libstdc++-v3/include/std/functional

   1 // <functional> -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /*
  27  * Copyright (c) 1997
  28  * Silicon Graphics Computer Systems, Inc.
  29  *
  30  * Permission to use, copy, modify, distribute and sell this software
  31  * and its documentation for any purpose is hereby granted without fee,
  32  * provided that the above copyright notice appear in all copies and
  33  * that both that copyright notice and this permission notice appear
  34  * in supporting documentation.  Silicon Graphics makes no
  35  * representations about the suitability of this software for any
  36  * purpose.  It is provided "as is" without express or implied warranty.
  37  *
  38  */
  39
  40 /** @file include/functional
  41  *  This is a Standard C++ Library header.
  42  */
  43
  44 #ifndef _GLIBCXX_FUNCTIONAL
  45 #define _GLIBCXX_FUNCTIONAL 1
  46
  47 #pragma GCC system_header
  48
  49 #include <bits/c++config.h>
  50 #include <bits/stl_function.h>
  51
  52 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  53
  54 #include <typeinfo>
  55 #include <new>
  56 #include <tuple>
  57 #include <type_traits>
  58 #include <bits/functexcept.h>
  59 #include <bits/functional_hash.h>
  60
  61 _GLIBCXX_BEGIN_NAMESPACE(std)
  62
  63 _GLIBCXX_HAS_NESTED_TYPE(result_type)
  64
  65   /// If we have found a result_type, extract it.
  66   template<bool _Has_result_type, typename _Functor>
  67     struct _Maybe_get_result_type
  68     { };
  69
  70   template<typename _Functor>
  71     struct _Maybe_get_result_type<true, _Functor>
  72     { typedef typename _Functor::result_type result_type; };
  73
  74   /**
  75    *  Base class for any function object that has a weak result type, as
  76    *  defined in 3.3/3 of TR1.
  77   */
  78   template<typename _Functor>
  79     struct _Weak_result_type_impl
  80     : _Maybe_get_result_type<__has_result_type<_Functor>::value, _Functor>
  81     { };
  82
  83   /// Retrieve the result type for a function type.
  84   template<typename _Res, typename... _ArgTypes>
  85     struct _Weak_result_type_impl<_Res(_ArgTypes...)>
  86     { typedef _Res result_type; };
  87
  88   template<typename _Res, typename... _ArgTypes>
  89     struct _Weak_result_type_impl<_Res(_ArgTypes......)>
  90     { typedef _Res result_type; };
  91
  92   template<typename _Res, typename... _ArgTypes>
  93     struct _Weak_result_type_impl<_Res(_ArgTypes...) const>
  94     { typedef _Res result_type; };
  95
  96   template<typename _Res, typename... _ArgTypes>
  97     struct _Weak_result_type_impl<_Res(_ArgTypes......) const>
  98     { typedef _Res result_type; };
  99
 100   template<typename _Res, typename... _ArgTypes>
 101     struct _Weak_result_type_impl<_Res(_ArgTypes...) volatile>
 102     { typedef _Res result_type; };
 103
 104   template<typename _Res, typename... _ArgTypes>
 105     struct _Weak_result_type_impl<_Res(_ArgTypes......) volatile>
 106     { typedef _Res result_type; };
 107
 108   template<typename _Res, typename... _ArgTypes>
 109     struct _Weak_result_type_impl<_Res(_ArgTypes...) const volatile>
 110     { typedef _Res result_type; };
 111
 112   template<typename _Res, typename... _ArgTypes>
 113     struct _Weak_result_type_impl<_Res(_ArgTypes......) const volatile>
 114     { typedef _Res result_type; };
 115
 116   /// Retrieve the result type for a function reference.
 117   template<typename _Res, typename... _ArgTypes>
 118     struct _Weak_result_type_impl<_Res(&)(_ArgTypes...)>
 119     { typedef _Res result_type; };
 120
 121   template<typename _Res, typename... _ArgTypes>
 122     struct _Weak_result_type_impl<_Res(&)(_ArgTypes......)>
 123     { typedef _Res result_type; };
 124
 125   /// Retrieve the result type for a function pointer.
 126   template<typename _Res, typename... _ArgTypes>
 127     struct _Weak_result_type_impl<_Res(*)(_ArgTypes...)>
 128     { typedef _Res result_type; };
 129
 130   template<typename _Res, typename... _ArgTypes>
 131     struct _Weak_result_type_impl<_Res(*)(_ArgTypes......)>
 132     { typedef _Res result_type; };
 133
 134   /// Retrieve result type for a member function pointer.
 135   template<typename _Res, typename _Class, typename... _ArgTypes>
 136     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)>
 137     { typedef _Res result_type; };
 138
 139   template<typename _Res, typename _Class, typename... _ArgTypes>
 140     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)>
 141     { typedef _Res result_type; };
 142
 143   /// Retrieve result type for a const member function pointer.
 144   template<typename _Res, typename _Class, typename... _ArgTypes>
 145     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) const>
 146     { typedef _Res result_type; };
 147
 148   template<typename _Res, typename _Class, typename... _ArgTypes>
 149     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) const>
 150     { typedef _Res result_type; };
 151
 152   /// Retrieve result type for a volatile member function pointer.
 153   template<typename _Res, typename _Class, typename... _ArgTypes>
 154     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) volatile>
 155     { typedef _Res result_type; };
 156
 157   template<typename _Res, typename _Class, typename... _ArgTypes>
 158     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) volatile>
 159     { typedef _Res result_type; };
 160
 161   /// Retrieve result type for a const volatile member function pointer.
 162   template<typename _Res, typename _Class, typename... _ArgTypes>
 163     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)
 164                                   const volatile>
 165     { typedef _Res result_type; };
 166
 167   template<typename _Res, typename _Class, typename... _ArgTypes>
 168     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)
 169                                   const volatile>
 170     { typedef _Res result_type; };
 171
 172   /**
 173    *  Strip top-level cv-qualifiers from the function object and let
 174    *  _Weak_result_type_impl perform the real work.
 175   */
 176   template<typename _Functor>
 177     struct _Weak_result_type
 178     : _Weak_result_type_impl<typename remove_cv<_Functor>::type>
 179     { };
 180
 181   /// Determines if the type _Tp derives from unary_function.
 182   template<typename _Tp>
 183     struct _Derives_from_unary_function : __sfinae_types
 184     {
 185     private:
 186       template<typename _T1, typename _Res>
 187         static __one __test(const volatile unary_function<_T1, _Res>*);
 188
 189       // It's tempting to change "..." to const volatile void*, but
 190       // that fails when _Tp is a function type.
 191       static __two __test(...);
 192
 193     public:
 194       static const bool value = sizeof(__test((_Tp*)0)) == 1;
 195     };
 196
 197   /// Determines if the type _Tp derives from binary_function.
 198   template<typename _Tp>
 199     struct _Derives_from_binary_function : __sfinae_types
 200     {
 201     private:
 202       template<typename _T1, typename _T2, typename _Res>
 203         static __one __test(const volatile binary_function<_T1, _T2, _Res>*);
 204
 205       // It's tempting to change "..." to const volatile void*, but
 206       // that fails when _Tp is a function type.
 207       static __two __test(...);
 208
 209     public:
 210       static const bool value = sizeof(__test((_Tp*)0)) == 1;
 211     };
 212
 213   /// Turns a function type into a function pointer type
 214   template<typename _Tp, bool _IsFunctionType = is_function<_Tp>::value>
 215     struct _Function_to_function_pointer
 216     {
 217       typedef _Tp type;
 218     };
 219
 220   template<typename _Tp>
 221     struct _Function_to_function_pointer<_Tp, true>
 222     {
 223       typedef _Tp* type;
 224     };
 225
 226   /**
 227    * Invoke a function object, which may be either a member pointer or a
 228    * function object. The first parameter will tell which.
 229    */
 230   template<typename _Functor, typename... _Args>
 231     inline
 232     typename enable_if<
 233              (!is_member_pointer<_Functor>::value
 234               && !is_function<_Functor>::value
 235               && !is_function<typename remove_pointer<_Functor>::type>::value),
 236              typename result_of<_Functor(_Args...)>::type
 237            >::type
 238     __invoke(_Functor& __f, _Args&&... __args)
 239     {
 240       return __f(std::forward<_Args>(__args)...);
 241     }
 242
 243   // To pick up function references (that will become function pointers)
 244   template<typename _Functor, typename... _Args>
 245     inline
 246     typename enable_if<
 247              (is_pointer<_Functor>::value
 248               && is_function<typename remove_pointer<_Functor>::type>::value),
 249              typename result_of<_Functor(_Args...)>::type
 250            >::type
 251     __invoke(_Functor __f, _Args&&... __args)
 252     {
 253       return __f(std::forward<_Args>(__args)...);
 254     }
 255
 256   /**
 257    *  Knowing which of unary_function and binary_function _Tp derives
 258    *  from, derives from the same and ensures that reference_wrapper
 259    *  will have a weak result type. See cases below.
 260    */
 261   template<bool _Unary, bool _Binary, typename _Tp>
 262     struct _Reference_wrapper_base_impl;
 263
 264   // Not a unary_function or binary_function, so try a weak result type.
 265   template<typename _Tp>
 266     struct _Reference_wrapper_base_impl<false, false, _Tp>
 267     : _Weak_result_type<_Tp>
 268     { };
 269
 270   // unary_function but not binary_function
 271   template<typename _Tp>
 272     struct _Reference_wrapper_base_impl<true, false, _Tp>
 273     : unary_function<typename _Tp::argument_type,
 274                      typename _Tp::result_type>
 275     { };
 276
 277   // binary_function but not unary_function
 278   template<typename _Tp>
 279     struct _Reference_wrapper_base_impl<false, true, _Tp>
 280     : binary_function<typename _Tp::first_argument_type,
 281                       typename _Tp::second_argument_type,
 282                       typename _Tp::result_type>
 283     { };
 284
 285   // Both unary_function and binary_function. Import result_type to
 286   // avoid conflicts.
 287    template<typename _Tp>
 288     struct _Reference_wrapper_base_impl<true, true, _Tp>
 289     : unary_function<typename _Tp::argument_type,
 290                      typename _Tp::result_type>,
 291       binary_function<typename _Tp::first_argument_type,
 292                       typename _Tp::second_argument_type,
 293                       typename _Tp::result_type>
 294     {
 295       typedef typename _Tp::result_type result_type;
 296     };
 297
 298   /**
 299    *  Derives from unary_function or binary_function when it
 300    *  can. Specializations handle all of the easy cases. The primary
 301    *  template determines what to do with a class type, which may
 302    *  derive from both unary_function and binary_function.
 303   */
 304   template<typename _Tp>
 305     struct _Reference_wrapper_base
 306     : _Reference_wrapper_base_impl<
 307       _Derives_from_unary_function<_Tp>::value,
 308       _Derives_from_binary_function<_Tp>::value,
 309       _Tp>
 310     { };
 311
 312   // - a function type (unary)
 313   template<typename _Res, typename _T1>
 314     struct _Reference_wrapper_base<_Res(_T1)>
 315     : unary_function<_T1, _Res>
 316     { };
 317
 318   template<typename _Res, typename _T1>
 319     struct _Reference_wrapper_base<_Res(_T1) const>
 320     : unary_function<_T1, _Res>
 321     { };
 322
 323   template<typename _Res, typename _T1>
 324     struct _Reference_wrapper_base<_Res(_T1) volatile>
 325     : unary_function<_T1, _Res>
 326     { };
 327
 328   template<typename _Res, typename _T1>
 329     struct _Reference_wrapper_base<_Res(_T1) const volatile>
 330     : unary_function<_T1, _Res>
 331     { };
 332
 333   // - a function type (binary)
 334   template<typename _Res, typename _T1, typename _T2>
 335     struct _Reference_wrapper_base<_Res(_T1, _T2)>
 336     : binary_function<_T1, _T2, _Res>
 337     { };
 338
 339   template<typename _Res, typename _T1, typename _T2>
 340     struct _Reference_wrapper_base<_Res(_T1, _T2) const>
 341     : binary_function<_T1, _T2, _Res>
 342     { };
 343
 344   template<typename _Res, typename _T1, typename _T2>
 345     struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
 346     : binary_function<_T1, _T2, _Res>
 347     { };
 348
 349   template<typename _Res, typename _T1, typename _T2>
 350     struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
 351     : binary_function<_T1, _T2, _Res>
 352     { };
 353
 354   // - a function pointer type (unary)
 355   template<typename _Res, typename _T1>
 356     struct _Reference_wrapper_base<_Res(*)(_T1)>
 357     : unary_function<_T1, _Res>
 358     { };
 359
 360   // - a function pointer type (binary)
 361   template<typename _Res, typename _T1, typename _T2>
 362     struct _Reference_wrapper_base<_Res(*)(_T1, _T2)>
 363     : binary_function<_T1, _T2, _Res>
 364     { };
 365
 366   // - a pointer to member function type (unary, no qualifiers)
 367   template<typename _Res, typename _T1>
 368     struct _Reference_wrapper_base<_Res (_T1::*)()>
 369     : unary_function<_T1*, _Res>
 370     { };
 371
 372   // - a pointer to member function type (binary, no qualifiers)
 373   template<typename _Res, typename _T1, typename _T2>
 374     struct _Reference_wrapper_base<_Res (_T1::*)(_T2)>
 375     : binary_function<_T1*, _T2, _Res>
 376     { };
 377
 378   // - a pointer to member function type (unary, const)
 379   template<typename _Res, typename _T1>
 380     struct _Reference_wrapper_base<_Res (_T1::*)() const>
 381     : unary_function<const _T1*, _Res>
 382     { };
 383
 384   // - a pointer to member function type (binary, const)
 385   template<typename _Res, typename _T1, typename _T2>
 386     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const>
 387     : binary_function<const _T1*, _T2, _Res>
 388     { };
 389
 390   // - a pointer to member function type (unary, volatile)
 391   template<typename _Res, typename _T1>
 392     struct _Reference_wrapper_base<_Res (_T1::*)() volatile>
 393     : unary_function<volatile _T1*, _Res>
 394     { };
 395
 396   // - a pointer to member function type (binary, volatile)
 397   template<typename _Res, typename _T1, typename _T2>
 398     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) volatile>
 399     : binary_function<volatile _T1*, _T2, _Res>
 400     { };
 401
 402   // - a pointer to member function type (unary, const volatile)
 403   template<typename _Res, typename _T1>
 404     struct _Reference_wrapper_base<_Res (_T1::*)() const volatile>
 405     : unary_function<const volatile _T1*, _Res>
 406     { };
 407
 408   // - a pointer to member function type (binary, const volatile)
 409   template<typename _Res, typename _T1, typename _T2>
 410     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const volatile>
 411     : binary_function<const volatile _T1*, _T2, _Res>
 412     { };
 413
 414   /**
 415    *  @brief Primary class template for reference_wrapper.
 416    *  @ingroup functors
 417    *  @{
 418    */
 419   template<typename _Tp>
 420     class reference_wrapper
 421     : public _Reference_wrapper_base<typename remove_cv<_Tp>::type>
 422     {
 423       // If _Tp is a function type, we can't form result_of<_Tp(...)>,
 424       // so turn it into a function pointer type.
 425       typedef typename _Function_to_function_pointer<_Tp>::type
 426         _M_func_type;
 427
 428       _Tp* _M_data;
 429     public:
 430       typedef _Tp type;
 431
 432       reference_wrapper(_Tp& __indata)
 433       : _M_data(std::__addressof(__indata))
 434       { }
 435
 436       reference_wrapper(_Tp&&) = delete;
 437
 438       reference_wrapper(const reference_wrapper<_Tp>& __inref):
 439       _M_data(__inref._M_data)
 440       { }
 441
 442       reference_wrapper&
 443       operator=(const reference_wrapper<_Tp>& __inref)
 444       {
 445         _M_data = __inref._M_data;
 446         return *this;
 447       }
 448
 449       operator _Tp&() const
 450       { return this->get(); }
 451
 452       _Tp&
 453       get() const
 454       { return *_M_data; }
 455
 456       template<typename... _Args>
 457         typename result_of<_M_func_type(_Args...)>::type
 458         operator()(_Args&&... __args) const
 459         {
 460           return __invoke(get(), std::forward<_Args>(__args)...);
 461         }
 462     };
 463
 464
 465   /// Denotes a reference should be taken to a variable.
 466   template<typename _Tp>
 467     inline reference_wrapper<_Tp>
 468     ref(_Tp& __t)
 469     { return reference_wrapper<_Tp>(__t); }
 470
 471   /// Denotes a const reference should be taken to a variable.
 472   template<typename _Tp>
 473     inline reference_wrapper<const _Tp>
 474     cref(const _Tp& __t)
 475     { return reference_wrapper<const _Tp>(__t); }
 476
 477   /// Partial specialization.
 478   template<typename _Tp>
 479     inline reference_wrapper<_Tp>
 480     ref(reference_wrapper<_Tp> __t)
 481     { return ref(__t.get()); }
 482
 483   /// Partial specialization.
 484   template<typename _Tp>
 485     inline reference_wrapper<const _Tp>
 486     cref(reference_wrapper<_Tp> __t)
 487     { return cref(__t.get()); }
 488
 489   // @} group functors
 490
 491   template<typename _MemberPointer>
 492     class _Mem_fn;
 493
 494   /**
 495    * Derives from @c unary_function or @c binary_function, or perhaps
 496    * nothing, depending on the number of arguments provided. The
 497    * primary template is the basis case, which derives nothing.
 498    */
 499   template<typename _Res, typename... _ArgTypes>
 500     struct _Maybe_unary_or_binary_function { };
 501
 502   /// Derives from @c unary_function, as appropriate.
 503   template<typename _Res, typename _T1>
 504     struct _Maybe_unary_or_binary_function<_Res, _T1>
 505     : std::unary_function<_T1, _Res> { };
 506
 507   /// Derives from @c binary_function, as appropriate.
 508   template<typename _Res, typename _T1, typename _T2>
 509     struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
 510     : std::binary_function<_T1, _T2, _Res> { };
 511
 512   /// Implementation of @c mem_fn for member function pointers.
 513   template<typename _Res, typename _Class, typename... _ArgTypes>
 514     class _Mem_fn<_Res (_Class::*)(_ArgTypes...)>
 515     : public _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>
 516     {
 517       typedef _Res (_Class::*_Functor)(_ArgTypes...);
 518
 519       template<typename _Tp>
 520         _Res
 521         _M_call(_Tp& __object, const volatile _Class *,
 522                 _ArgTypes... __args) const
 523         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 524
 525       template<typename _Tp>
 526         _Res
 527         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 528         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 529
 530     public:
 531       typedef _Res result_type;
 532
 533       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 534
 535       // Handle objects
 536       _Res
 537       operator()(_Class& __object, _ArgTypes... __args) const
 538       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 539
 540       // Handle pointers
 541       _Res
 542       operator()(_Class* __object, _ArgTypes... __args) const
 543       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 544
 545       // Handle smart pointers, references and pointers to derived
 546       template<typename _Tp>
 547         _Res
 548         operator()(_Tp& __object, _ArgTypes... __args) const
 549         {
 550           return _M_call(__object, &__object,
 551               std::forward<_ArgTypes>(__args)...);
 552         }
 553
 554     private:
 555       _Functor __pmf;
 556     };
 557
 558   /// Implementation of @c mem_fn for const member function pointers.
 559   template<typename _Res, typename _Class, typename... _ArgTypes>
 560     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const>
 561     : public _Maybe_unary_or_binary_function<_Res, const _Class*,
 562                                              _ArgTypes...>
 563     {
 564       typedef _Res (_Class::*_Functor)(_ArgTypes...) const;
 565
 566       template<typename _Tp>
 567         _Res
 568         _M_call(_Tp& __object, const volatile _Class *,
 569                 _ArgTypes... __args) const
 570         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 571
 572       template<typename _Tp>
 573         _Res
 574         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 575         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 576
 577     public:
 578       typedef _Res result_type;
 579
 580       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 581
 582       // Handle objects
 583       _Res
 584       operator()(const _Class& __object, _ArgTypes... __args) const
 585       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 586
 587       // Handle pointers
 588       _Res
 589       operator()(const _Class* __object, _ArgTypes... __args) const
 590       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 591
 592       // Handle smart pointers, references and pointers to derived
 593       template<typename _Tp>
 594         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 595         {
 596           return _M_call(__object, &__object,
 597               std::forward<_ArgTypes>(__args)...);
 598         }
 599
 600     private:
 601       _Functor __pmf;
 602     };
 603
 604   /// Implementation of @c mem_fn for volatile member function pointers.
 605   template<typename _Res, typename _Class, typename... _ArgTypes>
 606     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) volatile>
 607     : public _Maybe_unary_or_binary_function<_Res, volatile _Class*,
 608                                              _ArgTypes...>
 609     {
 610       typedef _Res (_Class::*_Functor)(_ArgTypes...) volatile;
 611
 612       template<typename _Tp>
 613         _Res
 614         _M_call(_Tp& __object, const volatile _Class *,
 615                 _ArgTypes... __args) const
 616         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 617
 618       template<typename _Tp>
 619         _Res
 620         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 621         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 622
 623     public:
 624       typedef _Res result_type;
 625
 626       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 627
 628       // Handle objects
 629       _Res
 630       operator()(volatile _Class& __object, _ArgTypes... __args) const
 631       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 632
 633       // Handle pointers
 634       _Res
 635       operator()(volatile _Class* __object, _ArgTypes... __args) const
 636       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 637
 638       // Handle smart pointers, references and pointers to derived
 639       template<typename _Tp>
 640         _Res
 641         operator()(_Tp& __object, _ArgTypes... __args) const
 642         {
 643           return _M_call(__object, &__object,
 644               std::forward<_ArgTypes>(__args)...);
 645         }
 646
 647     private:
 648       _Functor __pmf;
 649     };
 650
 651   /// Implementation of @c mem_fn for const volatile member function pointers.
 652   template<typename _Res, typename _Class, typename... _ArgTypes>
 653     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const volatile>
 654     : public _Maybe_unary_or_binary_function<_Res, const volatile _Class*,
 655                                              _ArgTypes...>
 656     {
 657       typedef _Res (_Class::*_Functor)(_ArgTypes...) const volatile;
 658
 659       template<typename _Tp>
 660         _Res
 661         _M_call(_Tp& __object, const volatile _Class *,
 662                 _ArgTypes... __args) const
 663         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 664
 665       template<typename _Tp>
 666         _Res
 667         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 668         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 669
 670     public:
 671       typedef _Res result_type;
 672
 673       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 674
 675       // Handle objects
 676       _Res
 677       operator()(const volatile _Class& __object, _ArgTypes... __args) const
 678       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 679
 680       // Handle pointers
 681       _Res
 682       operator()(const volatile _Class* __object, _ArgTypes... __args) const
 683       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 684
 685       // Handle smart pointers, references and pointers to derived
 686       template<typename _Tp>
 687         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 688         {
 689           return _M_call(__object, &__object,
 690               std::forward<_ArgTypes>(__args)...);
 691         }
 692
 693     private:
 694       _Functor __pmf;
 695     };
 696
 697
 698   template<typename _Tp, bool>
 699     struct _Mem_fn_const_or_non
 700     {
 701       typedef const _Tp& type;
 702     };
 703
 704   template<typename _Tp>
 705     struct _Mem_fn_const_or_non<_Tp, false>
 706     {
 707       typedef _Tp& type;
 708     };
 709
 710   template<typename _Res, typename _Class>
 711     class _Mem_fn<_Res _Class::*>
 712     {
 713       // This bit of genius is due to Peter Dimov, improved slightly by
 714       // Douglas Gregor.
 715       template<typename _Tp>
 716         _Res&
 717         _M_call(_Tp& __object, _Class *) const
 718         { return __object.*__pm; }
 719
 720       template<typename _Tp, typename _Up>
 721         _Res&
 722         _M_call(_Tp& __object, _Up * const *) const
 723         { return (*__object).*__pm; }
 724
 725       template<typename _Tp, typename _Up>
 726         const _Res&
 727         _M_call(_Tp& __object, const _Up * const *) const
 728         { return (*__object).*__pm; }
 729
 730       template<typename _Tp>
 731         const _Res&
 732         _M_call(_Tp& __object, const _Class *) const
 733         { return __object.*__pm; }
 734
 735       template<typename _Tp>
 736         const _Res&
 737         _M_call(_Tp& __ptr, const volatile void*) const
 738         { return (*__ptr).*__pm; }
 739
 740       template<typename _Tp> static _Tp& __get_ref();
 741
 742       template<typename _Tp>
 743         static __sfinae_types::__one __check_const(_Tp&, _Class*);
 744       template<typename _Tp, typename _Up>
 745         static __sfinae_types::__one __check_const(_Tp&, _Up * const *);
 746       template<typename _Tp, typename _Up>
 747         static __sfinae_types::__two __check_const(_Tp&, const _Up * const *);
 748       template<typename _Tp>
 749         static __sfinae_types::__two __check_const(_Tp&, const _Class*);
 750       template<typename _Tp>
 751         static __sfinae_types::__two __check_const(_Tp&, const volatile void*);
 752
 753     public:
 754       template<typename _Tp>
 755         struct _Result_type
 756         : _Mem_fn_const_or_non<_Res,
 757           (sizeof(__sfinae_types::__two)
 758            == sizeof(__check_const<_Tp>(__get_ref<_Tp>(), (_Tp*)0)))>
 759         { };
 760
 761       template<typename _Signature>
 762         struct result;
 763
 764       template<typename _CVMem, typename _Tp>
 765         struct result<_CVMem(_Tp)>
 766         : public _Result_type<_Tp> { };
 767
 768       template<typename _CVMem, typename _Tp>
 769         struct result<_CVMem(_Tp&)>
 770         : public _Result_type<_Tp> { };
 771
 772       explicit
 773       _Mem_fn(_Res _Class::*__pm) : __pm(__pm) { }
 774
 775       // Handle objects
 776       _Res&
 777       operator()(_Class& __object) const
 778       { return __object.*__pm; }
 779
 780       const _Res&
 781       operator()(const _Class& __object) const
 782       { return __object.*__pm; }
 783
 784       // Handle pointers
 785       _Res&
 786       operator()(_Class* __object) const
 787       { return __object->*__pm; }
 788
 789       const _Res&
 790       operator()(const _Class* __object) const
 791       { return __object->*__pm; }
 792
 793       // Handle smart pointers and derived
 794       template<typename _Tp>
 795         typename _Result_type<_Tp>::type
 796         operator()(_Tp& __unknown) const
 797         { return _M_call(__unknown, &__unknown); }
 798
 799     private:
 800       _Res _Class::*__pm;
 801     };
 802
 803   /**
 804    *  @brief Returns a function object that forwards to the member
 805    *  pointer @a pm.
 806    *  @ingroup functors
 807    */
 808   template<typename _Tp, typename _Class>
 809     inline _Mem_fn<_Tp _Class::*>
 810     mem_fn(_Tp _Class::* __pm)
 811     {
 812       return _Mem_fn<_Tp _Class::*>(__pm);
 813     }
 814
 815   /**
 816    *  @brief Determines if the given type _Tp is a function object
 817    *  should be treated as a subexpression when evaluating calls to
 818    *  function objects returned by bind(). [TR1 3.6.1]
 819    *  @ingroup binders
 820    */
 821   template<typename _Tp>
 822     struct is_bind_expression
 823     : public false_type { };
 824
 825   /**
 826    *  @brief Determines if the given type _Tp is a placeholder in a
 827    *  bind() expression and, if so, which placeholder it is. [TR1 3.6.2]
 828    *  @ingroup binders
 829    */
 830   template<typename _Tp>
 831     struct is_placeholder
 832     : public integral_constant<int, 0>
 833     { };
 834
 835   /// The type of placeholder objects defined by libstdc++.
 836   template<int _Num> struct _Placeholder { };
 837
 838   /** @namespace std::placeholders
 839    *  @brief ISO C++ 0x entities sub namespace for functional.
 840    *  @ingroup binders
 841    *
 842    *  Define a large number of placeholders. There is no way to
 843    *  simplify this with variadic templates, because we're introducing
 844    *  unique names for each.
 845    */
 846   namespace placeholders
 847   {
 848     extern const _Placeholder<1> _1;
 849     extern const _Placeholder<2> _2;
 850     extern const _Placeholder<3> _3;
 851     extern const _Placeholder<4> _4;
 852     extern const _Placeholder<5> _5;
 853     extern const _Placeholder<6> _6;
 854     extern const _Placeholder<7> _7;
 855     extern const _Placeholder<8> _8;
 856     extern const _Placeholder<9> _9;
 857     extern const _Placeholder<10> _10;
 858     extern const _Placeholder<11> _11;
 859     extern const _Placeholder<12> _12;
 860     extern const _Placeholder<13> _13;
 861     extern const _Placeholder<14> _14;
 862     extern const _Placeholder<15> _15;
 863     extern const _Placeholder<16> _16;
 864     extern const _Placeholder<17> _17;
 865     extern const _Placeholder<18> _18;
 866     extern const _Placeholder<19> _19;
 867     extern const _Placeholder<20> _20;
 868     extern const _Placeholder<21> _21;
 869     extern const _Placeholder<22> _22;
 870     extern const _Placeholder<23> _23;
 871     extern const _Placeholder<24> _24;
 872     extern const _Placeholder<25> _25;
 873     extern const _Placeholder<26> _26;
 874     extern const _Placeholder<27> _27;
 875     extern const _Placeholder<28> _28;
 876     extern const _Placeholder<29> _29;
 877   }
 878
 879   /**
 880    *  Partial specialization of is_placeholder that provides the placeholder
 881    *  number for the placeholder objects defined by libstdc++.
 882    *  @ingroup binders
 883    */
 884   template<int _Num>
 885     struct is_placeholder<_Placeholder<_Num> >
 886     : public integral_constant<int, _Num>
 887     { };
 888
 889   /**
 890    * Used by _Safe_tuple_element to indicate that there is no tuple
 891    * element at this position.
 892    */
 893   struct _No_tuple_element;
 894
 895   /**
 896    * Implementation helper for _Safe_tuple_element. This primary
 897    * template handles the case where it is safe to use @c
 898    * tuple_element.
 899    */
 900   template<int __i, typename _Tuple, bool _IsSafe>
 901     struct _Safe_tuple_element_impl
 902     : tuple_element<__i, _Tuple> { };
 903
 904   /**
 905    * Implementation helper for _Safe_tuple_element. This partial
 906    * specialization handles the case where it is not safe to use @c
 907    * tuple_element. We just return @c _No_tuple_element.
 908    */
 909   template<int __i, typename _Tuple>
 910     struct _Safe_tuple_element_impl<__i, _Tuple, false>
 911     {
 912       typedef _No_tuple_element type;
 913     };
 914
 915   /**
 916    * Like tuple_element, but returns @c _No_tuple_element when
 917    * tuple_element would return an error.
 918    */
 919  template<int __i, typename _Tuple>
 920    struct _Safe_tuple_element
 921    : _Safe_tuple_element_impl<__i, _Tuple,
 922                               (__i >= 0 && __i < tuple_size<_Tuple>::value)>
 923    { };
 924
 925   /**
 926    *  Maps an argument to bind() into an actual argument to the bound
 927    *  function object [TR1 3.6.3/5]. Only the first parameter should
 928    *  be specified: the rest are used to determine among the various
 929    *  implementations. Note that, although this class is a function
 930    *  object, it isn't entirely normal because it takes only two
 931    *  parameters regardless of the number of parameters passed to the
 932    *  bind expression. The first parameter is the bound argument and
 933    *  the second parameter is a tuple containing references to the
 934    *  rest of the arguments.
 935    */
 936   template<typename _Arg,
 937            bool _IsBindExp = is_bind_expression<_Arg>::value,
 938            bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
 939     class _Mu;
 940
 941   /**
 942    *  If the argument is reference_wrapper<_Tp>, returns the
 943    *  underlying reference. [TR1 3.6.3/5 bullet 1]
 944    */
 945   template<typename _Tp>
 946     class _Mu<reference_wrapper<_Tp>, false, false>
 947     {
 948     public:
 949       typedef _Tp& result_type;
 950
 951       /* Note: This won't actually work for const volatile
 952        * reference_wrappers, because reference_wrapper::get() is const
 953        * but not volatile-qualified. This might be a defect in the TR.
 954        */
 955       template<typename _CVRef, typename _Tuple>
 956         result_type
 957         operator()(_CVRef& __arg, _Tuple&) const volatile
 958         { return __arg.get(); }
 959     };
 960
 961   /**
 962    *  If the argument is a bind expression, we invoke the underlying
 963    *  function object with the same cv-qualifiers as we are given and
 964    *  pass along all of our arguments (unwrapped). [TR1 3.6.3/5 bullet 2]
 965    */
 966   template<typename _Arg>
 967     class _Mu<_Arg, true, false>
 968     {
 969     public:
 970       template<typename _CVArg, typename... _Args>
 971         auto
 972         operator()(_CVArg& __arg,
 973                    tuple<_Args...>& __tuple) const volatile
 974         -> decltype(__arg(declval<_Args>()...))
 975         {
 976           // Construct an index tuple and forward to __call
 977           typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
 978             _Indexes;
 979           return this->__call(__arg, __tuple, _Indexes());
 980         }
 981
 982     private:
 983       // Invokes the underlying function object __arg by unpacking all
 984       // of the arguments in the tuple.
 985       template<typename _CVArg, typename... _Args, int... _Indexes>
 986         auto
 987         __call(_CVArg& __arg, tuple<_Args...>& __tuple,
 988                const _Index_tuple<_Indexes...>&) const volatile
 989         -> decltype(__arg(declval<_Args>()...))
 990         {
 991           return __arg(std::forward<_Args>(get<_Indexes>(__tuple))...);
 992         }
 993     };
 994
 995   /**
 996    *  If the argument is a placeholder for the Nth argument, returns
 997    *  a reference to the Nth argument to the bind function object.
 998    *  [TR1 3.6.3/5 bullet 3]
 999    */
1000   template<typename _Arg>
1001     class _Mu<_Arg, false, true>
1002     {
1003     public:
1004       template<typename _Signature> class result;
1005
1006       template<typename _CVMu, typename _CVArg, typename _Tuple>
1007         class result<_CVMu(_CVArg, _Tuple)>
1008         {
1009           // Add a reference, if it hasn't already been done for us.
1010           // This allows us to be a little bit sloppy in constructing
1011           // the tuple that we pass to result_of<...>.
1012           typedef typename _Safe_tuple_element<(is_placeholder<_Arg>::value
1013                                                 - 1), _Tuple>::type
1014             __base_type;
1015
1016         public:
1017           typedef typename add_rvalue_reference<__base_type>::type type;
1018         };
1019
1020       template<typename _Tuple>
1021         typename result<_Mu(_Arg, _Tuple)>::type
1022         operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
1023         {
1024           return std::forward<typename result<_Mu(_Arg, _Tuple)>::type>(
1025               ::std::get<(is_placeholder<_Arg>::value - 1)>(__tuple));
1026         }
1027     };
1028
1029   /**
1030    *  If the argument is just a value, returns a reference to that
1031    *  value. The cv-qualifiers on the reference are the same as the
1032    *  cv-qualifiers on the _Mu object. [TR1 3.6.3/5 bullet 4]
1033    */
1034   template<typename _Arg>
1035     class _Mu<_Arg, false, false>
1036     {
1037     public:
1038       template<typename _Signature> struct result;
1039
1040       template<typename _CVMu, typename _CVArg, typename _Tuple>
1041         struct result<_CVMu(_CVArg, _Tuple)>
1042         {
1043           typedef typename add_lvalue_reference<_CVArg>::type type;
1044         };
1045
1046       // Pick up the cv-qualifiers of the argument
1047       template<typename _CVArg, typename _Tuple>
1048         _CVArg&&
1049         operator()(_CVArg&& __arg, _Tuple&) const volatile
1050         { return std::forward<_CVArg>(__arg); }
1051     };
1052
1053   /**
1054    *  Maps member pointers into instances of _Mem_fn but leaves all
1055    *  other function objects untouched. Used by tr1::bind(). The
1056    *  primary template handles the non--member-pointer case.
1057    */
1058   template<typename _Tp>
1059     struct _Maybe_wrap_member_pointer
1060     {
1061       typedef _Tp type;
1062
1063       static const _Tp&
1064       __do_wrap(const _Tp& __x)
1065       { return __x; }
1066
1067       static _Tp&&
1068       __do_wrap(_Tp&& __x)
1069       { return static_cast<_Tp&&>(__x); }
1070     };
1071
1072   /**
1073    *  Maps member pointers into instances of _Mem_fn but leaves all
1074    *  other function objects untouched. Used by tr1::bind(). This
1075    *  partial specialization handles the member pointer case.
1076    */
1077   template<typename _Tp, typename _Class>
1078     struct _Maybe_wrap_member_pointer<_Tp _Class::*>
1079     {
1080       typedef _Mem_fn<_Tp _Class::*> type;
1081
1082       static type
1083       __do_wrap(_Tp _Class::* __pm)
1084       { return type(__pm); }
1085     };
1086
1087   // Specialization needed to prevent "forming reference to void" errors when
1088   // bind<void>() is called, because argument deduction instantiates
1089   // _Maybe_wrap_member_pointer<void> outside the immediate context where
1090   // SFINAE applies.
1091   template<>
1092     struct _Maybe_wrap_member_pointer<void>
1093     {
1094       typedef void type;
1095     };
1096
1097   // std::get<I> for volatile-qualified tuples
1098   template<size_t _Ind, typename... _Tp>
1099     inline auto
1100     __volget(volatile tuple<_Tp...>& __tuple)
1101     -> typename tuple_element<_Ind, tuple<_Tp...>>::type volatile&
1102     { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
1103
1104   // std::get<I> for const-volatile-qualified tuples
1105   template<size_t _Ind, typename... _Tp>
1106     inline auto
1107     __volget(const volatile tuple<_Tp...>& __tuple)
1108     -> typename tuple_element<_Ind, tuple<_Tp...>>::type const volatile&
1109     { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
1110
1111   /// Type of the function object returned from bind().
1112   template<typename _Signature>
1113     struct _Bind;
1114
1115    template<typename _Functor, typename... _Bound_args>
1116     class _Bind<_Functor(_Bound_args...)>
1117     : public _Weak_result_type<_Functor>
1118     {
1119       typedef _Bind __self_type;
1120       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1121         _Bound_indexes;
1122
1123       _Functor _M_f;
1124       tuple<_Bound_args...> _M_bound_args;
1125
1126       // Call unqualified
1127       template<typename _Result, typename... _Args, int... _Indexes>
1128         _Result
1129         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
1130         {
1131           return _M_f(_Mu<_Bound_args>()
1132                       (get<_Indexes>(_M_bound_args), __args)...);
1133         }
1134
1135       // Call as const
1136       template<typename _Result, typename... _Args, int... _Indexes>
1137         _Result
1138         __call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
1139         {
1140           return _M_f(_Mu<_Bound_args>()
1141                       (get<_Indexes>(_M_bound_args), __args)...);
1142         }
1143
1144       // Call as volatile
1145       template<typename _Result, typename... _Args, int... _Indexes>
1146         _Result
1147         __call_v(tuple<_Args...>&& __args,
1148                  _Index_tuple<_Indexes...>) volatile
1149         {
1150           return _M_f(_Mu<_Bound_args>()
1151                       (__volget<_Indexes>(_M_bound_args), __args)...);
1152         }
1153
1154       // Call as const volatile
1155       template<typename _Result, typename... _Args, int... _Indexes>
1156         _Result
1157         __call_c_v(tuple<_Args...>&& __args,
1158                    _Index_tuple<_Indexes...>) const volatile
1159         {
1160           return _M_f(_Mu<_Bound_args>()
1161                       (__volget<_Indexes>(_M_bound_args), __args)...);
1162         }
1163
1164      public:
1165       template<typename... _Args>
1166         explicit _Bind(const _Functor& __f, _Args&&... __args)
1167         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1168         { }
1169
1170       template<typename... _Args>
1171         explicit _Bind(_Functor&& __f, _Args&&... __args)
1172         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1173         { }
1174
1175       _Bind(const _Bind&) = default;
1176
1177       _Bind(_Bind&& __b)
1178       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1179       { }
1180
1181       // Call unqualified
1182       template<typename... _Args, typename _Result
1183         = decltype( std::declval<_Functor>()(
1184               _Mu<_Bound_args>()( std::declval<_Bound_args&>(),
1185                                   std::declval<tuple<_Args...>&>() )... ) )>
1186         _Result
1187         operator()(_Args&&... __args)
1188         {
1189           return this->__call<_Result>(
1190               std::forward_as_tuple(std::forward<_Args>(__args)...),
1191               _Bound_indexes());
1192         }
1193
1194       // Call as const
1195       template<typename... _Args, typename _Result
1196         = decltype( std::declval<const _Functor>()(
1197               _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
1198                                   std::declval<tuple<_Args...>&>() )... ) )>
1199         _Result
1200         operator()(_Args&&... __args) const
1201         {
1202           return this->__call_c<_Result>(
1203               std::forward_as_tuple(std::forward<_Args>(__args)...),
1204               _Bound_indexes());
1205         }
1206
1207       // Call as volatile
1208       template<typename... _Args, typename _Result
1209         = decltype( std::declval<volatile _Functor>()(
1210               _Mu<_Bound_args>()( std::declval<volatile _Bound_args&>(),
1211                                   std::declval<tuple<_Args...>&>() )... ) )>
1212         _Result
1213         operator()(_Args&&... __args) volatile
1214         {
1215           return this->__call_v<_Result>(
1216               std::forward_as_tuple(std::forward<_Args>(__args)...),
1217               _Bound_indexes());
1218         }
1219
1220       // Call as const volatile
1221       template<typename... _Args, typename _Result
1222         = decltype( std::declval<const volatile _Functor>()(
1223               _Mu<_Bound_args>()( std::declval<const volatile _Bound_args&>(),
1224                                   std::declval<tuple<_Args...>&>() )... ) )>
1225         _Result
1226         operator()(_Args&&... __args) const volatile
1227         {
1228           return this->__call_c_v<_Result>(
1229               std::forward_as_tuple(std::forward<_Args>(__args)...),
1230               _Bound_indexes());
1231         }
1232     };
1233
1234   /// Type of the function object returned from bind<R>().
1235   template<typename _Result, typename _Signature>
1236     struct _Bind_result;
1237
1238   template<typename _Result, typename _Functor, typename... _Bound_args>
1239     class _Bind_result<_Result, _Functor(_Bound_args...)>
1240     {
1241       typedef _Bind_result __self_type;
1242       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1243         _Bound_indexes;
1244
1245       _Functor _M_f;
1246       tuple<_Bound_args...> _M_bound_args;
1247
1248       // sfinae types
1249       template<typename _Res>
1250         struct __enable_if_void : enable_if<is_void<_Res>::value, int> { };
1251       template<typename _Res>
1252         struct __disable_if_void : enable_if<!is_void<_Res>::value, int> { };
1253
1254       // Call unqualified
1255       template<typename _Res, typename... _Args, int... _Indexes>
1256         _Result
1257         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1258             typename __disable_if_void<_Res>::type = 0)
1259         {
1260           return _M_f(_Mu<_Bound_args>()
1261                       (get<_Indexes>(_M_bound_args), __args)...);
1262         }
1263
1264       // Call unqualified, return void
1265       template<typename _Res, typename... _Args, int... _Indexes>
1266         void
1267         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1268             typename __enable_if_void<_Res>::type = 0)
1269         {
1270           _M_f(_Mu<_Bound_args>()
1271                (get<_Indexes>(_M_bound_args), __args)...);
1272         }
1273
1274       // Call as const
1275       template<typename _Res, typename... _Args, int... _Indexes>
1276         _Result
1277         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1278             typename __disable_if_void<_Res>::type = 0) const
1279         {
1280           return _M_f(_Mu<_Bound_args>()
1281                       (get<_Indexes>(_M_bound_args), __args)...);
1282         }
1283
1284       // Call as const, return void
1285       template<typename _Res, typename... _Args, int... _Indexes>
1286         void
1287         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1288             typename __enable_if_void<_Res>::type = 0) const
1289         {
1290           _M_f(_Mu<_Bound_args>()
1291                (get<_Indexes>(_M_bound_args),  __args)...);
1292         }
1293
1294       // Call as volatile
1295       template<typename _Res, typename... _Args, int... _Indexes>
1296         _Result
1297         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1298             typename __disable_if_void<_Res>::type = 0) volatile
1299         {
1300           return _M_f(_Mu<_Bound_args>()
1301                       (__volget<_Indexes>(_M_bound_args), __args)...);
1302         }
1303
1304       // Call as volatile, return void
1305       template<typename _Res, typename... _Args, int... _Indexes>
1306         void
1307         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1308             typename __enable_if_void<_Res>::type = 0) volatile
1309         {
1310           _M_f(_Mu<_Bound_args>()
1311                (__volget<_Indexes>(_M_bound_args), __args)...);
1312         }
1313
1314       // Call as const volatile
1315       template<typename _Res, typename... _Args, int... _Indexes>
1316         _Result
1317         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1318             typename __disable_if_void<_Res>::type = 0) const volatile
1319         {
1320           return _M_f(_Mu<_Bound_args>()
1321                       (__volget<_Indexes>(_M_bound_args), __args)...);
1322         }
1323
1324       // Call as const volatile, return void
1325       template<typename _Res, typename... _Args, int... _Indexes>
1326         void
1327         __call(tuple<_Args...>&& __args,
1328                _Index_tuple<_Indexes...>,
1329             typename __enable_if_void<_Res>::type = 0) const volatile
1330         {
1331           _M_f(_Mu<_Bound_args>()
1332                (__volget<_Indexes>(_M_bound_args), __args)...);
1333         }
1334
1335     public:
1336       typedef _Result result_type;
1337
1338       template<typename... _Args>
1339         explicit _Bind_result(const _Functor& __f, _Args&&... __args)
1340         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1341         { }
1342
1343       template<typename... _Args>
1344         explicit _Bind_result(_Functor&& __f, _Args&&... __args)
1345         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1346         { }
1347
1348       _Bind_result(const _Bind_result&) = default;
1349
1350       _Bind_result(_Bind_result&& __b)
1351       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1352       { }
1353
1354       // Call unqualified
1355       template<typename... _Args>
1356         result_type
1357         operator()(_Args&&... __args)
1358         {
1359           return this->__call<_Result>(
1360               std::forward_as_tuple(std::forward<_Args>(__args)...),
1361               _Bound_indexes());
1362         }
1363
1364       // Call as const
1365       template<typename... _Args>
1366         result_type
1367         operator()(_Args&&... __args) const
1368         {
1369           return this->__call<_Result>(
1370               std::forward_as_tuple(std::forward<_Args>(__args)...),
1371               _Bound_indexes());
1372         }
1373
1374       // Call as volatile
1375       template<typename... _Args>
1376         result_type
1377         operator()(_Args&&... __args) volatile
1378         {
1379           return this->__call<_Result>(
1380               std::forward_as_tuple(std::forward<_Args>(__args)...),
1381               _Bound_indexes());
1382         }
1383
1384       // Call as const volatile
1385       template<typename... _Args>
1386         result_type
1387         operator()(_Args&&... __args) const volatile
1388         {
1389           return this->__call<_Result>(
1390               std::forward_as_tuple(std::forward<_Args>(__args)...),
1391               _Bound_indexes());
1392         }
1393     };
1394
1395   /**
1396    *  @brief Class template _Bind is always a bind expression.
1397    *  @ingroup binders
1398    */
1399   template<typename _Signature>
1400     struct is_bind_expression<_Bind<_Signature> >
1401     : public true_type { };
1402
1403   /**
1404    *  @brief Class template _Bind is always a bind expression.
1405    *  @ingroup binders
1406    */
1407   template<typename _Result, typename _Signature>
1408     struct is_bind_expression<_Bind_result<_Result, _Signature> >
1409     : public true_type { };
1410
1411   template<typename _Functor, typename... _ArgTypes>
1412     struct _Bind_helper
1413     {
1414       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1415         __maybe_type;
1416       typedef typename __maybe_type::type __functor_type;
1417       typedef _Bind<__functor_type(typename decay<_ArgTypes>::type...)> type;
1418     };
1419
1420   /**
1421    *  @brief Function template for std::bind.
1422    *  @ingroup binders
1423    */
1424   template<typename _Functor, typename... _ArgTypes>
1425     inline
1426     typename _Bind_helper<_Functor, _ArgTypes...>::type
1427     bind(_Functor&& __f, _ArgTypes&&... __args)
1428     {
1429       typedef _Bind_helper<_Functor, _ArgTypes...> __helper_type;
1430       typedef typename __helper_type::__maybe_type __maybe_type;
1431       typedef typename __helper_type::type __result_type;
1432       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1433                            std::forward<_ArgTypes>(__args)...);
1434     }
1435
1436   template<typename _Result, typename _Functor, typename... _ArgTypes>
1437     struct _Bindres_helper
1438     {
1439       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1440         __maybe_type;
1441       typedef typename __maybe_type::type __functor_type;
1442       typedef _Bind_result<_Result,
1443                            __functor_type(typename decay<_ArgTypes>::type...)>
1444         type;
1445     };
1446
1447   /**
1448    *  @brief Function template for std::bind<R>.
1449    *  @ingroup binders
1450    */
1451   template<typename _Result, typename _Functor, typename... _ArgTypes>
1452     inline
1453     typename _Bindres_helper<_Result, _Functor, _ArgTypes...>::type
1454     bind(_Functor&& __f, _ArgTypes&&... __args)
1455     {
1456       typedef _Bindres_helper<_Result, _Functor, _ArgTypes...> __helper_type;
1457       typedef typename __helper_type::__maybe_type __maybe_type;
1458       typedef typename __helper_type::type __result_type;
1459       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1460                            std::forward<_ArgTypes>(__args)...);
1461     }
1462
1463   /**
1464    *  @brief Exception class thrown when class template function's
1465    *  operator() is called with an empty target.
1466    *  @ingroup exceptions
1467    */
1468   class bad_function_call : public std::exception { };
1469
1470   /**
1471    *  Trait identifying "location-invariant" types, meaning that the
1472    *  address of the object (or any of its members) will not escape.
1473    *  Also implies a trivial copy constructor and assignment operator.
1474    */
1475   template<typename _Tp>
1476     struct __is_location_invariant
1477     : integral_constant<bool, (is_pointer<_Tp>::value
1478                                || is_member_pointer<_Tp>::value)>
1479     { };
1480
1481   class _Undefined_class;
1482
1483   union _Nocopy_types
1484   {
1485     void*       _M_object;
1486     const void* _M_const_object;
1487     void (*_M_function_pointer)();
1488     void (_Undefined_class::*_M_member_pointer)();
1489   };
1490
1491   union _Any_data
1492   {
1493     void*       _M_access()       { return &_M_pod_data[0]; }
1494     const void* _M_access() const { return &_M_pod_data[0]; }
1495
1496     template<typename _Tp>
1497       _Tp&
1498       _M_access()
1499       { return *static_cast<_Tp*>(_M_access()); }
1500
1501     template<typename _Tp>
1502       const _Tp&
1503       _M_access() const
1504       { return *static_cast<const _Tp*>(_M_access()); }
1505
1506     _Nocopy_types _M_unused;
1507     char _M_pod_data[sizeof(_Nocopy_types)];
1508   };
1509
1510   enum _Manager_operation
1511   {
1512     __get_type_info,
1513     __get_functor_ptr,
1514     __clone_functor,
1515     __destroy_functor
1516   };
1517
1518   // Simple type wrapper that helps avoid annoying const problems
1519   // when casting between void pointers and pointers-to-pointers.
1520   template<typename _Tp>
1521     struct _Simple_type_wrapper
1522     {
1523       _Simple_type_wrapper(_Tp __value) : __value(__value) { }
1524
1525       _Tp __value;
1526     };
1527
1528   template<typename _Tp>
1529     struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
1530     : __is_location_invariant<_Tp>
1531     { };
1532
1533   // Converts a reference to a function object into a callable
1534   // function object.
1535   template<typename _Functor>
1536     inline _Functor&
1537     __callable_functor(_Functor& __f)
1538     { return __f; }
1539
1540   template<typename _Member, typename _Class>
1541     inline _Mem_fn<_Member _Class::*>
1542     __callable_functor(_Member _Class::* &__p)
1543     { return mem_fn(__p); }
1544
1545   template<typename _Member, typename _Class>
1546     inline _Mem_fn<_Member _Class::*>
1547     __callable_functor(_Member _Class::* const &__p)
1548     { return mem_fn(__p); }
1549
1550   template<typename _Signature>
1551     class function;
1552
1553   /// Base class of all polymorphic function object wrappers.
1554   class _Function_base
1555   {
1556   public:
1557     static const std::size_t _M_max_size = sizeof(_Nocopy_types);
1558     static const std::size_t _M_max_align = __alignof__(_Nocopy_types);
1559
1560     template<typename _Functor>
1561       class _Base_manager
1562       {
1563       protected:
1564         static const bool __stored_locally =
1565         (__is_location_invariant<_Functor>::value
1566          && sizeof(_Functor) <= _M_max_size
1567          && __alignof__(_Functor) <= _M_max_align
1568          && (_M_max_align % __alignof__(_Functor) == 0));
1569
1570         typedef integral_constant<bool, __stored_locally> _Local_storage;
1571
1572         // Retrieve a pointer to the function object
1573         static _Functor*
1574         _M_get_pointer(const _Any_data& __source)
1575         {
1576           const _Functor* __ptr =
1577             __stored_locally? &__source._M_access<_Functor>()
1578             /* have stored a pointer */ : __source._M_access<_Functor*>();
1579           return const_cast<_Functor*>(__ptr);
1580         }
1581
1582         // Clone a location-invariant function object that fits within
1583         // an _Any_data structure.
1584         static void
1585         _M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
1586         {
1587           new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
1588         }
1589
1590         // Clone a function object that is not location-invariant or
1591         // that cannot fit into an _Any_data structure.
1592         static void
1593         _M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
1594         {
1595           __dest._M_access<_Functor*>() =
1596             new _Functor(*__source._M_access<_Functor*>());
1597         }
1598
1599         // Destroying a location-invariant object may still require
1600         // destruction.
1601         static void
1602         _M_destroy(_Any_data& __victim, true_type)
1603         {
1604           __victim._M_access<_Functor>().~_Functor();
1605         }
1606
1607         // Destroying an object located on the heap.
1608         static void
1609         _M_destroy(_Any_data& __victim, false_type)
1610         {
1611           delete __victim._M_access<_Functor*>();
1612         }
1613
1614       public:
1615         static bool
1616         _M_manager(_Any_data& __dest, const _Any_data& __source,
1617                    _Manager_operation __op)
1618         {
1619           switch (__op)
1620             {
1621 #ifdef __GXX_RTTI
1622             case __get_type_info:
1623               __dest._M_access<const type_info*>() = &typeid(_Functor);
1624               break;
1625 #endif
1626             case __get_functor_ptr:
1627               __dest._M_access<_Functor*>() = _M_get_pointer(__source);
1628               break;
1629
1630             case __clone_functor:
1631               _M_clone(__dest, __source, _Local_storage());
1632               break;
1633
1634             case __destroy_functor:
1635               _M_destroy(__dest, _Local_storage());
1636               break;
1637             }
1638           return false;
1639         }
1640
1641         static void
1642         _M_init_functor(_Any_data& __functor, _Functor&& __f)
1643         { _M_init_functor(__functor, std::move(__f), _Local_storage()); }
1644
1645         template<typename _Signature>
1646           static bool
1647           _M_not_empty_function(const function<_Signature>& __f)
1648           { return static_cast<bool>(__f); }
1649
1650         template<typename _Tp>
1651           static bool
1652           _M_not_empty_function(const _Tp*& __fp)
1653           { return __fp; }
1654
1655         template<typename _Class, typename _Tp>
1656           static bool
1657           _M_not_empty_function(_Tp _Class::* const& __mp)
1658           { return __mp; }
1659
1660         template<typename _Tp>
1661           static bool
1662           _M_not_empty_function(const _Tp&)
1663           { return true; }
1664
1665       private:
1666         static void
1667         _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
1668         { new (__functor._M_access()) _Functor(std::move(__f)); }
1669
1670         static void
1671         _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
1672         { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
1673       };
1674
1675     template<typename _Functor>
1676       class _Ref_manager : public _Base_manager<_Functor*>
1677       {
1678         typedef _Function_base::_Base_manager<_Functor*> _Base;
1679
1680     public:
1681         static bool
1682         _M_manager(_Any_data& __dest, const _Any_data& __source,
1683                    _Manager_operation __op)
1684         {
1685           switch (__op)
1686             {
1687 #ifdef __GXX_RTTI
1688             case __get_type_info:
1689               __dest._M_access<const type_info*>() = &typeid(_Functor);
1690               break;
1691 #endif
1692             case __get_functor_ptr:
1693               __dest._M_access<_Functor*>() = *_Base::_M_get_pointer(__source);
1694               return is_const<_Functor>::value;
1695               break;
1696
1697             default:
1698               _Base::_M_manager(__dest, __source, __op);
1699             }
1700           return false;
1701         }
1702
1703         static void
1704         _M_init_functor(_Any_data& __functor, reference_wrapper<_Functor> __f)
1705         {
1706           // TBD: Use address_of function instead.
1707           _Base::_M_init_functor(__functor, &__f.get());
1708         }
1709       };
1710
1711     _Function_base() : _M_manager(0) { }
1712
1713     ~_Function_base()
1714     {
1715       if (_M_manager)
1716         _M_manager(_M_functor, _M_functor, __destroy_functor);
1717     }
1718
1719
1720     bool _M_empty() const { return !_M_manager; }
1721
1722     typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
1723                                   _Manager_operation);
1724
1725     _Any_data     _M_functor;
1726     _Manager_type _M_manager;
1727   };
1728
1729   template<typename _Signature, typename _Functor>
1730     class _Function_handler;
1731
1732   template<typename _Res, typename _Functor, typename... _ArgTypes>
1733     class _Function_handler<_Res(_ArgTypes...), _Functor>
1734     : public _Function_base::_Base_manager<_Functor>
1735     {
1736       typedef _Function_base::_Base_manager<_Functor> _Base;
1737
1738     public:
1739       static _Res
1740       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1741       {
1742         return (*_Base::_M_get_pointer(__functor))(
1743             std::forward<_ArgTypes>(__args)...);
1744       }
1745     };
1746
1747   template<typename _Functor, typename... _ArgTypes>
1748     class _Function_handler<void(_ArgTypes...), _Functor>
1749     : public _Function_base::_Base_manager<_Functor>
1750     {
1751       typedef _Function_base::_Base_manager<_Functor> _Base;
1752
1753      public:
1754       static void
1755       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1756       {
1757         (*_Base::_M_get_pointer(__functor))(
1758             std::forward<_ArgTypes>(__args)...);
1759       }
1760     };
1761
1762   template<typename _Res, typename _Functor, typename... _ArgTypes>
1763     class _Function_handler<_Res(_ArgTypes...), reference_wrapper<_Functor> >
1764     : public _Function_base::_Ref_manager<_Functor>
1765     {
1766       typedef _Function_base::_Ref_manager<_Functor> _Base;
1767
1768      public:
1769       static _Res
1770       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1771       {
1772         return __callable_functor(**_Base::_M_get_pointer(__functor))(
1773               std::forward<_ArgTypes>(__args)...);
1774       }
1775     };
1776
1777   template<typename _Functor, typename... _ArgTypes>
1778     class _Function_handler<void(_ArgTypes...), reference_wrapper<_Functor> >
1779     : public _Function_base::_Ref_manager<_Functor>
1780     {
1781       typedef _Function_base::_Ref_manager<_Functor> _Base;
1782
1783      public:
1784       static void
1785       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1786       {
1787         __callable_functor(**_Base::_M_get_pointer(__functor))(
1788             std::forward<_ArgTypes>(__args)...);
1789       }
1790     };
1791
1792   template<typename _Class, typename _Member, typename _Res,
1793            typename... _ArgTypes>
1794     class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
1795     : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
1796     {
1797       typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
1798         _Base;
1799
1800      public:
1801       static _Res
1802       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1803       {
1804         return mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1805             std::forward<_ArgTypes>(__args)...);
1806       }
1807     };
1808
1809   template<typename _Class, typename _Member, typename... _ArgTypes>
1810     class _Function_handler<void(_ArgTypes...), _Member _Class::*>
1811     : public _Function_base::_Base_manager<
1812                  _Simple_type_wrapper< _Member _Class::* > >
1813     {
1814       typedef _Member _Class::* _Functor;
1815       typedef _Simple_type_wrapper<_Functor> _Wrapper;
1816       typedef _Function_base::_Base_manager<_Wrapper> _Base;
1817
1818      public:
1819       static bool
1820       _M_manager(_Any_data& __dest, const _Any_data& __source,
1821                  _Manager_operation __op)
1822       {
1823         switch (__op)
1824           {
1825 #ifdef __GXX_RTTI
1826           case __get_type_info:
1827             __dest._M_access<const type_info*>() = &typeid(_Functor);
1828             break;
1829 #endif
1830           case __get_functor_ptr:
1831             __dest._M_access<_Functor*>() =
1832               &_Base::_M_get_pointer(__source)->__value;
1833             break;
1834
1835           default:
1836             _Base::_M_manager(__dest, __source, __op);
1837           }
1838         return false;
1839       }
1840
1841       static void
1842       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1843       {
1844         mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1845             std::forward<_ArgTypes>(__args)...);
1846       }
1847     };
1848
1849   /**
1850    *  @brief Primary class template for std::function.
1851    *  @ingroup functors
1852    *
1853    *  Polymorphic function wrapper.
1854    */
1855   template<typename _Res, typename... _ArgTypes>
1856     class function<_Res(_ArgTypes...)>
1857     : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
1858       private _Function_base
1859     {
1860       typedef _Res _Signature_type(_ArgTypes...);
1861
1862       struct _Useless { };
1863
1864     public:
1865       typedef _Res result_type;
1866
1867       // [3.7.2.1] construct/copy/destroy
1868
1869       /**
1870        *  @brief Default construct creates an empty function call wrapper.
1871        *  @post @c !(bool)*this
1872        */
1873       function() : _Function_base() { }
1874
1875       /**
1876        *  @brief Creates an empty function call wrapper.
1877        *  @post @c !(bool)*this
1878        */
1879       function(nullptr_t) : _Function_base() { }
1880
1881       /**
1882        *  @brief %Function copy constructor.
1883        *  @param x A %function object with identical call signature.
1884        *  @post @c (bool)*this == (bool)x
1885        *
1886        *  The newly-created %function contains a copy of the target of @a
1887        *  x (if it has one).
1888        */
1889       function(const function& __x);
1890
1891       /**
1892        *  @brief %Function move constructor.
1893        *  @param x A %function object rvalue with identical call signature.
1894        *
1895        *  The newly-created %function contains the target of @a x
1896        *  (if it has one).
1897        */
1898       function(function&& __x) : _Function_base()
1899       {
1900         __x.swap(*this);
1901       }
1902
1903       // TODO: needs allocator_arg_t
1904
1905       /**
1906        *  @brief Builds a %function that targets a copy of the incoming
1907        *  function object.
1908        *  @param f A %function object that is callable with parameters of
1909        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
1910        *  to @c Res.
1911        *
1912        *  The newly-created %function object will target a copy of @a
1913        *  f. If @a f is @c reference_wrapper<F>, then this function
1914        *  object will contain a reference to the function object @c
1915        *  f.get(). If @a f is a NULL function pointer or NULL
1916        *  pointer-to-member, the newly-created object will be empty.
1917        *
1918        *  If @a f is a non-NULL function pointer or an object of type @c
1919        *  reference_wrapper<F>, this function will not throw.
1920        */
1921       template<typename _Functor>
1922         function(_Functor __f,
1923                  typename enable_if<
1924                            !is_integral<_Functor>::value, _Useless>::type
1925                    = _Useless());
1926
1927       /**
1928        *  @brief %Function assignment operator.
1929        *  @param x A %function with identical call signature.
1930        *  @post @c (bool)*this == (bool)x
1931        *  @returns @c *this
1932        *
1933        *  The target of @a x is copied to @c *this. If @a x has no
1934        *  target, then @c *this will be empty.
1935        *
1936        *  If @a x targets a function pointer or a reference to a function
1937        *  object, then this operation will not throw an %exception.
1938        */
1939       function&
1940       operator=(const function& __x)
1941       {
1942         function(__x).swap(*this);
1943         return *this;
1944       }
1945
1946       /**
1947        *  @brief %Function move-assignment operator.
1948        *  @param x A %function rvalue with identical call signature.
1949        *  @returns @c *this
1950        *
1951        *  The target of @a x is moved to @c *this. If @a x has no
1952        *  target, then @c *this will be empty.
1953        *
1954        *  If @a x targets a function pointer or a reference to a function
1955        *  object, then this operation will not throw an %exception.
1956        */
1957       function&
1958       operator=(function&& __x)
1959       {
1960         function(std::move(__x)).swap(*this);
1961         return *this;
1962       }
1963
1964       /**
1965        *  @brief %Function assignment to zero.
1966        *  @post @c !(bool)*this
1967        *  @returns @c *this
1968        *
1969        *  The target of @c *this is deallocated, leaving it empty.
1970        */
1971       function&
1972       operator=(nullptr_t)
1973       {
1974         if (_M_manager)
1975           {
1976             _M_manager(_M_functor, _M_functor, __destroy_functor);
1977             _M_manager = 0;
1978             _M_invoker = 0;
1979           }
1980         return *this;
1981       }
1982
1983       /**
1984        *  @brief %Function assignment to a new target.
1985        *  @param f A %function object that is callable with parameters of
1986        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
1987        *  to @c Res.
1988        *  @return @c *this
1989        *
1990        *  This  %function object wrapper will target a copy of @a
1991        *  f. If @a f is @c reference_wrapper<F>, then this function
1992        *  object will contain a reference to the function object @c
1993        *  f.get(). If @a f is a NULL function pointer or NULL
1994        *  pointer-to-member, @c this object will be empty.
1995        *
1996        *  If @a f is a non-NULL function pointer or an object of type @c
1997        *  reference_wrapper<F>, this function will not throw.
1998        */
1999       template<typename _Functor>
2000         typename enable_if<!is_integral<_Functor>::value, function&>::type
2001         operator=(_Functor&& __f)
2002         {
2003           function(std::forward<_Functor>(__f)).swap(*this);
2004           return *this;
2005         }
2006
2007       /// @overload
2008       template<typename _Functor>
2009         typename enable_if<!is_integral<_Functor>::value, function&>::type
2010         operator=(reference_wrapper<_Functor> __f)
2011         {
2012           function(__f).swap(*this);
2013           return *this;
2014         }
2015
2016       // [3.7.2.2] function modifiers
2017
2018       /**
2019        *  @brief Swap the targets of two %function objects.
2020        *  @param f A %function with identical call signature.
2021        *
2022        *  Swap the targets of @c this function object and @a f. This
2023        *  function will not throw an %exception.
2024        */
2025       void swap(function& __x)
2026       {
2027         std::swap(_M_functor, __x._M_functor);
2028         std::swap(_M_manager, __x._M_manager);
2029         std::swap(_M_invoker, __x._M_invoker);
2030       }
2031
2032       // TODO: needs allocator_arg_t
2033       /*
2034       template<typename _Functor, typename _Alloc>
2035         void
2036         assign(_Functor&& __f, const _Alloc& __a)
2037         {
2038           function(allocator_arg, __a,
2039                    std::forward<_Functor>(__f)).swap(*this);
2040         }
2041       */
2042
2043       // [3.7.2.3] function capacity
2044
2045       /**
2046        *  @brief Determine if the %function wrapper has a target.
2047        *
2048        *  @return @c true when this %function object contains a target,
2049        *  or @c false when it is empty.
2050        *
2051        *  This function will not throw an %exception.
2052        */
2053       explicit operator bool() const
2054       { return !_M_empty(); }
2055
2056       // [3.7.2.4] function invocation
2057
2058       /**
2059        *  @brief Invokes the function targeted by @c *this.
2060        *  @returns the result of the target.
2061        *  @throws bad_function_call when @c !(bool)*this
2062        *
2063        *  The function call operator invokes the target function object
2064        *  stored by @c this.
2065        */
2066       _Res operator()(_ArgTypes... __args) const;
2067
2068 #ifdef __GXX_RTTI
2069       // [3.7.2.5] function target access
2070       /**
2071        *  @brief Determine the type of the target of this function object
2072        *  wrapper.
2073        *
2074        *  @returns the type identifier of the target function object, or
2075        *  @c typeid(void) if @c !(bool)*this.
2076        *
2077        *  This function will not throw an %exception.
2078        */
2079       const type_info& target_type() const;
2080
2081       /**
2082        *  @brief Access the stored target function object.
2083        *
2084        *  @return Returns a pointer to the stored target function object,
2085        *  if @c typeid(Functor).equals(target_type()); otherwise, a NULL
2086        *  pointer.
2087        *
2088        * This function will not throw an %exception.
2089        */
2090       template<typename _Functor>       _Functor* target();
2091
2092       /// @overload
2093       template<typename _Functor> const _Functor* target() const;
2094 #endif
2095
2096     private:
2097       typedef _Res (*_Invoker_type)(const _Any_data&, _ArgTypes...);
2098       _Invoker_type _M_invoker;
2099   };
2100
2101   // Out-of-line member definitions.
2102   template<typename _Res, typename... _ArgTypes>
2103     function<_Res(_ArgTypes...)>::
2104     function(const function& __x)
2105     : _Function_base()
2106     {
2107       if (static_cast<bool>(__x))
2108         {
2109           _M_invoker = __x._M_invoker;
2110           _M_manager = __x._M_manager;
2111           __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
2112         }
2113     }
2114
2115   template<typename _Res, typename... _ArgTypes>
2116     template<typename _Functor>
2117       function<_Res(_ArgTypes...)>::
2118       function(_Functor __f,
2119                typename enable_if<
2120                         !is_integral<_Functor>::value, _Useless>::type)
2121       : _Function_base()
2122       {
2123         typedef _Function_handler<_Signature_type, _Functor> _My_handler;
2124
2125         if (_My_handler::_M_not_empty_function(__f))
2126           {
2127             _M_invoker = &_My_handler::_M_invoke;
2128             _M_manager = &_My_handler::_M_manager;
2129             _My_handler::_M_init_functor(_M_functor, std::move(__f));
2130           }
2131       }
2132
2133   template<typename _Res, typename... _ArgTypes>
2134     _Res
2135     function<_Res(_ArgTypes...)>::
2136     operator()(_ArgTypes... __args) const
2137     {
2138       if (_M_empty())
2139         __throw_bad_function_call();
2140       return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
2141     }
2142
2143 #ifdef __GXX_RTTI
2144   template<typename _Res, typename... _ArgTypes>
2145     const type_info&
2146     function<_Res(_ArgTypes...)>::
2147     target_type() const
2148     {
2149       if (_M_manager)
2150         {
2151           _Any_data __typeinfo_result;
2152           _M_manager(__typeinfo_result, _M_functor, __get_type_info);
2153           return *__typeinfo_result._M_access<const type_info*>();
2154         }
2155       else
2156         return typeid(void);
2157     }
2158
2159   template<typename _Res, typename... _ArgTypes>
2160     template<typename _Functor>
2161       _Functor*
2162       function<_Res(_ArgTypes...)>::
2163       target()
2164       {
2165         if (typeid(_Functor) == target_type() && _M_manager)
2166           {
2167             _Any_data __ptr;
2168             if (_M_manager(__ptr, _M_functor, __get_functor_ptr)
2169                 && !is_const<_Functor>::value)
2170               return 0;
2171             else
2172               return __ptr._M_access<_Functor*>();
2173           }
2174         else
2175           return 0;
2176       }
2177
2178   template<typename _Res, typename... _ArgTypes>
2179     template<typename _Functor>
2180       const _Functor*
2181       function<_Res(_ArgTypes...)>::
2182       target() const
2183       {
2184         if (typeid(_Functor) == target_type() && _M_manager)
2185           {
2186             _Any_data __ptr;
2187             _M_manager(__ptr, _M_functor, __get_functor_ptr);
2188             return __ptr._M_access<const _Functor*>();
2189           }
2190         else
2191           return 0;
2192       }
2193 #endif
2194
2195   // [20.7.15.2.6] null pointer comparisons
2196
2197   /**
2198    *  @brief Compares a polymorphic function object wrapper against 0
2199    *  (the NULL pointer).
2200    *  @returns @c true if the wrapper has no target, @c false otherwise
2201    *
2202    *  This function will not throw an %exception.
2203    */
2204   template<typename _Res, typename... _Args>
2205     inline bool
2206     operator==(const function<_Res(_Args...)>& __f, nullptr_t)
2207     { return !static_cast<bool>(__f); }
2208
2209   /// @overload
2210   template<typename _Res, typename... _Args>
2211     inline bool
2212     operator==(nullptr_t, const function<_Res(_Args...)>& __f)
2213     { return !static_cast<bool>(__f); }
2214
2215   /**
2216    *  @brief Compares a polymorphic function object wrapper against 0
2217    *  (the NULL pointer).
2218    *  @returns @c false if the wrapper has no target, @c true otherwise
2219    *
2220    *  This function will not throw an %exception.
2221    */
2222   template<typename _Res, typename... _Args>
2223     inline bool
2224     operator!=(const function<_Res(_Args...)>& __f, nullptr_t)
2225     { return static_cast<bool>(__f); }
2226
2227   /// @overload
2228   template<typename _Res, typename... _Args>
2229     inline bool
2230     operator!=(nullptr_t, const function<_Res(_Args...)>& __f)
2231     { return static_cast<bool>(__f); }
2232
2233   // [20.7.15.2.7] specialized algorithms
2234
2235   /**
2236    *  @brief Swap the targets of two polymorphic function object wrappers.
2237    *
2238    *  This function will not throw an %exception.
2239    */
2240   template<typename _Res, typename... _Args>
2241     inline void
2242     swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y)
2243     { __x.swap(__y); }
2244
2245 _GLIBCXX_END_NAMESPACE
2246
2247 #endif // __GXX_EXPERIMENTAL_CXX0X__
2248
2249 #endif // _GLIBCXX_FUNCTIONAL