	operator()(_Args&&... __args) const volatile
1333	{
1334	  return this->__call<_Result>(
1335	      std::forward_as_tuple(std::forward<_Args>(__args)...),
1336	      _Bound_indexes());
1337	}
1338    };
1339
1340  /**
1341   *  @brief Class template _Bind is always a bind expression.
1342   *  @ingroup binders
1343   */
1344  template<typename _Signature>
1345    struct is_bind_expression<_Bind<_Signature> >
1346    : public true_type { };
1347
1348  /**
1349   *  @brief Class template _Bind is always a bind expression.
1350   *  @ingroup binders
1351   */
1352  template<typename _Signature>
1353    struct is_bind_expression<const _Bind<_Signature> >
1354    : public true_type { };
1355
1356  /**
1357   *  @brief Class template _Bind is always a bind expression.
1358   *  @ingroup binders
1359   */
1360  template<typename _Signature>
1361    struct is_bind_expression<volatile _Bind<_Signature> >
1362    : public true_type { };
1363
1364  /**
1365   *  @brief Class template _Bind is always a bind expression.
1366   *  @ingroup binders
1367   */
1368  template<typename _Signature>
1369    struct is_bind_expression<const volatile _Bind<_Signature>>
1370    : public true_type { };
1371
1372  /**
1373   *  @brief Class template _Bind_result is always a bind expression.
1374   *  @ingroup binders
1375   */
1376  template<typename _Result, typename _Signature>
1377    struct is_bind_expression<_Bind_result<_Result, _Signature>>
1378    : public true_type { };
1379
1380  /**
1381   *  @brief Class template _Bind_result is always a bind expression.
1382   *  @ingroup binders
1383   */
1384  template<typename _Result, typename _Signature>
1385    struct is_bind_expression<const _Bind_result<_Result, _Signature>>
1386    : public true_type { };
1387
1388  /**
1389   *  @brief Class template _Bind_result is always a bind expression.
1390   *  @ingroup binders
1391   */
1392  template<typename _Result, typename _Signature>
1393    struct is_bind_expression<volatile _Bind_result<_Result, _Signature>>
1394    : public true_type { };
1395
1396  /**
1397   *  @brief Class template _Bind_result is always a bind expression.
1398   *  @ingroup binders
1399   */
1400  template<typename _Result, typename _Signature>
1401    struct is_bind_expression<const volatile _Bind_result<_Result, _Signature>>
1402    : public true_type { };
1403
1404  template<typename _Func, typename... _BoundArgs>
1405    struct _Bind_check_arity { };
1406
1407  template<typename _Ret, typename... _Args, typename... _BoundArgs>
1408    struct _Bind_check_arity<_Ret (*)(_Args...), _BoundArgs...>
1409    {
1410      static_assert(sizeof...(_BoundArgs) == sizeof...(_Args),
1411                   "Wrong number of arguments for function");
1412    };
1413
1414  template<typename _Ret, typename... _Args, typename... _BoundArgs>
1415    struct _Bind_check_arity<_Ret (*)(_Args......), _BoundArgs...>
1416    {
1417      static_assert(sizeof...(_BoundArgs) >= sizeof...(_Args),
1418                   "Wrong number of arguments for function");
1419    };
1420
1421  template<typename _Tp, typename _Class, typename... _BoundArgs>
1422    struct _Bind_check_arity<_Tp _Class::*, _BoundArgs...>
1423    {
1424      using _Arity = typename _Mem_fn<_Tp _Class::*>::_Arity;
1425      using _Varargs = typename _Mem_fn<_Tp _Class::*>::_Varargs;
1426      static_assert(_Varargs::value
1427		    ? sizeof...(_BoundArgs) >= _Arity::value + 1
1428		    : sizeof...(_BoundArgs) == _Arity::value + 1,
1429		    "Wrong number of arguments for pointer-to-member");
1430    };
1431
1432  // Trait type used to remove std::bind() from overload set via SFINAE
1433  // when first argument has integer type, so that std::bind() will
1434  // not be a better match than ::bind() from the BSD Sockets API.
1435  template<typename _Tp, typename _Tp2 = typename decay<_Tp>::type>
1436    using __is_socketlike = __or_<is_integral<_Tp2>, is_enum<_Tp2>>;
1437
1438  template<bool _SocketLike, typename _Func, typename... _BoundArgs>
1439    struct _Bind_helper
1440    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
1441    {
1442      typedef _Maybe_wrap_member_pointer<typename decay<_Func>::type>
1443	__maybe_type;
1444      typedef typename __maybe_type::type __func_type;
1445      typedef _Bind<__func_type(typename decay<_BoundArgs>::type...)> type;
1446    };
1447
1448  // Partial specialization for is_socketlike == true, does not define
1449  // nested type so std::bind() will not participate in overload resolution
1450  // when the first argument might be a socket file descriptor.
1451  template<typename _Func, typename... _BoundArgs>
1452    struct _Bind_helper<true, _Func, _BoundArgs...>
1453    { };
1454
1455  /**
1456   *  @brief Function template for std::bind.
1457   *  @ingroup binders
1458   */
1459  template<typename _Func, typename... _BoundArgs>
1460    inline typename
1461    _Bind_helper<__is_socketlike<_Func>::value, _Func, _BoundArgs...>::type
1462    bind(_Func&& __f, _BoundArgs&&... __args)
1463    {
1464      typedef _Bind_helper<false, _Func, _BoundArgs...> __helper_type;
1465      typedef typename __helper_type::__maybe_type __maybe_type;
1466      typedef typename __helper_type::type __result_type;
1467      return __result_type(__maybe_type::__do_wrap(std::forward<_Func>(__f)),
1468			   std::forward<_BoundArgs>(__args)...);
1469    }
1470
1471  template<typename _Result, typename _Func, typename... _BoundArgs>
1472    struct _Bindres_helper
1473    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
1474    {
1475      typedef _Maybe_wrap_member_pointer<typename decay<_Func>::type>
1476	__maybe_type;
1477      typedef typename __maybe_type::type __functor_type;
1478      typedef _Bind_result<_Result,
1479			   __functor_type(typename decay<_BoundArgs>::type...)>
1480	type;
1481    };
1482
1483  /**
1484   *  @brief Function template for std::bind<R>.
1485   *  @ingroup binders
1486   */
1487  template<typename _Result, typename _Func, typename... _BoundArgs>
1488    inline
1489    typename _Bindres_helper<_Result, _Func, _BoundArgs...>::type
1490    bind(_Func&& __f, _BoundArgs&&... __args)
1491    {
1492      typedef _Bindres_helper<_Result, _Func, _BoundArgs...> __helper_type;
1493      typedef typename __helper_type::__maybe_type __maybe_type;
1494      typedef typename __helper_type::type __result_type;
1495      return __result_type(__maybe_type::__do_wrap(std::forward<_Func>(__f)),
1496			   std::forward<_BoundArgs>(__args)...);
1497    }
1498
1499  template<typename _Signature>
1500    struct _Bind_simple;
1501
1502  template<typename _Callable, typename... _Args>
1503    struct _Bind_simple<_Callable(_Args...)>
1504    {
1505      typedef typename result_of<_Callable(_Args...)>::type result_type;
1506
1507      template<typename _Tp, typename... _Up>
1508        explicit
1509        _Bind_simple(_Tp&& __f, _Up&&... __args)
1510        : _M_bound(std::forward<_Tp>(__f), std::forward<_Up>(__args)...)
1511        { }
1512
1513      _Bind_simple(const _Bind_simple&) = default;
1514      _Bind_simple(_Bind_simple&&) = default;
1515
1516      result_type
1517      operator()()
1518      {
1519        typedef typename _Build_index_tuple<sizeof...(_Args)>::__type _Indices;
1520        return _M_invoke(_Indices());
1521      }
1522
1523    private:
1524      template<std::size_t... _Indices>
1525        typename result_of<_Callable(_Args...)>::type
1526        _M_invoke(_Index_tuple<_Indices...>)
1527        {
1528	  // std::bind always forwards bound arguments as lvalues,
1529	  // but this type can call functions which only accept rvalues.
1530          return std::forward<_Callable>(std::get<0>(_M_bound))(
1531              std::forward<_Args>(std::get<_Indices+1>(_M_bound))...);
1532        }
1533
1534      std::tuple<_Callable, _Args...> _M_bound;
1535    };
1536
1537  template<typename _Func, typename... _BoundArgs>
1538    struct _Bind_simple_helper
1539    : _Bind_check_arity<typename decay<_Func>::type, _BoundArgs...>
1540    {
1541      typedef _Maybe_wrap_member_pointer<typename decay<_Func>::type>
1542        __maybe_type;
1543      typedef typename __maybe_type::type __func_type;
1544      typedef _Bind_simple<__func_type(typename decay<_BoundArgs>::type...)>
1545       	__type;
1546    };
1547
1548  // Simplified version of std::bind for internal use, without support for
1549  // unbound arguments, placeholders or nested bind expressions.
1550  template<typename _Callable, typename... _Args>
1551    typename _Bind_simple_helper<_Callable, _Args...>::__type
1552    __bind_simple(_Callable&& __callable, _Args&&... __args)
1553    {
1554      typedef _Bind_simple_helper<_Callable, _Args...> __helper_type;
1555      typedef typename __helper_type::__maybe_type __maybe_type;
1556      typedef typename __helper_type::__type __result_type;
1557      return __result_type(
1558          __maybe_type::__do_wrap( std::forward<_Callable>(__callable)),
1559          std::forward<_Args>(__args)...);
1560    }
1561
1562  /**
1563   *  @brief Exception class thrown when class template function's
1564   *  operator() is called with an empty target.
1565   *  @ingroup exceptions
1566   */
1567  class bad_function_call : public std::exception
1568  {
1569  public:
1570    virtual ~bad_function_call() noexcept;
1571
1572    const char* what() const noexcept;
1573  };
1574
1575  /**
1576   *  Trait identifying "location-invariant" types, meaning that the
1577   *  address of the object (or any of its members) will not escape.
1578   *  Trivially copyable types are location-invariant and users can
1579   *  specialize this trait for other types.
1580   */
1581  template<typename _Tp>
1582    struct __is_location_invariant
1583    : is_trivially_copyable<_Tp>::type
1584    { };
1585
1586  class _Undefined_class;
1587
1588  union _Nocopy_types
1589  {
1590    void*       _M_object;
1591    const void* _M_const_object;
1592    void (*_M_function_pointer)();
1593    void (_Undefined_class::*_M_member_pointer)();
1594  };
1595
1596  union [[gnu::may_alias]] _Any_data
1597  {
1598    void*       _M_access()       { return &_M_pod_data[0]; }
1599    const void* _M_access() const { return &_M_pod_data[0]; }
1600
1601    template<typename _Tp>
1602      _Tp&
1603      _M_access()
1604      { return *static_cast<_Tp*>(_M_access()); }
1605
1606    template<typename _Tp>
1607      const _Tp&
1608      _M_access() const
1609      { return *static_cast<const _Tp*>(_M_access()); }
1610
1611    _Nocopy_types _M_unused;
1612    char _M_pod_data[sizeof(_Nocopy_types)];
1613  };
1614
1615  enum _Manager_operation
1616  {
1617    __get_type_info,
1618    __get_functor_ptr,
1619    __clone_functor,
1620    __destroy_functor
1621  };
1622
1623  // Simple type wrapper that helps avoid annoying const problems
1624  // when casting between void pointers and pointers-to-pointers.
1625  template<typename _Tp>
1626    struct _Simple_type_wrapper
1627    {
1628      _Simple_type_wrapper(_Tp __value) : __value(__value) { }
1629
1630      _Tp __value;
1631    };
1632
1633  template<typename _Tp>
1634    struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
1635    : __is_location_invariant<_Tp>
1636    { };
1637
1638  // Converts a reference to a function object into a callable
1639  // function object.
1640  template<typename _Functor>
1641    inline _Functor&
1642    __callable_functor(_Functor& __f)
1643    { return __f; }
1644
1645  template<typename _Member, typename _Class>
1646    inline _Mem_fn<_Member _Class::*>
1647    __callable_functor(_Member _Class::* &__p)
1648    { return std::mem_fn(__p); }
1649
1650  template<typename _Member, typename _Class>
1651    inline _Mem_fn<_Member _Class::*>
1652    __callable_functor(_Member _Class::* const &__p)
1653    { return std::mem_fn(__p); }
1654
1655  template<typename _Member, typename _Class>
1656    inline _Mem_fn<_Member _Class::*>
1657    __callable_functor(_Member _Class::* volatile &__p)
1658    { return std::mem_fn(__p); }
1659
1660  template<typename _Member, typename _Class>
1661    inline _Mem_fn<_Member _Class::*>
1662    __callable_functor(_Member _Class::* const volatile &__p)
1663    { return std::mem_fn(__p); }
1664
1665  template<typename _Signature>
1666    class function;
1667
1668  /// Base class of all polymorphic function object wrappers.
1669  class _Function_base
1670  {
1671  public:
1672    static const std::size_t _M_max_size = sizeof(_Nocopy_types);
1673    static const std::size_t _M_max_align = __alignof__(_Nocopy_types);
1674
1675    template<typename _Functor>
1676      class _Base_manager
1677      {
1678      protected:
1679	static const bool __stored_locally =
1680	(__is_location_invariant<_Functor>::value
1681	 && sizeof(_Functor) <= _M_max_size
1682	 && __alignof__(_Functor) <= _M_max_align
1683	 && (_M_max_align % __alignof__(_Functor) == 0));
1684
1685	typedef integral_constant<bool, __stored_locally> _Local_storage;
1686
1687	// Retrieve a pointer to the function object
1688	static _Functor*
1689	_M_get_pointer(const _Any_data& __source)
1690	{
1691	  const _Functor* __ptr =
1692	    __stored_locally? std::__addressof(__source._M_access<_Functor>())
1693	    /* have stored a pointer */ : __source._M_access<_Functor*>();
1694	  return const_cast<_Functor*>(__ptr);
1695	}
1696
1697	// Clone a location-invariant function object that fits within
1698	// an _Any_data structure.
1699	static void
1700	_M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
1701	{
1702	  ::new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
1703	}
1704
1705	// Clone a function object that is not location-invariant or
1706	// that cannot fit into an _Any_data structure.
1707	static void
1708	_M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
1709	{
1710	  __dest._M_access<_Functor*>() =
1711	    new _Functor(*__source._M_access<_Functor*>());
1712	}
1713
1714	// Destroying a location-invariant object may still require
1715	// destruction.
1716	static void
1717	_M_destroy(_Any_data& __victim, true_type)
1718	{
1719	  __victim._M_access<_Functor>().~_Functor();
1720	}
1721
1722	// Destroying an object located on the heap.
1723	static void
1724	_M_destroy(_Any_data& __victim, false_type)
1725	{
1726	  delete __victim._M_access<_Functor*>();
1727	}
1728
1729      public:
1730	static bool
1731	_M_manager(_Any_data& __dest, const _Any_data& __source,
1732		   _Manager_operation __op)
1733	{
1734	  switch (__op)
1735	    {
1736#if __cpp_rtti
1737	    case __get_type_info:
1738	      __dest._M_access<const type_info*>() = &typeid(_Functor);
1739	      break;
1740#endif
1741	    case __get_functor_ptr:
1742	      __dest._M_access<_Functor*>() = _M_get_pointer(__source);
1743	      break;
1744
1745	    case __clone_functor:
1746	      _M_clone(__dest, __source, _Local_storage());
1747	      break;
1748
1749	    case __destroy_functor:
1750	      _M_destroy(__dest, _Local_storage());
1751	      break;
1752	    }
1753	  return false;
1754	}
1755
1756	static void
1757	_M_init_functor(_Any_data& __functor, _Functor&& __f)
1758	{ _M_init_functor(__functor, std::move(__f), _Local_storage()); }
1759
1760	template<typename _Signature>
1761	  static bool
1762	  _M_not_empty_function(const function<_Signature>& __f)
1763	  { return static_cast<bool>(__f); }
1764
1765	template<typename _Tp>
1766	  static bool
1767	  _M_not_empty_function(_Tp* __fp)
1768	  { return __fp != nullptr; }
1769
1770	template<typename _Class, typename _Tp>
1771	  static bool
1772	  _M_not_empty_function(_Tp _Class::* __mp)
1773	  { return __mp != nullptr; }
1774
1775	template<typename _Tp>
1776	  static bool
1777	  _M_not_empty_function(const _Tp&)
1778	  { return true; }
1779
1780      private:
1781	static void
1782	_M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
1783	{ ::new (__functor._M_access()) _Functor(std::move(__f)); }
1784
1785	static void
1786	_M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
1787	{ __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
1788      };
1789
1790    template<typename _Functor>
1791      class _Ref_manager : public _Base_manager<_Functor*>
1792      {
1793	typedef _Function_base::_Base_manager<_Functor*> _Base;
1794
1795      public:
1796	static bool
1797	_M_manager(_Any_data& __dest, const _Any_data& __source,
1798		   _Manager_operation __op)
1799	{
1800	  switch (__op)
1801	    {
1802#if __cpp_rtti
1803	    case __get_type_info:
1804	      __dest._M_access<const type_info*>() = &typeid(_Functor);
1805	      break;
1806#endif
1807	    case __get_functor_ptr:
1808	      __dest._M_access<_Functor*>() = *_Base::_M_get_pointer(__source);
1809	      return is_const<_Functor>::value;
1810	      break;
1811
1812	    default:
1813	      _Base::_M_manager(__dest, __source, __op);
1814	    }
1815	  return false;
1816	}
1817
1818	static void
1819	_M_init_functor(_Any_data& __functor, reference_wrapper<_Functor> __f)
1820	{
1821	  _Base::_M_init_functor(__functor, std::__addressof(__f.get()));
1822	}
1823      };
1824
1825    _Function_base() : _M_manager(nullptr) { }
1826
1827    ~_Function_base()
1828    {
1829      if (_M_manager)
1830	_M_manager(_M_functor, _M_functor, __destroy_functor);
1831    }
1832
1833
1834    bool _M_empty() const { return !_M_manager; }
1835
1836    typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
1837				  _Manager_operation);
1838
1839    _Any_data     _M_functor;
1840    _Manager_type _M_manager;
1841  };
1842
1843  template<typename _Signature, typename _Functor>
1844    class _Function_handler;
1845
1846  template<typename _Res, typename _Functor, typename... _ArgTypes>
1847    class _Function_handler<_Res(_ArgTypes...), _Functor>
1848    : public _Function_base::_Base_manager<_Functor>
1849    {
1850      typedef _Function_base::_Base_manager<_Functor> _Base;
1851
1852    public:
1853      static _Res
1854      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
1855      {
1856	return (*_Base::_M_get_pointer(__functor))(
1857	    std::forward<_ArgTypes>(__args)...);
1858      }
1859    };
1860
1861  template<typename _Functor, typename... _ArgTypes>
1862    class _Function_handler<void(_ArgTypes...), _Functor>
1863    : public _Function_base::_Base_manager<_Functor>
1864    {
1865      typedef _Function_base::_Base_manager<_Functor> _Base;
1866
1867     public:
1868      static void
1869      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
1870      {
1871	(*_Base::_M_get_pointer(__functor))(
1872	    std::forward<_ArgTypes>(__args)...);
1873      }
1874    };
1875
1876  template<typename _Res, typename _Functor, typename... _ArgTypes>
1877    class _Function_handler<_Res(_ArgTypes...), reference_wrapper<_Functor> >
1878    : public _Function_base::_Ref_manager<_Functor>
1879    {
1880      typedef _Function_base::_Ref_manager<_Functor> _Base;
1881
1882     public:
1883      static _Res
1884      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
1885      {
1886	return std::__callable_functor(**_Base::_M_get_pointer(__functor))(
1887	      std::forward<_ArgTypes>(__args)...);
1888      }
1889    };
1890
1891  template<typename _Functor, typename... _ArgTypes>
1892    class _Function_handler<void(_ArgTypes...), reference_wrapper<_Functor> >
1893    : public _Function_base::_Ref_manager<_Functor>
1894    {
1895      typedef _Function_base::_Ref_manager<_Functor> _Base;
1896
1897     public:
1898      static void
1899      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
1900      {
1901	std::__callable_functor(**_Base::_M_get_pointer(__functor))(
1902	    std::forward<_ArgTypes>(__args)...);
1903      }
1904    };
1905
1906  template<typename _Class, typename _Member, typename _Res,
1907	   typename... _ArgTypes>
1908    class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
1909    : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
1910    {
1911      typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
1912	_Base;
1913
1914     public:
1915      static _Res
1916      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
1917      {
1918	return std::mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1919	    std::forward<_ArgTypes>(__args)...);
1920      }
1921    };
1922
1923  template<typename _Class, typename _Member, typename... _ArgTypes>
1924    class _Function_handler<void(_ArgTypes...), _Member _Class::*>
1925    : public _Function_base::_Base_manager<
1926		 _Simple_type_wrapper< _Member _Class::* > >
1927    {
1928      typedef _Member _Class::* _Functor;
1929      typedef _Simple_type_wrapper<_Functor> _Wrapper;
1930      typedef _Function_base::_Base_manager<_Wrapper> _Base;
1931
1932    public:
1933      static bool
1934      _M_manager(_Any_data& __dest, const _Any_data& __source,
1935		 _Manager_operation __op)
1936      {
1937	switch (__op)
1938	  {
1939#if __cpp_rtti
1940	  case __get_type_info:
1941	    __dest._M_access<const type_info*>() = &typeid(_Functor);
1942	    break;
1943#endif
1944	  case __get_functor_ptr:
1945	    __dest._M_access<_Functor*>() =
1946	      &_Base::_M_get_pointer(__source)->__value;
1947	    break;
1948
1949	  default:
1950	    _Base::_M_manager(__dest, __source, __op);
1951	  }
1952	return false;
1953      }
1954
1955      static void
1956      _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
1957      {
1958	std::mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1959	    std::forward<_ArgTypes>(__args)...);
1960      }
1961    };
1962
1963  template<typename _From, typename _To>
1964    using __check_func_return_type
1965      = __or_<is_void<_To>, is_convertible<_From, _To>>;
1966
1967  /**
1968   *  @brief Primary class template for std::function.
1969   *  @ingroup functors
1970   *
1971   *  Polymorphic function wrapper.
1972   */
1973  template<typename _Res, typename... _ArgTypes>
1974    class function<_Res(_ArgTypes...)>
1975    : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
1976      private _Function_base
1977    {
1978      typedef _Res _Signature_type(_ArgTypes...);
1979
1980      template<typename _Func,
1981	       typename _Res2 = typename result_of<_Func&(_ArgTypes...)>::type>
1982	struct _Callable : __check_func_return_type<_Res2, _Res> { };
1983
1984      // Used so the return type convertibility checks aren't done when
1985      // performing overload resolution for copy construction/assignment.
1986      template<typename _Tp>
1987	struct _Callable<function, _Tp> : false_type { };
1988
1989      template<typename _Cond, typename _Tp>
1990	using _Requires = typename enable_if<_Cond::value, _Tp>::type;
1991
1992    public:
1993      typedef _Res result_type;
1994
1995      // [3.7.2.1] construct/copy/destroy
1996
1997      /**
1998       *  @brief Default construct creates an empty function call wrapper.
1999       *  @post @c !(bool)*this
2000       */
2001      function() noexcept
2002      : _Function_base() { }
2003
2004      /**
2005       *  @brief Creates an empty function call wrapper.
2006       *  @post @c !(bool)*this
2007       */
2008      function(nullptr_t) noexcept
2009      : _Function_base() { }
2010
2011      /**
2012       *  @brief %Function copy constructor.
2013       *  @param __x A %function object with identical call signature.
2014       *  @post @c bool(*this) == bool(__x)
2015       *
2016       *  The newly-created %function contains a copy of the target of @a
2017       *  __x (if it has one).
2018       */
2019      function(const function& __x);
2020
2021      /**
2022       *  @brief %Function move constructor.
2023       *  @param __x A %function object rvalue with identical call signature.
2024       *
2025       *  The newly-created %function contains the target of @a __x
2026       *  (if it has one).
2027       */
2028      function(function&& __x) noexcept : _Function_base()
2029      {
2030	__x.swap(*this);
2031      }
2032
2033      // TODO: needs allocator_arg_t
2034
2035      /**
2036       *  @brief Builds a %function that targets a copy of the incoming
2037       *  function object.
2038       *  @param __f A %function object that is callable with parameters of
2039       *  type @c T1, @c T2, ..., @c TN and returns a value convertible
2040       *  to @c Res.
2041       *
2042       *  The newly-created %function object will target a copy of
2043       *  @a __f. If @a __f is @c reference_wrapper<F>, then this function
2044       *  object will contain a reference to the function object @c
2045       *  __f.get(). If @a __f is a NULL function pointer or NULL
2046       *  pointer-to-member, the newly-created object will be empty.
2047       *
2048       *  If @a __f is a non-NULL function pointer or an object of type @c
2049       *  reference_wrapper<F>, this function will not throw.
2050       */
2051      template<typename _Functor,
2052	       typename = _Requires<__not_<is_same<_Functor, function>>, void>,
2053	       typename = _Requires<_Callable<_Functor>, void>>
2054	function(_Functor);
2055
2056      /**
2057       *  @brief %Function assignment operator.
2058       *  @param __x A %function with identical call signature.
2059       *  @post @c (bool)*this == (bool)x
2060       *  @returns @c *this
2061       *
2062       *  The target of @a __x is copied to @c *this. If @a __x has no
2063       *  target, then @c *this will be empty.
2064       *
2065       *  If @a __x targets a function pointer or a reference to a function
2066       *  object, then this operation will not throw an %exception.
2067       */
2068      function&
2069      operator=(const function& __x)
2070      {
2071	function(__x).swap(*this);
2072	return *this;
2073      }
2074
2075      /**
2076       *  @brief %Function move-assignment operator.
2077       *  @param __x A %function rvalue with identical call signature.
2078       *  @returns @c *this
2079       *
2080       *  The target of @a __x is moved to @c *this. If @a __x has no
2081       *  target, then @c *this will be empty.
2082       *
2083       *  If @a __x targets a function pointer or a reference to a function
2084       *  object, then this operation will not throw an %exception.
2085       */
2086      function&
2087      operator=(function&& __x) noexcept
2088      {
2089	function(std::move(__x)).swap(*this);
2090	return *this;
2091      }
2092
2093      /**
2094       *  @brief %Function assignment to zero.
2095       *  @post @c !(bool)*this
2096       *  @returns @c *this
2097       *
2098       *  The target of @c *this is deallocated, leaving it empty.
2099       */
2100      function&
2101      operator=(nullptr_t) noexcept
2102      {
2103	if (_M_manager)
2104	  {
2105	    _M_manager(_M_functor, _M_functor, __destroy_functor);
2106	    _M_manager = nullptr;
2107	    _M_invoker = nullptr;
2108	  }
2109	return *this;
2110      }
2111
2112      /**
2113       *  @brief %Function assignment to a new target.
2114       *  @param __f A %function object that is callable with parameters of
2115       *  type @c T1, @c T2, ..., @c TN and returns a value convertible
2116       *  to @c Res.
2117       *  @return @c *this
2118       *
2119       *  This  %function object wrapper will target a copy of @a
2120       *  __f. If @a __f is @c reference_wrapper<F>, then this function
2121       *  object will contain a reference to the function object @c
2122       *  __f.get(). If @a __f is a NULL function pointer or NULL
2123       *  pointer-to-member, @c this object will be empty.
2124       *
2125       *  If @a __f is a non-NULL function pointer or an object of type @c
2126       *  reference_wrapper<F>, this function will not throw.
2127       */
2128      template<typename _Functor>
2129	_Requires<_Callable<typename decay<_Functor>::type>, function&>
2130	operator=(_Functor&& __f)
2131	{
2132	  function(std::forward<_Functor>(__f)).swap(*this);
2133	  return *this;
2134	}
2135
2136      /// @overload
2137      template<typename _Functor>
2138	function&
2139	operator=(reference_wrapper<_Functor> __f) noexcept
2140	{
2141	  function(__f).swap(*this);
2142	  return *this;
2143	}
2144
2145      // [3.7.2.2] function modifiers
2146
2147      /**
2148       *  @brief Swap the targets of two %function objects.
2149       *  @param __x A %function with identical call signature.
2150       *
2151       *  Swap the targets of @c this function object and @a __f. This
2152       *  function will not throw an %exception.
2153       */
2154      void swap(function& __x) noexcept
2155      {
2156	std::swap(_M_functor, __x._M_functor);
2157	std::swap(_M_manager, __x._M_manager);
2158	std::swap(_M_invoker, __x._M_invoker);
2159      }
2160
2161      // TODO: needs allocator_arg_t
2162      /*
2163      template<typename _Functor, typename _Alloc>
2164	void
2165	assign(_Functor&& __f, const _Alloc& __a)
2166	{
2167	  function(allocator_arg, __a,
2168		   std::forward<_Functor>(__f)).swap(*this);
2169	}
2170      */
2171
2172      // [3.7.2.3] function capacity
2173
2174      /**
2175       *  @brief Determine if the %function wrapper has a target.
2176       *
2177       *  @return @c true when this %function object contains a target,
2178       *  or @c false when it is empty.
2179       *
2180       *  This function will not throw an %exception.
2181       */
2182      explicit operator bool() const noexcept
2183      { return !_M_empty(); }
2184
2185      // [3.7.2.4] function invocation
2186
2187      /**
2188       *  @brief Invokes the function targeted by @c *this.
2189       *  @returns the result of the target.
2190       *  @throws bad_function_call when @c !(bool)*this
2191       *
2192       *  The function call operator invokes the target function object
2193       *  stored by @c this.
2194       */
2195      _Res operator()(_ArgTypes... __args) const;
2196
2197#if __cpp_rtti
2198      // [3.7.2.5] function target access
2199      /**
2200       *  @brief Determine the type of the target of this function object
2201       *  wrapper.
2202       *
2203       *  @returns the type identifier of the target function object, or
2204       *  @c typeid(void) if @c !(bool)*this.
2205       *
2206       *  This function will not throw an %exception.
2207       */
2208      const type_info& target_type() const noexcept;
2209
2210      /**
2211       *  @brief Access the stored target function object.
2212       *
2213       *  @return Returns a pointer to the stored target function object,
2214       *  if @c typeid(Functor).equals(target_type()); otherwise, a NULL
2215       *  pointer.
2216       *
2217       * This function will not throw an %exception.
2218       */
2219      template<typename _Functor>       _Functor* target() noexcept;
2220
2221      /// @overload
2222      template<typename _Functor> const _Functor* target() const noexcept;
2223#endif
2224
2225    private:
2226      using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...);
2227      _Invoker_type _M_invoker;
2228  };
2229
2230  // Out-of-line member definitions.
2231  template<typename _Res, typename... _ArgTypes>
2232    function<_Res(_ArgTypes...)>::
2233    function(const function& __x)
2234    : _Function_base()
2235    {
2236      if (static_cast<bool>(__x))
2237	{
2238	  __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
2239	  _M_invoker = __x._M_invoker;
2240	  _M_manager = __x._M_manager;
2241	}
2242    }
2243
2244  template<typename _Res, typename... _ArgTypes>
2245    template<typename _Functor, typename, typename>
2246      function<_Res(_ArgTypes...)>::
2247      function(_Functor __f)
2248      : _Function_base()
2249      {
2250	typedef _Function_handler<_Signature_type, _Functor> _My_handler;
2251
2252	if (_My_handler::_M_not_empty_function(__f))
2253	  {
2254	    _My_handler::_M_init_functor(_M_functor, std::move(__f));
2255	    _M_invoker = &_My_handler::_M_invoke;
2256	    _M_manager = &_My_handler::_M_manager;
2257	  }
2258      }
2259
2260  template<typename _Res, typename... _ArgTypes>
2261    _Res
2262    function<_Res(_ArgTypes...)>::
2263    operator()(_ArgTypes... __args) const
2264    {
2265      if (_M_empty())
2266	__throw_bad_function_call();
2267      return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
2268    }
2269
2270#if __cpp_rtti
2271  template<typename _Res, typename... _ArgTypes>
2272    const type_info&
2273    function<_Res(_ArgTypes...)>::
2274    target_type() const noexcept
2275    {
2276      if (_M_manager)
2277	{
2278	  _Any_data __typeinfo_result;
2279	  _M_manager(__typeinfo_result, _M_functor, __get_type_info);
2280	  return *__typeinfo_result._M_access<const type_info*>();
2281	}
2282      else
2283	return typeid(void);
2284    }
2285
2286  template<typename _Res, typename... _ArgTypes>
2287    template<typename _Functor>
2288      _Functor*
2289      function<_Res(_ArgTypes...)>::
2290      target() noexcept
2291      {
2292	if (typeid(_Functor) == target_type() && _M_manager)
2293	  {
2294	    _Any_data __ptr;
2295	    if (_M_manager(__ptr, _M_functor, __get_functor_ptr)
2296		&& !is_const<_Functor>::value)
2297	      return 0;
2298	    else
2299	      return __ptr._M_access<_Functor*>();
2300	  }
2301	else
2302	  return 0;
2303      }
2304
2305  template<typename _Res, typename... _ArgTypes>
2306    template<typename _Functor>
2307      const _Functor*
2308      function<_Res(_ArgTypes...)>::
2309      target() const noexcept
2310      {
2311	if (typeid(_Functor) == target_type() && _M_manager)
2312	  {
2313	    _Any_data __ptr;
2314	    _M_manager(__ptr, _M_functor, __get_functor_ptr);
2315	    return __ptr._M_access<const _Functor*>();
2316	  }
2317	else
2318	  return 0;
2319      }
2320#endif
2321
2322  // [20.7.15.2.6] null pointer comparisons
2323
2324  /**
2325   *  @brief Compares a polymorphic function object wrapper against 0
2326   *  (the NULL pointer).
2327   *  @returns @c true if the wrapper has no target, @c false otherwise
2328   *
2329   *  This function will not throw an %exception.
2330   */
2331  template<typename _Res, typename... _Args>
2332    inline bool
2333    operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
2334    { return !static_cast<bool>(__f); }
2335
2336  /// @overload
2337  template<typename _Res, typename... _Args>
2338    inline bool
2339    operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
2340    { return !static_cast<bool>(__f); }
2341
2342  /**
2343   *  @brief Compares a polymorphic function object wrapper against 0
2344   *  (the NULL pointer).
2345   *  @returns @c false if the wrapper has no target, @c true otherwise
2346   *
2347   *  This function will not throw an %exception.
2348   */
2349  template<typename _Res, typename... _Args>
2350    inline bool
2351    operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
2352    { return static_cast<bool>(__f); }
2353
2354  /// @overload
2355  template<typename _Res, typename... _Args>
2356    inline bool
2357    operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
2358    { return static_cast<bool>(__f); }
2359
2360  // [20.7.15.2.7] specialized algorithms
2361
2362  /**
2363   *  @brief Swap the targets of two polymorphic function object wrappers.
2364   *
2365   *  This function will not throw an %exception.
2366   */
2367  // _GLIBCXX_RESOLVE_LIB_DEFECTS
2368  // 2062. Effect contradictions w/o no-throw guarantee of std::function swaps
2369  template<typename _Res, typename... _Args>
2370    inline void
2371    swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept
2372    { __x.swap(__y); }
2373
2374_GLIBCXX_END_NAMESPACE_VERSION
2375} // namespace std
2376
2377#endif // C++11
2378
2379#endif // _GLIBCXX_FUNCTIONAL
2380