mirrored from git://gcc.gnu.org/git/gcc.git
-
Notifications
You must be signed in to change notification settings - Fork 4.4k
/
std_function.h
795 lines (686 loc) · 22.8 KB
/
std_function.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
// Implementation of std::function -*- C++ -*-
// Copyright (C) 2004-2019 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/bits/std_function.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{functional}
*/
#ifndef _GLIBCXX_STD_FUNCTION_H
#define _GLIBCXX_STD_FUNCTION_H 1
#pragma GCC system_header
#if __cplusplus < 201103L
# include <bits/c++0x_warning.h>
#else
#if __cpp_rtti
# include <typeinfo>
#endif
#include <bits/stl_function.h>
#include <bits/invoke.h>
#include <bits/refwrap.h>
#include <bits/functexcept.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @brief Exception class thrown when class template function's
* operator() is called with an empty target.
* @ingroup exceptions
*/
class bad_function_call : public std::exception
{
public:
virtual ~bad_function_call() noexcept;
const char* what() const noexcept;
};
/**
* Trait identifying "location-invariant" types, meaning that the
* address of the object (or any of its members) will not escape.
* Trivially copyable types are location-invariant and users can
* specialize this trait for other types.
*/
template<typename _Tp>
struct __is_location_invariant
: is_trivially_copyable<_Tp>::type
{ };
class _Undefined_class;
union _Nocopy_types
{
void* _M_object;
const void* _M_const_object;
void (*_M_function_pointer)();
void (_Undefined_class::*_M_member_pointer)();
};
union [[gnu::may_alias]] _Any_data
{
void* _M_access() { return &_M_pod_data[0]; }
const void* _M_access() const { return &_M_pod_data[0]; }
template<typename _Tp>
_Tp&
_M_access()
{ return *static_cast<_Tp*>(_M_access()); }
template<typename _Tp>
const _Tp&
_M_access() const
{ return *static_cast<const _Tp*>(_M_access()); }
_Nocopy_types _M_unused;
char _M_pod_data[sizeof(_Nocopy_types)];
};
enum _Manager_operation
{
__get_type_info,
__get_functor_ptr,
__clone_functor,
__destroy_functor
};
// Simple type wrapper that helps avoid annoying const problems
// when casting between void pointers and pointers-to-pointers.
template<typename _Tp>
struct _Simple_type_wrapper
{
_Simple_type_wrapper(_Tp __value) : __value(__value) { }
_Tp __value;
};
template<typename _Tp>
struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
: __is_location_invariant<_Tp>
{ };
template<typename _Signature>
class function;
/// Base class of all polymorphic function object wrappers.
class _Function_base
{
public:
static const size_t _M_max_size = sizeof(_Nocopy_types);
static const size_t _M_max_align = __alignof__(_Nocopy_types);
template<typename _Functor>
class _Base_manager
{
protected:
static const bool __stored_locally =
(__is_location_invariant<_Functor>::value
&& sizeof(_Functor) <= _M_max_size
&& __alignof__(_Functor) <= _M_max_align
&& (_M_max_align % __alignof__(_Functor) == 0));
typedef integral_constant<bool, __stored_locally> _Local_storage;
// Retrieve a pointer to the function object
static _Functor*
_M_get_pointer(const _Any_data& __source)
{
if _GLIBCXX17_CONSTEXPR (__stored_locally)
{
const _Functor& __f = __source._M_access<_Functor>();
return const_cast<_Functor*>(std::__addressof(__f));
}
else // have stored a pointer
return __source._M_access<_Functor*>();
}
// Clone a location-invariant function object that fits within
// an _Any_data structure.
static void
_M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
{
::new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
}
// Clone a function object that is not location-invariant or
// that cannot fit into an _Any_data structure.
static void
_M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
{
__dest._M_access<_Functor*>() =
new _Functor(*__source._M_access<const _Functor*>());
}
// Destroying a location-invariant object may still require
// destruction.
static void
_M_destroy(_Any_data& __victim, true_type)
{
__victim._M_access<_Functor>().~_Functor();
}
// Destroying an object located on the heap.
static void
_M_destroy(_Any_data& __victim, false_type)
{
delete __victim._M_access<_Functor*>();
}
public:
static bool
_M_manager(_Any_data& __dest, const _Any_data& __source,
_Manager_operation __op)
{
switch (__op)
{
#if __cpp_rtti
case __get_type_info:
__dest._M_access<const type_info*>() = &typeid(_Functor);
break;
#endif
case __get_functor_ptr:
__dest._M_access<_Functor*>() = _M_get_pointer(__source);
break;
case __clone_functor:
_M_clone(__dest, __source, _Local_storage());
break;
case __destroy_functor:
_M_destroy(__dest, _Local_storage());
break;
}
return false;
}
static void
_M_init_functor(_Any_data& __functor, _Functor&& __f)
{ _M_init_functor(__functor, std::move(__f), _Local_storage()); }
template<typename _Signature>
static bool
_M_not_empty_function(const function<_Signature>& __f)
{ return static_cast<bool>(__f); }
template<typename _Tp>
static bool
_M_not_empty_function(_Tp* __fp)
{ return __fp != nullptr; }
template<typename _Class, typename _Tp>
static bool
_M_not_empty_function(_Tp _Class::* __mp)
{ return __mp != nullptr; }
template<typename _Tp>
static bool
_M_not_empty_function(const _Tp&)
{ return true; }
private:
static void
_M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
{ ::new (__functor._M_access()) _Functor(std::move(__f)); }
static void
_M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
{ __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
};
_Function_base() : _M_manager(nullptr) { }
~_Function_base()
{
if (_M_manager)
_M_manager(_M_functor, _M_functor, __destroy_functor);
}
bool _M_empty() const { return !_M_manager; }
typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
_Manager_operation);
_Any_data _M_functor;
_Manager_type _M_manager;
};
template<typename _Signature, typename _Functor>
class _Function_handler;
template<typename _Res, typename _Functor, typename... _ArgTypes>
class _Function_handler<_Res(_ArgTypes...), _Functor>
: public _Function_base::_Base_manager<_Functor>
{
typedef _Function_base::_Base_manager<_Functor> _Base;
public:
static _Res
_M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
{
return (*_Base::_M_get_pointer(__functor))(
std::forward<_ArgTypes>(__args)...);
}
};
template<typename _Functor, typename... _ArgTypes>
class _Function_handler<void(_ArgTypes...), _Functor>
: public _Function_base::_Base_manager<_Functor>
{
typedef _Function_base::_Base_manager<_Functor> _Base;
public:
static void
_M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
{
(*_Base::_M_get_pointer(__functor))(
std::forward<_ArgTypes>(__args)...);
}
};
template<typename _Class, typename _Member, typename _Res,
typename... _ArgTypes>
class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
: public _Function_handler<void(_ArgTypes...), _Member _Class::*>
{
typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
_Base;
public:
static _Res
_M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
{
return std::__invoke(_Base::_M_get_pointer(__functor)->__value,
std::forward<_ArgTypes>(__args)...);
}
};
template<typename _Class, typename _Member, typename... _ArgTypes>
class _Function_handler<void(_ArgTypes...), _Member _Class::*>
: public _Function_base::_Base_manager<
_Simple_type_wrapper< _Member _Class::* > >
{
typedef _Member _Class::* _Functor;
typedef _Simple_type_wrapper<_Functor> _Wrapper;
typedef _Function_base::_Base_manager<_Wrapper> _Base;
public:
static bool
_M_manager(_Any_data& __dest, const _Any_data& __source,
_Manager_operation __op)
{
switch (__op)
{
#if __cpp_rtti
case __get_type_info:
__dest._M_access<const type_info*>() = &typeid(_Functor);
break;
#endif
case __get_functor_ptr:
__dest._M_access<_Functor*>() =
&_Base::_M_get_pointer(__source)->__value;
break;
default:
_Base::_M_manager(__dest, __source, __op);
}
return false;
}
static void
_M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
{
std::__invoke(_Base::_M_get_pointer(__functor)->__value,
std::forward<_ArgTypes>(__args)...);
}
};
template<typename _From, typename _To>
using __check_func_return_type
= __or_<is_void<_To>, is_same<_From, _To>, is_convertible<_From, _To>>;
/**
* @brief Primary class template for std::function.
* @ingroup functors
*
* Polymorphic function wrapper.
*/
template<typename _Res, typename... _ArgTypes>
class function<_Res(_ArgTypes...)>
: public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
private _Function_base
{
template<typename _Func,
typename _Res2 = typename result_of<_Func&(_ArgTypes...)>::type>
struct _Callable : __check_func_return_type<_Res2, _Res> { };
// Used so the return type convertibility checks aren't done when
// performing overload resolution for copy construction/assignment.
template<typename _Tp>
struct _Callable<function, _Tp> : false_type { };
template<typename _Cond, typename _Tp>
using _Requires = typename enable_if<_Cond::value, _Tp>::type;
public:
typedef _Res result_type;
// [3.7.2.1] construct/copy/destroy
/**
* @brief Default construct creates an empty function call wrapper.
* @post @c !(bool)*this
*/
function() noexcept
: _Function_base() { }
/**
* @brief Creates an empty function call wrapper.
* @post @c !(bool)*this
*/
function(nullptr_t) noexcept
: _Function_base() { }
/**
* @brief %Function copy constructor.
* @param __x A %function object with identical call signature.
* @post @c bool(*this) == bool(__x)
*
* The newly-created %function contains a copy of the target of @a
* __x (if it has one).
*/
function(const function& __x);
/**
* @brief %Function move constructor.
* @param __x A %function object rvalue with identical call signature.
*
* The newly-created %function contains the target of @a __x
* (if it has one).
*/
function(function&& __x) noexcept : _Function_base()
{
__x.swap(*this);
}
/**
* @brief Builds a %function that targets a copy of the incoming
* function object.
* @param __f A %function object that is callable with parameters of
* type @c T1, @c T2, ..., @c TN and returns a value convertible
* to @c Res.
*
* The newly-created %function object will target a copy of
* @a __f. If @a __f is @c reference_wrapper<F>, then this function
* object will contain a reference to the function object @c
* __f.get(). If @a __f is a NULL function pointer or NULL
* pointer-to-member, the newly-created object will be empty.
*
* If @a __f is a non-NULL function pointer or an object of type @c
* reference_wrapper<F>, this function will not throw.
*/
template<typename _Functor,
typename = _Requires<__not_<is_same<_Functor, function>>, void>,
typename = _Requires<_Callable<_Functor>, void>>
function(_Functor);
/**
* @brief %Function assignment operator.
* @param __x A %function with identical call signature.
* @post @c (bool)*this == (bool)x
* @returns @c *this
*
* The target of @a __x is copied to @c *this. If @a __x has no
* target, then @c *this will be empty.
*
* If @a __x targets a function pointer or a reference to a function
* object, then this operation will not throw an %exception.
*/
function&
operator=(const function& __x)
{
function(__x).swap(*this);
return *this;
}
/**
* @brief %Function move-assignment operator.
* @param __x A %function rvalue with identical call signature.
* @returns @c *this
*
* The target of @a __x is moved to @c *this. If @a __x has no
* target, then @c *this will be empty.
*
* If @a __x targets a function pointer or a reference to a function
* object, then this operation will not throw an %exception.
*/
function&
operator=(function&& __x) noexcept
{
function(std::move(__x)).swap(*this);
return *this;
}
/**
* @brief %Function assignment to zero.
* @post @c !(bool)*this
* @returns @c *this
*
* The target of @c *this is deallocated, leaving it empty.
*/
function&
operator=(nullptr_t) noexcept
{
if (_M_manager)
{
_M_manager(_M_functor, _M_functor, __destroy_functor);
_M_manager = nullptr;
_M_invoker = nullptr;
}
return *this;
}
/**
* @brief %Function assignment to a new target.
* @param __f A %function object that is callable with parameters of
* type @c T1, @c T2, ..., @c TN and returns a value convertible
* to @c Res.
* @return @c *this
*
* This %function object wrapper will target a copy of @a
* __f. If @a __f is @c reference_wrapper<F>, then this function
* object will contain a reference to the function object @c
* __f.get(). If @a __f is a NULL function pointer or NULL
* pointer-to-member, @c this object will be empty.
*
* If @a __f is a non-NULL function pointer or an object of type @c
* reference_wrapper<F>, this function will not throw.
*/
template<typename _Functor>
_Requires<_Callable<typename decay<_Functor>::type>, function&>
operator=(_Functor&& __f)
{
function(std::forward<_Functor>(__f)).swap(*this);
return *this;
}
/// @overload
template<typename _Functor>
function&
operator=(reference_wrapper<_Functor> __f) noexcept
{
function(__f).swap(*this);
return *this;
}
// [3.7.2.2] function modifiers
/**
* @brief Swap the targets of two %function objects.
* @param __x A %function with identical call signature.
*
* Swap the targets of @c this function object and @a __f. This
* function will not throw an %exception.
*/
void swap(function& __x) noexcept
{
std::swap(_M_functor, __x._M_functor);
std::swap(_M_manager, __x._M_manager);
std::swap(_M_invoker, __x._M_invoker);
}
// [3.7.2.3] function capacity
/**
* @brief Determine if the %function wrapper has a target.
*
* @return @c true when this %function object contains a target,
* or @c false when it is empty.
*
* This function will not throw an %exception.
*/
explicit operator bool() const noexcept
{ return !_M_empty(); }
// [3.7.2.4] function invocation
/**
* @brief Invokes the function targeted by @c *this.
* @returns the result of the target.
* @throws bad_function_call when @c !(bool)*this
*
* The function call operator invokes the target function object
* stored by @c this.
*/
_Res operator()(_ArgTypes... __args) const;
#if __cpp_rtti
// [3.7.2.5] function target access
/**
* @brief Determine the type of the target of this function object
* wrapper.
*
* @returns the type identifier of the target function object, or
* @c typeid(void) if @c !(bool)*this.
*
* This function will not throw an %exception.
*/
const type_info& target_type() const noexcept;
/**
* @brief Access the stored target function object.
*
* @return Returns a pointer to the stored target function object,
* if @c typeid(_Functor).equals(target_type()); otherwise, a NULL
* pointer.
*
* This function does not throw exceptions.
*
* @{
*/
template<typename _Functor> _Functor* target() noexcept;
template<typename _Functor> const _Functor* target() const noexcept;
// @}
#endif
private:
using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...);
_Invoker_type _M_invoker;
};
#if __cpp_deduction_guides >= 201606
template<typename>
struct __function_guide_helper
{ };
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
struct __function_guide_helper<
_Res (_Tp::*) (_Args...) noexcept(_Nx)
>
{ using type = _Res(_Args...); };
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
struct __function_guide_helper<
_Res (_Tp::*) (_Args...) & noexcept(_Nx)
>
{ using type = _Res(_Args...); };
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
struct __function_guide_helper<
_Res (_Tp::*) (_Args...) const noexcept(_Nx)
>
{ using type = _Res(_Args...); };
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
struct __function_guide_helper<
_Res (_Tp::*) (_Args...) const & noexcept(_Nx)
>
{ using type = _Res(_Args...); };
template<typename _Res, typename... _ArgTypes>
function(_Res(*)(_ArgTypes...)) -> function<_Res(_ArgTypes...)>;
template<typename _Functor, typename _Signature = typename
__function_guide_helper<decltype(&_Functor::operator())>::type>
function(_Functor) -> function<_Signature>;
#endif
// Out-of-line member definitions.
template<typename _Res, typename... _ArgTypes>
function<_Res(_ArgTypes...)>::
function(const function& __x)
: _Function_base()
{
if (static_cast<bool>(__x))
{
__x._M_manager(_M_functor, __x._M_functor, __clone_functor);
_M_invoker = __x._M_invoker;
_M_manager = __x._M_manager;
}
}
template<typename _Res, typename... _ArgTypes>
template<typename _Functor, typename, typename>
function<_Res(_ArgTypes...)>::
function(_Functor __f)
: _Function_base()
{
typedef _Function_handler<_Res(_ArgTypes...), _Functor> _My_handler;
if (_My_handler::_M_not_empty_function(__f))
{
_My_handler::_M_init_functor(_M_functor, std::move(__f));
_M_invoker = &_My_handler::_M_invoke;
_M_manager = &_My_handler::_M_manager;
}
}
template<typename _Res, typename... _ArgTypes>
_Res
function<_Res(_ArgTypes...)>::
operator()(_ArgTypes... __args) const
{
if (_M_empty())
__throw_bad_function_call();
return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
}
#if __cpp_rtti
template<typename _Res, typename... _ArgTypes>
const type_info&
function<_Res(_ArgTypes...)>::
target_type() const noexcept
{
if (_M_manager)
{
_Any_data __typeinfo_result;
_M_manager(__typeinfo_result, _M_functor, __get_type_info);
return *__typeinfo_result._M_access<const type_info*>();
}
else
return typeid(void);
}
template<typename _Res, typename... _ArgTypes>
template<typename _Functor>
_Functor*
function<_Res(_ArgTypes...)>::
target() noexcept
{
const function* __const_this = this;
const _Functor* __func = __const_this->template target<_Functor>();
return const_cast<_Functor*>(__func);
}
template<typename _Res, typename... _ArgTypes>
template<typename _Functor>
const _Functor*
function<_Res(_ArgTypes...)>::
target() const noexcept
{
if (typeid(_Functor) == target_type() && _M_manager)
{
_Any_data __ptr;
_M_manager(__ptr, _M_functor, __get_functor_ptr);
return __ptr._M_access<const _Functor*>();
}
else
return nullptr;
}
#endif
// [20.7.15.2.6] null pointer comparisons
/**
* @brief Compares a polymorphic function object wrapper against 0
* (the NULL pointer).
* @returns @c true if the wrapper has no target, @c false otherwise
*
* This function will not throw an %exception.
*/
template<typename _Res, typename... _Args>
inline bool
operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
{ return !static_cast<bool>(__f); }
/// @overload
template<typename _Res, typename... _Args>
inline bool
operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
{ return !static_cast<bool>(__f); }
/**
* @brief Compares a polymorphic function object wrapper against 0
* (the NULL pointer).
* @returns @c false if the wrapper has no target, @c true otherwise
*
* This function will not throw an %exception.
*/
template<typename _Res, typename... _Args>
inline bool
operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
{ return static_cast<bool>(__f); }
/// @overload
template<typename _Res, typename... _Args>
inline bool
operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
{ return static_cast<bool>(__f); }
// [20.7.15.2.7] specialized algorithms
/**
* @brief Swap the targets of two polymorphic function object wrappers.
*
* This function will not throw an %exception.
*/
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 2062. Effect contradictions w/o no-throw guarantee of std::function swaps
template<typename _Res, typename... _Args>
inline void
swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept
{ __x.swap(__y); }
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // C++11
#endif // _GLIBCXX_STD_FUNCTION_H