libstdc++
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00001 // Implementation of std::function -*- C++ -*- 00002 00003 // Copyright (C) 2004-2018 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file include/bits/std_function.h 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{functional} 00028 */ 00029 00030 #ifndef _GLIBCXX_STD_FUNCTION_H 00031 #define _GLIBCXX_STD_FUNCTION_H 1 00032 00033 #pragma GCC system_header 00034 00035 #if __cplusplus < 201103L 00036 # include <bits/c++0x_warning.h> 00037 #else 00038 00039 #if __cpp_rtti 00040 # include <typeinfo> 00041 #endif 00042 #include <bits/stl_function.h> 00043 #include <bits/invoke.h> 00044 #include <bits/refwrap.h> 00045 #include <bits/functexcept.h> 00046 00047 namespace std _GLIBCXX_VISIBILITY(default) 00048 { 00049 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00050 00051 /** 00052 * @brief Exception class thrown when class template function's 00053 * operator() is called with an empty target. 00054 * @ingroup exceptions 00055 */ 00056 class bad_function_call : public std::exception 00057 { 00058 public: 00059 virtual ~bad_function_call() noexcept; 00060 00061 const char* what() const noexcept; 00062 }; 00063 00064 /** 00065 * Trait identifying "location-invariant" types, meaning that the 00066 * address of the object (or any of its members) will not escape. 00067 * Trivially copyable types are location-invariant and users can 00068 * specialize this trait for other types. 00069 */ 00070 template<typename _Tp> 00071 struct __is_location_invariant 00072 : is_trivially_copyable<_Tp>::type 00073 { }; 00074 00075 class _Undefined_class; 00076 00077 union _Nocopy_types 00078 { 00079 void* _M_object; 00080 const void* _M_const_object; 00081 void (*_M_function_pointer)(); 00082 void (_Undefined_class::*_M_member_pointer)(); 00083 }; 00084 00085 union [[gnu::may_alias]] _Any_data 00086 { 00087 void* _M_access() { return &_M_pod_data[0]; } 00088 const void* _M_access() const { return &_M_pod_data[0]; } 00089 00090 template<typename _Tp> 00091 _Tp& 00092 _M_access() 00093 { return *static_cast<_Tp*>(_M_access()); } 00094 00095 template<typename _Tp> 00096 const _Tp& 00097 _M_access() const 00098 { return *static_cast<const _Tp*>(_M_access()); } 00099 00100 _Nocopy_types _M_unused; 00101 char _M_pod_data[sizeof(_Nocopy_types)]; 00102 }; 00103 00104 enum _Manager_operation 00105 { 00106 __get_type_info, 00107 __get_functor_ptr, 00108 __clone_functor, 00109 __destroy_functor 00110 }; 00111 00112 // Simple type wrapper that helps avoid annoying const problems 00113 // when casting between void pointers and pointers-to-pointers. 00114 template<typename _Tp> 00115 struct _Simple_type_wrapper 00116 { 00117 _Simple_type_wrapper(_Tp __value) : __value(__value) { } 00118 00119 _Tp __value; 00120 }; 00121 00122 template<typename _Tp> 00123 struct __is_location_invariant<_Simple_type_wrapper<_Tp> > 00124 : __is_location_invariant<_Tp> 00125 { }; 00126 00127 template<typename _Signature> 00128 class function; 00129 00130 /// Base class of all polymorphic function object wrappers. 00131 class _Function_base 00132 { 00133 public: 00134 static const std::size_t _M_max_size = sizeof(_Nocopy_types); 00135 static const std::size_t _M_max_align = __alignof__(_Nocopy_types); 00136 00137 template<typename _Functor> 00138 class _Base_manager 00139 { 00140 protected: 00141 static const bool __stored_locally = 00142 (__is_location_invariant<_Functor>::value 00143 && sizeof(_Functor) <= _M_max_size 00144 && __alignof__(_Functor) <= _M_max_align 00145 && (_M_max_align % __alignof__(_Functor) == 0)); 00146 00147 typedef integral_constant<bool, __stored_locally> _Local_storage; 00148 00149 // Retrieve a pointer to the function object 00150 static _Functor* 00151 _M_get_pointer(const _Any_data& __source) 00152 { 00153 const _Functor* __ptr = 00154 __stored_locally? std::__addressof(__source._M_access<_Functor>()) 00155 /* have stored a pointer */ : __source._M_access<_Functor*>(); 00156 return const_cast<_Functor*>(__ptr); 00157 } 00158 00159 // Clone a location-invariant function object that fits within 00160 // an _Any_data structure. 00161 static void 00162 _M_clone(_Any_data& __dest, const _Any_data& __source, true_type) 00163 { 00164 ::new (__dest._M_access()) _Functor(__source._M_access<_Functor>()); 00165 } 00166 00167 // Clone a function object that is not location-invariant or 00168 // that cannot fit into an _Any_data structure. 00169 static void 00170 _M_clone(_Any_data& __dest, const _Any_data& __source, false_type) 00171 { 00172 __dest._M_access<_Functor*>() = 00173 new _Functor(*__source._M_access<_Functor*>()); 00174 } 00175 00176 // Destroying a location-invariant object may still require 00177 // destruction. 00178 static void 00179 _M_destroy(_Any_data& __victim, true_type) 00180 { 00181 __victim._M_access<_Functor>().~_Functor(); 00182 } 00183 00184 // Destroying an object located on the heap. 00185 static void 00186 _M_destroy(_Any_data& __victim, false_type) 00187 { 00188 delete __victim._M_access<_Functor*>(); 00189 } 00190 00191 public: 00192 static bool 00193 _M_manager(_Any_data& __dest, const _Any_data& __source, 00194 _Manager_operation __op) 00195 { 00196 switch (__op) 00197 { 00198 #if __cpp_rtti 00199 case __get_type_info: 00200 __dest._M_access<const type_info*>() = &typeid(_Functor); 00201 break; 00202 #endif 00203 case __get_functor_ptr: 00204 __dest._M_access<_Functor*>() = _M_get_pointer(__source); 00205 break; 00206 00207 case __clone_functor: 00208 _M_clone(__dest, __source, _Local_storage()); 00209 break; 00210 00211 case __destroy_functor: 00212 _M_destroy(__dest, _Local_storage()); 00213 break; 00214 } 00215 return false; 00216 } 00217 00218 static void 00219 _M_init_functor(_Any_data& __functor, _Functor&& __f) 00220 { _M_init_functor(__functor, std::move(__f), _Local_storage()); } 00221 00222 template<typename _Signature> 00223 static bool 00224 _M_not_empty_function(const function<_Signature>& __f) 00225 { return static_cast<bool>(__f); } 00226 00227 template<typename _Tp> 00228 static bool 00229 _M_not_empty_function(_Tp* __fp) 00230 { return __fp != nullptr; } 00231 00232 template<typename _Class, typename _Tp> 00233 static bool 00234 _M_not_empty_function(_Tp _Class::* __mp) 00235 { return __mp != nullptr; } 00236 00237 template<typename _Tp> 00238 static bool 00239 _M_not_empty_function(const _Tp&) 00240 { return true; } 00241 00242 private: 00243 static void 00244 _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type) 00245 { ::new (__functor._M_access()) _Functor(std::move(__f)); } 00246 00247 static void 00248 _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type) 00249 { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); } 00250 }; 00251 00252 _Function_base() : _M_manager(nullptr) { } 00253 00254 ~_Function_base() 00255 { 00256 if (_M_manager) 00257 _M_manager(_M_functor, _M_functor, __destroy_functor); 00258 } 00259 00260 bool _M_empty() const { return !_M_manager; } 00261 00262 typedef bool (*_Manager_type)(_Any_data&, const _Any_data&, 00263 _Manager_operation); 00264 00265 _Any_data _M_functor; 00266 _Manager_type _M_manager; 00267 }; 00268 00269 template<typename _Signature, typename _Functor> 00270 class _Function_handler; 00271 00272 template<typename _Res, typename _Functor, typename... _ArgTypes> 00273 class _Function_handler<_Res(_ArgTypes...), _Functor> 00274 : public _Function_base::_Base_manager<_Functor> 00275 { 00276 typedef _Function_base::_Base_manager<_Functor> _Base; 00277 00278 public: 00279 static _Res 00280 _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) 00281 { 00282 return (*_Base::_M_get_pointer(__functor))( 00283 std::forward<_ArgTypes>(__args)...); 00284 } 00285 }; 00286 00287 template<typename _Functor, typename... _ArgTypes> 00288 class _Function_handler<void(_ArgTypes...), _Functor> 00289 : public _Function_base::_Base_manager<_Functor> 00290 { 00291 typedef _Function_base::_Base_manager<_Functor> _Base; 00292 00293 public: 00294 static void 00295 _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) 00296 { 00297 (*_Base::_M_get_pointer(__functor))( 00298 std::forward<_ArgTypes>(__args)...); 00299 } 00300 }; 00301 00302 template<typename _Class, typename _Member, typename _Res, 00303 typename... _ArgTypes> 00304 class _Function_handler<_Res(_ArgTypes...), _Member _Class::*> 00305 : public _Function_handler<void(_ArgTypes...), _Member _Class::*> 00306 { 00307 typedef _Function_handler<void(_ArgTypes...), _Member _Class::*> 00308 _Base; 00309 00310 public: 00311 static _Res 00312 _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) 00313 { 00314 return std::__invoke(_Base::_M_get_pointer(__functor)->__value, 00315 std::forward<_ArgTypes>(__args)...); 00316 } 00317 }; 00318 00319 template<typename _Class, typename _Member, typename... _ArgTypes> 00320 class _Function_handler<void(_ArgTypes...), _Member _Class::*> 00321 : public _Function_base::_Base_manager< 00322 _Simple_type_wrapper< _Member _Class::* > > 00323 { 00324 typedef _Member _Class::* _Functor; 00325 typedef _Simple_type_wrapper<_Functor> _Wrapper; 00326 typedef _Function_base::_Base_manager<_Wrapper> _Base; 00327 00328 public: 00329 static bool 00330 _M_manager(_Any_data& __dest, const _Any_data& __source, 00331 _Manager_operation __op) 00332 { 00333 switch (__op) 00334 { 00335 #if __cpp_rtti 00336 case __get_type_info: 00337 __dest._M_access<const type_info*>() = &typeid(_Functor); 00338 break; 00339 #endif 00340 case __get_functor_ptr: 00341 __dest._M_access<_Functor*>() = 00342 &_Base::_M_get_pointer(__source)->__value; 00343 break; 00344 00345 default: 00346 _Base::_M_manager(__dest, __source, __op); 00347 } 00348 return false; 00349 } 00350 00351 static void 00352 _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args) 00353 { 00354 std::__invoke(_Base::_M_get_pointer(__functor)->__value, 00355 std::forward<_ArgTypes>(__args)...); 00356 } 00357 }; 00358 00359 template<typename _From, typename _To> 00360 using __check_func_return_type 00361 = __or_<is_void<_To>, is_same<_From, _To>, is_convertible<_From, _To>>; 00362 00363 /** 00364 * @brief Primary class template for std::function. 00365 * @ingroup functors 00366 * 00367 * Polymorphic function wrapper. 00368 */ 00369 template<typename _Res, typename... _ArgTypes> 00370 class function<_Res(_ArgTypes...)> 00371 : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>, 00372 private _Function_base 00373 { 00374 template<typename _Func, 00375 typename _Res2 = typename result_of<_Func&(_ArgTypes...)>::type> 00376 struct _Callable : __check_func_return_type<_Res2, _Res> { }; 00377 00378 // Used so the return type convertibility checks aren't done when 00379 // performing overload resolution for copy construction/assignment. 00380 template<typename _Tp> 00381 struct _Callable<function, _Tp> : false_type { }; 00382 00383 template<typename _Cond, typename _Tp> 00384 using _Requires = typename enable_if<_Cond::value, _Tp>::type; 00385 00386 public: 00387 typedef _Res result_type; 00388 00389 // [3.7.2.1] construct/copy/destroy 00390 00391 /** 00392 * @brief Default construct creates an empty function call wrapper. 00393 * @post @c !(bool)*this 00394 */ 00395 function() noexcept 00396 : _Function_base() { } 00397 00398 /** 00399 * @brief Creates an empty function call wrapper. 00400 * @post @c !(bool)*this 00401 */ 00402 function(nullptr_t) noexcept 00403 : _Function_base() { } 00404 00405 /** 00406 * @brief %Function copy constructor. 00407 * @param __x A %function object with identical call signature. 00408 * @post @c bool(*this) == bool(__x) 00409 * 00410 * The newly-created %function contains a copy of the target of @a 00411 * __x (if it has one). 00412 */ 00413 function(const function& __x); 00414 00415 /** 00416 * @brief %Function move constructor. 00417 * @param __x A %function object rvalue with identical call signature. 00418 * 00419 * The newly-created %function contains the target of @a __x 00420 * (if it has one). 00421 */ 00422 function(function&& __x) noexcept : _Function_base() 00423 { 00424 __x.swap(*this); 00425 } 00426 00427 /** 00428 * @brief Builds a %function that targets a copy of the incoming 00429 * function object. 00430 * @param __f A %function object that is callable with parameters of 00431 * type @c T1, @c T2, ..., @c TN and returns a value convertible 00432 * to @c Res. 00433 * 00434 * The newly-created %function object will target a copy of 00435 * @a __f. If @a __f is @c reference_wrapper<F>, then this function 00436 * object will contain a reference to the function object @c 00437 * __f.get(). If @a __f is a NULL function pointer or NULL 00438 * pointer-to-member, the newly-created object will be empty. 00439 * 00440 * If @a __f is a non-NULL function pointer or an object of type @c 00441 * reference_wrapper<F>, this function will not throw. 00442 */ 00443 template<typename _Functor, 00444 typename = _Requires<__not_<is_same<_Functor, function>>, void>, 00445 typename = _Requires<_Callable<_Functor>, void>> 00446 function(_Functor); 00447 00448 /** 00449 * @brief %Function assignment operator. 00450 * @param __x A %function with identical call signature. 00451 * @post @c (bool)*this == (bool)x 00452 * @returns @c *this 00453 * 00454 * The target of @a __x is copied to @c *this. If @a __x has no 00455 * target, then @c *this will be empty. 00456 * 00457 * If @a __x targets a function pointer or a reference to a function 00458 * object, then this operation will not throw an %exception. 00459 */ 00460 function& 00461 operator=(const function& __x) 00462 { 00463 function(__x).swap(*this); 00464 return *this; 00465 } 00466 00467 /** 00468 * @brief %Function move-assignment operator. 00469 * @param __x A %function rvalue with identical call signature. 00470 * @returns @c *this 00471 * 00472 * The target of @a __x is moved to @c *this. If @a __x has no 00473 * target, then @c *this will be empty. 00474 * 00475 * If @a __x targets a function pointer or a reference to a function 00476 * object, then this operation will not throw an %exception. 00477 */ 00478 function& 00479 operator=(function&& __x) noexcept 00480 { 00481 function(std::move(__x)).swap(*this); 00482 return *this; 00483 } 00484 00485 /** 00486 * @brief %Function assignment to zero. 00487 * @post @c !(bool)*this 00488 * @returns @c *this 00489 * 00490 * The target of @c *this is deallocated, leaving it empty. 00491 */ 00492 function& 00493 operator=(nullptr_t) noexcept 00494 { 00495 if (_M_manager) 00496 { 00497 _M_manager(_M_functor, _M_functor, __destroy_functor); 00498 _M_manager = nullptr; 00499 _M_invoker = nullptr; 00500 } 00501 return *this; 00502 } 00503 00504 /** 00505 * @brief %Function assignment to a new target. 00506 * @param __f A %function object that is callable with parameters of 00507 * type @c T1, @c T2, ..., @c TN and returns a value convertible 00508 * to @c Res. 00509 * @return @c *this 00510 * 00511 * This %function object wrapper will target a copy of @a 00512 * __f. If @a __f is @c reference_wrapper<F>, then this function 00513 * object will contain a reference to the function object @c 00514 * __f.get(). If @a __f is a NULL function pointer or NULL 00515 * pointer-to-member, @c this object will be empty. 00516 * 00517 * If @a __f is a non-NULL function pointer or an object of type @c 00518 * reference_wrapper<F>, this function will not throw. 00519 */ 00520 template<typename _Functor> 00521 _Requires<_Callable<typename decay<_Functor>::type>, function&> 00522 operator=(_Functor&& __f) 00523 { 00524 function(std::forward<_Functor>(__f)).swap(*this); 00525 return *this; 00526 } 00527 00528 /// @overload 00529 template<typename _Functor> 00530 function& 00531 operator=(reference_wrapper<_Functor> __f) noexcept 00532 { 00533 function(__f).swap(*this); 00534 return *this; 00535 } 00536 00537 // [3.7.2.2] function modifiers 00538 00539 /** 00540 * @brief Swap the targets of two %function objects. 00541 * @param __x A %function with identical call signature. 00542 * 00543 * Swap the targets of @c this function object and @a __f. This 00544 * function will not throw an %exception. 00545 */ 00546 void swap(function& __x) noexcept 00547 { 00548 std::swap(_M_functor, __x._M_functor); 00549 std::swap(_M_manager, __x._M_manager); 00550 std::swap(_M_invoker, __x._M_invoker); 00551 } 00552 00553 // [3.7.2.3] function capacity 00554 00555 /** 00556 * @brief Determine if the %function wrapper has a target. 00557 * 00558 * @return @c true when this %function object contains a target, 00559 * or @c false when it is empty. 00560 * 00561 * This function will not throw an %exception. 00562 */ 00563 explicit operator bool() const noexcept 00564 { return !_M_empty(); } 00565 00566 // [3.7.2.4] function invocation 00567 00568 /** 00569 * @brief Invokes the function targeted by @c *this. 00570 * @returns the result of the target. 00571 * @throws bad_function_call when @c !(bool)*this 00572 * 00573 * The function call operator invokes the target function object 00574 * stored by @c this. 00575 */ 00576 _Res operator()(_ArgTypes... __args) const; 00577 00578 #if __cpp_rtti 00579 // [3.7.2.5] function target access 00580 /** 00581 * @brief Determine the type of the target of this function object 00582 * wrapper. 00583 * 00584 * @returns the type identifier of the target function object, or 00585 * @c typeid(void) if @c !(bool)*this. 00586 * 00587 * This function will not throw an %exception. 00588 */ 00589 const type_info& target_type() const noexcept; 00590 00591 /** 00592 * @brief Access the stored target function object. 00593 * 00594 * @return Returns a pointer to the stored target function object, 00595 * if @c typeid(_Functor).equals(target_type()); otherwise, a NULL 00596 * pointer. 00597 * 00598 * This function does not throw exceptions. 00599 * 00600 * @{ 00601 */ 00602 template<typename _Functor> _Functor* target() noexcept; 00603 00604 template<typename _Functor> const _Functor* target() const noexcept; 00605 // @} 00606 #endif 00607 00608 private: 00609 using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...); 00610 _Invoker_type _M_invoker; 00611 }; 00612 00613 #if __cpp_deduction_guides >= 201606 00614 template<typename> 00615 struct __function_guide_helper 00616 { }; 00617 00618 template<typename _Res, typename _Tp, bool _Nx, typename... _Args> 00619 struct __function_guide_helper< 00620 _Res (_Tp::*) (_Args...) noexcept(_Nx) 00621 > 00622 { using type = _Res(_Args...); }; 00623 00624 template<typename _Res, typename _Tp, bool _Nx, typename... _Args> 00625 struct __function_guide_helper< 00626 _Res (_Tp::*) (_Args...) & noexcept(_Nx) 00627 > 00628 { using type = _Res(_Args...); }; 00629 00630 template<typename _Res, typename _Tp, bool _Nx, typename... _Args> 00631 struct __function_guide_helper< 00632 _Res (_Tp::*) (_Args...) const noexcept(_Nx) 00633 > 00634 { using type = _Res(_Args...); }; 00635 00636 template<typename _Res, typename _Tp, bool _Nx, typename... _Args> 00637 struct __function_guide_helper< 00638 _Res (_Tp::*) (_Args...) const & noexcept(_Nx) 00639 > 00640 { using type = _Res(_Args...); }; 00641 00642 template<typename _Res, typename... _ArgTypes> 00643 function(_Res(*)(_ArgTypes...)) -> function<_Res(_ArgTypes...)>; 00644 00645 template<typename _Functor, typename _Signature = typename 00646 __function_guide_helper<decltype(&_Functor::operator())>::type> 00647 function(_Functor) -> function<_Signature>; 00648 #endif 00649 00650 // Out-of-line member definitions. 00651 template<typename _Res, typename... _ArgTypes> 00652 function<_Res(_ArgTypes...)>:: 00653 function(const function& __x) 00654 : _Function_base() 00655 { 00656 if (static_cast<bool>(__x)) 00657 { 00658 __x._M_manager(_M_functor, __x._M_functor, __clone_functor); 00659 _M_invoker = __x._M_invoker; 00660 _M_manager = __x._M_manager; 00661 } 00662 } 00663 00664 template<typename _Res, typename... _ArgTypes> 00665 template<typename _Functor, typename, typename> 00666 function<_Res(_ArgTypes...)>:: 00667 function(_Functor __f) 00668 : _Function_base() 00669 { 00670 typedef _Function_handler<_Res(_ArgTypes...), _Functor> _My_handler; 00671 00672 if (_My_handler::_M_not_empty_function(__f)) 00673 { 00674 _My_handler::_M_init_functor(_M_functor, std::move(__f)); 00675 _M_invoker = &_My_handler::_M_invoke; 00676 _M_manager = &_My_handler::_M_manager; 00677 } 00678 } 00679 00680 template<typename _Res, typename... _ArgTypes> 00681 _Res 00682 function<_Res(_ArgTypes...)>:: 00683 operator()(_ArgTypes... __args) const 00684 { 00685 if (_M_empty()) 00686 __throw_bad_function_call(); 00687 return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...); 00688 } 00689 00690 #if __cpp_rtti 00691 template<typename _Res, typename... _ArgTypes> 00692 const type_info& 00693 function<_Res(_ArgTypes...)>:: 00694 target_type() const noexcept 00695 { 00696 if (_M_manager) 00697 { 00698 _Any_data __typeinfo_result; 00699 _M_manager(__typeinfo_result, _M_functor, __get_type_info); 00700 return *__typeinfo_result._M_access<const type_info*>(); 00701 } 00702 else 00703 return typeid(void); 00704 } 00705 00706 template<typename _Res, typename... _ArgTypes> 00707 template<typename _Functor> 00708 _Functor* 00709 function<_Res(_ArgTypes...)>:: 00710 target() noexcept 00711 { 00712 const function* __const_this = this; 00713 const _Functor* __func = __const_this->template target<_Functor>(); 00714 return const_cast<_Functor*>(__func); 00715 } 00716 00717 template<typename _Res, typename... _ArgTypes> 00718 template<typename _Functor> 00719 const _Functor* 00720 function<_Res(_ArgTypes...)>:: 00721 target() const noexcept 00722 { 00723 if (typeid(_Functor) == target_type() && _M_manager) 00724 { 00725 _Any_data __ptr; 00726 _M_manager(__ptr, _M_functor, __get_functor_ptr); 00727 return __ptr._M_access<const _Functor*>(); 00728 } 00729 else 00730 return nullptr; 00731 } 00732 #endif 00733 00734 // [20.7.15.2.6] null pointer comparisons 00735 00736 /** 00737 * @brief Compares a polymorphic function object wrapper against 0 00738 * (the NULL pointer). 00739 * @returns @c true if the wrapper has no target, @c false otherwise 00740 * 00741 * This function will not throw an %exception. 00742 */ 00743 template<typename _Res, typename... _Args> 00744 inline bool 00745 operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept 00746 { return !static_cast<bool>(__f); } 00747 00748 /// @overload 00749 template<typename _Res, typename... _Args> 00750 inline bool 00751 operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept 00752 { return !static_cast<bool>(__f); } 00753 00754 /** 00755 * @brief Compares a polymorphic function object wrapper against 0 00756 * (the NULL pointer). 00757 * @returns @c false if the wrapper has no target, @c true otherwise 00758 * 00759 * This function will not throw an %exception. 00760 */ 00761 template<typename _Res, typename... _Args> 00762 inline bool 00763 operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept 00764 { return static_cast<bool>(__f); } 00765 00766 /// @overload 00767 template<typename _Res, typename... _Args> 00768 inline bool 00769 operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept 00770 { return static_cast<bool>(__f); } 00771 00772 00773 // [20.7.15.2.7] specialized algorithms 00774 00775 /** 00776 * @brief Swap the targets of two polymorphic function object wrappers. 00777 * 00778 * This function will not throw an %exception. 00779 */ 00780 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00781 // 2062. Effect contradictions w/o no-throw guarantee of std::function swaps 00782 template<typename _Res, typename... _Args> 00783 inline void 00784 swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept 00785 { __x.swap(__y); } 00786 00787 _GLIBCXX_END_NAMESPACE_VERSION 00788 } // namespace std 00789 00790 #endif // C++11 00791 00792 #endif // _GLIBCXX_STD_FUNCTION_H