libstdc++
std_function.h
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1 // Implementation of std::function -*- C++ -*-
2 
3 // Copyright (C) 2004-2019 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 /** @file include/bits/std_function.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{functional}
28  */
29 
30 #ifndef _GLIBCXX_STD_FUNCTION_H
31 #define _GLIBCXX_STD_FUNCTION_H 1
32 
33 #pragma GCC system_header
34 
35 #if __cplusplus < 201103L
36 # include <bits/c++0x_warning.h>
37 #else
38 
39 #if __cpp_rtti
40 # include <typeinfo>
41 #endif
42 #include <bits/stl_function.h>
43 #include <bits/invoke.h>
44 #include <bits/refwrap.h>
45 #include <bits/functexcept.h>
46 
47 namespace std _GLIBCXX_VISIBILITY(default)
48 {
49 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50 
51  /**
52  * @brief Exception class thrown when class template function's
53  * operator() is called with an empty target.
54  * @ingroup exceptions
55  */
57  {
58  public:
59  virtual ~bad_function_call() noexcept;
60 
61  const char* what() const noexcept;
62  };
63 
64  /**
65  * Trait identifying "location-invariant" types, meaning that the
66  * address of the object (or any of its members) will not escape.
67  * Trivially copyable types are location-invariant and users can
68  * specialize this trait for other types.
69  */
70  template<typename _Tp>
72  : is_trivially_copyable<_Tp>::type
73  { };
74 
75  class _Undefined_class;
76 
77  union _Nocopy_types
78  {
79  void* _M_object;
80  const void* _M_const_object;
81  void (*_M_function_pointer)();
82  void (_Undefined_class::*_M_member_pointer)();
83  };
84 
85  union [[gnu::may_alias]] _Any_data
86  {
87  void* _M_access() { return &_M_pod_data[0]; }
88  const void* _M_access() const { return &_M_pod_data[0]; }
89 
90  template<typename _Tp>
91  _Tp&
92  _M_access()
93  { return *static_cast<_Tp*>(_M_access()); }
94 
95  template<typename _Tp>
96  const _Tp&
97  _M_access() const
98  { return *static_cast<const _Tp*>(_M_access()); }
99 
100  _Nocopy_types _M_unused;
101  char _M_pod_data[sizeof(_Nocopy_types)];
102  };
103 
104  enum _Manager_operation
105  {
106  __get_type_info,
107  __get_functor_ptr,
108  __clone_functor,
109  __destroy_functor
110  };
111 
112  // Simple type wrapper that helps avoid annoying const problems
113  // when casting between void pointers and pointers-to-pointers.
114  template<typename _Tp>
115  struct _Simple_type_wrapper
116  {
117  _Simple_type_wrapper(_Tp __value) : __value(__value) { }
118 
119  _Tp __value;
120  };
121 
122  template<typename _Tp>
123  struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
124  : __is_location_invariant<_Tp>
125  { };
126 
127  template<typename _Signature>
128  class function;
129 
130  /// Base class of all polymorphic function object wrappers.
132  {
133  public:
134  static const size_t _M_max_size = sizeof(_Nocopy_types);
135  static const size_t _M_max_align = __alignof__(_Nocopy_types);
136 
137  template<typename _Functor>
138  class _Base_manager
139  {
140  protected:
141  static const bool __stored_locally =
143  && sizeof(_Functor) <= _M_max_size
144  && __alignof__(_Functor) <= _M_max_align
145  && (_M_max_align % __alignof__(_Functor) == 0));
146 
147  typedef integral_constant<bool, __stored_locally> _Local_storage;
148 
149  // Retrieve a pointer to the function object
150  static _Functor*
151  _M_get_pointer(const _Any_data& __source)
152  {
153  if _GLIBCXX17_CONSTEXPR (__stored_locally)
154  {
155  const _Functor& __f = __source._M_access<_Functor>();
156  return const_cast<_Functor*>(std::__addressof(__f));
157  }
158  else // have stored a pointer
159  return __source._M_access<_Functor*>();
160  }
161 
162  // Clone a location-invariant function object that fits within
163  // an _Any_data structure.
164  static void
165  _M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
166  {
167  ::new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
168  }
169 
170  // Clone a function object that is not location-invariant or
171  // that cannot fit into an _Any_data structure.
172  static void
173  _M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
174  {
175  __dest._M_access<_Functor*>() =
176  new _Functor(*__source._M_access<const _Functor*>());
177  }
178 
179  // Destroying a location-invariant object may still require
180  // destruction.
181  static void
182  _M_destroy(_Any_data& __victim, true_type)
183  {
184  __victim._M_access<_Functor>().~_Functor();
185  }
186 
187  // Destroying an object located on the heap.
188  static void
189  _M_destroy(_Any_data& __victim, false_type)
190  {
191  delete __victim._M_access<_Functor*>();
192  }
193 
194  public:
195  static bool
196  _M_manager(_Any_data& __dest, const _Any_data& __source,
197  _Manager_operation __op)
198  {
199  switch (__op)
200  {
201 #if __cpp_rtti
202  case __get_type_info:
203  __dest._M_access<const type_info*>() = &typeid(_Functor);
204  break;
205 #endif
206  case __get_functor_ptr:
207  __dest._M_access<_Functor*>() = _M_get_pointer(__source);
208  break;
209 
210  case __clone_functor:
211  _M_clone(__dest, __source, _Local_storage());
212  break;
213 
214  case __destroy_functor:
215  _M_destroy(__dest, _Local_storage());
216  break;
217  }
218  return false;
219  }
220 
221  static void
222  _M_init_functor(_Any_data& __functor, _Functor&& __f)
223  { _M_init_functor(__functor, std::move(__f), _Local_storage()); }
224 
225  template<typename _Signature>
226  static bool
227  _M_not_empty_function(const function<_Signature>& __f)
228  { return static_cast<bool>(__f); }
229 
230  template<typename _Tp>
231  static bool
232  _M_not_empty_function(_Tp* __fp)
233  { return __fp != nullptr; }
234 
235  template<typename _Class, typename _Tp>
236  static bool
237  _M_not_empty_function(_Tp _Class::* __mp)
238  { return __mp != nullptr; }
239 
240  template<typename _Tp>
241  static bool
242  _M_not_empty_function(const _Tp&)
243  { return true; }
244 
245  private:
246  static void
247  _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
248  { ::new (__functor._M_access()) _Functor(std::move(__f)); }
249 
250  static void
251  _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
252  { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
253  };
254 
255  _Function_base() : _M_manager(nullptr) { }
256 
257  ~_Function_base()
258  {
259  if (_M_manager)
260  _M_manager(_M_functor, _M_functor, __destroy_functor);
261  }
262 
263  bool _M_empty() const { return !_M_manager; }
264 
265  typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
266  _Manager_operation);
267 
268  _Any_data _M_functor;
269  _Manager_type _M_manager;
270  };
271 
272  template<typename _Signature, typename _Functor>
273  class _Function_handler;
274 
275  template<typename _Res, typename _Functor, typename... _ArgTypes>
276  class _Function_handler<_Res(_ArgTypes...), _Functor>
277  : public _Function_base::_Base_manager<_Functor>
278  {
279  typedef _Function_base::_Base_manager<_Functor> _Base;
280 
281  public:
282  static _Res
283  _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
284  {
285  return (*_Base::_M_get_pointer(__functor))(
286  std::forward<_ArgTypes>(__args)...);
287  }
288  };
289 
290  template<typename _Functor, typename... _ArgTypes>
291  class _Function_handler<void(_ArgTypes...), _Functor>
292  : public _Function_base::_Base_manager<_Functor>
293  {
294  typedef _Function_base::_Base_manager<_Functor> _Base;
295 
296  public:
297  static void
298  _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
299  {
300  (*_Base::_M_get_pointer(__functor))(
301  std::forward<_ArgTypes>(__args)...);
302  }
303  };
304 
305  template<typename _Class, typename _Member, typename _Res,
306  typename... _ArgTypes>
307  class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
308  : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
309  {
310  typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
311  _Base;
312 
313  public:
314  static _Res
315  _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
316  {
317  return std::__invoke(_Base::_M_get_pointer(__functor)->__value,
318  std::forward<_ArgTypes>(__args)...);
319  }
320  };
321 
322  template<typename _Class, typename _Member, typename... _ArgTypes>
323  class _Function_handler<void(_ArgTypes...), _Member _Class::*>
324  : public _Function_base::_Base_manager<
325  _Simple_type_wrapper< _Member _Class::* > >
326  {
327  typedef _Member _Class::* _Functor;
328  typedef _Simple_type_wrapper<_Functor> _Wrapper;
329  typedef _Function_base::_Base_manager<_Wrapper> _Base;
330 
331  public:
332  static bool
333  _M_manager(_Any_data& __dest, const _Any_data& __source,
334  _Manager_operation __op)
335  {
336  switch (__op)
337  {
338 #if __cpp_rtti
339  case __get_type_info:
340  __dest._M_access<const type_info*>() = &typeid(_Functor);
341  break;
342 #endif
343  case __get_functor_ptr:
344  __dest._M_access<_Functor*>() =
345  &_Base::_M_get_pointer(__source)->__value;
346  break;
347 
348  default:
349  _Base::_M_manager(__dest, __source, __op);
350  }
351  return false;
352  }
353 
354  static void
355  _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
356  {
357  std::__invoke(_Base::_M_get_pointer(__functor)->__value,
358  std::forward<_ArgTypes>(__args)...);
359  }
360  };
361 
362  template<typename _From, typename _To>
363  using __check_func_return_type
364  = __or_<is_void<_To>, is_same<_From, _To>, is_convertible<_From, _To>>;
365 
366  /**
367  * @brief Primary class template for std::function.
368  * @ingroup functors
369  *
370  * Polymorphic function wrapper.
371  */
372  template<typename _Res, typename... _ArgTypes>
373  class function<_Res(_ArgTypes...)>
374  : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
375  private _Function_base
376  {
377  template<typename _Func,
378  typename _Res2 = typename result_of<_Func&(_ArgTypes...)>::type>
379  struct _Callable : __check_func_return_type<_Res2, _Res> { };
380 
381  // Used so the return type convertibility checks aren't done when
382  // performing overload resolution for copy construction/assignment.
383  template<typename _Tp>
384  struct _Callable<function, _Tp> : false_type { };
385 
386  template<typename _Cond, typename _Tp>
387  using _Requires = typename enable_if<_Cond::value, _Tp>::type;
388 
389  public:
390  typedef _Res result_type;
391 
392  // [3.7.2.1] construct/copy/destroy
393 
394  /**
395  * @brief Default construct creates an empty function call wrapper.
396  * @post @c !(bool)*this
397  */
398  function() noexcept
399  : _Function_base() { }
400 
401  /**
402  * @brief Creates an empty function call wrapper.
403  * @post @c !(bool)*this
404  */
405  function(nullptr_t) noexcept
406  : _Function_base() { }
407 
408  /**
409  * @brief %Function copy constructor.
410  * @param __x A %function object with identical call signature.
411  * @post @c bool(*this) == bool(__x)
412  *
413  * The newly-created %function contains a copy of the target of @a
414  * __x (if it has one).
415  */
416  function(const function& __x);
417 
418  /**
419  * @brief %Function move constructor.
420  * @param __x A %function object rvalue with identical call signature.
421  *
422  * The newly-created %function contains the target of @a __x
423  * (if it has one).
424  */
425  function(function&& __x) noexcept : _Function_base()
426  {
427  __x.swap(*this);
428  }
429 
430  /**
431  * @brief Builds a %function that targets a copy of the incoming
432  * function object.
433  * @param __f A %function object that is callable with parameters of
434  * type @c T1, @c T2, ..., @c TN and returns a value convertible
435  * to @c Res.
436  *
437  * The newly-created %function object will target a copy of
438  * @a __f. If @a __f is @c reference_wrapper<F>, then this function
439  * object will contain a reference to the function object @c
440  * __f.get(). If @a __f is a NULL function pointer or NULL
441  * pointer-to-member, the newly-created object will be empty.
442  *
443  * If @a __f is a non-NULL function pointer or an object of type @c
444  * reference_wrapper<F>, this function will not throw.
445  */
446  template<typename _Functor,
447  typename = _Requires<__not_<is_same<_Functor, function>>, void>,
448  typename = _Requires<_Callable<_Functor>, void>>
449  function(_Functor);
450 
451  /**
452  * @brief %Function assignment operator.
453  * @param __x A %function with identical call signature.
454  * @post @c (bool)*this == (bool)x
455  * @returns @c *this
456  *
457  * The target of @a __x is copied to @c *this. If @a __x has no
458  * target, then @c *this will be empty.
459  *
460  * If @a __x targets a function pointer or a reference to a function
461  * object, then this operation will not throw an %exception.
462  */
463  function&
464  operator=(const function& __x)
465  {
466  function(__x).swap(*this);
467  return *this;
468  }
469 
470  /**
471  * @brief %Function move-assignment operator.
472  * @param __x A %function rvalue with identical call signature.
473  * @returns @c *this
474  *
475  * The target of @a __x is moved to @c *this. If @a __x has no
476  * target, then @c *this will be empty.
477  *
478  * If @a __x targets a function pointer or a reference to a function
479  * object, then this operation will not throw an %exception.
480  */
481  function&
482  operator=(function&& __x) noexcept
483  {
484  function(std::move(__x)).swap(*this);
485  return *this;
486  }
487 
488  /**
489  * @brief %Function assignment to zero.
490  * @post @c !(bool)*this
491  * @returns @c *this
492  *
493  * The target of @c *this is deallocated, leaving it empty.
494  */
495  function&
496  operator=(nullptr_t) noexcept
497  {
498  if (_M_manager)
499  {
500  _M_manager(_M_functor, _M_functor, __destroy_functor);
501  _M_manager = nullptr;
502  _M_invoker = nullptr;
503  }
504  return *this;
505  }
506 
507  /**
508  * @brief %Function assignment to a new target.
509  * @param __f A %function object that is callable with parameters of
510  * type @c T1, @c T2, ..., @c TN and returns a value convertible
511  * to @c Res.
512  * @return @c *this
513  *
514  * This %function object wrapper will target a copy of @a
515  * __f. If @a __f is @c reference_wrapper<F>, then this function
516  * object will contain a reference to the function object @c
517  * __f.get(). If @a __f is a NULL function pointer or NULL
518  * pointer-to-member, @c this object will be empty.
519  *
520  * If @a __f is a non-NULL function pointer or an object of type @c
521  * reference_wrapper<F>, this function will not throw.
522  */
523  template<typename _Functor>
524  _Requires<_Callable<typename decay<_Functor>::type>, function&>
525  operator=(_Functor&& __f)
526  {
527  function(std::forward<_Functor>(__f)).swap(*this);
528  return *this;
529  }
530 
531  /// @overload
532  template<typename _Functor>
533  function&
535  {
536  function(__f).swap(*this);
537  return *this;
538  }
539 
540  // [3.7.2.2] function modifiers
541 
542  /**
543  * @brief Swap the targets of two %function objects.
544  * @param __x A %function with identical call signature.
545  *
546  * Swap the targets of @c this function object and @a __f. This
547  * function will not throw an %exception.
548  */
549  void swap(function& __x) noexcept
550  {
551  std::swap(_M_functor, __x._M_functor);
552  std::swap(_M_manager, __x._M_manager);
553  std::swap(_M_invoker, __x._M_invoker);
554  }
555 
556  // [3.7.2.3] function capacity
557 
558  /**
559  * @brief Determine if the %function wrapper has a target.
560  *
561  * @return @c true when this %function object contains a target,
562  * or @c false when it is empty.
563  *
564  * This function will not throw an %exception.
565  */
566  explicit operator bool() const noexcept
567  { return !_M_empty(); }
568 
569  // [3.7.2.4] function invocation
570 
571  /**
572  * @brief Invokes the function targeted by @c *this.
573  * @returns the result of the target.
574  * @throws bad_function_call when @c !(bool)*this
575  *
576  * The function call operator invokes the target function object
577  * stored by @c this.
578  */
579  _Res operator()(_ArgTypes... __args) const;
580 
581 #if __cpp_rtti
582  // [3.7.2.5] function target access
583  /**
584  * @brief Determine the type of the target of this function object
585  * wrapper.
586  *
587  * @returns the type identifier of the target function object, or
588  * @c typeid(void) if @c !(bool)*this.
589  *
590  * This function will not throw an %exception.
591  */
592  const type_info& target_type() const noexcept;
593 
594  /**
595  * @brief Access the stored target function object.
596  *
597  * @return Returns a pointer to the stored target function object,
598  * if @c typeid(_Functor).equals(target_type()); otherwise, a NULL
599  * pointer.
600  *
601  * This function does not throw exceptions.
602  *
603  * @{
604  */
605  template<typename _Functor> _Functor* target() noexcept;
606 
607  template<typename _Functor> const _Functor* target() const noexcept;
608  // @}
609 #endif
610 
611  private:
612  using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...);
613  _Invoker_type _M_invoker;
614  };
615 
616 #if __cpp_deduction_guides >= 201606
617  template<typename>
618  struct __function_guide_helper
619  { };
620 
621  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
622  struct __function_guide_helper<
623  _Res (_Tp::*) (_Args...) noexcept(_Nx)
624  >
625  { using type = _Res(_Args...); };
626 
627  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
628  struct __function_guide_helper<
629  _Res (_Tp::*) (_Args...) & noexcept(_Nx)
630  >
631  { using type = _Res(_Args...); };
632 
633  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
634  struct __function_guide_helper<
635  _Res (_Tp::*) (_Args...) const noexcept(_Nx)
636  >
637  { using type = _Res(_Args...); };
638 
639  template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
640  struct __function_guide_helper<
641  _Res (_Tp::*) (_Args...) const & noexcept(_Nx)
642  >
643  { using type = _Res(_Args...); };
644 
645  template<typename _Res, typename... _ArgTypes>
646  function(_Res(*)(_ArgTypes...)) -> function<_Res(_ArgTypes...)>;
647 
648  template<typename _Functor, typename _Signature = typename
649  __function_guide_helper<decltype(&_Functor::operator())>::type>
650  function(_Functor) -> function<_Signature>;
651 #endif
652 
653  // Out-of-line member definitions.
654  template<typename _Res, typename... _ArgTypes>
655  function<_Res(_ArgTypes...)>::
656  function(const function& __x)
657  : _Function_base()
658  {
659  if (static_cast<bool>(__x))
660  {
661  __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
662  _M_invoker = __x._M_invoker;
663  _M_manager = __x._M_manager;
664  }
665  }
666 
667  template<typename _Res, typename... _ArgTypes>
668  template<typename _Functor, typename, typename>
669  function<_Res(_ArgTypes...)>::
670  function(_Functor __f)
671  : _Function_base()
672  {
673  typedef _Function_handler<_Res(_ArgTypes...), _Functor> _My_handler;
674 
675  if (_My_handler::_M_not_empty_function(__f))
676  {
677  _My_handler::_M_init_functor(_M_functor, std::move(__f));
678  _M_invoker = &_My_handler::_M_invoke;
679  _M_manager = &_My_handler::_M_manager;
680  }
681  }
682 
683  template<typename _Res, typename... _ArgTypes>
684  _Res
685  function<_Res(_ArgTypes...)>::
686  operator()(_ArgTypes... __args) const
687  {
688  if (_M_empty())
689  __throw_bad_function_call();
690  return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
691  }
692 
693 #if __cpp_rtti
694  template<typename _Res, typename... _ArgTypes>
695  const type_info&
696  function<_Res(_ArgTypes...)>::
697  target_type() const noexcept
698  {
699  if (_M_manager)
700  {
701  _Any_data __typeinfo_result;
702  _M_manager(__typeinfo_result, _M_functor, __get_type_info);
703  return *__typeinfo_result._M_access<const type_info*>();
704  }
705  else
706  return typeid(void);
707  }
708 
709  template<typename _Res, typename... _ArgTypes>
710  template<typename _Functor>
711  _Functor*
712  function<_Res(_ArgTypes...)>::
713  target() noexcept
714  {
715  const function* __const_this = this;
716  const _Functor* __func = __const_this->template target<_Functor>();
717  return const_cast<_Functor*>(__func);
718  }
719 
720  template<typename _Res, typename... _ArgTypes>
721  template<typename _Functor>
722  const _Functor*
723  function<_Res(_ArgTypes...)>::
724  target() const noexcept
725  {
726  if (typeid(_Functor) == target_type() && _M_manager)
727  {
728  _Any_data __ptr;
729  _M_manager(__ptr, _M_functor, __get_functor_ptr);
730  return __ptr._M_access<const _Functor*>();
731  }
732  else
733  return nullptr;
734  }
735 #endif
736 
737  // [20.7.15.2.6] null pointer comparisons
738 
739  /**
740  * @brief Compares a polymorphic function object wrapper against 0
741  * (the NULL pointer).
742  * @returns @c true if the wrapper has no target, @c false otherwise
743  *
744  * This function will not throw an %exception.
745  */
746  template<typename _Res, typename... _Args>
747  inline bool
748  operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
749  { return !static_cast<bool>(__f); }
750 
751  /// @overload
752  template<typename _Res, typename... _Args>
753  inline bool
754  operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
755  { return !static_cast<bool>(__f); }
756 
757  /**
758  * @brief Compares a polymorphic function object wrapper against 0
759  * (the NULL pointer).
760  * @returns @c false if the wrapper has no target, @c true otherwise
761  *
762  * This function will not throw an %exception.
763  */
764  template<typename _Res, typename... _Args>
765  inline bool
766  operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
767  { return static_cast<bool>(__f); }
768 
769  /// @overload
770  template<typename _Res, typename... _Args>
771  inline bool
772  operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
773  { return static_cast<bool>(__f); }
774 
775 
776  // [20.7.15.2.7] specialized algorithms
777 
778  /**
779  * @brief Swap the targets of two polymorphic function object wrappers.
780  *
781  * This function will not throw an %exception.
782  */
783  // _GLIBCXX_RESOLVE_LIB_DEFECTS
784  // 2062. Effect contradictions w/o no-throw guarantee of std::function swaps
785  template<typename _Res, typename... _Args>
786  inline void
787  swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept
788  { __x.swap(__y); }
789 
790 _GLIBCXX_END_NAMESPACE_VERSION
791 } // namespace std
792 
793 #endif // C++11
794 
795 #endif // _GLIBCXX_STD_FUNCTION_H
Exception class thrown when class template function's operator() is called with an empty target.
Definition: std_function.h:56
const char * what() const noexcept
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:2087
function & operator=(function &&__x) noexcept
Function move-assignment operator.
Definition: std_function.h:482
_Requires< _Callable< typename decay< _Functor >::type >, function & > operator=(_Functor &&__f)
Function assignment to a new target.
Definition: std_function.h:525
function & operator=(const function &__x)
Function assignment operator.
Definition: std_function.h:464
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:47
ISO C++ entities toplevel namespace is std.
result_of
Definition: type_traits:2207
constexpr __invoke_result< _Callable, _Args... >::type __invoke(_Callable &&__fn, _Args &&... __args) noexcept(__is_nothrow_invocable< _Callable, _Args... >::value)
Invoke a callable object.
Definition: invoke.h:89
Primary class template for reference_wrapper.
Definition: type_traits:2061
void swap(function &__x) noexcept
Swap the targets of two function objects.
Definition: std_function.h:549
Part of RTTI.
Definition: typeinfo:88
Base class of all polymorphic function object wrappers.
Definition: std_function.h:131
function & operator=(reference_wrapper< _Functor > __f) noexcept
Definition: std_function.h:534
function & operator=(nullptr_t) noexcept
Function assignment to zero.
Definition: std_function.h:496
Base class for all library exceptions.
Definition: exception.h:60
integral_constant
Definition: type_traits:57