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   /// Turns a function type into a function pointer type
 216   template<typename _Tp, bool _IsFunctionType = is_function<_Tp>::value>
 217     struct _Function_to_function_pointer
 218     {
 219       typedef _Tp type;
 220     };
 221
 222   template<typename _Tp>
 223     struct _Function_to_function_pointer<_Tp, true>
 224     {
 225       typedef _Tp* type;
 226     };
 227
 228   /**
 229    * Invoke a function object, which may be either a member pointer or a
 230    * function object. The first parameter will tell which.
 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 __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   // Not a unary_function or binary_function, so try a weak result type.
 267   template<typename _Tp>
 268     struct _Reference_wrapper_base_impl<false, false, _Tp>
 269     : _Weak_result_type<_Tp>
 270     { };
 271
 272   // unary_function but not binary_function
 273   template<typename _Tp>
 274     struct _Reference_wrapper_base_impl<true, false, _Tp>
 275     : unary_function<typename _Tp::argument_type,
 276                      typename _Tp::result_type>
 277     { };
 278
 279   // binary_function but not unary_function
 280   template<typename _Tp>
 281     struct _Reference_wrapper_base_impl<false, true, _Tp>
 282     : binary_function<typename _Tp::first_argument_type,
 283                       typename _Tp::second_argument_type,
 284                       typename _Tp::result_type>
 285     { };
 286
 287   // Both unary_function and binary_function. Import result_type to
 288   // avoid conflicts.
 289    template<typename _Tp>
 290     struct _Reference_wrapper_base_impl<true, true, _Tp>
 291     : unary_function<typename _Tp::argument_type,
 292                      typename _Tp::result_type>,
 293       binary_function<typename _Tp::first_argument_type,
 294                       typename _Tp::second_argument_type,
 295                       typename _Tp::result_type>
 296     {
 297       typedef typename _Tp::result_type result_type;
 298     };
 299
 300   /**
 301    *  Derives from unary_function or binary_function when it
 302    *  can. Specializations handle all of the easy cases. The primary
 303    *  template determines what to do with a class type, which may
 304    *  derive from both unary_function and binary_function.
 305   */
 306   template<typename _Tp>
 307     struct _Reference_wrapper_base
 308     : _Reference_wrapper_base_impl<
 309       _Derives_from_unary_function<_Tp>::value,
 310       _Derives_from_binary_function<_Tp>::value,
 311       _Tp>
 312     { };
 313
 314   // - a function type (unary)
 315   template<typename _Res, typename _T1>
 316     struct _Reference_wrapper_base<_Res(_T1)>
 317     : unary_function<_T1, _Res>
 318     { };
 319
 320   template<typename _Res, typename _T1>
 321     struct _Reference_wrapper_base<_Res(_T1) const>
 322     : unary_function<_T1, _Res>
 323     { };
 324
 325   template<typename _Res, typename _T1>
 326     struct _Reference_wrapper_base<_Res(_T1) volatile>
 327     : unary_function<_T1, _Res>
 328     { };
 329
 330   template<typename _Res, typename _T1>
 331     struct _Reference_wrapper_base<_Res(_T1) const volatile>
 332     : unary_function<_T1, _Res>
 333     { };
 334
 335   // - a function type (binary)
 336   template<typename _Res, typename _T1, typename _T2>
 337     struct _Reference_wrapper_base<_Res(_T1, _T2)>
 338     : binary_function<_T1, _T2, _Res>
 339     { };
 340
 341   template<typename _Res, typename _T1, typename _T2>
 342     struct _Reference_wrapper_base<_Res(_T1, _T2) const>
 343     : binary_function<_T1, _T2, _Res>
 344     { };
 345
 346   template<typename _Res, typename _T1, typename _T2>
 347     struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
 348     : binary_function<_T1, _T2, _Res>
 349     { };
 350
 351   template<typename _Res, typename _T1, typename _T2>
 352     struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
 353     : binary_function<_T1, _T2, _Res>
 354     { };
 355
 356   // - a function pointer type (unary)
 357   template<typename _Res, typename _T1>
 358     struct _Reference_wrapper_base<_Res(*)(_T1)>
 359     : unary_function<_T1, _Res>
 360     { };
 361
 362   // - a function pointer type (binary)
 363   template<typename _Res, typename _T1, typename _T2>
 364     struct _Reference_wrapper_base<_Res(*)(_T1, _T2)>
 365     : binary_function<_T1, _T2, _Res>
 366     { };
 367
 368   // - a pointer to member function type (unary, no qualifiers)
 369   template<typename _Res, typename _T1>
 370     struct _Reference_wrapper_base<_Res (_T1::*)()>
 371     : unary_function<_T1*, _Res>
 372     { };
 373
 374   // - a pointer to member function type (binary, no qualifiers)
 375   template<typename _Res, typename _T1, typename _T2>
 376     struct _Reference_wrapper_base<_Res (_T1::*)(_T2)>
 377     : binary_function<_T1*, _T2, _Res>
 378     { };
 379
 380   // - a pointer to member function type (unary, const)
 381   template<typename _Res, typename _T1>
 382     struct _Reference_wrapper_base<_Res (_T1::*)() const>
 383     : unary_function<const _T1*, _Res>
 384     { };
 385
 386   // - a pointer to member function type (binary, const)
 387   template<typename _Res, typename _T1, typename _T2>
 388     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const>
 389     : binary_function<const _T1*, _T2, _Res>
 390     { };
 391
 392   // - a pointer to member function type (unary, volatile)
 393   template<typename _Res, typename _T1>
 394     struct _Reference_wrapper_base<_Res (_T1::*)() volatile>
 395     : unary_function<volatile _T1*, _Res>
 396     { };
 397
 398   // - a pointer to member function type (binary, volatile)
 399   template<typename _Res, typename _T1, typename _T2>
 400     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) volatile>
 401     : binary_function<volatile _T1*, _T2, _Res>
 402     { };
 403
 404   // - a pointer to member function type (unary, const volatile)
 405   template<typename _Res, typename _T1>
 406     struct _Reference_wrapper_base<_Res (_T1::*)() const volatile>
 407     : unary_function<const volatile _T1*, _Res>
 408     { };
 409
 410   // - a pointer to member function type (binary, const volatile)
 411   template<typename _Res, typename _T1, typename _T2>
 412     struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const volatile>
 413     : binary_function<const volatile _T1*, _T2, _Res>
 414     { };
 415
 416   /**
 417    *  @brief Primary class template for reference_wrapper.
 418    *  @ingroup functors
 419    *  @{
 420    */
 421   template<typename _Tp>
 422     class reference_wrapper
 423     : public _Reference_wrapper_base<typename remove_cv<_Tp>::type>
 424     {
 425       // If _Tp is a function type, we can't form result_of<_Tp(...)>,
 426       // so turn it into a function pointer type.
 427       typedef typename _Function_to_function_pointer<_Tp>::type
 428         _M_func_type;
 429
 430       _Tp* _M_data;
 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<_M_func_type(_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   /// Partial specialization.
 480   template<typename _Tp>
 481     inline reference_wrapper<_Tp>
 482     ref(reference_wrapper<_Tp> __t)
 483     { return ref(__t.get()); }
 484
 485   /// Partial specialization.
 486   template<typename _Tp>
 487     inline reference_wrapper<const _Tp>
 488     cref(reference_wrapper<_Tp> __t)
 489     { return cref(__t.get()); }
 490
 491   // @} group functors
 492
 493   template<typename _MemberPointer>
 494     class _Mem_fn;
 495
 496   /**
 497    * Derives from @c unary_function or @c binary_function, or perhaps
 498    * nothing, depending on the number of arguments provided. The
 499    * primary template is the basis case, which derives nothing.
 500    */
 501   template<typename _Res, typename... _ArgTypes>
 502     struct _Maybe_unary_or_binary_function { };
 503
 504   /// Derives from @c unary_function, as appropriate.
 505   template<typename _Res, typename _T1>
 506     struct _Maybe_unary_or_binary_function<_Res, _T1>
 507     : std::unary_function<_T1, _Res> { };
 508
 509   /// Derives from @c binary_function, as appropriate.
 510   template<typename _Res, typename _T1, typename _T2>
 511     struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
 512     : std::binary_function<_T1, _T2, _Res> { };
 513
 514   /// Implementation of @c mem_fn for member function pointers.
 515   template<typename _Res, typename _Class, typename... _ArgTypes>
 516     class _Mem_fn<_Res (_Class::*)(_ArgTypes...)>
 517     : public _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>
 518     {
 519       typedef _Res (_Class::*_Functor)(_ArgTypes...);
 520
 521       template<typename _Tp>
 522         _Res
 523         _M_call(_Tp& __object, const volatile _Class *,
 524                 _ArgTypes... __args) const
 525         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 526
 527       template<typename _Tp>
 528         _Res
 529         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 530         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 531
 532     public:
 533       typedef _Res result_type;
 534
 535       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 536
 537       // Handle objects
 538       _Res
 539       operator()(_Class& __object, _ArgTypes... __args) const
 540       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 541
 542       // Handle pointers
 543       _Res
 544       operator()(_Class* __object, _ArgTypes... __args) const
 545       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 546
 547       // Handle smart pointers, references and pointers to derived
 548       template<typename _Tp>
 549         _Res
 550         operator()(_Tp& __object, _ArgTypes... __args) const
 551         {
 552           return _M_call(__object, &__object,
 553               std::forward<_ArgTypes>(__args)...);
 554         }
 555
 556     private:
 557       _Functor __pmf;
 558     };
 559
 560   /// Implementation of @c mem_fn for const member function pointers.
 561   template<typename _Res, typename _Class, typename... _ArgTypes>
 562     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const>
 563     : public _Maybe_unary_or_binary_function<_Res, const _Class*,
 564                                              _ArgTypes...>
 565     {
 566       typedef _Res (_Class::*_Functor)(_ArgTypes...) const;
 567
 568       template<typename _Tp>
 569         _Res
 570         _M_call(_Tp& __object, const volatile _Class *,
 571                 _ArgTypes... __args) const
 572         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 573
 574       template<typename _Tp>
 575         _Res
 576         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 577         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 578
 579     public:
 580       typedef _Res result_type;
 581
 582       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 583
 584       // Handle objects
 585       _Res
 586       operator()(const _Class& __object, _ArgTypes... __args) const
 587       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 588
 589       // Handle pointers
 590       _Res
 591       operator()(const _Class* __object, _ArgTypes... __args) const
 592       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 593
 594       // Handle smart pointers, references and pointers to derived
 595       template<typename _Tp>
 596         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 597         {
 598           return _M_call(__object, &__object,
 599               std::forward<_ArgTypes>(__args)...);
 600         }
 601
 602     private:
 603       _Functor __pmf;
 604     };
 605
 606   /// Implementation of @c mem_fn for volatile member function pointers.
 607   template<typename _Res, typename _Class, typename... _ArgTypes>
 608     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) volatile>
 609     : public _Maybe_unary_or_binary_function<_Res, volatile _Class*,
 610                                              _ArgTypes...>
 611     {
 612       typedef _Res (_Class::*_Functor)(_ArgTypes...) volatile;
 613
 614       template<typename _Tp>
 615         _Res
 616         _M_call(_Tp& __object, const volatile _Class *,
 617                 _ArgTypes... __args) const
 618         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 619
 620       template<typename _Tp>
 621         _Res
 622         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 623         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 624
 625     public:
 626       typedef _Res result_type;
 627
 628       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 629
 630       // Handle objects
 631       _Res
 632       operator()(volatile _Class& __object, _ArgTypes... __args) const
 633       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 634
 635       // Handle pointers
 636       _Res
 637       operator()(volatile _Class* __object, _ArgTypes... __args) const
 638       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 639
 640       // Handle smart pointers, references and pointers to derived
 641       template<typename _Tp>
 642         _Res
 643         operator()(_Tp& __object, _ArgTypes... __args) const
 644         {
 645           return _M_call(__object, &__object,
 646               std::forward<_ArgTypes>(__args)...);
 647         }
 648
 649     private:
 650       _Functor __pmf;
 651     };
 652
 653   /// Implementation of @c mem_fn for const volatile member function pointers.
 654   template<typename _Res, typename _Class, typename... _ArgTypes>
 655     class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const volatile>
 656     : public _Maybe_unary_or_binary_function<_Res, const volatile _Class*,
 657                                              _ArgTypes...>
 658     {
 659       typedef _Res (_Class::*_Functor)(_ArgTypes...) const volatile;
 660
 661       template<typename _Tp>
 662         _Res
 663         _M_call(_Tp& __object, const volatile _Class *,
 664                 _ArgTypes... __args) const
 665         { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 666
 667       template<typename _Tp>
 668         _Res
 669         _M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
 670         { return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
 671
 672     public:
 673       typedef _Res result_type;
 674
 675       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 676
 677       // Handle objects
 678       _Res
 679       operator()(const volatile _Class& __object, _ArgTypes... __args) const
 680       { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
 681
 682       // Handle pointers
 683       _Res
 684       operator()(const volatile _Class* __object, _ArgTypes... __args) const
 685       { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
 686
 687       // Handle smart pointers, references and pointers to derived
 688       template<typename _Tp>
 689         _Res operator()(_Tp& __object, _ArgTypes... __args) const
 690         {
 691           return _M_call(__object, &__object,
 692               std::forward<_ArgTypes>(__args)...);
 693         }
 694
 695     private:
 696       _Functor __pmf;
 697     };
 698
 699
 700   template<typename _Tp, bool>
 701     struct _Mem_fn_const_or_non
 702     {
 703       typedef const _Tp& type;
 704     };
 705
 706   template<typename _Tp>
 707     struct _Mem_fn_const_or_non<_Tp, false>
 708     {
 709       typedef _Tp& type;
 710     };
 711
 712   template<typename _Res, typename _Class>
 713     class _Mem_fn<_Res _Class::*>
 714     {
 715       // This bit of genius is due to Peter Dimov, improved slightly by
 716       // Douglas Gregor.
 717       template<typename _Tp>
 718         _Res&
 719         _M_call(_Tp& __object, _Class *) const
 720         { return __object.*__pm; }
 721
 722       template<typename _Tp, typename _Up>
 723         _Res&
 724         _M_call(_Tp& __object, _Up * const *) const
 725         { return (*__object).*__pm; }
 726
 727       template<typename _Tp, typename _Up>
 728         const _Res&
 729         _M_call(_Tp& __object, const _Up * const *) const
 730         { return (*__object).*__pm; }
 731
 732       template<typename _Tp>
 733         const _Res&
 734         _M_call(_Tp& __object, const _Class *) const
 735         { return __object.*__pm; }
 736
 737       template<typename _Tp>
 738         const _Res&
 739         _M_call(_Tp& __ptr, const volatile void*) const
 740         { return (*__ptr).*__pm; }
 741
 742       template<typename _Tp> static _Tp& __get_ref();
 743
 744       template<typename _Tp>
 745         static __sfinae_types::__one __check_const(_Tp&, _Class*);
 746       template<typename _Tp, typename _Up>
 747         static __sfinae_types::__one __check_const(_Tp&, _Up * const *);
 748       template<typename _Tp, typename _Up>
 749         static __sfinae_types::__two __check_const(_Tp&, const _Up * const *);
 750       template<typename _Tp>
 751         static __sfinae_types::__two __check_const(_Tp&, const _Class*);
 752       template<typename _Tp>
 753         static __sfinae_types::__two __check_const(_Tp&, const volatile void*);
 754
 755     public:
 756       template<typename _Tp>
 757         struct _Result_type
 758         : _Mem_fn_const_or_non<_Res,
 759           (sizeof(__sfinae_types::__two)
 760            == sizeof(__check_const<_Tp>(__get_ref<_Tp>(), (_Tp*)0)))>
 761         { };
 762
 763       template<typename _Signature>
 764         struct result;
 765
 766       template<typename _CVMem, typename _Tp>
 767         struct result<_CVMem(_Tp)>
 768         : public _Result_type<_Tp> { };
 769
 770       template<typename _CVMem, typename _Tp>
 771         struct result<_CVMem(_Tp&)>
 772         : public _Result_type<_Tp> { };
 773
 774       explicit
 775       _Mem_fn(_Res _Class::*__pm) : __pm(__pm) { }
 776
 777       // Handle objects
 778       _Res&
 779       operator()(_Class& __object) const
 780       { return __object.*__pm; }
 781
 782       const _Res&
 783       operator()(const _Class& __object) const
 784       { return __object.*__pm; }
 785
 786       // Handle pointers
 787       _Res&
 788       operator()(_Class* __object) const
 789       { return __object->*__pm; }
 790
 791       const _Res&
 792       operator()(const _Class* __object) const
 793       { return __object->*__pm; }
 794
 795       // Handle smart pointers and derived
 796       template<typename _Tp>
 797         typename _Result_type<_Tp>::type
 798         operator()(_Tp& __unknown) const
 799         { return _M_call(__unknown, &__unknown); }
 800
 801     private:
 802       _Res _Class::*__pm;
 803     };
 804
 805   /**
 806    *  @brief Returns a function object that forwards to the member
 807    *  pointer @a pm.
 808    *  @ingroup functors
 809    */
 810   template<typename _Tp, typename _Class>
 811     inline _Mem_fn<_Tp _Class::*>
 812     mem_fn(_Tp _Class::* __pm)
 813     {
 814       return _Mem_fn<_Tp _Class::*>(__pm);
 815     }
 816
 817   /**
 818    *  @brief Determines if the given type _Tp is a function object
 819    *  should be treated as a subexpression when evaluating calls to
 820    *  function objects returned by bind(). [TR1 3.6.1]
 821    *  @ingroup binders
 822    */
 823   template<typename _Tp>
 824     struct is_bind_expression
 825     : public false_type { };
 826
 827   /**
 828    *  @brief Determines if the given type _Tp is a placeholder in a
 829    *  bind() expression and, if so, which placeholder it is. [TR1 3.6.2]
 830    *  @ingroup binders
 831    */
 832   template<typename _Tp>
 833     struct is_placeholder
 834     : public integral_constant<int, 0>
 835     { };
 836
 837   /// The type of placeholder objects defined by libstdc++.
 838   template<int _Num> struct _Placeholder { };
 839
 840   _GLIBCXX_END_NAMESPACE_VERSION
 841
 842   /** @namespace std::placeholders
 843    *  @brief ISO C++ 0x entities sub namespace for functional.
 844    *  @ingroup binders
 845    *
 846    *  Define a large number of placeholders. There is no way to
 847    *  simplify this with variadic templates, because we're introducing
 848    *  unique names for each.
 849    */
 850   namespace placeholders
 851   {
 852   _GLIBCXX_BEGIN_NAMESPACE_VERSION
 853     extern const _Placeholder<1> _1;
 854     extern const _Placeholder<2> _2;
 855     extern const _Placeholder<3> _3;
 856     extern const _Placeholder<4> _4;
 857     extern const _Placeholder<5> _5;
 858     extern const _Placeholder<6> _6;
 859     extern const _Placeholder<7> _7;
 860     extern const _Placeholder<8> _8;
 861     extern const _Placeholder<9> _9;
 862     extern const _Placeholder<10> _10;
 863     extern const _Placeholder<11> _11;
 864     extern const _Placeholder<12> _12;
 865     extern const _Placeholder<13> _13;
 866     extern const _Placeholder<14> _14;
 867     extern const _Placeholder<15> _15;
 868     extern const _Placeholder<16> _16;
 869     extern const _Placeholder<17> _17;
 870     extern const _Placeholder<18> _18;
 871     extern const _Placeholder<19> _19;
 872     extern const _Placeholder<20> _20;
 873     extern const _Placeholder<21> _21;
 874     extern const _Placeholder<22> _22;
 875     extern const _Placeholder<23> _23;
 876     extern const _Placeholder<24> _24;
 877     extern const _Placeholder<25> _25;
 878     extern const _Placeholder<26> _26;
 879     extern const _Placeholder<27> _27;
 880     extern const _Placeholder<28> _28;
 881     extern const _Placeholder<29> _29;
 882   _GLIBCXX_END_NAMESPACE_VERSION
 883   }
 884
 885   _GLIBCXX_BEGIN_NAMESPACE_VERSION
 886
 887   /**
 888    *  Partial specialization of is_placeholder that provides the placeholder
 889    *  number for the placeholder objects defined by libstdc++.
 890    *  @ingroup binders
 891    */
 892   template<int _Num>
 893     struct is_placeholder<_Placeholder<_Num> >
 894     : public integral_constant<int, _Num>
 895     { };
 896
 897   /**
 898    * Used by _Safe_tuple_element to indicate that there is no tuple
 899    * element at this position.
 900    */
 901   struct _No_tuple_element;
 902
 903   /**
 904    * Implementation helper for _Safe_tuple_element. This primary
 905    * template handles the case where it is safe to use @c
 906    * tuple_element.
 907    */
 908   template<int __i, typename _Tuple, bool _IsSafe>
 909     struct _Safe_tuple_element_impl
 910     : tuple_element<__i, _Tuple> { };
 911
 912   /**
 913    * Implementation helper for _Safe_tuple_element. This partial
 914    * specialization handles the case where it is not safe to use @c
 915    * tuple_element. We just return @c _No_tuple_element.
 916    */
 917   template<int __i, typename _Tuple>
 918     struct _Safe_tuple_element_impl<__i, _Tuple, false>
 919     {
 920       typedef _No_tuple_element type;
 921     };
 922
 923   /**
 924    * Like tuple_element, but returns @c _No_tuple_element when
 925    * tuple_element would return an error.
 926    */
 927  template<int __i, typename _Tuple>
 928    struct _Safe_tuple_element
 929    : _Safe_tuple_element_impl<__i, _Tuple,
 930                               (__i >= 0 && __i < tuple_size<_Tuple>::value)>
 931    { };
 932
 933   /**
 934    *  Maps an argument to bind() into an actual argument to the bound
 935    *  function object [TR1 3.6.3/5]. Only the first parameter should
 936    *  be specified: the rest are used to determine among the various
 937    *  implementations. Note that, although this class is a function
 938    *  object, it isn't entirely normal because it takes only two
 939    *  parameters regardless of the number of parameters passed to the
 940    *  bind expression. The first parameter is the bound argument and
 941    *  the second parameter is a tuple containing references to the
 942    *  rest of the arguments.
 943    */
 944   template<typename _Arg,
 945            bool _IsBindExp = is_bind_expression<_Arg>::value,
 946            bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
 947     class _Mu;
 948
 949   /**
 950    *  If the argument is reference_wrapper<_Tp>, returns the
 951    *  underlying reference. [TR1 3.6.3/5 bullet 1]
 952    */
 953   template<typename _Tp>
 954     class _Mu<reference_wrapper<_Tp>, false, false>
 955     {
 956     public:
 957       typedef _Tp& result_type;
 958
 959       /* Note: This won't actually work for const volatile
 960        * reference_wrappers, because reference_wrapper::get() is const
 961        * but not volatile-qualified. This might be a defect in the TR.
 962        */
 963       template<typename _CVRef, typename _Tuple>
 964         result_type
 965         operator()(_CVRef& __arg, _Tuple&) const volatile
 966         { return __arg.get(); }
 967     };
 968
 969   /**
 970    *  If the argument is a bind expression, we invoke the underlying
 971    *  function object with the same cv-qualifiers as we are given and
 972    *  pass along all of our arguments (unwrapped). [TR1 3.6.3/5 bullet 2]
 973    */
 974   template<typename _Arg>
 975     class _Mu<_Arg, true, false>
 976     {
 977     public:
 978       template<typename _CVArg, typename... _Args>
 979         auto
 980         operator()(_CVArg& __arg,
 981                    tuple<_Args...>& __tuple) const volatile
 982         -> decltype(__arg(declval<_Args>()...))
 983         {
 984           // Construct an index tuple and forward to __call
 985           typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
 986             _Indexes;
 987           return this->__call(__arg, __tuple, _Indexes());
 988         }
 989
 990     private:
 991       // Invokes the underlying function object __arg by unpacking all
 992       // of the arguments in the tuple.
 993       template<typename _CVArg, typename... _Args, int... _Indexes>
 994         auto
 995         __call(_CVArg& __arg, tuple<_Args...>& __tuple,
 996                const _Index_tuple<_Indexes...>&) const volatile
 997         -> decltype(__arg(declval<_Args>()...))
 998         {
 999           return __arg(std::forward<_Args>(get<_Indexes>(__tuple))...);
1000         }
1001     };
1002
1003   /**
1004    *  If the argument is a placeholder for the Nth argument, returns
1005    *  a reference to the Nth argument to the bind function object.
1006    *  [TR1 3.6.3/5 bullet 3]
1007    */
1008   template<typename _Arg>
1009     class _Mu<_Arg, false, true>
1010     {
1011     public:
1012       template<typename _Signature> class result;
1013
1014       template<typename _CVMu, typename _CVArg, typename _Tuple>
1015         class result<_CVMu(_CVArg, _Tuple)>
1016         {
1017           // Add a reference, if it hasn't already been done for us.
1018           // This allows us to be a little bit sloppy in constructing
1019           // the tuple that we pass to result_of<...>.
1020           typedef typename _Safe_tuple_element<(is_placeholder<_Arg>::value
1021                                                 - 1), _Tuple>::type
1022             __base_type;
1023
1024         public:
1025           typedef typename add_rvalue_reference<__base_type>::type type;
1026         };
1027
1028       template<typename _Tuple>
1029         typename result<_Mu(_Arg, _Tuple)>::type
1030         operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
1031         {
1032           return std::forward<typename result<_Mu(_Arg, _Tuple)>::type>(
1033               ::std::get<(is_placeholder<_Arg>::value - 1)>(__tuple));
1034         }
1035     };
1036
1037   /**
1038    *  If the argument is just a value, returns a reference to that
1039    *  value. The cv-qualifiers on the reference are the same as the
1040    *  cv-qualifiers on the _Mu object. [TR1 3.6.3/5 bullet 4]
1041    */
1042   template<typename _Arg>
1043     class _Mu<_Arg, false, false>
1044     {
1045     public:
1046       template<typename _Signature> struct result;
1047
1048       template<typename _CVMu, typename _CVArg, typename _Tuple>
1049         struct result<_CVMu(_CVArg, _Tuple)>
1050         {
1051           typedef typename add_lvalue_reference<_CVArg>::type type;
1052         };
1053
1054       // Pick up the cv-qualifiers of the argument
1055       template<typename _CVArg, typename _Tuple>
1056         _CVArg&&
1057         operator()(_CVArg&& __arg, _Tuple&) const volatile
1058         { return std::forward<_CVArg>(__arg); }
1059     };
1060
1061   /**
1062    *  Maps member pointers into instances of _Mem_fn but leaves all
1063    *  other function objects untouched. Used by tr1::bind(). The
1064    *  primary template handles the non--member-pointer case.
1065    */
1066   template<typename _Tp>
1067     struct _Maybe_wrap_member_pointer
1068     {
1069       typedef _Tp type;
1070
1071       static const _Tp&
1072       __do_wrap(const _Tp& __x)
1073       { return __x; }
1074
1075       static _Tp&&
1076       __do_wrap(_Tp&& __x)
1077       { return static_cast<_Tp&&>(__x); }
1078     };
1079
1080   /**
1081    *  Maps member pointers into instances of _Mem_fn but leaves all
1082    *  other function objects untouched. Used by tr1::bind(). This
1083    *  partial specialization handles the member pointer case.
1084    */
1085   template<typename _Tp, typename _Class>
1086     struct _Maybe_wrap_member_pointer<_Tp _Class::*>
1087     {
1088       typedef _Mem_fn<_Tp _Class::*> type;
1089
1090       static type
1091       __do_wrap(_Tp _Class::* __pm)
1092       { return type(__pm); }
1093     };
1094
1095   // Specialization needed to prevent "forming reference to void" errors when
1096   // bind<void>() is called, because argument deduction instantiates
1097   // _Maybe_wrap_member_pointer<void> outside the immediate context where
1098   // SFINAE applies.
1099   template<>
1100     struct _Maybe_wrap_member_pointer<void>
1101     {
1102       typedef void type;
1103     };
1104
1105   // std::get<I> for volatile-qualified tuples
1106   template<size_t _Ind, typename... _Tp>
1107     inline auto
1108     __volget(volatile tuple<_Tp...>& __tuple)
1109     -> typename tuple_element<_Ind, tuple<_Tp...>>::type volatile&
1110     { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }
1111
1112   // std::get<I> for const-volatile-qualified tuples
1113   template<size_t _Ind, typename... _Tp>
1114     inline auto
1115     __volget(const volatile tuple<_Tp...>& __tuple)
1116     -> typename tuple_element<_Ind, tuple<_Tp...>>::type const volatile&
1117     { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }
1118
1119   /// Type of the function object returned from bind().
1120   template<typename _Signature>
1121     struct _Bind;
1122
1123    template<typename _Functor, typename... _Bound_args>
1124     class _Bind<_Functor(_Bound_args...)>
1125     : public _Weak_result_type<_Functor>
1126     {
1127       typedef _Bind __self_type;
1128       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1129         _Bound_indexes;
1130
1131       _Functor _M_f;
1132       tuple<_Bound_args...> _M_bound_args;
1133
1134       // Call unqualified
1135       template<typename _Result, typename... _Args, int... _Indexes>
1136         _Result
1137         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
1138         {
1139           return _M_f(_Mu<_Bound_args>()
1140                       (get<_Indexes>(_M_bound_args), __args)...);
1141         }
1142
1143       // Call as const
1144       template<typename _Result, typename... _Args, int... _Indexes>
1145         _Result
1146         __call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
1147         {
1148           return _M_f(_Mu<_Bound_args>()
1149                       (get<_Indexes>(_M_bound_args), __args)...);
1150         }
1151
1152       // Call as volatile
1153       template<typename _Result, typename... _Args, int... _Indexes>
1154         _Result
1155         __call_v(tuple<_Args...>&& __args,
1156                  _Index_tuple<_Indexes...>) volatile
1157         {
1158           return _M_f(_Mu<_Bound_args>()
1159                       (__volget<_Indexes>(_M_bound_args), __args)...);
1160         }
1161
1162       // Call as const volatile
1163       template<typename _Result, typename... _Args, int... _Indexes>
1164         _Result
1165         __call_c_v(tuple<_Args...>&& __args,
1166                    _Index_tuple<_Indexes...>) const volatile
1167         {
1168           return _M_f(_Mu<_Bound_args>()
1169                       (__volget<_Indexes>(_M_bound_args), __args)...);
1170         }
1171
1172      public:
1173       template<typename... _Args>
1174         explicit _Bind(const _Functor& __f, _Args&&... __args)
1175         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1176         { }
1177
1178       template<typename... _Args>
1179         explicit _Bind(_Functor&& __f, _Args&&... __args)
1180         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1181         { }
1182
1183       _Bind(const _Bind&) = default;
1184
1185       _Bind(_Bind&& __b)
1186       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1187       { }
1188
1189       // Call unqualified
1190       template<typename... _Args, typename _Result
1191         = decltype( std::declval<_Functor>()(
1192               _Mu<_Bound_args>()( std::declval<_Bound_args&>(),
1193                                   std::declval<tuple<_Args...>&>() )... ) )>
1194         _Result
1195         operator()(_Args&&... __args)
1196         {
1197           return this->__call<_Result>(
1198               std::forward_as_tuple(std::forward<_Args>(__args)...),
1199               _Bound_indexes());
1200         }
1201
1202       // Call as const
1203       template<typename... _Args, typename _Result
1204         = decltype( std::declval<const _Functor>()(
1205               _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
1206                                   std::declval<tuple<_Args...>&>() )... ) )>
1207         _Result
1208         operator()(_Args&&... __args) const
1209         {
1210           return this->__call_c<_Result>(
1211               std::forward_as_tuple(std::forward<_Args>(__args)...),
1212               _Bound_indexes());
1213         }
1214
1215       // Call as volatile
1216       template<typename... _Args, typename _Result
1217         = decltype( std::declval<volatile _Functor>()(
1218               _Mu<_Bound_args>()( std::declval<volatile _Bound_args&>(),
1219                                   std::declval<tuple<_Args...>&>() )... ) )>
1220         _Result
1221         operator()(_Args&&... __args) volatile
1222         {
1223           return this->__call_v<_Result>(
1224               std::forward_as_tuple(std::forward<_Args>(__args)...),
1225               _Bound_indexes());
1226         }
1227
1228       // Call as const volatile
1229       template<typename... _Args, typename _Result
1230         = decltype( std::declval<const volatile _Functor>()(
1231               _Mu<_Bound_args>()( std::declval<const volatile _Bound_args&>(),
1232                                   std::declval<tuple<_Args...>&>() )... ) )>
1233         _Result
1234         operator()(_Args&&... __args) const volatile
1235         {
1236           return this->__call_c_v<_Result>(
1237               std::forward_as_tuple(std::forward<_Args>(__args)...),
1238               _Bound_indexes());
1239         }
1240     };
1241
1242   /// Type of the function object returned from bind<R>().
1243   template<typename _Result, typename _Signature>
1244     struct _Bind_result;
1245
1246   template<typename _Result, typename _Functor, typename... _Bound_args>
1247     class _Bind_result<_Result, _Functor(_Bound_args...)>
1248     {
1249       typedef _Bind_result __self_type;
1250       typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
1251         _Bound_indexes;
1252
1253       _Functor _M_f;
1254       tuple<_Bound_args...> _M_bound_args;
1255
1256       // sfinae types
1257       template<typename _Res>
1258         struct __enable_if_void : enable_if<is_void<_Res>::value, int> { };
1259       template<typename _Res>
1260         struct __disable_if_void : enable_if<!is_void<_Res>::value, int> { };
1261
1262       // Call unqualified
1263       template<typename _Res, typename... _Args, int... _Indexes>
1264         _Result
1265         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1266             typename __disable_if_void<_Res>::type = 0)
1267         {
1268           return _M_f(_Mu<_Bound_args>()
1269                       (get<_Indexes>(_M_bound_args), __args)...);
1270         }
1271
1272       // Call unqualified, return void
1273       template<typename _Res, typename... _Args, int... _Indexes>
1274         void
1275         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1276             typename __enable_if_void<_Res>::type = 0)
1277         {
1278           _M_f(_Mu<_Bound_args>()
1279                (get<_Indexes>(_M_bound_args), __args)...);
1280         }
1281
1282       // Call as const
1283       template<typename _Res, typename... _Args, int... _Indexes>
1284         _Result
1285         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1286             typename __disable_if_void<_Res>::type = 0) const
1287         {
1288           return _M_f(_Mu<_Bound_args>()
1289                       (get<_Indexes>(_M_bound_args), __args)...);
1290         }
1291
1292       // Call as const, return void
1293       template<typename _Res, typename... _Args, int... _Indexes>
1294         void
1295         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1296             typename __enable_if_void<_Res>::type = 0) const
1297         {
1298           _M_f(_Mu<_Bound_args>()
1299                (get<_Indexes>(_M_bound_args),  __args)...);
1300         }
1301
1302       // Call as volatile
1303       template<typename _Res, typename... _Args, int... _Indexes>
1304         _Result
1305         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1306             typename __disable_if_void<_Res>::type = 0) volatile
1307         {
1308           return _M_f(_Mu<_Bound_args>()
1309                       (__volget<_Indexes>(_M_bound_args), __args)...);
1310         }
1311
1312       // Call as volatile, return void
1313       template<typename _Res, typename... _Args, int... _Indexes>
1314         void
1315         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1316             typename __enable_if_void<_Res>::type = 0) volatile
1317         {
1318           _M_f(_Mu<_Bound_args>()
1319                (__volget<_Indexes>(_M_bound_args), __args)...);
1320         }
1321
1322       // Call as const volatile
1323       template<typename _Res, typename... _Args, int... _Indexes>
1324         _Result
1325         __call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
1326             typename __disable_if_void<_Res>::type = 0) const volatile
1327         {
1328           return _M_f(_Mu<_Bound_args>()
1329                       (__volget<_Indexes>(_M_bound_args), __args)...);
1330         }
1331
1332       // Call as const volatile, return void
1333       template<typename _Res, typename... _Args, int... _Indexes>
1334         void
1335         __call(tuple<_Args...>&& __args,
1336                _Index_tuple<_Indexes...>,
1337             typename __enable_if_void<_Res>::type = 0) const volatile
1338         {
1339           _M_f(_Mu<_Bound_args>()
1340                (__volget<_Indexes>(_M_bound_args), __args)...);
1341         }
1342
1343     public:
1344       typedef _Result result_type;
1345
1346       template<typename... _Args>
1347         explicit _Bind_result(const _Functor& __f, _Args&&... __args)
1348         : _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
1349         { }
1350
1351       template<typename... _Args>
1352         explicit _Bind_result(_Functor&& __f, _Args&&... __args)
1353         : _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
1354         { }
1355
1356       _Bind_result(const _Bind_result&) = default;
1357
1358       _Bind_result(_Bind_result&& __b)
1359       : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
1360       { }
1361
1362       // Call unqualified
1363       template<typename... _Args>
1364         result_type
1365         operator()(_Args&&... __args)
1366         {
1367           return this->__call<_Result>(
1368               std::forward_as_tuple(std::forward<_Args>(__args)...),
1369               _Bound_indexes());
1370         }
1371
1372       // Call as const
1373       template<typename... _Args>
1374         result_type
1375         operator()(_Args&&... __args) const
1376         {
1377           return this->__call<_Result>(
1378               std::forward_as_tuple(std::forward<_Args>(__args)...),
1379               _Bound_indexes());
1380         }
1381
1382       // Call as volatile
1383       template<typename... _Args>
1384         result_type
1385         operator()(_Args&&... __args) volatile
1386         {
1387           return this->__call<_Result>(
1388               std::forward_as_tuple(std::forward<_Args>(__args)...),
1389               _Bound_indexes());
1390         }
1391
1392       // Call as const volatile
1393       template<typename... _Args>
1394         result_type
1395         operator()(_Args&&... __args) const volatile
1396         {
1397           return this->__call<_Result>(
1398               std::forward_as_tuple(std::forward<_Args>(__args)...),
1399               _Bound_indexes());
1400         }
1401     };
1402
1403   /**
1404    *  @brief Class template _Bind is always a bind expression.
1405    *  @ingroup binders
1406    */
1407   template<typename _Signature>
1408     struct is_bind_expression<_Bind<_Signature> >
1409     : public true_type { };
1410
1411   /**
1412    *  @brief Class template _Bind is always a bind expression.
1413    *  @ingroup binders
1414    */
1415   template<typename _Result, typename _Signature>
1416     struct is_bind_expression<_Bind_result<_Result, _Signature> >
1417     : public true_type { };
1418
1419   template<typename _Functor, typename... _ArgTypes>
1420     struct _Bind_helper
1421     {
1422       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1423         __maybe_type;
1424       typedef typename __maybe_type::type __functor_type;
1425       typedef _Bind<__functor_type(typename decay<_ArgTypes>::type...)> type;
1426     };
1427
1428   /**
1429    *  @brief Function template for std::bind.
1430    *  @ingroup binders
1431    */
1432   template<typename _Functor, typename... _ArgTypes>
1433     inline
1434     typename _Bind_helper<_Functor, _ArgTypes...>::type
1435     bind(_Functor&& __f, _ArgTypes&&... __args)
1436     {
1437       typedef _Bind_helper<_Functor, _ArgTypes...> __helper_type;
1438       typedef typename __helper_type::__maybe_type __maybe_type;
1439       typedef typename __helper_type::type __result_type;
1440       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1441                            std::forward<_ArgTypes>(__args)...);
1442     }
1443
1444   template<typename _Result, typename _Functor, typename... _ArgTypes>
1445     struct _Bindres_helper
1446     {
1447       typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
1448         __maybe_type;
1449       typedef typename __maybe_type::type __functor_type;
1450       typedef _Bind_result<_Result,
1451                            __functor_type(typename decay<_ArgTypes>::type...)>
1452         type;
1453     };
1454
1455   /**
1456    *  @brief Function template for std::bind<R>.
1457    *  @ingroup binders
1458    */
1459   template<typename _Result, typename _Functor, typename... _ArgTypes>
1460     inline
1461     typename _Bindres_helper<_Result, _Functor, _ArgTypes...>::type
1462     bind(_Functor&& __f, _ArgTypes&&... __args)
1463     {
1464       typedef _Bindres_helper<_Result, _Functor, _ArgTypes...> __helper_type;
1465       typedef typename __helper_type::__maybe_type __maybe_type;
1466       typedef typename __helper_type::type __result_type;
1467       return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
1468                            std::forward<_ArgTypes>(__args)...);
1469     }
1470
1471   /**
1472    *  @brief Exception class thrown when class template function's
1473    *  operator() is called with an empty target.
1474    *  @ingroup exceptions
1475    */
1476   class bad_function_call : public std::exception { };
1477
1478   /**
1479    *  Trait identifying "location-invariant" types, meaning that the
1480    *  address of the object (or any of its members) will not escape.
1481    *  Also implies a trivial copy constructor and assignment operator.
1482    */
1483   template<typename _Tp>
1484     struct __is_location_invariant
1485     : integral_constant<bool, (is_pointer<_Tp>::value
1486                                || is_member_pointer<_Tp>::value)>
1487     { };
1488
1489   class _Undefined_class;
1490
1491   union _Nocopy_types
1492   {
1493     void*       _M_object;
1494     const void* _M_const_object;
1495     void (*_M_function_pointer)();
1496     void (_Undefined_class::*_M_member_pointer)();
1497   };
1498
1499   union _Any_data
1500   {
1501     void*       _M_access()       { return &_M_pod_data[0]; }
1502     const void* _M_access() const { return &_M_pod_data[0]; }
1503
1504     template<typename _Tp>
1505       _Tp&
1506       _M_access()
1507       { return *static_cast<_Tp*>(_M_access()); }
1508
1509     template<typename _Tp>
1510       const _Tp&
1511       _M_access() const
1512       { return *static_cast<const _Tp*>(_M_access()); }
1513
1514     _Nocopy_types _M_unused;
1515     char _M_pod_data[sizeof(_Nocopy_types)];
1516   };
1517
1518   enum _Manager_operation
1519   {
1520     __get_type_info,
1521     __get_functor_ptr,
1522     __clone_functor,
1523     __destroy_functor
1524   };
1525
1526   // Simple type wrapper that helps avoid annoying const problems
1527   // when casting between void pointers and pointers-to-pointers.
1528   template<typename _Tp>
1529     struct _Simple_type_wrapper
1530     {
1531       _Simple_type_wrapper(_Tp __value) : __value(__value) { }
1532
1533       _Tp __value;
1534     };
1535
1536   template<typename _Tp>
1537     struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
1538     : __is_location_invariant<_Tp>
1539     { };
1540
1541   // Converts a reference to a function object into a callable
1542   // function object.
1543   template<typename _Functor>
1544     inline _Functor&
1545     __callable_functor(_Functor& __f)
1546     { return __f; }
1547
1548   template<typename _Member, typename _Class>
1549     inline _Mem_fn<_Member _Class::*>
1550     __callable_functor(_Member _Class::* &__p)
1551     { return mem_fn(__p); }
1552
1553   template<typename _Member, typename _Class>
1554     inline _Mem_fn<_Member _Class::*>
1555     __callable_functor(_Member _Class::* const &__p)
1556     { return mem_fn(__p); }
1557
1558   template<typename _Signature>
1559     class function;
1560
1561   /// Base class of all polymorphic function object wrappers.
1562   class _Function_base
1563   {
1564   public:
1565     static const std::size_t _M_max_size = sizeof(_Nocopy_types);
1566     static const std::size_t _M_max_align = __alignof__(_Nocopy_types);
1567
1568     template<typename _Functor>
1569       class _Base_manager
1570       {
1571       protected:
1572         static const bool __stored_locally =
1573         (__is_location_invariant<_Functor>::value
1574          && sizeof(_Functor) <= _M_max_size
1575          && __alignof__(_Functor) <= _M_max_align
1576          && (_M_max_align % __alignof__(_Functor) == 0));
1577
1578         typedef integral_constant<bool, __stored_locally> _Local_storage;
1579
1580         // Retrieve a pointer to the function object
1581         static _Functor*
1582         _M_get_pointer(const _Any_data& __source)
1583         {
1584           const _Functor* __ptr =
1585             __stored_locally? &__source._M_access<_Functor>()
1586             /* have stored a pointer */ : __source._M_access<_Functor*>();
1587           return const_cast<_Functor*>(__ptr);
1588         }
1589
1590         // Clone a location-invariant function object that fits within
1591         // an _Any_data structure.
1592         static void
1593         _M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
1594         {
1595           new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
1596         }
1597
1598         // Clone a function object that is not location-invariant or
1599         // that cannot fit into an _Any_data structure.
1600         static void
1601         _M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
1602         {
1603           __dest._M_access<_Functor*>() =
1604             new _Functor(*__source._M_access<_Functor*>());
1605         }
1606
1607         // Destroying a location-invariant object may still require
1608         // destruction.
1609         static void
1610         _M_destroy(_Any_data& __victim, true_type)
1611         {
1612           __victim._M_access<_Functor>().~_Functor();
1613         }
1614
1615         // Destroying an object located on the heap.
1616         static void
1617         _M_destroy(_Any_data& __victim, false_type)
1618         {
1619           delete __victim._M_access<_Functor*>();
1620         }
1621
1622       public:
1623         static bool
1624         _M_manager(_Any_data& __dest, const _Any_data& __source,
1625                    _Manager_operation __op)
1626         {
1627           switch (__op)
1628             {
1629 #ifdef __GXX_RTTI
1630             case __get_type_info:
1631               __dest._M_access<const type_info*>() = &typeid(_Functor);
1632               break;
1633 #endif
1634             case __get_functor_ptr:
1635               __dest._M_access<_Functor*>() = _M_get_pointer(__source);
1636               break;
1637
1638             case __clone_functor:
1639               _M_clone(__dest, __source, _Local_storage());
1640               break;
1641
1642             case __destroy_functor:
1643               _M_destroy(__dest, _Local_storage());
1644               break;
1645             }
1646           return false;
1647         }
1648
1649         static void
1650         _M_init_functor(_Any_data& __functor, _Functor&& __f)
1651         { _M_init_functor(__functor, std::move(__f), _Local_storage()); }
1652
1653         template<typename _Signature>
1654           static bool
1655           _M_not_empty_function(const function<_Signature>& __f)
1656           { return static_cast<bool>(__f); }
1657
1658         template<typename _Tp>
1659           static bool
1660           _M_not_empty_function(const _Tp*& __fp)
1661           { return __fp; }
1662
1663         template<typename _Class, typename _Tp>
1664           static bool
1665           _M_not_empty_function(_Tp _Class::* const& __mp)
1666           { return __mp; }
1667
1668         template<typename _Tp>
1669           static bool
1670           _M_not_empty_function(const _Tp&)
1671           { return true; }
1672
1673       private:
1674         static void
1675         _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
1676         { new (__functor._M_access()) _Functor(std::move(__f)); }
1677
1678         static void
1679         _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
1680         { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
1681       };
1682
1683     template<typename _Functor>
1684       class _Ref_manager : public _Base_manager<_Functor*>
1685       {
1686         typedef _Function_base::_Base_manager<_Functor*> _Base;
1687
1688     public:
1689         static bool
1690         _M_manager(_Any_data& __dest, const _Any_data& __source,
1691                    _Manager_operation __op)
1692         {
1693           switch (__op)
1694             {
1695 #ifdef __GXX_RTTI
1696             case __get_type_info:
1697               __dest._M_access<const type_info*>() = &typeid(_Functor);
1698               break;
1699 #endif
1700             case __get_functor_ptr:
1701               __dest._M_access<_Functor*>() = *_Base::_M_get_pointer(__source);
1702               return is_const<_Functor>::value;
1703               break;
1704
1705             default:
1706               _Base::_M_manager(__dest, __source, __op);
1707             }
1708           return false;
1709         }
1710
1711         static void
1712         _M_init_functor(_Any_data& __functor, reference_wrapper<_Functor> __f)
1713         {
1714           // TBD: Use address_of function instead.
1715           _Base::_M_init_functor(__functor, &__f.get());
1716         }
1717       };
1718
1719     _Function_base() : _M_manager(0) { }
1720
1721     ~_Function_base()
1722     {
1723       if (_M_manager)
1724         _M_manager(_M_functor, _M_functor, __destroy_functor);
1725     }
1726
1727
1728     bool _M_empty() const { return !_M_manager; }
1729
1730     typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
1731                                   _Manager_operation);
1732
1733     _Any_data     _M_functor;
1734     _Manager_type _M_manager;
1735   };
1736
1737   template<typename _Signature, typename _Functor>
1738     class _Function_handler;
1739
1740   template<typename _Res, typename _Functor, typename... _ArgTypes>
1741     class _Function_handler<_Res(_ArgTypes...), _Functor>
1742     : public _Function_base::_Base_manager<_Functor>
1743     {
1744       typedef _Function_base::_Base_manager<_Functor> _Base;
1745
1746     public:
1747       static _Res
1748       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1749       {
1750         return (*_Base::_M_get_pointer(__functor))(
1751             std::forward<_ArgTypes>(__args)...);
1752       }
1753     };
1754
1755   template<typename _Functor, typename... _ArgTypes>
1756     class _Function_handler<void(_ArgTypes...), _Functor>
1757     : public _Function_base::_Base_manager<_Functor>
1758     {
1759       typedef _Function_base::_Base_manager<_Functor> _Base;
1760
1761      public:
1762       static void
1763       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1764       {
1765         (*_Base::_M_get_pointer(__functor))(
1766             std::forward<_ArgTypes>(__args)...);
1767       }
1768     };
1769
1770   template<typename _Res, typename _Functor, typename... _ArgTypes>
1771     class _Function_handler<_Res(_ArgTypes...), reference_wrapper<_Functor> >
1772     : public _Function_base::_Ref_manager<_Functor>
1773     {
1774       typedef _Function_base::_Ref_manager<_Functor> _Base;
1775
1776      public:
1777       static _Res
1778       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1779       {
1780         return __callable_functor(**_Base::_M_get_pointer(__functor))(
1781               std::forward<_ArgTypes>(__args)...);
1782       }
1783     };
1784
1785   template<typename _Functor, typename... _ArgTypes>
1786     class _Function_handler<void(_ArgTypes...), reference_wrapper<_Functor> >
1787     : public _Function_base::_Ref_manager<_Functor>
1788     {
1789       typedef _Function_base::_Ref_manager<_Functor> _Base;
1790
1791      public:
1792       static void
1793       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1794       {
1795         __callable_functor(**_Base::_M_get_pointer(__functor))(
1796             std::forward<_ArgTypes>(__args)...);
1797       }
1798     };
1799
1800   template<typename _Class, typename _Member, typename _Res,
1801            typename... _ArgTypes>
1802     class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
1803     : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
1804     {
1805       typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
1806         _Base;
1807
1808      public:
1809       static _Res
1810       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1811       {
1812         return mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1813             std::forward<_ArgTypes>(__args)...);
1814       }
1815     };
1816
1817   template<typename _Class, typename _Member, typename... _ArgTypes>
1818     class _Function_handler<void(_ArgTypes...), _Member _Class::*>
1819     : public _Function_base::_Base_manager<
1820                  _Simple_type_wrapper< _Member _Class::* > >
1821     {
1822       typedef _Member _Class::* _Functor;
1823       typedef _Simple_type_wrapper<_Functor> _Wrapper;
1824       typedef _Function_base::_Base_manager<_Wrapper> _Base;
1825
1826      public:
1827       static bool
1828       _M_manager(_Any_data& __dest, const _Any_data& __source,
1829                  _Manager_operation __op)
1830       {
1831         switch (__op)
1832           {
1833 #ifdef __GXX_RTTI
1834           case __get_type_info:
1835             __dest._M_access<const type_info*>() = &typeid(_Functor);
1836             break;
1837 #endif
1838           case __get_functor_ptr:
1839             __dest._M_access<_Functor*>() =
1840               &_Base::_M_get_pointer(__source)->__value;
1841             break;
1842
1843           default:
1844             _Base::_M_manager(__dest, __source, __op);
1845           }
1846         return false;
1847       }
1848
1849       static void
1850       _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
1851       {
1852         mem_fn(_Base::_M_get_pointer(__functor)->__value)(
1853             std::forward<_ArgTypes>(__args)...);
1854       }
1855     };
1856
1857   /**
1858    *  @brief Primary class template for std::function.
1859    *  @ingroup functors
1860    *
1861    *  Polymorphic function wrapper.
1862    */
1863   template<typename _Res, typename... _ArgTypes>
1864     class function<_Res(_ArgTypes...)>
1865     : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
1866       private _Function_base
1867     {
1868       typedef _Res _Signature_type(_ArgTypes...);
1869
1870       struct _Useless { };
1871
1872     public:
1873       typedef _Res result_type;
1874
1875       // [3.7.2.1] construct/copy/destroy
1876
1877       /**
1878        *  @brief Default construct creates an empty function call wrapper.
1879        *  @post @c !(bool)*this
1880        */
1881       function() : _Function_base() { }
1882
1883       /**
1884        *  @brief Creates an empty function call wrapper.
1885        *  @post @c !(bool)*this
1886        */
1887       function(nullptr_t) : _Function_base() { }
1888
1889       /**
1890        *  @brief %Function copy constructor.
1891        *  @param x A %function object with identical call signature.
1892        *  @post @c (bool)*this == (bool)x
1893        *
1894        *  The newly-created %function contains a copy of the target of @a
1895        *  x (if it has one).
1896        */
1897       function(const function& __x);
1898
1899       /**
1900        *  @brief %Function move constructor.
1901        *  @param x A %function object rvalue with identical call signature.
1902        *
1903        *  The newly-created %function contains the target of @a x
1904        *  (if it has one).
1905        */
1906       function(function&& __x) : _Function_base()
1907       {
1908         __x.swap(*this);
1909       }
1910
1911       // TODO: needs allocator_arg_t
1912
1913       /**
1914        *  @brief Builds a %function that targets a copy of the incoming
1915        *  function object.
1916        *  @param f A %function object that is callable with parameters of
1917        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
1918        *  to @c Res.
1919        *
1920        *  The newly-created %function object will target a copy of @a
1921        *  f. If @a f is @c reference_wrapper<F>, then this function
1922        *  object will contain a reference to the function object @c
1923        *  f.get(). If @a f is a NULL function pointer or NULL
1924        *  pointer-to-member, the newly-created object will be empty.
1925        *
1926        *  If @a f is a non-NULL function pointer or an object of type @c
1927        *  reference_wrapper<F>, this function will not throw.
1928        */
1929       template<typename _Functor>
1930         function(_Functor __f,
1931                  typename enable_if<
1932                            !is_integral<_Functor>::value, _Useless>::type
1933                    = _Useless());
1934
1935       /**
1936        *  @brief %Function assignment operator.
1937        *  @param x A %function with identical call signature.
1938        *  @post @c (bool)*this == (bool)x
1939        *  @returns @c *this
1940        *
1941        *  The target of @a x is copied to @c *this. If @a x has no
1942        *  target, then @c *this will be empty.
1943        *
1944        *  If @a x targets a function pointer or a reference to a function
1945        *  object, then this operation will not throw an %exception.
1946        */
1947       function&
1948       operator=(const function& __x)
1949       {
1950         function(__x).swap(*this);
1951         return *this;
1952       }
1953
1954       /**
1955        *  @brief %Function move-assignment operator.
1956        *  @param x A %function rvalue with identical call signature.
1957        *  @returns @c *this
1958        *
1959        *  The target of @a x is moved to @c *this. If @a x has no
1960        *  target, then @c *this will be empty.
1961        *
1962        *  If @a x targets a function pointer or a reference to a function
1963        *  object, then this operation will not throw an %exception.
1964        */
1965       function&
1966       operator=(function&& __x)
1967       {
1968         function(std::move(__x)).swap(*this);
1969         return *this;
1970       }
1971
1972       /**
1973        *  @brief %Function assignment to zero.
1974        *  @post @c !(bool)*this
1975        *  @returns @c *this
1976        *
1977        *  The target of @c *this is deallocated, leaving it empty.
1978        */
1979       function&
1980       operator=(nullptr_t)
1981       {
1982         if (_M_manager)
1983           {
1984             _M_manager(_M_functor, _M_functor, __destroy_functor);
1985             _M_manager = 0;
1986             _M_invoker = 0;
1987           }
1988         return *this;
1989       }
1990
1991       /**
1992        *  @brief %Function assignment to a new target.
1993        *  @param f A %function object that is callable with parameters of
1994        *  type @c T1, @c T2, ..., @c TN and returns a value convertible
1995        *  to @c Res.
1996        *  @return @c *this
1997        *
1998        *  This  %function object wrapper will target a copy of @a
1999        *  f. If @a f is @c reference_wrapper<F>, then this function
2000        *  object will contain a reference to the function object @c
2001        *  f.get(). If @a f is a NULL function pointer or NULL
2002        *  pointer-to-member, @c this object will be empty.
2003        *
2004        *  If @a f is a non-NULL function pointer or an object of type @c
2005        *  reference_wrapper<F>, this function will not throw.
2006        */
2007       template<typename _Functor>
2008         typename enable_if<!is_integral<_Functor>::value, function&>::type
2009         operator=(_Functor&& __f)
2010         {
2011           function(std::forward<_Functor>(__f)).swap(*this);
2012           return *this;
2013         }
2014
2015       /// @overload
2016       template<typename _Functor>
2017         typename enable_if<!is_integral<_Functor>::value, function&>::type
2018         operator=(reference_wrapper<_Functor> __f)
2019         {
2020           function(__f).swap(*this);
2021           return *this;
2022         }
2023
2024       // [3.7.2.2] function modifiers
2025
2026       /**
2027        *  @brief Swap the targets of two %function objects.
2028        *  @param f A %function with identical call signature.
2029        *
2030        *  Swap the targets of @c this function object and @a f. This
2031        *  function will not throw an %exception.
2032        */
2033       void swap(function& __x)
2034       {
2035         std::swap(_M_functor, __x._M_functor);
2036         std::swap(_M_manager, __x._M_manager);
2037         std::swap(_M_invoker, __x._M_invoker);
2038       }
2039
2040       // TODO: needs allocator_arg_t
2041       /*
2042       template<typename _Functor, typename _Alloc>
2043         void
2044         assign(_Functor&& __f, const _Alloc& __a)
2045         {
2046           function(allocator_arg, __a,
2047                    std::forward<_Functor>(__f)).swap(*this);
2048         }
2049       */
2050
2051       // [3.7.2.3] function capacity
2052
2053       /**
2054        *  @brief Determine if the %function wrapper has a target.
2055        *
2056        *  @return @c true when this %function object contains a target,
2057        *  or @c false when it is empty.
2058        *
2059        *  This function will not throw an %exception.
2060        */
2061       explicit operator bool() const
2062       { return !_M_empty(); }
2063
2064       // [3.7.2.4] function invocation
2065
2066       /**
2067        *  @brief Invokes the function targeted by @c *this.
2068        *  @returns the result of the target.
2069        *  @throws bad_function_call when @c !(bool)*this
2070        *
2071        *  The function call operator invokes the target function object
2072        *  stored by @c this.
2073        */
2074       _Res operator()(_ArgTypes... __args) const;
2075
2076 #ifdef __GXX_RTTI
2077       // [3.7.2.5] function target access
2078       /**
2079        *  @brief Determine the type of the target of this function object
2080        *  wrapper.
2081        *
2082        *  @returns the type identifier of the target function object, or
2083        *  @c typeid(void) if @c !(bool)*this.
2084        *
2085        *  This function will not throw an %exception.
2086        */
2087       const type_info& target_type() const;
2088
2089       /**
2090        *  @brief Access the stored target function object.
2091        *
2092        *  @return Returns a pointer to the stored target function object,
2093        *  if @c typeid(Functor).equals(target_type()); otherwise, a NULL
2094        *  pointer.
2095        *
2096        * This function will not throw an %exception.
2097        */
2098       template<typename _Functor>       _Functor* target();
2099
2100       /// @overload
2101       template<typename _Functor> const _Functor* target() const;
2102 #endif
2103
2104     private:
2105       typedef _Res (*_Invoker_type)(const _Any_data&, _ArgTypes...);
2106       _Invoker_type _M_invoker;
2107   };
2108
2109   // Out-of-line member definitions.
2110   template<typename _Res, typename... _ArgTypes>
2111     function<_Res(_ArgTypes...)>::
2112     function(const function& __x)
2113     : _Function_base()
2114     {
2115       if (static_cast<bool>(__x))
2116         {
2117           _M_invoker = __x._M_invoker;
2118           _M_manager = __x._M_manager;
2119           __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
2120         }
2121     }
2122
2123   template<typename _Res, typename... _ArgTypes>
2124     template<typename _Functor>
2125       function<_Res(_ArgTypes...)>::
2126       function(_Functor __f,
2127                typename enable_if<
2128                         !is_integral<_Functor>::value, _Useless>::type)
2129       : _Function_base()
2130       {
2131         typedef _Function_handler<_Signature_type, _Functor> _My_handler;
2132
2133         if (_My_handler::_M_not_empty_function(__f))
2134           {
2135             _M_invoker = &_My_handler::_M_invoke;
2136             _M_manager = &_My_handler::_M_manager;
2137             _My_handler::_M_init_functor(_M_functor, std::move(__f));
2138           }
2139       }
2140
2141   template<typename _Res, typename... _ArgTypes>
2142     _Res
2143     function<_Res(_ArgTypes...)>::
2144     operator()(_ArgTypes... __args) const
2145     {
2146       if (_M_empty())
2147         __throw_bad_function_call();
2148       return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
2149     }
2150
2151 #ifdef __GXX_RTTI
2152   template<typename _Res, typename... _ArgTypes>
2153     const type_info&
2154     function<_Res(_ArgTypes...)>::
2155     target_type() const
2156     {
2157       if (_M_manager)
2158         {
2159           _Any_data __typeinfo_result;
2160           _M_manager(__typeinfo_result, _M_functor, __get_type_info);
2161           return *__typeinfo_result._M_access<const type_info*>();
2162         }
2163       else
2164         return typeid(void);
2165     }
2166
2167   template<typename _Res, typename... _ArgTypes>
2168     template<typename _Functor>
2169       _Functor*
2170       function<_Res(_ArgTypes...)>::
2171       target()
2172       {
2173         if (typeid(_Functor) == target_type() && _M_manager)
2174           {
2175             _Any_data __ptr;
2176             if (_M_manager(__ptr, _M_functor, __get_functor_ptr)
2177                 && !is_const<_Functor>::value)
2178               return 0;
2179             else
2180               return __ptr._M_access<_Functor*>();
2181           }
2182         else
2183           return 0;
2184       }
2185
2186   template<typename _Res, typename... _ArgTypes>
2187     template<typename _Functor>
2188       const _Functor*
2189       function<_Res(_ArgTypes...)>::
2190       target() const
2191       {
2192         if (typeid(_Functor) == target_type() && _M_manager)
2193           {
2194             _Any_data __ptr;
2195             _M_manager(__ptr, _M_functor, __get_functor_ptr);
2196             return __ptr._M_access<const _Functor*>();
2197           }
2198         else
2199           return 0;
2200       }
2201 #endif
2202
2203   // [20.7.15.2.6] null pointer comparisons
2204
2205   /**
2206    *  @brief Compares a polymorphic function object wrapper against 0
2207    *  (the NULL pointer).
2208    *  @returns @c true if the wrapper has no target, @c false otherwise
2209    *
2210    *  This function will not throw an %exception.
2211    */
2212   template<typename _Res, typename... _Args>
2213     inline bool
2214     operator==(const function<_Res(_Args...)>& __f, nullptr_t)
2215     { return !static_cast<bool>(__f); }
2216
2217   /// @overload
2218   template<typename _Res, typename... _Args>
2219     inline bool
2220     operator==(nullptr_t, const function<_Res(_Args...)>& __f)
2221     { return !static_cast<bool>(__f); }
2222
2223   /**
2224    *  @brief Compares a polymorphic function object wrapper against 0
2225    *  (the NULL pointer).
2226    *  @returns @c false if the wrapper has no target, @c true otherwise
2227    *
2228    *  This function will not throw an %exception.
2229    */
2230   template<typename _Res, typename... _Args>
2231     inline bool
2232     operator!=(const function<_Res(_Args...)>& __f, nullptr_t)
2233     { return static_cast<bool>(__f); }
2234
2235   /// @overload
2236   template<typename _Res, typename... _Args>
2237     inline bool
2238     operator!=(nullptr_t, const function<_Res(_Args...)>& __f)
2239     { return static_cast<bool>(__f); }
2240
2241   // [20.7.15.2.7] specialized algorithms
2242
2243   /**
2244    *  @brief Swap the targets of two polymorphic function object wrappers.
2245    *
2246    *  This function will not throw an %exception.
2247    */
2248   template<typename _Res, typename... _Args>
2249     inline void
2250     swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y)
2251     { __x.swap(__y); }
2252
2253 _GLIBCXX_END_NAMESPACE_VERSION
2254 } // namespace std
2255
2256 #endif // __GXX_EXPERIMENTAL_CXX0X__
2257
2258 #endif // _GLIBCXX_FUNCTIONAL