libstdc++-v3/include/std/functional

   1 // <functional> -*- C++ -*-
   2
   3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   4 // 2011 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 namespace std _GLIBCXX_VISIBILITY(default)
  62 {
  63 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  64
  65 _GLIBCXX_HAS_NESTED_TYPE(result_type)
  66
  67   /// If we have found a result_type, extract it.
  68   template<bool _Has_result_type, typename _Functor>
  69     struct _Maybe_get_result_type
  70     { };
  71
  72   template<typename _Functor>
  73     struct _Maybe_get_result_type<true, _Functor>
  74     { typedef typename _Functor::result_type result_type; };
  75
  76   /**
  77    *  Base class for any function object that has a weak result type, as
  78    *  defined in 3.3/3 of TR1.
  79   */
  80   template<typename _Functor>
  81     struct _Weak_result_type_impl
  82     : _Maybe_get_result_type<__has_result_type<_Functor>::value, _Functor>
  83     { };
  84
  85   /// Retrieve the result type for a function type.
  86   template<typename _Res, typename... _ArgTypes>
  87     struct _Weak_result_type_impl<_Res(_ArgTypes...)>
  88     { typedef _Res result_type; };
  89
  90   template<typename _Res, typename... _ArgTypes>
  91     struct _Weak_result_type_impl<_Res(_ArgTypes......)>
  92     { typedef _Res result_type; };
  93
  94   template<typename _Res, typename... _ArgTypes>
  95     struct _Weak_result_type_impl<_Res(_ArgTypes...) const>
  96     { typedef _Res result_type; };
  97
  98   template<typename _Res, typename... _ArgTypes>
  99     struct _Weak_result_type_impl<_Res(_ArgTypes......) const>
 100     { typedef _Res result_type; };
 101
 102   template<typename _Res, typename... _ArgTypes>
 103     struct _Weak_result_type_impl<_Res(_ArgTypes...) volatile>
 104     { typedef _Res result_type; };
 105
 106   template<typename _Res, typename... _ArgTypes>
 107     struct _Weak_result_type_impl<_Res(_ArgTypes......) volatile>
 108     { typedef _Res result_type; };
 109
 110   template<typename _Res, typename... _ArgTypes>
 111     struct _Weak_result_type_impl<_Res(_ArgTypes...) const volatile>
 112     { typedef _Res result_type; };
 113
 114   template<typename _Res, typename... _ArgTypes>
 115     struct _Weak_result_type_impl<_Res(_ArgTypes......) const volatile>
 116     { typedef _Res result_type; };
 117
 118   /// Retrieve the result type for a function reference.
 119   template<typename _Res, typename... _ArgTypes>
 120     struct _Weak_result_type_impl<_Res(&)(_ArgTypes...)>
 121     { typedef _Res result_type; };
 122
 123   template<typename _Res, typename... _ArgTypes>
 124     struct _Weak_result_type_impl<_Res(&)(_ArgTypes......)>
 125     { typedef _Res result_type; };
 126
 127   /// Retrieve the result type for a function pointer.
 128   template<typename _Res, typename... _ArgTypes>
 129     struct _Weak_result_type_impl<_Res(*)(_ArgTypes...)>
 130     { typedef _Res result_type; };
 131
 132   template<typename _Res, typename... _ArgTypes>
 133     struct _Weak_result_type_impl<_Res(*)(_ArgTypes......)>
 134     { typedef _Res result_type; };
 135
 136   /// Retrieve result type for a member function pointer.
 137   template<typename _Res, typename _Class, typename... _ArgTypes>
 138     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)>
 139     { typedef _Res result_type; };
 140
 141   template<typename _Res, typename _Class, typename... _ArgTypes>
 142     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)>
 143     { typedef _Res result_type; };
 144
 145   /// Retrieve result type for a const member function pointer.
 146   template<typename _Res, typename _Class, typename... _ArgTypes>
 147     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) const>
 148     { typedef _Res result_type; };
 149
 150   template<typename _Res, typename _Class, typename... _ArgTypes>
 151     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) const>
 152     { typedef _Res result_type; };
 153
 154   /// Retrieve result type for a volatile member function pointer.
 155   template<typename _Res, typename _Class, typename... _ArgTypes>
 156     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) volatile>
 157     { typedef _Res result_type; };
 158
 159   template<typename _Res, typename _Class, typename... _ArgTypes>
 160     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) volatile>
 161     { typedef _Res result_type; };
 162
 163   /// Retrieve result type for a const volatile member function pointer.
 164   template<typename _Res, typename _Class, typename... _ArgTypes>
 165     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)
 166                                   const volatile>
 167     { typedef _Res result_type; };
 168
 169   template<typename _Res, typename _Class, typename... _ArgTypes>
 170     struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)
 171                                   const volatile>
 172     { typedef _Res result_type; };
 173
 174   /**
 175    *  Strip top-level cv-qualifiers from the function object and let
 176    *  _Weak_result_type_impl perform the real work.
 177   */
 178   template<typename _Functor>
 179     struct _Weak_result_type
 180     : _Weak_result_type_impl<typename remove_cv<_Functor>::type>
 181     { };
 182
 183   /// Determines if the type _Tp derives from unary_function.
 184   template<typename _Tp>
 185     struct _Derives_from_unary_function : __sfinae_types
 186     {
 187     private:
 188       template<typename _T1, typename _Res>
 189         static __one __test(const volatile unary_function<_T1, _Res>*);
 190
 191       // It's tempting to change "..." to const volatile void*, but
 192       // that fails when _Tp is a function type.
 193       static __two __test(...);
 194
 195     public:
 196       static const bool value = sizeof(__test((_Tp*)0)) == 1;
 197     };
 198
 199   /// Determines if the type _Tp derives from binary_function.
 200   template<typename _Tp>
 201     struct _Derives_from_binary_function : __sfinae_types
 202     {
 203     private:
 204       template<typename _T1, typename _T2, typename _Res>
 205         static __one __test(const volatile binary_function<_T1, _T2, _Res>*);
 206
 207       // It's tempting to change "..." to const volatile void*, but
 208       // that fails when _Tp is a function type.
 209       static __two __test(...);
 210
 211     public:
 212       static const bool value = sizeof(__test((_Tp*)0)) == 1;
 213     };
 214
 215   /**
 216    * Invoke a function object, which may be either a member pointer or a
 217    * function object. The first parameter will tell which.
 218    */
 219   template<typename _Functor, typename... _Args>
 220     inline
 221     typename enable_if<
 222              (!is_member_pointer<_Functor>::value
 223               && !is_function<_Functor>::value
 224               && !is_function<typename remove_pointer<_Functor>::type>::value),
 225              typename result_of<_Functor(_Args&&...)>::type
 226            >::type
 227     __invoke(_Functor& __f, _Args&&... __args)
 228     {
 229       return __f(std::forward<_Args>(__args)...);
 230     }
 231
 232   template<typename _Functor, typename... _Args>
 233     inline
 234     typename enable_if<
 235              (is_member_pointer<_Functor>::value
 236               && !is_function<_Functor>::value
 237               && !is_function<typename remove_pointer<_Functor>::type>::value),
 238              typename result_of<_Functor(_Args&&...)>::type
 239            >::type
 240     __invoke(_Functor& __f, _Args&&... __args)
 241     {
 242       return mem_fn(__f)(std::forward<_Args>(__args)...);
 243     }
 244
 245   // To pick up function references (that will become function pointers)
 246   template<typename _Functor, typename... _Args>
 247     inline
 248     typename enable_if<
 249              (is_pointer<_Functor>::value
 250               && is_function<typename remove_pointer<_Functor>::type>::value),
 251              typename result_of<_Functor(_Args&&...)>::type
 252            >::type
 253     __invoke(_Functor __f, _Args&&... __args)
 254     {
 255       return __f(std::forward<_Args>(__args)...);
 256     }
 257
 258   /**
 259    *  Knowing which of unary_function and binary_function _Tp derives
 260    *  from, derives from the same and ensures that reference_wrapper
 261    *  will have a weak result type. See cases below.
 262    */
 263   template<bool _Unary, bool _Binary, typename _Tp>
 264     struct _Reference_wrapper_base_impl;
 265
 266   // None of the nested argument types.
 267   template<typename _Tp>
 268     struct _Reference_wrapper_base_impl<false, false, _Tp>
 269     : _Weak_result_type<_Tp>
 270     { };
 271
 272   // Nested argument_type only.
 273   template<typename _Tp>
 274     struct _Reference_wrapper_base_impl<true, false, _Tp>
 275     : _Weak_result_type<_Tp>
 276     {
 277       typedef typename _Tp::argument_type argument_type;
 278     };
 279
 280   // Nested first_argument_type and second_argument_type only.
 281   template<typename _Tp>
 282     struct _Reference_wrapper_base_impl<false, true, _Tp>
 283     : _Weak_result_type<_Tp>
 284     {
 285       typedef typename _Tp::first_argument_type first_argument_type;
 286       typedef typename _Tp::second_argument_type second_argument_type;
 287     };
 288
 289   // All the nested argument types.
 290    template<typename _Tp>
 291     struct _Reference_wrapper_base_impl<true, true, _Tp>
 292     : _Weak_result_type<_Tp>
 293     {
 294       typedef typename _Tp::argument_type argument_type;
 295       typedef typename _Tp::first_argument_type first_argument_type;
 296       typedef typename _Tp::second_argument_type second_argument_type;
 297     };
 298
 299   _GLIBCXX_HAS_NESTED_TYPE(argument_type)
 300   _GLIBCXX_HAS_NESTED_TYPE(first_argument_type)
 301   _GLIBCXX_HAS_NESTED_TYPE(second_argument_type)
 302
 303   /**
 304    *  Derives from unary_function or binary_function when it
 305    *  can. Specializations handle all of the easy cases. The primary
 306    *  template determines what to do with a class type, which may
 307    *  derive from both unary_function and binary_function.
 308   */
 309   template<typename _Tp>
 310     struct _Reference_wrapper_base
 311     : _Reference_wrapper_base_impl<
 312       __has_argument_type<_Tp>::value,
 313       __has_first_argument_type<_Tp>::value
 314       && __has_second_argument_type<_Tp>::value,
 315       _Tp>
 316     { };
 317
 318   // - a function type (unary)
 319   template<typename _Res, typename _T1>
 320     struct _Reference_wrapper_base<_Res(_T1)>
 321     : unary_function<_T1, _Res>
 322     { };
 323
 324   template<typename _Res, typename _T1>
 325     struct _Reference_wrapper_base<_Res(_T1) const>
 326     : unary_function<_T1, _Res>
 327     { };
 328
 329   template<typename _Res, typename _T1>
 330     struct _Reference_wrapper_base<_Res(_T1) volatile>
 331     : unary_function<_T1, _Res>
 332     { };
 333
 334   template<typename _Res, typename _T1>
 335     struct _Reference_wrapper_base<_Res(_T1) const volatile>
 336     : unary_function<_T1, _Res>
 337     { };
 338
 339   // - a function type (binary)
 340   template<typename _Res, typename _T1, typename _T2>
 341     struct _Reference_wrapper_base<_Res(_T1, _T2)>
 342     : binary_function<_T1, _T2, _Res>
 343     { };
 344
 345   template<typename _Res, typename _T1, typename _T2>
 346     struct _Reference_wrapper_base<_Res(_T1, _T2) const>
 347     : binary_function<_T1, _T2, _Res>
 348     { };
 349
 350   template<typename _Res, typename _T1, typename _T2>
 351     struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
 352     : binary_function<_T1, _T2, _Res>
 353     { };
 354
 355   template<typename _Res, typename _T1, typename _T2>
 356     struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
 357     : binary_function<_T1, _T2, _Res>
 358     { };
 359
 360   // - a function pointer type (unary)
 361   template<typename _Res, typename _T1>
 362     struct _Reference_wrapper_base<_Res(*)(_T1)>
 363     : unary_function<_T1, _Res>
 364     { };
 365
 366   // - a function pointer type (binary)
 367   template<typename _Res, typename _T1, typename _T2>
 368     struct _Reference_wrapper_base<_Res(*)(_T1, _T2)>
 369     : binary_function<_T1, _T2, _Res>
 370     { };
 371
 372   // - a pointer to member function type (unary, no qualifiers)
 373   template<typename _Res, typename _T1>
 374     struct _Reference_wrapper_base<_Res (_T1::*)()>
 375     : unary_function<_T1*, _Res>
 376     { };
 377
 378   // - a pointer to member function type (binary, no qualifiers)
 379   template<typename _Res, typename _T1, typename _T2>
 380     struct _Reference_wrapper_base<_Res (_T1::*)(_T2)>
 381     : binary_function<_T1*, _T2, _Res>
 382     { };
 383
 384   // - a pointer to member function type (unary, const)
 385   template<typename _Res, typename _T1>
 386     struct _Reference_wrapper_base<_Res (_T1::*)() const>
 387     : unary_function<const _T1*, _Res>
 388     { };
 389
 390   // - a pointer to member function type (binary, const)
 391   template<typename _Res, typename _T1, typename _T2>
 392     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const>
 393     : binary_function<const _T1*, _T2, _Res>
 394     { };
 395
 396   // - a pointer to member function type (unary, volatile)
 397   template<typename _Res, typename _T1>
 398     struct _Reference_wrapper_base<_Res (_T1::*)() volatile>
 399     : unary_function<volatile _T1*, _Res>
 400     { };
 401
 402   // - a pointer to member function type (binary, volatile)
 403   template<typename _Res, typename _T1, typename _T2>
 404     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) volatile>
 405     : binary_function<volatile _T1*, _T2, _Res>
 406     { };
 407
 408   // - a pointer to member function type (unary, const volatile)
 409   template<typename _Res, typename _T1>
 410     struct _Reference_wrapper_base<_Res (_T1::*)() const volatile>
 411     : unary_function<const volatile _T1*, _Res>
 412     { };
 413
 414   // - a pointer to member function type (binary, const volatile)
 415   template<typename _Res, typename _T1, typename _T2>
 416     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const volatile>
 417     : binary_function<const volatile _T1*, _T2, _Res>
 418     { };
 419
 420   /**
 421    *  @brief Primary class template for reference_wrapper.
 422    *  @ingroup functors
 423    *  @{
 424    */
 425   template<typename _Tp>
 426     class reference_wrapper
 427     : public _Reference_wrapper_base<typename remove_cv<_Tp>::type>
 428     {
 429       _Tp* _M_data;
 430
 431     public:
 432       typedef _Tp type;
 433
 434       reference_wrapper(_Tp& __indata)
 435       : _M_data(std::__addressof(__indata))
 436       { }
 437
 438       reference_wrapper(_Tp&&) = delete;
 439
 440       reference_wrapper(const reference_wrapper<_Tp>& __inref):
 441       _M_data(__inref._M_data)
 442       { }
 443
 444       reference_wrapper&
 445       operator=(const reference_wrapper<_Tp>& __inref)
 446       {
 447         _M_data = __inref._M_data;
 448         return *this;
 449       }
 450
 451       operator _Tp&() const
 452       { return this->get(); }
 453
 454       _Tp&
 455       get() const
 456       { return *_M_data; }
 457
 458       template<typename... _Args>
 459         typename result_of<_Tp&(_Args&&...)>::type
 460         operator()(_Args&&... __args) const
 461         {
 462           return __invoke(get(), std::forward<_Args>(__args)...);
 463         }
 464     };
 465
 466
 467   /// Denotes a reference should be taken to a variable.
 468   template<typename _Tp>
 469     inline reference_wrapper<_Tp>
 470     ref(_Tp& __t)
 471     { return reference_wrapper<_Tp>(__t); }
 472
 473   /// Denotes a const reference should be taken to a variable.
 474   template<typename _Tp>
 475     inline reference_wrapper<const _Tp>
 476     cref(const _Tp& __t)
 477     { return reference_wrapper<const _Tp>(__t); }
 478
 479   template<typename _Tp>
 480     void ref(const _Tp&&) = delete;
 481
 482   template<typename _Tp>
 483     void cref(const _Tp&&) = delete;
 484
 485   /// Partial specialization.
 486   template<typename _Tp>
 487     inline reference_wrapper<_Tp>
 488     ref(reference_wrapper<_Tp> __t)
 489     { return ref(__t.get()); }
 490
 491   /// Partial specialization.
 492   template<typename _Tp>
 493     inline reference_wrapper<const _Tp>
 494     cref(reference_wrapper<_Tp> __t)
 495     { return cref(__t.get()); }
 496
 497   // @} group functors
 498
 499   template<typename _MemberPointer>
 500     class _Mem_fn;
 501
 502   /**
 503    * Derives from @c unary_function or @c binary_function, or perhaps
 504    * nothing, depending on the number of arguments provided. The
 505    * primary template is the basis case, which derives nothing.
 506    */
 507   template<typename _Res, typename... _ArgTypes>
 508     struct _Maybe_unary_or_binary_function { };
 509
 510   /// Derives from @c unary_function, as appropriate.
 511   template<typename _Res, typename _T1>
 512     struct _Maybe_unary_or_binary_function<_Res, _T1>
 513     : std::unary_function<_T1, _Res> { };
 514
 515   /// Derives from @c binary_function, as appropriate.
 516   template<typename _Res, typename _T1, typename _T2>
 517     struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
 518     : std::binary_function<_T1, _T2, _Res> { };
 519
 520   /// Implementation of @c mem_fn for member function pointers.
 521   template<typename _Res, typename _Class, typename... _ArgTypes>
 522     class _Mem_fn<_Res (_Class::*)(_ArgTypes...)>
 523     : public _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>
 524     {
 525       typedef _Res (_Class::*_Functor)(_ArgTypes...);
 526
 527       template<typename _Tp>
 528         _Res
 529         _M_call(_Tp& __object, const volatile _Class *,
 530                 _ArgTypes... __args) const
 531         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 532
 533       template<typename _Tp>
 534         _Res
 535         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 536         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 537
 538     public:
 539       typedef _Res result_type;
 540
 541       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 542
 543       // Handle objects
 544       _Res
 545       operator()(_Class& __object, _ArgTypes... __args) const
 546       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 547
 548       // Handle pointers
 549       _Res
 550       operator()(_Class* __object, _ArgTypes... __args) const
 551       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 552
 553       // Handle smart pointers, references and pointers to derived
 554       template<typename _Tp>
 555         _Res
 556         operator()(_Tp& __object, _ArgTypes... __args) const
 557         {
 558           return _M_call(__object, &__object,
 559               std::forward<_ArgTypes>(__args)...);
 560         }
 561
 562     private:
 563       _Functor __pmf;
 564     };
 565
 566   /// Implementation of @c mem_fn for const member function pointers.
 567   template<typename _Res, typename _Class, typename... _ArgTypes>
 568     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const>
 569     : public _Maybe_unary_or_binary_function<_Res, const _Class*,
 570                                              _ArgTypes...>
 571     {
 572       typedef _Res (_Class::*_Functor)(_ArgTypes...) const;
 573
 574       template<typename _Tp>
 575         _Res
 576         _M_call(_Tp& __object, const volatile _Class *,
 577                 _ArgTypes... __args) const
 578         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 579
 580       template<typename _Tp>
 581         _Res
 582         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 583         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 584
 585     public:
 586       typedef _Res result_type;
 587
 588       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 589
 590       // Handle objects
 591       _Res
 592       operator()(const _Class& __object, _ArgTypes... __args) const
 593       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 594
 595       // Handle pointers
 596       _Res
 597       operator()(const _Class* __object, _ArgTypes... __args) const
 598       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 599
 600       // Handle smart pointers, references and pointers to derived
 601       template<typename _Tp>
 602         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 603         {
 604           return _M_call(__object, &__object,
 605               std::forward<_ArgTypes>(__args)...);
 606         }
 607
 608     private:
 609       _Functor __pmf;
 610     };
 611
 612   /// Implementation of @c mem_fn for volatile member function pointers.
 613   template<typename _Res, typename _Class, typename... _ArgTypes>
 614     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) volatile>
 615     : public _Maybe_unary_or_binary_function<_Res, volatile _Class*,
 616                                              _ArgTypes...>
 617     {
 618       typedef _Res (_Class::*_Functor)(_ArgTypes...) volatile;
 619
 620       template<typename _Tp>
 621         _Res
 622         _M_call(_Tp& __object, const volatile _Class *,
 623                 _ArgTypes... __args) const
 624         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 625
 626       template<typename _Tp>
 627         _Res
 628         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 629         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 630
 631     public:
 632       typedef _Res result_type;
 633
 634       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 635
 636       // Handle objects
 637       _Res
 638       operator()(volatile _Class& __object, _ArgTypes... __args) const
 639       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 640
 641       // Handle pointers
 642       _Res
 643       operator()(volatile _Class* __object, _ArgTypes... __args) const
 644       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 645
 646       // Handle smart pointers, references and pointers to derived
 647       template<typename _Tp>
 648         _Res
 649         operator()(_Tp& __object, _ArgTypes... __args) const
 650         {
 651           return _M_call(__object, &__object,
 652               std::forward<_ArgTypes>(__args)...);
 653         }
 654
 655     private:
 656       _Functor __pmf;
 657     };
 658
 659   /// Implementation of @c mem_fn for const volatile member function pointers.
 660   template<typename _Res, typename _Class, typename... _ArgTypes>
 661     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const volatile>
 662     : public _Maybe_unary_or_binary_function<_Res, const volatile _Class*,
 663                                              _ArgTypes...>
 664     {
 665       typedef _Res (_Class::*_Functor)(_ArgTypes...) const volatile;
 666
 667       template<typename _Tp>
 668         _Res
 669         _M_call(_Tp& __object, const volatile _Class *,
 670                 _ArgTypes... __args) const
 671         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 672
 673       template<typename _Tp>
 674         _Res
 675         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 676         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 677
 678     public:
 679       typedef _Res result_type;
 680
 681       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 682
 683       // Handle objects
 684       _Res
 685       operator()(const volatile _Class& __object, _ArgTypes... __args) const
 686       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 687
 688       // Handle pointers
 689       _Res
 690       operator()(const volatile _Class* __object, _ArgTypes... __args) const
 691       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 692
 693       // Handle smart pointers, references and pointers to derived
 694       template<typename _Tp>
 695         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 696         {
 697           return _M_call(__object, &__object,
 698               std::forward<_ArgTypes>(__args)...);
 699         }
 700
 701     private:
 702       _Functor __pmf;
 703     };
 704
 705
 706   template<typename _Tp, bool>
 707     struct _Mem_fn_const_or_non
 708     {
 709       typedef const _Tp& type;
 710     };
 711
 712   template<typename _Tp>
 713     struct _Mem_fn_const_or_non<_Tp, false>
 714     {
 715       typedef _Tp& type;
 716     };
 717
 718   template<typename _Res, typename _Class>
 719     class _Mem_fn<_Res _Class::*>
 720     {
 721       // This bit of genius is due to Peter Dimov, improved slightly by
 722       // Douglas Gregor.
 723       template<typename _Tp>
 724         _Res&
 725         _M_call(_Tp& __object, _Class *) const
 726         { return __object.*__pm; }
 727
 728       template<typename _Tp, typename _Up>
 729         _Res&
 730         _M_call(_Tp& __object, _Up * const *) const
 731         { return (*__object).*__pm; }
 732
 733       template<typename _Tp, typename _Up>
 734         const _Res&
 735         _M_call(_Tp& __object, const _Up * const *) const
 736         { return (*__object).*__pm; }
 737
 738       template<typename _Tp>
 739         const _Res&
 740         _M_call(_Tp& __object, const _Class *) const
 741         { return __object.*__pm; }
 742
 743       template<typename _Tp>
 744         const _Res&
 745         _M_call(_Tp& __ptr, const volatile void*) const
 746         { return (*__ptr).*__pm; }
 747
 748       template<typename _Tp> static _Tp& __get_ref();
 749
 750       template<typename _Tp>
 751         static __sfinae_types::__one __check_const(_Tp&, _Class*);
 752       template<typename _Tp, typename _Up>
 753         static __sfinae_types::__one __check_const(_Tp&, _Up * const *);
 754       template<typename _Tp, typename _Up>
 755         static __sfinae_types::__two __check_const(_Tp&, const _Up * const *);
 756       template<typename _Tp>
 757         static __sfinae_types::__two __check_const(_Tp&, const _Class*);
 758       template<typename _Tp>
 759         static __sfinae_types::__two __check_const(_Tp&, const volatile void*);
 760
 761     public:
 762       template<typename _Tp>
 763         struct _Result_type
 764         : _Mem_fn_const_or_non<_Res,
 765           (sizeof(__sfinae_types::__two)
 766            == sizeof(__check_const<_Tp>(__get_ref<_Tp>(), (_Tp*)0)))>
 767         { };
 768
 769       template<typename _Signature>
 770         struct result;
 771
 772       template<typename _CVMem, typename _Tp>
 773         struct result<_CVMem(_Tp)>
 774         : public _Result_type<_Tp> { };
 775
 776       template<typename _CVMem, typename _Tp>
 777         struct result<_CVMem(_Tp&)>
 778         : public _Result_type<_Tp> { };
 779
 780       explicit
 781       _Mem_fn(_Res _Class::*__pm) : __pm(__pm) { }
 782
 783       // Handle objects
 784       _Res&
 785       operator()(_Class& __object) const
 786       { return __object.*__pm; }
 787
 788       const _Res&
 789       operator()(const _Class& __object) const
 790       { return __object.*__pm; }
 791
 792       // Handle pointers
 793       _Res&
 794       operator()(_Class* __object) const
 795       { return __object->*__pm; }
 796
 797       const _Res&
 798       operator()(const _Class* __object) const
 799       { return __object->*__pm; }
 800
 801       // Handle smart pointers and derived
 802       template<typename _Tp>
 803         typename _Result_type<_Tp>::type
 804         operator()(_Tp& __unknown) const
 805         { return _M_call(__unknown, &__unknown); }
 806
 807     private:
 808       _Res _Class::*__pm;
 809     };
 810
 811   /**
 812    *  @brief Returns a function object that forwards to the member
 813    *  pointer @a pm.
 814    *  @ingroup functors
 815    */
 816   template<typename _Tp, typename _Class>
 817     inline _Mem_fn<_Tp _Class::*>
 818     mem_fn(_Tp _Class::* __pm)
 819     {
 820       return _Mem_fn<_Tp _Class::*>(__pm);
 821     }
 822
 823   /**
 824    *  @brief Determines if the given type _Tp is a function object
 825    *  should be treated as a subexpression when evaluating calls to
 826    *  function objects returned by bind(). [TR1 3.6.1]
 827    *  @ingroup binders
 828    */
 829   template<typename _Tp>
 830     struct is_bind_expression
 831     : public false_type { };
 832
 833   /**
 834    *  @brief Determines if the given type _Tp is a placeholder in a
 835    *  bind() expression and, if so, which placeholder it is. [TR1 3.6.2]
 836    *  @ingroup binders
 837    */
 838   template<typename _Tp>
 839     struct is_placeholder
 840     : public integral_constant<int, 0>
 841     { };
 842
 843   /// The type of placeholder objects defined by libstdc++.
 844   template<int _Num> struct _Placeholder { };
 845
 846   _GLIBCXX_END_NAMESPACE_VERSION
 847
 848   /** @namespace std::placeholders
 849    *  @brief ISO C++ 0x entities sub namespace for functional.
 850    *  @ingroup binders
 851    *
 852    *  Define a large number of placeholders. There is no way to
 853    *  simplify this with variadic templates, because we're introducing
 854    *  unique names for each.
 855    */
 856   namespace placeholders
 857   {
 858   _GLIBCXX_BEGIN_NAMESPACE_VERSION
 859     extern const _Placeholder<1> _1;
 860     extern const _Placeholder<2> _2;
 861     extern const _Placeholder<3> _3;
 862     extern const _Placeholder<4> _4;
 863     extern const _Placeholder<5> _5;
 864     extern const _Placeholder<6> _6;
 865     extern const _Placeholder<7> _7;
 866     extern const _Placeholder<8> _8;
 867     extern const _Placeholder<9> _9;
 868     extern const _Placeholder<10> _10;
 869     extern const _Placeholder<11> _11;
 870     extern const _Placeholder<12> _12;
 871     extern const _Placeholder<13> _13;
 872     extern const _Placeholder<14> _14;
 873     extern const _Placeholder<15> _15;
 874     extern const _Placeholder<16> _16;
 875     extern const _Placeholder<17> _17;
 876     extern const _Placeholder<18> _18;
 877     extern const _Placeholder<19> _19;
 878     extern const _Placeholder<20> _20;
 879     extern const _Placeholder<21> _21;
 880     extern const _Placeholder<22> _22;
 881     extern const _Placeholder<23> _23;
 882     extern const _Placeholder<24> _24;
 883     extern const _Placeholder<25> _25;
 884     extern const _Placeholder<26> _26;
 885     extern const _Placeholder<27> _27;
 886     extern const _Placeholder<28> _28;
 887     extern const _Placeholder<29> _29;
 888   _GLIBCXX_END_NAMESPACE_VERSION
 889   }
 890
 891   _GLIBCXX_BEGIN_NAMESPACE_VERSION
 892
 893   /**
 894    *  Partial specialization of is_placeholder that provides the placeholder
 895    *  number for the placeholder objects defined by libstdc++.
 896    *  @ingroup binders
 897    */
 898   template<int _Num>
 899     struct is_placeholder<_Placeholder<_Num> >
 900     : public integral_constant<int, _Num>
 901     { };
 902
 903   /**
 904    * Used by _Safe_tuple_element to indicate that there is no tuple
 905    * element at this position.
 906    */
 907   struct _No_tuple_element;
 908
 909   /**
 910    * Implementation helper for _Safe_tuple_element. This primary
 911    * template handles the case where it is safe to use @c
 912    * tuple_element.
 913    */
 914   template<int __i, typename _Tuple, bool _IsSafe>
 915     struct _Safe_tuple_element_impl
 916     : tuple_element<__i, _Tuple> { };
 917
 918   /**
 919    * Implementation helper for _Safe_tuple_element. This partial
 920    * specialization handles the case where it is not safe to use @c
 921    * tuple_element. We just return @c _No_tuple_element.
 922    */
 923   template<int __i, typename _Tuple>
 924     struct _Safe_tuple_element_impl<__i, _Tuple, false>
 925     {
 926       typedef _No_tuple_element type;
 927     };
 928
 929   /**
 930    * Like tuple_element, but returns @c _No_tuple_element when
 931    * tuple_element would return an error.
 932    */
 933  template<int __i, typename _Tuple>
 934    struct _Safe_tuple_element
 935    : _Safe_tuple_element_impl<__i, _Tuple,
 936                               (__i >= 0 && __i < tuple_size<_Tuple>::value)>
 937    { };
 938
 939   /**
 940    *  Maps an argument to bind() into an actual argument to the bound
 941    *  function object [TR1 3.6.3/5]. Only the first parameter should
 942    *  be specified: the rest are used to determine among the various
 943    *  implementations. Note that, although this class is a function
 944    *  object, it isn't entirely normal because it takes only two
 945    *  parameters regardless of the number of parameters passed to the
 946    *  bind expression. The first parameter is the bound argument and
 947    *  the second parameter is a tuple containing references to the
 948    *  rest of the arguments.
 949    */
 950   template<typename _Arg,
 951            bool _IsBindExp = is_bind_expression<_Arg>::value,
 952            bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
 953     class _Mu;
 954
 955   /**
 956    *  If the argument is reference_wrapper<_Tp>, returns the
 957    *  underlying reference. [TR1 3.6.3/5 bullet 1]
 958    */
 959   template<typename _Tp>
 960     class _Mu<reference_wrapper<_Tp>, false, false>
 961     {
 962     public:
 963       typedef _Tp& result_type;
 964
 965       /* Note: This won't actually work for const volatile
 966        * reference_wrappers, because reference_wrapper::get() is const
 967        * but not volatile-qualified. This might be a defect in the TR.
 968        */
 969       template<typename _CVRef, typename _Tuple>
 970         result_type
 971         operator()(_CVRef& __arg, _Tuple&) const volatile
 972         { return __arg.get(); }
 973     };
 974
 975   /**
 976    *  If the argument is a bind expression, we invoke the underlying
 977    *  function object with the same cv-qualifiers as we are given and
 978    *  pass along all of our arguments (unwrapped). [TR1 3.6.3/5 bullet 2]
 979    */
 980   template<typename _Arg>
 981     class _Mu<_Arg, true, false>
 982     {
 983     public:
 984       template<typename _CVArg, typename... _Args>
 985         auto
 986         operator()(_CVArg& __arg,
 987                    tuple<_Args...>& __tuple) const volatile
 988         -> decltype(__arg(declval<_Args>()...))
 989         {
 990           // Construct an index tuple and forward to __call
 991           typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
 992             _Indexes;
 993           return this->__call(__arg, __tuple, _Indexes());
 994         }
 995
 996     private:
 997       // Invokes the underlying function object __arg by unpacking all
 998       // of the arguments in the tuple.
 999       template<typename _CVArg, typename... _Args, int... _Indexes>
1000         auto
1001         __call(_CVArg& __arg, tuple<_Args...>& __tuple,
1002                const _Index_tuple<_Indexes...>&) const volatile
1003         -> decltype(__arg(declval<_Args>()...))
1004         {
1005           return __arg(std::forward<_Args>(get<_Indexes>(__tuple))...);
1006         }
1007     };
1008
1009   /**
1010    *  If the argument is a placeholder for the Nth argument, returns
1011    *  a reference to the Nth argument to the bind function object.
1012    *  [TR1 3.6.3/5 bullet 3]
1013    */
1014   template<typename _Arg>
1015     class _Mu<_Arg, false, true>
1016     {
1017     public:
1018       template<typename _Signature> class result;
1019
1020       template<typename _CVMu, typename _CVArg, typename _Tuple>
1021         class result<_CVMu(_CVArg, _Tuple)>
1022         {
1023           // Add a reference, if it hasn't already been done for us.
1024           // This allows us to be a little bit sloppy in constructing
1025           // the tuple that we pass to result_of<...>.
1026           typedef typename _Safe_tuple_element<(is_placeholder<_Arg>::value
1027                                                 - 1), _Tuple>::type
1028             __base_type;
1029
1030         public:
1031           typedef typename add_rvalue_reference<__base_type>::type type;
1032         };
1033
1034       template<typename _Tuple>
1035         typename result<_Mu(_Arg, _Tuple)>::type
1036         operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
1037         {
1038           return std::forward<typename result<_Mu(_Arg, _Tuple)>::type>(
1039               ::std::get<(is_placeholder<_Arg>::value - 1)>(__tuple));
1040         }
1041     };
1042
1043   /**
1044    *  If the argument is just a value, returns a reference to that
1045    *  value. The cv-qualifiers on the reference are the same as the
1046    *  cv-qualifiers on the _Mu object. [TR1 3.6.3/5 bullet 4]
1047    */
1048   template<typename _Arg>
1049     class _Mu<_Arg, false, false>
1050     {
1051     public:
1052       template<typename _Signature> struct result;
1053
1054       template<typename _CVMu, typename _CVArg, typename _Tuple>
1055         struct result<_CVMu(_CVArg, _Tuple)>
1056         {
1057           typedef typename add_lvalue_reference<_CVArg>::type type;
1058         };
1059
1060       // Pick up the cv-qualifiers of the argument
1061       template<typename _CVArg, typename _Tuple>
1062         _CVArg&&
1063         operator()(_CVArg&& __arg, _Tuple&) const volatile
1064         { return std::forward<_CVArg>(__arg); }
1065     };
1066
1067   /**
1068    *  Maps member pointers into instances of _Mem_fn but leaves all
1069    *  other function objects untouched. Used by tr1::bind(). The
1070    *  primary template handles the non--member-pointer case.
1071    */
1072   template<typename _Tp>
1073     struct _Maybe_wrap_member_pointer
1074     {
1075       typedef _Tp type;
1076
1077       static const _Tp&
1078       __do_wrap(const _Tp& __x)
1079       { return __x; }
1080
1081       static _Tp&&
1082       __do_wrap(_Tp&& __x)
1083       { return static_cast<_Tp&&>(__x); }
1084     };
1085
1086   /**
1087    *  Maps member pointers into instances of _Mem_fn but leaves all
1088    *  other function objects untouched. Used by tr1::bind(). This
1089    *  partial specialization handles the member pointer case.
1090    */
1091   template<typename _Tp, typename _Class>
1092     struct _Maybe_wrap_member_pointer<_Tp _Class::*>
1093     {
1094       typedef _Mem_fn<_Tp _Class::*> type;
1095
1096       static type
1097       __do_wrap(_Tp _Class::* __pm)
1098       { return type(__pm); }
1099     };
1100
1101   // Specialization needed to prevent "forming reference to void" errors when
1102   // bind<void>() is called, because argument deduction instantiates
1103   // _Maybe_wrap_member_pointer<void> outside the immediate context where
1104   // SFINAE applies.
1105   template<>
1106     struct _Maybe_wrap_member_pointer<void>
1107     {
1108       typedef void type;
1109     };
1110
1111   // std::get<I> for volatile-qualified tuples
1112   template<size_t _Ind, typename... _Tp>
1113     inline auto
1114     __volget(volatile tuple<_Tp...>& __tuple)
1115     -> typename tuple_element<_Ind, tuple<_Tp...>>::type volatile&
1116     { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
1117
1118   // std::get<I> for const-volatile-qualified tuples
1119   template<size_t _Ind, typename... _Tp>
1120     inline auto
1121     __volget(const volatile tuple<_Tp...>& __tuple)
1122     -> typename tuple_element<_Ind, tuple<_Tp...>>::type const volatile&
1123     { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
1124
1125   /// Type of the function object returned from bind().
1126   template<typename _Signature>
1127     struct _Bind;
1128
1129    template<typename _Functor, typename... _Bound_args>
1130     class _Bind<_Functor(_Bound_args...)>
1131     : public _Weak_result_type<_Functor>
1132     {
1133       typedef _Bind __self_type;
1134       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1135         _Bound_indexes;
1136
1137       _Functor _M_f;
1138       tuple<_Bound_args...> _M_bound_args;
1139
1140       // Call unqualified
1141       template<typename _Result, typename... _Args, int... _Indexes>
1142         _Result
1143         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
1144         {
1145           return _M_f(_Mu<_Bound_args>()
1146                       (get<_Indexes>(_M_bound_args), __args)...);
1147         }
1148
1149       // Call as const
1150       template<typename _Result, typename... _Args, int... _Indexes>
1151         _Result
1152         __call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
1153         {
1154           return _M_f(_Mu<_Bound_args>()
1155                       (get<_Indexes>(_M_bound_args), __args)...);
1156         }
1157
1158       // Call as volatile
1159       template<typename _Result, typename... _Args, int... _Indexes>
1160         _Result
1161         __call_v(tuple<_Args...>&& __args,
1162                  _Index_tuple<_Indexes...>) volatile
1163         {
1164           return _M_f(_Mu<_Bound_args>()
1165                       (__volget<_Indexes>(_M_bound_args), __args)...);
1166         }
1167
1168       // Call as const volatile
1169       template<typename _Result, typename... _Args, int... _Indexes>
1170         _Result
1171         __call_c_v(tuple<_Args...>&& __args,
1172                    _Index_tuple<_Indexes...>) const volatile
1173         {
1174           return _M_f(_Mu<_Bound_args>()
1175                       (__volget<_Indexes>(_M_bound_args), __args)...);
1176         }
1177
1178      public:
1179       template<typename... _Args>
1180         explicit _Bind(const _Functor& __f, _Args&&... __args)
1181         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1182         { }
1183
1184       template<typename... _Args>
1185         explicit _Bind(_Functor&& __f, _Args&&... __args)
1186         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1187         { }
1188
1189       _Bind(const _Bind&) = default;
1190
1191       _Bind(_Bind&& __b)
1192       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1193       { }
1194
1195       // Call unqualified
1196       template<typename... _Args, typename _Result
1197         = decltype( std::declval<_Functor>()(
1198               _Mu<_Bound_args>()( std::declval<_Bound_args&>(),
1199                                   std::declval<tuple<_Args...>&>() )... ) )>
1200         _Result
1201         operator()(_Args&&... __args)
1202         {
1203           return this->__call<_Result>(
1204               std::forward_as_tuple(std::forward<_Args>(__args)...),
1205               _Bound_indexes());
1206         }
1207
1208       // Call as const
1209       template<typename... _Args, typename _Result
1210         = decltype( std::declval<const _Functor>()(
1211               _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
1212                                   std::declval<tuple<_Args...>&>() )... ) )>
1213         _Result
1214         operator()(_Args&&... __args) const
1215         {
1216           return this->__call_c<_Result>(
1217               std::forward_as_tuple(std::forward<_Args>(__args)...),
1218               _Bound_indexes());
1219         }
1220
1221       // Call as volatile
1222       template<typename... _Args, typename _Result
1223         = decltype( std::declval<volatile _Functor>()(
1224               _Mu<_Bound_args>()( std::declval<volatile _Bound_args&>(),
1225                                   std::declval<tuple<_Args...>&>() )... ) )>
1226         _Result
1227         operator()(_Args&&... __args) volatile
1228         {
1229           return this->__call_v<_Result>(
1230               std::forward_as_tuple(std::forward<_Args>(__args)...),
1231               _Bound_indexes());
1232         }
1233
1234       // Call as const volatile
1235       template<typename... _Args, typename _Result
1236         = decltype( std::declval<const volatile _Functor>()(
1237               _Mu<_Bound_args>()( std::declval<const volatile _Bound_args&>(),
1238                                   std::declval<tuple<_Args...>&>() )... ) )>
1239         _Result
1240         operator()(_Args&&... __args) const volatile
1241         {
1242           return this->__call_c_v<_Result>(
1243               std::forward_as_tuple(std::forward<_Args>(__args)...),
1244               _Bound_indexes());
1245         }
1246     };
1247
1248   /// Type of the function object returned from bind<R>().
1249   template<typename _Result, typename _Signature>
1250     struct _Bind_result;
1251
1252   template<typename _Result, typename _Functor, typename... _Bound_args>
1253     class _Bind_result<_Result, _Functor(_Bound_args...)>
1254     {
1255       typedef _Bind_result __self_type;
1256       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1257         _Bound_indexes;
1258
1259       _Functor _M_f;
1260       tuple<_Bound_args...> _M_bound_args;
1261
1262       // sfinae types
1263       template<typename _Res>
1264         struct __enable_if_void : enable_if<is_void<_Res>::value, int> { };
1265       template<typename _Res>
1266         struct __disable_if_void : enable_if<!is_void<_Res>::value, int> { };
1267
1268       // Call unqualified
1269       template<typename _Res, typename... _Args, int... _Indexes>
1270         _Result
1271         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1272             typename __disable_if_void<_Res>::type = 0)
1273         {
1274           return _M_f(_Mu<_Bound_args>()
1275                       (get<_Indexes>(_M_bound_args), __args)...);
1276         }
1277
1278       // Call unqualified, return void
1279       template<typename _Res, typename... _Args, int... _Indexes>
1280         void
1281         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1282             typename __enable_if_void<_Res>::type = 0)
1283         {
1284           _M_f(_Mu<_Bound_args>()
1285                (get<_Indexes>(_M_bound_args), __args)...);
1286         }
1287
1288       // Call as const
1289       template<typename _Res, typename... _Args, int... _Indexes>
1290         _Result
1291         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1292             typename __disable_if_void<_Res>::type = 0) const
1293         {
1294           return _M_f(_Mu<_Bound_args>()
1295                       (get<_Indexes>(_M_bound_args), __args)...);
1296         }
1297
1298       // Call as const, return void
1299       template<typename _Res, typename... _Args, int... _Indexes>
1300         void
1301         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1302             typename __enable_if_void<_Res>::type = 0) const
1303         {
1304           _M_f(_Mu<_Bound_args>()
1305                (get<_Indexes>(_M_bound_args),  __args)...);
1306         }
1307
1308       // Call as volatile
1309       template<typename _Res, typename... _Args, int... _Indexes>
1310         _Result
1311         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1312             typename __disable_if_void<_Res>::type = 0) volatile
1313         {
1314           return _M_f(_Mu<_Bound_args>()
1315                       (__volget<_Indexes>(_M_bound_args), __args)...);
1316         }
1317
1318       // Call as volatile, return void
1319       template<typename _Res, typename... _Args, int... _Indexes>
1320         void
1321         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1322             typename __enable_if_void<_Res>::type = 0) volatile
1323         {
1324           _M_f(_Mu<_Bound_args>()
1325                (__volget<_Indexes>(_M_bound_args), __args)...);
1326         }
1327
1328       // Call as const volatile
1329       template<typename _Res, typename... _Args, int... _Indexes>
1330         _Result
1331         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1332             typename __disable_if_void<_Res>::type = 0) const volatile
1333         {
1334           return _M_f(_Mu<_Bound_args>()
1335                       (__volget<_Indexes>(_M_bound_args), __args)...);
1336         }
1337
1338       // Call as const volatile, return void
1339       template<typename _Res, typename... _Args, int... _Indexes>
1340         void
1341         __call(tuple<_Args...>&& __args,
1342                _Index_tuple<_Indexes...>,
1343             typename __enable_if_void<_Res>::type = 0) const volatile
1344         {
1345           _M_f(_Mu<_Bound_args>()
1346                (__volget<_Indexes>(_M_bound_args), __args)...);
1347         }
1348
1349     public:
1350       typedef _Result result_type;
1351
1352       template<typename... _Args>
1353         explicit _Bind_result(const _Functor& __f, _Args&&... __args)
1354         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1355         { }
1356
1357       template<typename... _Args>
1358         explicit _Bind_result(_Functor&& __f, _Args&&... __args)
1359         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1360         { }
1361
1362       _Bind_result(const _Bind_result&) = default;
1363
1364       _Bind_result(_Bind_result&& __b)
1365       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1366       { }
1367
1368       // Call unqualified
1369       template<typename... _Args>
1370         result_type
1371         operator()(_Args&&... __args)
1372         {
1373           return this->__call<_Result>(
1374               std::forward_as_tuple(std::forward<_Args>(__args)...),
1375               _Bound_indexes());
1376         }
1377
1378       // Call as const
1379       template<typename... _Args>
1380         result_type
1381         operator()(_Args&&... __args) const
1382         {
1383           return this->__call<_Result>(
1384               std::forward_as_tuple(std::forward<_Args>(__args)...),
1385               _Bound_indexes());
1386         }
1387
1388       // Call as volatile
1389       template<typename... _Args>
1390         result_type
1391         operator()(_Args&&... __args) volatile
1392         {
1393           return this->__call<_Result>(
1394               std::forward_as_tuple(std::forward<_Args>(__args)...),
1395               _Bound_indexes());
1396         }
1397
1398       // Call as const volatile
1399       template<typename... _Args>
1400         result_type
1401         operator()(_Args&&... __args) const volatile
1402         {
1403           return this->__call<_Result>(
1404               std::forward_as_tuple(std::forward<_Args>(__args)...),
1405               _Bound_indexes());
1406         }
1407     };
1408
1409   /**
1410    *  @brief Class template _Bind is always a bind expression.
1411    *  @ingroup binders
1412    */
1413   template<typename _Signature>
1414     struct is_bind_expression<_Bind<_Signature> >
1415     : public true_type { };
1416
1417   /**
1418    *  @brief Class template _Bind is always a bind expression.
1419    *  @ingroup binders
1420    */
1421   template<typename _Result, typename _Signature>
1422     struct is_bind_expression<_Bind_result<_Result, _Signature> >
1423     : public true_type { };
1424
1425   template<typename _Functor, typename... _ArgTypes>
1426     struct _Bind_helper
1427     {
1428       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1429         __maybe_type;
1430       typedef typename __maybe_type::type __functor_type;
1431       typedef _Bind<__functor_type(typename decay<_ArgTypes>::type...)> type;
1432     };
1433
1434   /**
1435    *  @brief Function template for std::bind.
1436    *  @ingroup binders
1437    */
1438   template<typename _Functor, typename... _ArgTypes>
1439     inline
1440     typename _Bind_helper<_Functor, _ArgTypes...>::type
1441     bind(_Functor&& __f, _ArgTypes&&... __args)
1442     {
1443       typedef _Bind_helper<_Functor, _ArgTypes...> __helper_type;
1444       typedef typename __helper_type::__maybe_type __maybe_type;
1445       typedef typename __helper_type::type __result_type;
1446       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1447                            std::forward<_ArgTypes>(__args)...);
1448     }
1449
1450   template<typename _Result, typename _Functor, typename... _ArgTypes>
1451     struct _Bindres_helper
1452     {
1453       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1454         __maybe_type;
1455       typedef typename __maybe_type::type __functor_type;
1456       typedef _Bind_result<_Result,
1457                            __functor_type(typename decay<_ArgTypes>::type...)>
1458         type;
1459     };
1460
1461   /**
1462    *  @brief Function template for std::bind<R>.
1463    *  @ingroup binders
1464    */
1465   template<typename _Result, typename _Functor, typename... _ArgTypes>
1466     inline
1467     typename _Bindres_helper<_Result, _Functor, _ArgTypes...>::type
1468     bind(_Functor&& __f, _ArgTypes&&... __args)
1469     {
1470       typedef _Bindres_helper<_Result, _Functor, _ArgTypes...> __helper_type;
1471       typedef typename __helper_type::__maybe_type __maybe_type;
1472       typedef typename __helper_type::type __result_type;
1473       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1474                            std::forward<_ArgTypes>(__args)...);
1475     }
1476
1477   /**
1478    *  @brief Exception class thrown when class template function's
1479    *  operator() is called with an empty target.
1480    *  @ingroup exceptions
1481    */
1482   class bad_function_call : public std::exception
1483   {
1484   public:
1485     virtual ~bad_function_call() throw();
1486   };
1487
1488   /**
1489    *  Trait identifying "location-invariant" types, meaning that the
1490    *  address of the object (or any of its members) will not escape.
1491    *  Also implies a trivial copy constructor and assignment operator.
1492    */
1493   template<typename _Tp>
1494     struct __is_location_invariant
1495     : integral_constant<bool, (is_pointer<_Tp>::value
1496                                || is_member_pointer<_Tp>::value)>
1497     { };
1498
1499   class _Undefined_class;
1500
1501   union _Nocopy_types
1502   {
1503     void*       _M_object;
1504     const void* _M_const_object;
1505     void (*_M_function_pointer)();
1506     void (_Undefined_class::*_M_member_pointer)();
1507   };
1508
1509   union _Any_data
1510   {
1511     void*       _M_access()       { return &_M_pod_data[0]; }
1512     const void* _M_access() const { return &_M_pod_data[0]; }
1513
1514     template<typename _Tp>
1515       _Tp&
1516       _M_access()
1517       { return *static_cast<_Tp*>(_M_access()); }
1518
1519     template<typename _Tp>
1520       const _Tp&
1521       _M_access() const
1522       { return *static_cast<const _Tp*>(_M_access()); }
1523
1524     _Nocopy_types _M_unused;
1525     char _M_pod_data[sizeof(_Nocopy_types)];
1526   };
1527
1528   enum _Manager_operation
1529   {
1530     __get_type_info,
1531     __get_functor_ptr,
1532     __clone_functor,
1533     __destroy_functor
1534   };
1535
1536   // Simple type wrapper that helps avoid annoying const problems
1537   // when casting between void pointers and pointers-to-pointers.
1538   template<typename _Tp>
1539     struct _Simple_type_wrapper
1540     {
1541       _Simple_type_wrapper(_Tp __value) : __value(__value) { }
1542
1543       _Tp __value;
1544     };
1545
1546   template<typename _Tp>
1547     struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
1548     : __is_location_invariant<_Tp>
1549     { };
1550
1551   // Converts a reference to a function object into a callable
1552   // function object.
1553   template<typename _Functor>
1554     inline _Functor&
1555     __callable_functor(_Functor& __f)
1556     { return __f; }
1557
1558   template<typename _Member, typename _Class>
1559     inline _Mem_fn<_Member _Class::*>
1560     __callable_functor(_Member _Class::* &__p)
1561     { return mem_fn(__p); }
1562
1563   template<typename _Member, typename _Class>
1564     inline _Mem_fn<_Member _Class::*>
1565     __callable_functor(_Member _Class::* const &__p)
1566     { return mem_fn(__p); }
1567
1568   template<typename _Signature>
1569     class function;
1570
1571   /// Base class of all polymorphic function object wrappers.
1572   class _Function_base
1573   {
1574   public:
1575     static const std::size_t _M_max_size = sizeof(_Nocopy_types);
1576     static const std::size_t _M_max_align = __alignof__(_Nocopy_types);
1577
1578     template<typename _Functor>
1579       class _Base_manager
1580       {
1581       protected:
1582         static const bool __stored_locally =
1583         (__is_location_invariant<_Functor>::value
1584          && sizeof(_Functor) <= _M_max_size
1585          && __alignof__(_Functor) <= _M_max_align
1586          && (_M_max_align % __alignof__(_Functor) == 0));
1587
1588         typedef integral_constant<bool, __stored_locally> _Local_storage;
1589
1590         // Retrieve a pointer to the function object
1591         static _Functor*
1592         _M_get_pointer(const _Any_data& __source)
1593         {
1594           const _Functor* __ptr =
1595             __stored_locally? std::__addressof(__source._M_access<_Functor>())
1596             /* have stored a pointer */ : __source._M_access<_Functor*>();
1597           return const_cast<_Functor*>(__ptr);
1598         }
1599
1600         // Clone a location-invariant function object that fits within
1601         // an _Any_data structure.
1602         static void
1603         _M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
1604         {
1605           new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
1606         }
1607
1608         // Clone a function object that is not location-invariant or
1609         // that cannot fit into an _Any_data structure.
1610         static void
1611         _M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
1612         {
1613           __dest._M_access<_Functor*>() =
1614             new _Functor(*__source._M_access<_Functor*>());
1615         }
1616
1617         // Destroying a location-invariant object may still require
1618         // destruction.
1619         static void
1620         _M_destroy(_Any_data& __victim, true_type)
1621         {
1622           __victim._M_access<_Functor>().~_Functor();
1623         }
1624
1625         // Destroying an object located on the heap.
1626         static void
1627         _M_destroy(_Any_data& __victim, false_type)
1628         {
1629           delete __victim._M_access<_Functor*>();
1630         }
1631
1632       public:
1633         static bool
1634         _M_manager(_Any_data& __dest, const _Any_data& __source,
1635                    _Manager_operation __op)
1636         {
1637           switch (__op)
1638             {
1639 #ifdef __GXX_RTTI
1640             case __get_type_info:
1641               __dest._M_access<const type_info*>() = &typeid(_Functor);
1642               break;
1643 #endif
1644             case __get_functor_ptr:
1645               __dest._M_access<_Functor*>() = _M_get_pointer(__source);
1646               break;
1647
1648             case __clone_functor:
1649               _M_clone(__dest, __source, _Local_storage());
1650               break;
1651
1652             case __destroy_functor:
1653               _M_destroy(__dest, _Local_storage());
1654               break;
1655             }
1656           return false;
1657         }
1658
1659         static void
1660         _M_init_functor(_Any_data& __functor, _Functor&& __f)
1661         { _M_init_functor(__functor, std::move(__f), _Local_storage()); }
1662
1663         template<typename _Signature>
1664           static bool
1665           _M_not_empty_function(const function<_Signature>& __f)
1666           { return static_cast<bool>(__f); }
1667
1668         template<typename _Tp>
1669           static bool
1670           _M_not_empty_function(const _Tp*& __fp)
1671           { return __fp; }
1672
1673         template<typename _Class, typename _Tp>
1674           static bool
1675           _M_not_empty_function(_Tp _Class::* const& __mp)
1676           { return __mp; }
1677
1678         template<typename _Tp>
1679           static bool
1680           _M_not_empty_function(const _Tp&)
1681           { return true; }
1682
1683       private:
1684         static void
1685         _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
1686         { new (__functor._M_access()) _Functor(std::move(__f)); }
1687
1688         static void
1689         _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
1690         { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
1691       };
1692
1693     template<typename _Functor>
1694       class _Ref_manager : public _Base_manager<_Functor*>
1695       {
1696         typedef _Function_base::_Base_manager<_Functor*> _Base;
1697
1698     public:
1699         static bool
1700         _M_manager(_Any_data& __dest, const _Any_data& __source,
1701                    _Manager_operation __op)
1702         {
1703           switch (__op)
1704             {
1705 #ifdef __GXX_RTTI
1706             case __get_type_info:
1707               __dest._M_access<const type_info*>() = &typeid(_Functor);
1708               break;
1709 #endif
1710             case __get_functor_ptr:
1711               __dest._M_access<_Functor*>() = *_Base::_M_get_pointer(__source);
1712               return is_const<_Functor>::value;
1713               break;
1714
1715             default:
1716               _Base::_M_manager(__dest, __source, __op);
1717             }
1718           return false;
1719         }
1720
1721         static void
1722         _M_init_functor(_Any_data& __functor, reference_wrapper<_Functor> __f)
1723         {
1724           // TBD: Use address_of function instead.
1725           _Base::_M_init_functor(__functor, &__f.get());
1726         }
1727       };
1728
1729     _Function_base() : _M_manager(0) { }
1730
1731     ~_Function_base()
1732     {
1733       if (_M_manager)
1734         _M_manager(_M_functor, _M_functor, __destroy_functor);
1735     }
1736
1737
1738     bool _M_empty() const { return !_M_manager; }
1739
1740     typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
1741                                   _Manager_operation);
1742
1743     _Any_data     _M_functor;
1744     _Manager_type _M_manager;
1745   };
1746
1747   template<typename _Signature, typename _Functor>
1748     class _Function_handler;
1749
1750   template<typename _Res, typename _Functor, typename... _ArgTypes>
1751     class _Function_handler<_Res(_ArgTypes...), _Functor>
1752     : public _Function_base::_Base_manager<_Functor>
1753     {
1754       typedef _Function_base::_Base_manager<_Functor> _Base;
1755
1756     public:
1757       static _Res
1758       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1759       {
1760         return (*_Base::_M_get_pointer(__functor))(
1761             std::forward<_ArgTypes>(__args)...);
1762       }
1763     };
1764
1765   template<typename _Functor, typename... _ArgTypes>
1766     class _Function_handler<void(_ArgTypes...), _Functor>
1767     : public _Function_base::_Base_manager<_Functor>
1768     {
1769       typedef _Function_base::_Base_manager<_Functor> _Base;
1770
1771      public:
1772       static void
1773       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1774       {
1775         (*_Base::_M_get_pointer(__functor))(
1776             std::forward<_ArgTypes>(__args)...);
1777       }
1778     };
1779
1780   template<typename _Res, typename _Functor, typename... _ArgTypes>
1781     class _Function_handler<_Res(_ArgTypes...), reference_wrapper<_Functor> >
1782     : public _Function_base::_Ref_manager<_Functor>
1783     {
1784       typedef _Function_base::_Ref_manager<_Functor> _Base;
1785
1786      public:
1787       static _Res
1788       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1789       {
1790         return __callable_functor(**_Base::_M_get_pointer(__functor))(
1791               std::forward<_ArgTypes>(__args)...);
1792       }
1793     };
1794
1795   template<typename _Functor, typename... _ArgTypes>
1796     class _Function_handler<void(_ArgTypes...), reference_wrapper<_Functor> >
1797     : public _Function_base::_Ref_manager<_Functor>
1798     {
1799       typedef _Function_base::_Ref_manager<_Functor> _Base;
1800
1801      public:
1802       static void
1803       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1804       {
1805         __callable_functor(**_Base::_M_get_pointer(__functor))(
1806             std::forward<_ArgTypes>(__args)...);
1807       }
1808     };
1809
1810   template<typename _Class, typename _Member, typename _Res,
1811            typename... _ArgTypes>
1812     class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
1813     : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
1814     {
1815       typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
1816         _Base;
1817
1818      public:
1819       static _Res
1820       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1821       {
1822         return mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1823             std::forward<_ArgTypes>(__args)...);
1824       }
1825     };
1826
1827   template<typename _Class, typename _Member, typename... _ArgTypes>
1828     class _Function_handler<void(_ArgTypes...), _Member _Class::*>
1829     : public _Function_base::_Base_manager<
1830                  _Simple_type_wrapper< _Member _Class::* > >
1831     {
1832       typedef _Member _Class::* _Functor;
1833       typedef _Simple_type_wrapper<_Functor> _Wrapper;
1834       typedef _Function_base::_Base_manager<_Wrapper> _Base;
1835
1836      public:
1837       static bool
1838       _M_manager(_Any_data& __dest, const _Any_data& __source,
1839                  _Manager_operation __op)
1840       {
1841         switch (__op)
1842           {
1843 #ifdef __GXX_RTTI
1844           case __get_type_info:
1845             __dest._M_access<const type_info*>() = &typeid(_Functor);
1846             break;
1847 #endif
1848           case __get_functor_ptr:
1849             __dest._M_access<_Functor*>() =
1850               &_Base::_M_get_pointer(__source)->__value;
1851             break;
1852
1853           default:
1854             _Base::_M_manager(__dest, __source, __op);
1855           }
1856         return false;
1857       }
1858
1859       static void
1860       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1861       {
1862         mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1863             std::forward<_ArgTypes>(__args)...);
1864       }
1865     };
1866
1867   /**
1868    *  @brief Primary class template for std::function.
1869    *  @ingroup functors
1870    *
1871    *  Polymorphic function wrapper.
1872    */
1873   template<typename _Res, typename... _ArgTypes>
1874     class function<_Res(_ArgTypes...)>
1875     : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
1876       private _Function_base
1877     {
1878       typedef _Res _Signature_type(_ArgTypes...);
1879
1880       struct _Useless { };
1881
1882     public:
1883       typedef _Res result_type;
1884
1885       // [3.7.2.1] construct/copy/destroy
1886
1887       /**
1888        *  @brief Default construct creates an empty function call wrapper.
1889        *  @post @c !(bool)*this
1890        */
1891       function() : _Function_base() { }
1892
1893       /**
1894        *  @brief Creates an empty function call wrapper.
1895        *  @post @c !(bool)*this
1896        */
1897       function(nullptr_t) : _Function_base() { }
1898
1899       /**
1900        *  @brief %Function copy constructor.
1901        *  @param x A %function object with identical call signature.
1902        *  @post @c (bool)*this == (bool)x
1903        *
1904        *  The newly-created %function contains a copy of the target of @a
1905        *  x (if it has one).
1906        */
1907       function(const function& __x);
1908
1909       /**
1910        *  @brief %Function move constructor.
1911        *  @param x A %function object rvalue with identical call signature.
1912        *
1913        *  The newly-created %function contains the target of @a x
1914        *  (if it has one).
1915        */
1916       function(function&& __x) : _Function_base()
1917       {
1918         __x.swap(*this);
1919       }
1920
1921       // TODO: needs allocator_arg_t
1922
1923       /**
1924        *  @brief Builds a %function that targets a copy of the incoming
1925        *  function object.
1926        *  @param f A %function object that is callable with parameters of
1927        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
1928        *  to @c Res.
1929        *
1930        *  The newly-created %function object will target a copy of @a
1931        *  f. If @a f is @c reference_wrapper<F>, then this function
1932        *  object will contain a reference to the function object @c
1933        *  f.get(). If @a f is a NULL function pointer or NULL
1934        *  pointer-to-member, the newly-created object will be empty.
1935        *
1936        *  If @a f is a non-NULL function pointer or an object of type @c
1937        *  reference_wrapper<F>, this function will not throw.
1938        */
1939       template<typename _Functor>
1940         function(_Functor __f,
1941                  typename enable_if<
1942                            !is_integral<_Functor>::value, _Useless>::type
1943                    = _Useless());
1944
1945       /**
1946        *  @brief %Function assignment operator.
1947        *  @param x A %function with identical call signature.
1948        *  @post @c (bool)*this == (bool)x
1949        *  @returns @c *this
1950        *
1951        *  The target of @a x is copied 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=(const function& __x)
1959       {
1960         function(__x).swap(*this);
1961         return *this;
1962       }
1963
1964       /**
1965        *  @brief %Function move-assignment operator.
1966        *  @param x A %function rvalue with identical call signature.
1967        *  @returns @c *this
1968        *
1969        *  The target of @a x is moved to @c *this. If @a x has no
1970        *  target, then @c *this will be empty.
1971        *
1972        *  If @a x targets a function pointer or a reference to a function
1973        *  object, then this operation will not throw an %exception.
1974        */
1975       function&
1976       operator=(function&& __x)
1977       {
1978         function(std::move(__x)).swap(*this);
1979         return *this;
1980       }
1981
1982       /**
1983        *  @brief %Function assignment to zero.
1984        *  @post @c !(bool)*this
1985        *  @returns @c *this
1986        *
1987        *  The target of @c *this is deallocated, leaving it empty.
1988        */
1989       function&
1990       operator=(nullptr_t)
1991       {
1992         if (_M_manager)
1993           {
1994             _M_manager(_M_functor, _M_functor, __destroy_functor);
1995             _M_manager = 0;
1996             _M_invoker = 0;
1997           }
1998         return *this;
1999       }
2000
2001       /**
2002        *  @brief %Function assignment to a new target.
2003        *  @param f A %function object that is callable with parameters of
2004        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
2005        *  to @c Res.
2006        *  @return @c *this
2007        *
2008        *  This  %function object wrapper will target a copy of @a
2009        *  f. If @a f is @c reference_wrapper<F>, then this function
2010        *  object will contain a reference to the function object @c
2011        *  f.get(). If @a f is a NULL function pointer or NULL
2012        *  pointer-to-member, @c this object will be empty.
2013        *
2014        *  If @a f is a non-NULL function pointer or an object of type @c
2015        *  reference_wrapper<F>, this function will not throw.
2016        */
2017       template<typename _Functor>
2018         typename enable_if<!is_integral<_Functor>::value, function&>::type
2019         operator=(_Functor&& __f)
2020         {
2021           function(std::forward<_Functor>(__f)).swap(*this);
2022           return *this;
2023         }
2024
2025       /// @overload
2026       template<typename _Functor>
2027         typename enable_if<!is_integral<_Functor>::value, function&>::type
2028         operator=(reference_wrapper<_Functor> __f)
2029         {
2030           function(__f).swap(*this);
2031           return *this;
2032         }
2033
2034       // [3.7.2.2] function modifiers
2035
2036       /**
2037        *  @brief Swap the targets of two %function objects.
2038        *  @param f A %function with identical call signature.
2039        *
2040        *  Swap the targets of @c this function object and @a f. This
2041        *  function will not throw an %exception.
2042        */
2043       void swap(function& __x)
2044       {
2045         std::swap(_M_functor, __x._M_functor);
2046         std::swap(_M_manager, __x._M_manager);
2047         std::swap(_M_invoker, __x._M_invoker);
2048       }
2049
2050       // TODO: needs allocator_arg_t
2051       /*
2052       template<typename _Functor, typename _Alloc>
2053         void
2054         assign(_Functor&& __f, const _Alloc& __a)
2055         {
2056           function(allocator_arg, __a,
2057                    std::forward<_Functor>(__f)).swap(*this);
2058         }
2059       */
2060
2061       // [3.7.2.3] function capacity
2062
2063       /**
2064        *  @brief Determine if the %function wrapper has a target.
2065        *
2066        *  @return @c true when this %function object contains a target,
2067        *  or @c false when it is empty.
2068        *
2069        *  This function will not throw an %exception.
2070        */
2071       explicit operator bool() const
2072       { return !_M_empty(); }
2073
2074       // [3.7.2.4] function invocation
2075
2076       /**
2077        *  @brief Invokes the function targeted by @c *this.
2078        *  @returns the result of the target.
2079        *  @throws bad_function_call when @c !(bool)*this
2080        *
2081        *  The function call operator invokes the target function object
2082        *  stored by @c this.
2083        */
2084       _Res operator()(_ArgTypes... __args) const;
2085
2086 #ifdef __GXX_RTTI
2087       // [3.7.2.5] function target access
2088       /**
2089        *  @brief Determine the type of the target of this function object
2090        *  wrapper.
2091        *
2092        *  @returns the type identifier of the target function object, or
2093        *  @c typeid(void) if @c !(bool)*this.
2094        *
2095        *  This function will not throw an %exception.
2096        */
2097       const type_info& target_type() const;
2098
2099       /**
2100        *  @brief Access the stored target function object.
2101        *
2102        *  @return Returns a pointer to the stored target function object,
2103        *  if @c typeid(Functor).equals(target_type()); otherwise, a NULL
2104        *  pointer.
2105        *
2106        * This function will not throw an %exception.
2107        */
2108       template<typename _Functor>       _Functor* target();
2109
2110       /// @overload
2111       template<typename _Functor> const _Functor* target() const;
2112 #endif
2113
2114     private:
2115       typedef _Res (*_Invoker_type)(const _Any_data&, _ArgTypes...);
2116       _Invoker_type _M_invoker;
2117   };
2118
2119   // Out-of-line member definitions.
2120   template<typename _Res, typename... _ArgTypes>
2121     function<_Res(_ArgTypes...)>::
2122     function(const function& __x)
2123     : _Function_base()
2124     {
2125       if (static_cast<bool>(__x))
2126         {
2127           _M_invoker = __x._M_invoker;
2128           _M_manager = __x._M_manager;
2129           __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
2130         }
2131     }
2132
2133   template<typename _Res, typename... _ArgTypes>
2134     template<typename _Functor>
2135       function<_Res(_ArgTypes...)>::
2136       function(_Functor __f,
2137                typename enable_if<
2138                         !is_integral<_Functor>::value, _Useless>::type)
2139       : _Function_base()
2140       {
2141         typedef _Function_handler<_Signature_type, _Functor> _My_handler;
2142
2143         if (_My_handler::_M_not_empty_function(__f))
2144           {
2145             _M_invoker = &_My_handler::_M_invoke;
2146             _M_manager = &_My_handler::_M_manager;
2147             _My_handler::_M_init_functor(_M_functor, std::move(__f));
2148           }
2149       }
2150
2151   template<typename _Res, typename... _ArgTypes>
2152     _Res
2153     function<_Res(_ArgTypes...)>::
2154     operator()(_ArgTypes... __args) const
2155     {
2156       if (_M_empty())
2157         __throw_bad_function_call();
2158       return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
2159     }
2160
2161 #ifdef __GXX_RTTI
2162   template<typename _Res, typename... _ArgTypes>
2163     const type_info&
2164     function<_Res(_ArgTypes...)>::
2165     target_type() const
2166     {
2167       if (_M_manager)
2168         {
2169           _Any_data __typeinfo_result;
2170           _M_manager(__typeinfo_result, _M_functor, __get_type_info);
2171           return *__typeinfo_result._M_access<const type_info*>();
2172         }
2173       else
2174         return typeid(void);
2175     }
2176
2177   template<typename _Res, typename... _ArgTypes>
2178     template<typename _Functor>
2179       _Functor*
2180       function<_Res(_ArgTypes...)>::
2181       target()
2182       {
2183         if (typeid(_Functor) == target_type() && _M_manager)
2184           {
2185             _Any_data __ptr;
2186             if (_M_manager(__ptr, _M_functor, __get_functor_ptr)
2187                 && !is_const<_Functor>::value)
2188               return 0;
2189             else
2190               return __ptr._M_access<_Functor*>();
2191           }
2192         else
2193           return 0;
2194       }
2195
2196   template<typename _Res, typename... _ArgTypes>
2197     template<typename _Functor>
2198       const _Functor*
2199       function<_Res(_ArgTypes...)>::
2200       target() const
2201       {
2202         if (typeid(_Functor) == target_type() && _M_manager)
2203           {
2204             _Any_data __ptr;
2205             _M_manager(__ptr, _M_functor, __get_functor_ptr);
2206             return __ptr._M_access<const _Functor*>();
2207           }
2208         else
2209           return 0;
2210       }
2211 #endif
2212
2213   // [20.7.15.2.6] null pointer comparisons
2214
2215   /**
2216    *  @brief Compares a polymorphic function object wrapper against 0
2217    *  (the NULL pointer).
2218    *  @returns @c true if the wrapper has no target, @c false 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   /**
2234    *  @brief Compares a polymorphic function object wrapper against 0
2235    *  (the NULL pointer).
2236    *  @returns @c false if the wrapper has no target, @c true otherwise
2237    *
2238    *  This function will not throw an %exception.
2239    */
2240   template<typename _Res, typename... _Args>
2241     inline bool
2242     operator!=(const function<_Res(_Args...)>& __f, nullptr_t)
2243     { return static_cast<bool>(__f); }
2244
2245   /// @overload
2246   template<typename _Res, typename... _Args>
2247     inline bool
2248     operator!=(nullptr_t, const function<_Res(_Args...)>& __f)
2249     { return static_cast<bool>(__f); }
2250
2251   // [20.7.15.2.7] specialized algorithms
2252
2253   /**
2254    *  @brief Swap the targets of two polymorphic function object wrappers.
2255    *
2256    *  This function will not throw an %exception.
2257    */
2258   template<typename _Res, typename... _Args>
2259     inline void
2260     swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y)
2261     { __x.swap(__y); }
2262
2263 _GLIBCXX_END_NAMESPACE_VERSION
2264 } // namespace std
2265
2266 #endif // __GXX_EXPERIMENTAL_CXX0X__
2267
2268 #endif // _GLIBCXX_FUNCTIONAL