summaryrefslogtreecommitdiff
path: root/libstdc++-v3/include/std/functional
blob: 45bee8112c505417320a2f7697a8f233a26a5e27 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
// <functional> -*- C++ -*-

// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
// 2011 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/*
 * Copyright (c) 1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 */

/** @file include/functional
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_FUNCTIONAL
#define _GLIBCXX_FUNCTIONAL 1

#pragma GCC system_header

#include <bits/c++config.h>
#include <bits/stl_function.h>

#ifdef __GXX_EXPERIMENTAL_CXX0X__

#include <typeinfo>
#include <new>
#include <tuple>
#include <type_traits>
#include <bits/functexcept.h>
#include <bits/functional_hash.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

_GLIBCXX_HAS_NESTED_TYPE(result_type)

  /// If we have found a result_type, extract it.
  template<bool _Has_result_type, typename _Functor>
    struct _Maybe_get_result_type
    { };

  template<typename _Functor>
    struct _Maybe_get_result_type<true, _Functor>
    { typedef typename _Functor::result_type result_type; };

  /**
   *  Base class for any function object that has a weak result type, as
   *  defined in 3.3/3 of TR1.
  */
  template<typename _Functor>
    struct _Weak_result_type_impl
    : _Maybe_get_result_type<__has_result_type<_Functor>::value, _Functor>
    { };

  /// Retrieve the result type for a function type.
  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...) const>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......) const>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...) volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......) volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes...) const volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(_ArgTypes......) const volatile>
    { typedef _Res result_type; };

  /// Retrieve the result type for a function reference.
  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(&)(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(&)(_ArgTypes......)>
    { typedef _Res result_type; };

  /// Retrieve the result type for a function pointer.
  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(*)(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res(*)(_ArgTypes......)>
    { typedef _Res result_type; };

  /// Retrieve result type for a member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)>
    { typedef _Res result_type; };

  /// Retrieve result type for a const member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) const>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) const>
    { typedef _Res result_type; };

  /// Retrieve result type for a volatile member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...) volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......) volatile>
    { typedef _Res result_type; };

  /// Retrieve result type for a const volatile member function pointer.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes...)
				  const volatile>
    { typedef _Res result_type; };

  template<typename _Res, typename _Class, typename... _ArgTypes>
    struct _Weak_result_type_impl<_Res (_Class::*)(_ArgTypes......)
				  const volatile>
    { typedef _Res result_type; };

  /**
   *  Strip top-level cv-qualifiers from the function object and let
   *  _Weak_result_type_impl perform the real work.
  */
  template<typename _Functor>
    struct _Weak_result_type
    : _Weak_result_type_impl<typename remove_cv<_Functor>::type>
    { };

  /// Determines if the type _Tp derives from unary_function.
  template<typename _Tp>
    struct _Derives_from_unary_function : __sfinae_types
    {
    private:
      template<typename _T1, typename _Res>
	static __one __test(const volatile unary_function<_T1, _Res>*);

      // It's tempting to change "..." to const volatile void*, but
      // that fails when _Tp is a function type.
      static __two __test(...);

    public:
      static const bool value = sizeof(__test((_Tp*)0)) == 1;
    };

  /// Determines if the type _Tp derives from binary_function.
  template<typename _Tp>
    struct _Derives_from_binary_function : __sfinae_types
    {
    private:
      template<typename _T1, typename _T2, typename _Res>
	static __one __test(const volatile binary_function<_T1, _T2, _Res>*);

      // It's tempting to change "..." to const volatile void*, but
      // that fails when _Tp is a function type.
      static __two __test(...);

    public:
      static const bool value = sizeof(__test((_Tp*)0)) == 1;
    };

  /**
   * Invoke a function object, which may be either a member pointer or a
   * function object. The first parameter will tell which.
   */
  template<typename _Functor, typename... _Args>
    inline
    typename enable_if<
	     (!is_member_pointer<_Functor>::value
	      && !is_function<_Functor>::value
	      && !is_function<typename remove_pointer<_Functor>::type>::value),
	     typename result_of<_Functor(_Args&&...)>::type
	   >::type
    __invoke(_Functor& __f, _Args&&... __args)
    {
      return __f(std::forward<_Args>(__args)...);
    }

  template<typename _Functor, typename... _Args>
    inline
    typename enable_if<
             (is_member_pointer<_Functor>::value
              && !is_function<_Functor>::value
              && !is_function<typename remove_pointer<_Functor>::type>::value),
             typename result_of<_Functor(_Args&&...)>::type
           >::type
    __invoke(_Functor& __f, _Args&&... __args)
    {
      return mem_fn(__f)(std::forward<_Args>(__args)...);
    }

  // To pick up function references (that will become function pointers)
  template<typename _Functor, typename... _Args>
    inline
    typename enable_if<
	     (is_pointer<_Functor>::value
	      && is_function<typename remove_pointer<_Functor>::type>::value),
	     typename result_of<_Functor(_Args&&...)>::type
	   >::type
    __invoke(_Functor __f, _Args&&... __args)
    {
      return __f(std::forward<_Args>(__args)...);
    }

  /**
   *  Knowing which of unary_function and binary_function _Tp derives
   *  from, derives from the same and ensures that reference_wrapper
   *  will have a weak result type. See cases below.
   */
  template<bool _Unary, bool _Binary, typename _Tp>
    struct _Reference_wrapper_base_impl;

  // None of the nested argument types.
  template<typename _Tp>
    struct _Reference_wrapper_base_impl<false, false, _Tp>
    : _Weak_result_type<_Tp>
    { };

  // Nested argument_type only.
  template<typename _Tp>
    struct _Reference_wrapper_base_impl<true, false, _Tp>
    : _Weak_result_type<_Tp>
    {
      typedef typename _Tp::argument_type argument_type;
    };

  // Nested first_argument_type and second_argument_type only.
  template<typename _Tp>
    struct _Reference_wrapper_base_impl<false, true, _Tp>
    : _Weak_result_type<_Tp>
    {
      typedef typename _Tp::first_argument_type first_argument_type;
      typedef typename _Tp::second_argument_type second_argument_type;
    };

  // All the nested argument types.
   template<typename _Tp>
    struct _Reference_wrapper_base_impl<true, true, _Tp>
    : _Weak_result_type<_Tp>
    {
      typedef typename _Tp::argument_type argument_type;
      typedef typename _Tp::first_argument_type first_argument_type;
      typedef typename _Tp::second_argument_type second_argument_type;
    };

  _GLIBCXX_HAS_NESTED_TYPE(argument_type)
  _GLIBCXX_HAS_NESTED_TYPE(first_argument_type)
  _GLIBCXX_HAS_NESTED_TYPE(second_argument_type)

  /**
   *  Derives from unary_function or binary_function when it
   *  can. Specializations handle all of the easy cases. The primary
   *  template determines what to do with a class type, which may
   *  derive from both unary_function and binary_function.
  */
  template<typename _Tp>
    struct _Reference_wrapper_base
    : _Reference_wrapper_base_impl<
      __has_argument_type<_Tp>::value,
      __has_first_argument_type<_Tp>::value
      && __has_second_argument_type<_Tp>::value,
      _Tp>
    { };

  // - a function type (unary)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1)>
    : unary_function<_T1, _Res>
    { };

  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1) const>
    : unary_function<_T1, _Res>
    { };

  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1) volatile>
    : unary_function<_T1, _Res>
    { };

  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(_T1) const volatile>
    : unary_function<_T1, _Res>
    { };

  // - a function type (binary)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2)>
    : binary_function<_T1, _T2, _Res>
    { };

  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2) const>
    : binary_function<_T1, _T2, _Res>
    { };

  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2) volatile>
    : binary_function<_T1, _T2, _Res>
    { };

  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(_T1, _T2) const volatile>
    : binary_function<_T1, _T2, _Res>
    { };

  // - a function pointer type (unary)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res(*)(_T1)>
    : unary_function<_T1, _Res>
    { };

  // - a function pointer type (binary)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res(*)(_T1, _T2)>
    : binary_function<_T1, _T2, _Res>
    { };

  // - a pointer to member function type (unary, no qualifiers)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)()>
    : unary_function<_T1*, _Res>
    { };

  // - a pointer to member function type (binary, no qualifiers)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2)>
    : binary_function<_T1*, _T2, _Res>
    { };

  // - a pointer to member function type (unary, const)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)() const>
    : unary_function<const _T1*, _Res>
    { };

  // - a pointer to member function type (binary, const)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const>
    : binary_function<const _T1*, _T2, _Res>
    { };

  // - a pointer to member function type (unary, volatile)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)() volatile>
    : unary_function<volatile _T1*, _Res>
    { };

  // - a pointer to member function type (binary, volatile)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) volatile>
    : binary_function<volatile _T1*, _T2, _Res>
    { };

  // - a pointer to member function type (unary, const volatile)
  template<typename _Res, typename _T1>
    struct _Reference_wrapper_base<_Res (_T1::*)() const volatile>
    : unary_function<const volatile _T1*, _Res>
    { };

  // - a pointer to member function type (binary, const volatile)
  template<typename _Res, typename _T1, typename _T2>
    struct _Reference_wrapper_base<_Res (_T1::*)(_T2) const volatile>
    : binary_function<const volatile _T1*, _T2, _Res>
    { };

  /**
   *  @brief Primary class template for reference_wrapper.
   *  @ingroup functors
   *  @{
   */
  template<typename _Tp>
    class reference_wrapper
    : public _Reference_wrapper_base<typename remove_cv<_Tp>::type>
    {
      _Tp* _M_data;

    public:
      typedef _Tp type;

      reference_wrapper(_Tp& __indata)
      : _M_data(std::__addressof(__indata))
      { }

      reference_wrapper(_Tp&&) = delete;

      reference_wrapper(const reference_wrapper<_Tp>& __inref):
      _M_data(__inref._M_data)
      { }

      reference_wrapper&
      operator=(const reference_wrapper<_Tp>& __inref)
      {
	_M_data = __inref._M_data;
	return *this;
      }

      operator _Tp&() const
      { return this->get(); }

      _Tp&
      get() const
      { return *_M_data; }

      template<typename... _Args>
	typename result_of<_Tp&(_Args&&...)>::type
	operator()(_Args&&... __args) const
	{
	  return __invoke(get(), std::forward<_Args>(__args)...);
	}
    };


  /// Denotes a reference should be taken to a variable.
  template<typename _Tp>
    inline reference_wrapper<_Tp>
    ref(_Tp& __t)
    { return reference_wrapper<_Tp>(__t); }

  /// Denotes a const reference should be taken to a variable.
  template<typename _Tp>
    inline reference_wrapper<const _Tp>
    cref(const _Tp& __t)
    { return reference_wrapper<const _Tp>(__t); }

  template<typename _Tp>
    void ref(const _Tp&&) = delete;

  template<typename _Tp>
    void cref(const _Tp&&) = delete;

  /// Partial specialization.
  template<typename _Tp>
    inline reference_wrapper<_Tp>
    ref(reference_wrapper<_Tp> __t)
    { return ref(__t.get()); }

  /// Partial specialization.
  template<typename _Tp>
    inline reference_wrapper<const _Tp>
    cref(reference_wrapper<_Tp> __t)
    { return cref(__t.get()); }

  // @} group functors

  template<typename _MemberPointer>
    class _Mem_fn;

  /**
   * Derives from @c unary_function or @c binary_function, or perhaps
   * nothing, depending on the number of arguments provided. The
   * primary template is the basis case, which derives nothing.
   */
  template<typename _Res, typename... _ArgTypes>
    struct _Maybe_unary_or_binary_function { };

  /// Derives from @c unary_function, as appropriate.
  template<typename _Res, typename _T1>
    struct _Maybe_unary_or_binary_function<_Res, _T1>
    : std::unary_function<_T1, _Res> { };

  /// Derives from @c binary_function, as appropriate.
  template<typename _Res, typename _T1, typename _T2>
    struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
    : std::binary_function<_T1, _T2, _Res> { };

  /// Implementation of @c mem_fn for member function pointers.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    class _Mem_fn<_Res (_Class::*)(_ArgTypes...)>
    : public _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>
    {
      typedef _Res (_Class::*_Functor)(_ArgTypes...);

      template<typename _Tp>
	_Res
	_M_call(_Tp& __object, const volatile _Class *,
		_ArgTypes... __args) const
	{ return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      template<typename _Tp>
	_Res
	_M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }

    public:
      typedef _Res result_type;

      explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }

      // Handle objects
      _Res
      operator()(_Class& __object, _ArgTypes... __args) const
      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle pointers
      _Res
      operator()(_Class* __object, _ArgTypes... __args) const
      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle smart pointers, references and pointers to derived
      template<typename _Tp>
	_Res
	operator()(_Tp& __object, _ArgTypes... __args) const
	{
	  return _M_call(__object, &__object,
	      std::forward<_ArgTypes>(__args)...);
	}

    private:
      _Functor __pmf;
    };

  /// Implementation of @c mem_fn for const member function pointers.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const>
    : public _Maybe_unary_or_binary_function<_Res, const _Class*,
					     _ArgTypes...>
    {
      typedef _Res (_Class::*_Functor)(_ArgTypes...) const;

      template<typename _Tp>
	_Res
	_M_call(_Tp& __object, const volatile _Class *,
		_ArgTypes... __args) const
	{ return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      template<typename _Tp>
	_Res
	_M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }

    public:
      typedef _Res result_type;

      explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }

      // Handle objects
      _Res
      operator()(const _Class& __object, _ArgTypes... __args) const
      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle pointers
      _Res
      operator()(const _Class* __object, _ArgTypes... __args) const
      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle smart pointers, references and pointers to derived
      template<typename _Tp>
	_Res operator()(_Tp& __object, _ArgTypes... __args) const
	{
	  return _M_call(__object, &__object,
	      std::forward<_ArgTypes>(__args)...);
	}

    private:
      _Functor __pmf;
    };

  /// Implementation of @c mem_fn for volatile member function pointers.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    class _Mem_fn<_Res (_Class::*)(_ArgTypes...) volatile>
    : public _Maybe_unary_or_binary_function<_Res, volatile _Class*,
					     _ArgTypes...>
    {
      typedef _Res (_Class::*_Functor)(_ArgTypes...) volatile;

      template<typename _Tp>
	_Res
	_M_call(_Tp& __object, const volatile _Class *,
		_ArgTypes... __args) const
	{ return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      template<typename _Tp>
	_Res
	_M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }

    public:
      typedef _Res result_type;

      explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }

      // Handle objects
      _Res
      operator()(volatile _Class& __object, _ArgTypes... __args) const
      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle pointers
      _Res
      operator()(volatile _Class* __object, _ArgTypes... __args) const
      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle smart pointers, references and pointers to derived
      template<typename _Tp>
	_Res
	operator()(_Tp& __object, _ArgTypes... __args) const
	{
	  return _M_call(__object, &__object,
	      std::forward<_ArgTypes>(__args)...);
	}

    private:
      _Functor __pmf;
    };

  /// Implementation of @c mem_fn for const volatile member function pointers.
  template<typename _Res, typename _Class, typename... _ArgTypes>
    class _Mem_fn<_Res (_Class::*)(_ArgTypes...) const volatile>
    : public _Maybe_unary_or_binary_function<_Res, const volatile _Class*,
					     _ArgTypes...>
    {
      typedef _Res (_Class::*_Functor)(_ArgTypes...) const volatile;

      template<typename _Tp>
	_Res
	_M_call(_Tp& __object, const volatile _Class *,
		_ArgTypes... __args) const
	{ return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      template<typename _Tp>
	_Res
	_M_call(_Tp& __ptr, const volatile void *, _ArgTypes... __args) const
	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }

    public:
      typedef _Res result_type;

      explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }

      // Handle objects
      _Res
      operator()(const volatile _Class& __object, _ArgTypes... __args) const
      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle pointers
      _Res
      operator()(const volatile _Class* __object, _ArgTypes... __args) const
      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }

      // Handle smart pointers, references and pointers to derived
      template<typename _Tp>
	_Res operator()(_Tp& __object, _ArgTypes... __args) const
	{
	  return _M_call(__object, &__object,
	      std::forward<_ArgTypes>(__args)...);
	}

    private:
      _Functor __pmf;
    };


  template<typename _Tp, bool>
    struct _Mem_fn_const_or_non
    {
      typedef const _Tp& type;
    };

  template<typename _Tp>
    struct _Mem_fn_const_or_non<_Tp, false>
    {
      typedef _Tp& type;
    };

  template<typename _Res, typename _Class>
    class _Mem_fn<_Res _Class::*>
    {
      // This bit of genius is due to Peter Dimov, improved slightly by
      // Douglas Gregor.
      template<typename _Tp>
	_Res&
	_M_call(_Tp& __object, _Class *) const
	{ return __object.*__pm; }

      template<typename _Tp, typename _Up>
	_Res&
	_M_call(_Tp& __object, _Up * const *) const
	{ return (*__object).*__pm; }

      template<typename _Tp, typename _Up>
	const _Res&
	_M_call(_Tp& __object, const _Up * const *) const
	{ return (*__object).*__pm; }

      template<typename _Tp>
	const _Res&
	_M_call(_Tp& __object, const _Class *) const
	{ return __object.*__pm; }

      template<typename _Tp>
	const _Res&
	_M_call(_Tp& __ptr, const volatile void*) const
	{ return (*__ptr).*__pm; }

      template<typename _Tp> static _Tp& __get_ref();

      template<typename _Tp>
	static __sfinae_types::__one __check_const(_Tp&, _Class*);
      template<typename _Tp, typename _Up>
	static __sfinae_types::__one __check_const(_Tp&, _Up * const *);
      template<typename _Tp, typename _Up>
	static __sfinae_types::__two __check_const(_Tp&, const _Up * const *);
      template<typename _Tp>
	static __sfinae_types::__two __check_const(_Tp&, const _Class*);
      template<typename _Tp>
	static __sfinae_types::__two __check_const(_Tp&, const volatile void*);

    public:
      template<typename _Tp>
	struct _Result_type
	: _Mem_fn_const_or_non<_Res,
	  (sizeof(__sfinae_types::__two)
	   == sizeof(__check_const<_Tp>(__get_ref<_Tp>(), (_Tp*)0)))>
	{ };

      template<typename _Signature>
	struct result;

      template<typename _CVMem, typename _Tp>
	struct result<_CVMem(_Tp)>
	: public _Result_type<_Tp> { };

      template<typename _CVMem, typename _Tp>
	struct result<_CVMem(_Tp&)>
	: public _Result_type<_Tp> { };

      explicit
      _Mem_fn(_Res _Class::*__pm) : __pm(__pm) { }

      // Handle objects
      _Res&
      operator()(_Class& __object) const
      { return __object.*__pm; }

      const _Res&
      operator()(const _Class& __object) const
      { return __object.*__pm; }

      // Handle pointers
      _Res&
      operator()(_Class* __object) const
      { return __object->*__pm; }

      const _Res&
      operator()(const _Class* __object) const
      { return __object->*__pm; }

      // Handle smart pointers and derived
      template<typename _Tp>
	typename _Result_type<_Tp>::type
	operator()(_Tp& __unknown) const
	{ return _M_call(__unknown, &__unknown); }

    private:
      _Res _Class::*__pm;
    };

  /**
   *  @brief Returns a function object that forwards to the member
   *  pointer @a pm.
   *  @ingroup functors
   */
  template<typename _Tp, typename _Class>
    inline _Mem_fn<_Tp _Class::*>
    mem_fn(_Tp _Class::* __pm)
    {
      return _Mem_fn<_Tp _Class::*>(__pm);
    }

  /**
   *  @brief Determines if the given type _Tp is a function object
   *  should be treated as a subexpression when evaluating calls to
   *  function objects returned by bind(). [TR1 3.6.1]
   *  @ingroup binders
   */
  template<typename _Tp>
    struct is_bind_expression
    : public false_type { };

  /**
   *  @brief Determines if the given type _Tp is a placeholder in a
   *  bind() expression and, if so, which placeholder it is. [TR1 3.6.2]
   *  @ingroup binders
   */
  template<typename _Tp>
    struct is_placeholder
    : public integral_constant<int, 0>
    { };

  /// The type of placeholder objects defined by libstdc++.
  template<int _Num> struct _Placeholder { };

  _GLIBCXX_END_NAMESPACE_VERSION

  /** @namespace std::placeholders
   *  @brief ISO C++ 0x entities sub namespace for functional.
   *  @ingroup binders
   *
   *  Define a large number of placeholders. There is no way to
   *  simplify this with variadic templates, because we're introducing
   *  unique names for each.
   */
  namespace placeholders
  {
  _GLIBCXX_BEGIN_NAMESPACE_VERSION
    extern const _Placeholder<1> _1;
    extern const _Placeholder<2> _2;
    extern const _Placeholder<3> _3;
    extern const _Placeholder<4> _4;
    extern const _Placeholder<5> _5;
    extern const _Placeholder<6> _6;
    extern const _Placeholder<7> _7;
    extern const _Placeholder<8> _8;
    extern const _Placeholder<9> _9;
    extern const _Placeholder<10> _10;
    extern const _Placeholder<11> _11;
    extern const _Placeholder<12> _12;
    extern const _Placeholder<13> _13;
    extern const _Placeholder<14> _14;
    extern const _Placeholder<15> _15;
    extern const _Placeholder<16> _16;
    extern const _Placeholder<17> _17;
    extern const _Placeholder<18> _18;
    extern const _Placeholder<19> _19;
    extern const _Placeholder<20> _20;
    extern const _Placeholder<21> _21;
    extern const _Placeholder<22> _22;
    extern const _Placeholder<23> _23;
    extern const _Placeholder<24> _24;
    extern const _Placeholder<25> _25;
    extern const _Placeholder<26> _26;
    extern const _Placeholder<27> _27;
    extern const _Placeholder<28> _28;
    extern const _Placeholder<29> _29;
  _GLIBCXX_END_NAMESPACE_VERSION
  }

  _GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**
   *  Partial specialization of is_placeholder that provides the placeholder
   *  number for the placeholder objects defined by libstdc++.
   *  @ingroup binders
   */
  template<int _Num>
    struct is_placeholder<_Placeholder<_Num> >
    : public integral_constant<int, _Num>
    { };

  /**
   * Used by _Safe_tuple_element to indicate that there is no tuple
   * element at this position.
   */
  struct _No_tuple_element;

  /**
   * Implementation helper for _Safe_tuple_element. This primary
   * template handles the case where it is safe to use @c
   * tuple_element.
   */
  template<int __i, typename _Tuple, bool _IsSafe>
    struct _Safe_tuple_element_impl
    : tuple_element<__i, _Tuple> { };

  /**
   * Implementation helper for _Safe_tuple_element. This partial
   * specialization handles the case where it is not safe to use @c
   * tuple_element. We just return @c _No_tuple_element.
   */
  template<int __i, typename _Tuple>
    struct _Safe_tuple_element_impl<__i, _Tuple, false>
    {
      typedef _No_tuple_element type;
    };

  /**
   * Like tuple_element, but returns @c _No_tuple_element when
   * tuple_element would return an error.
   */
 template<int __i, typename _Tuple>
   struct _Safe_tuple_element
   : _Safe_tuple_element_impl<__i, _Tuple,
			      (__i >= 0 && __i < tuple_size<_Tuple>::value)>
   { };

  /**
   *  Maps an argument to bind() into an actual argument to the bound
   *  function object [TR1 3.6.3/5]. Only the first parameter should
   *  be specified: the rest are used to determine among the various
   *  implementations. Note that, although this class is a function
   *  object, it isn't entirely normal because it takes only two
   *  parameters regardless of the number of parameters passed to the
   *  bind expression. The first parameter is the bound argument and
   *  the second parameter is a tuple containing references to the
   *  rest of the arguments.
   */
  template<typename _Arg,
	   bool _IsBindExp = is_bind_expression<_Arg>::value,
	   bool _IsPlaceholder = (is_placeholder<_Arg>::value > 0)>
    class _Mu;

  /**
   *  If the argument is reference_wrapper<_Tp>, returns the
   *  underlying reference. [TR1 3.6.3/5 bullet 1]
   */
  template<typename _Tp>
    class _Mu<reference_wrapper<_Tp>, false, false>
    {
    public:
      typedef _Tp& result_type;

      /* Note: This won't actually work for const volatile
       * reference_wrappers, because reference_wrapper::get() is const
       * but not volatile-qualified. This might be a defect in the TR.
       */
      template<typename _CVRef, typename _Tuple>
	result_type
	operator()(_CVRef& __arg, _Tuple&) const volatile
	{ return __arg.get(); }
    };

  /**
   *  If the argument is a bind expression, we invoke the underlying
   *  function object with the same cv-qualifiers as we are given and
   *  pass along all of our arguments (unwrapped). [TR1 3.6.3/5 bullet 2]
   */
  template<typename _Arg>
    class _Mu<_Arg, true, false>
    {
    public:
      template<typename _CVArg, typename... _Args>
	auto
	operator()(_CVArg& __arg,
		   tuple<_Args...>& __tuple) const volatile
	-> decltype(__arg(declval<_Args>()...))
	{
	  // Construct an index tuple and forward to __call
	  typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
	    _Indexes;
	  return this->__call(__arg, __tuple, _Indexes());
	}

    private:
      // Invokes the underlying function object __arg by unpacking all
      // of the arguments in the tuple.
      template<typename _CVArg, typename... _Args, int... _Indexes>
	auto
	__call(_CVArg& __arg, tuple<_Args...>& __tuple,
	       const _Index_tuple<_Indexes...>&) const volatile
	-> decltype(__arg(declval<_Args>()...))
	{
	  return __arg(std::forward<_Args>(get<_Indexes>(__tuple))...);
	}
    };

  /**
   *  If the argument is a placeholder for the Nth argument, returns
   *  a reference to the Nth argument to the bind function object.
   *  [TR1 3.6.3/5 bullet 3]
   */
  template<typename _Arg>
    class _Mu<_Arg, false, true>
    {
    public:
      template<typename _Signature> class result;

      template<typename _CVMu, typename _CVArg, typename _Tuple>
	class result<_CVMu(_CVArg, _Tuple)>
	{
	  // Add a reference, if it hasn't already been done for us.
	  // This allows us to be a little bit sloppy in constructing
	  // the tuple that we pass to result_of<...>.
	  typedef typename _Safe_tuple_element<(is_placeholder<_Arg>::value
						- 1), _Tuple>::type
	    __base_type;

	public:
	  typedef typename add_rvalue_reference<__base_type>::type type;
	};

      template<typename _Tuple>
	typename result<_Mu(_Arg, _Tuple)>::type
	operator()(const volatile _Arg&, _Tuple& __tuple) const volatile
	{
	  return std::forward<typename result<_Mu(_Arg, _Tuple)>::type>(
	      ::std::get<(is_placeholder<_Arg>::value - 1)>(__tuple));
	}
    };

  /**
   *  If the argument is just a value, returns a reference to that
   *  value. The cv-qualifiers on the reference are the same as the
   *  cv-qualifiers on the _Mu object. [TR1 3.6.3/5 bullet 4]
   */
  template<typename _Arg>
    class _Mu<_Arg, false, false>
    {
    public:
      template<typename _Signature> struct result;

      template<typename _CVMu, typename _CVArg, typename _Tuple>
	struct result<_CVMu(_CVArg, _Tuple)>
	{
	  typedef typename add_lvalue_reference<_CVArg>::type type;
	};

      // Pick up the cv-qualifiers of the argument
      template<typename _CVArg, typename _Tuple>
	_CVArg&&
	operator()(_CVArg&& __arg, _Tuple&) const volatile
	{ return std::forward<_CVArg>(__arg); }
    };

  /**
   *  Maps member pointers into instances of _Mem_fn but leaves all
   *  other function objects untouched. Used by tr1::bind(). The
   *  primary template handles the non--member-pointer case.
   */
  template<typename _Tp>
    struct _Maybe_wrap_member_pointer
    {
      typedef _Tp type;

      static const _Tp&
      __do_wrap(const _Tp& __x)
      { return __x; }

      static _Tp&&
      __do_wrap(_Tp&& __x)
      { return static_cast<_Tp&&>(__x); }
    };

  /**
   *  Maps member pointers into instances of _Mem_fn but leaves all
   *  other function objects untouched. Used by tr1::bind(). This
   *  partial specialization handles the member pointer case.
   */
  template<typename _Tp, typename _Class>
    struct _Maybe_wrap_member_pointer<_Tp _Class::*>
    {
      typedef _Mem_fn<_Tp _Class::*> type;

      static type
      __do_wrap(_Tp _Class::* __pm)
      { return type(__pm); }
    };

  // Specialization needed to prevent "forming reference to void" errors when
  // bind<void>() is called, because argument deduction instantiates
  // _Maybe_wrap_member_pointer<void> outside the immediate context where
  // SFINAE applies.
  template<>
    struct _Maybe_wrap_member_pointer<void>
    {
      typedef void type;
    };

  // std::get<I> for volatile-qualified tuples
  template<size_t _Ind, typename... _Tp>
    inline auto
    __volget(volatile tuple<_Tp...>& __tuple)
    -> typename tuple_element<_Ind, tuple<_Tp...>>::type volatile&
    { return std::get<_Ind>(const_cast<tuple<_Tp...>&>(__tuple)); }

  // std::get<I> for const-volatile-qualified tuples
  template<size_t _Ind, typename... _Tp>
    inline auto
    __volget(const volatile tuple<_Tp...>& __tuple)
    -> typename tuple_element<_Ind, tuple<_Tp...>>::type const volatile&
    { return std::get<_Ind>(const_cast<const tuple<_Tp...>&>(__tuple)); }

  /// Type of the function object returned from bind().
  template<typename _Signature>
    struct _Bind;

   template<typename _Functor, typename... _Bound_args>
    class _Bind<_Functor(_Bound_args...)>
    : public _Weak_result_type<_Functor>
    {
      typedef _Bind __self_type;
      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
	_Bound_indexes;

      _Functor _M_f;
      tuple<_Bound_args...> _M_bound_args;

      // Call unqualified
      template<typename _Result, typename... _Args, int... _Indexes>
	_Result
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>)
	{
	  return _M_f(_Mu<_Bound_args>()
		      (get<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as const
      template<typename _Result, typename... _Args, int... _Indexes>
	_Result
	__call_c(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>) const
	{
	  return _M_f(_Mu<_Bound_args>()
		      (get<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as volatile
      template<typename _Result, typename... _Args, int... _Indexes>
	_Result
	__call_v(tuple<_Args...>&& __args,
		 _Index_tuple<_Indexes...>) volatile
	{
	  return _M_f(_Mu<_Bound_args>()
		      (__volget<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as const volatile
      template<typename _Result, typename... _Args, int... _Indexes>
	_Result
	__call_c_v(tuple<_Args...>&& __args,
		   _Index_tuple<_Indexes...>) const volatile
	{
	  return _M_f(_Mu<_Bound_args>()
		      (__volget<_Indexes>(_M_bound_args), __args)...);
	}

     public:
      template<typename... _Args>
	explicit _Bind(const _Functor& __f, _Args&&... __args)
	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
	{ }

      template<typename... _Args>
	explicit _Bind(_Functor&& __f, _Args&&... __args)
	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
	{ }

      _Bind(const _Bind&) = default;

      _Bind(_Bind&& __b)
      : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
      { }

      // Call unqualified
      template<typename... _Args, typename _Result
	= decltype( std::declval<_Functor>()(
	      _Mu<_Bound_args>()( std::declval<_Bound_args&>(),
				  std::declval<tuple<_Args...>&>() )... ) )>
	_Result
	operator()(_Args&&... __args)
	{
	  return this->__call<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}

      // Call as const
      template<typename... _Args, typename _Result
	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
		       typename add_const<_Functor>::type>::type>()(
	      _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
				  std::declval<tuple<_Args...>&>() )... ) )>
	_Result
	operator()(_Args&&... __args) const
	{
	  return this->__call_c<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}

      // Call as volatile
      template<typename... _Args, typename _Result
	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
                       typename add_volatile<_Functor>::type>::type>()(
	      _Mu<_Bound_args>()( std::declval<volatile _Bound_args&>(),
				  std::declval<tuple<_Args...>&>() )... ) )>
	_Result
	operator()(_Args&&... __args) volatile
	{
	  return this->__call_v<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}

      // Call as const volatile
      template<typename... _Args, typename _Result
	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
                       typename add_cv<_Functor>::type>::type>()(
	      _Mu<_Bound_args>()( std::declval<const volatile _Bound_args&>(),
				  std::declval<tuple<_Args...>&>() )... ) )>
	_Result
	operator()(_Args&&... __args) const volatile
	{
	  return this->__call_c_v<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}
    };

  /// Type of the function object returned from bind<R>().
  template<typename _Result, typename _Signature>
    struct _Bind_result;

  template<typename _Result, typename _Functor, typename... _Bound_args>
    class _Bind_result<_Result, _Functor(_Bound_args...)>
    {
      typedef _Bind_result __self_type;
      typedef typename _Build_index_tuple<sizeof...(_Bound_args)>::__type
	_Bound_indexes;

      _Functor _M_f;
      tuple<_Bound_args...> _M_bound_args;

      // sfinae types
      template<typename _Res>
	struct __enable_if_void : enable_if<is_void<_Res>::value, int> { };
      template<typename _Res>
	struct __disable_if_void : enable_if<!is_void<_Res>::value, int> { };

      // Call unqualified
      template<typename _Res, typename... _Args, int... _Indexes>
	_Result
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
	    typename __disable_if_void<_Res>::type = 0)
	{
	  return _M_f(_Mu<_Bound_args>()
		      (get<_Indexes>(_M_bound_args), __args)...);
	}

      // Call unqualified, return void
      template<typename _Res, typename... _Args, int... _Indexes>
	void
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
	    typename __enable_if_void<_Res>::type = 0)
	{
	  _M_f(_Mu<_Bound_args>()
	       (get<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as const
      template<typename _Res, typename... _Args, int... _Indexes>
	_Result
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
	    typename __disable_if_void<_Res>::type = 0) const
	{
	  return _M_f(_Mu<_Bound_args>()
		      (get<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as const, return void
      template<typename _Res, typename... _Args, int... _Indexes>
	void
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
	    typename __enable_if_void<_Res>::type = 0) const
	{
	  _M_f(_Mu<_Bound_args>()
	       (get<_Indexes>(_M_bound_args),  __args)...);
	}

      // Call as volatile
      template<typename _Res, typename... _Args, int... _Indexes>
	_Result
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
	    typename __disable_if_void<_Res>::type = 0) volatile
	{
	  return _M_f(_Mu<_Bound_args>()
		      (__volget<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as volatile, return void
      template<typename _Res, typename... _Args, int... _Indexes>
	void
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
	    typename __enable_if_void<_Res>::type = 0) volatile
	{
	  _M_f(_Mu<_Bound_args>()
	       (__volget<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as const volatile
      template<typename _Res, typename... _Args, int... _Indexes>
	_Result
	__call(tuple<_Args...>&& __args, _Index_tuple<_Indexes...>,
	    typename __disable_if_void<_Res>::type = 0) const volatile
	{
	  return _M_f(_Mu<_Bound_args>()
		      (__volget<_Indexes>(_M_bound_args), __args)...);
	}

      // Call as const volatile, return void
      template<typename _Res, typename... _Args, int... _Indexes>
	void
	__call(tuple<_Args...>&& __args,
	       _Index_tuple<_Indexes...>,
	    typename __enable_if_void<_Res>::type = 0) const volatile
	{
	  _M_f(_Mu<_Bound_args>()
	       (__volget<_Indexes>(_M_bound_args), __args)...);
	}

    public:
      typedef _Result result_type;

      template<typename... _Args>
	explicit _Bind_result(const _Functor& __f, _Args&&... __args)
	: _M_f(__f), _M_bound_args(std::forward<_Args>(__args)...)
	{ }

      template<typename... _Args>
	explicit _Bind_result(_Functor&& __f, _Args&&... __args)
	: _M_f(std::move(__f)), _M_bound_args(std::forward<_Args>(__args)...)
	{ }

      _Bind_result(const _Bind_result&) = default;

      _Bind_result(_Bind_result&& __b)
      : _M_f(std::move(__b._M_f)), _M_bound_args(std::move(__b._M_bound_args))
      { }

      // Call unqualified
      template<typename... _Args>
	result_type
	operator()(_Args&&... __args)
	{
	  return this->__call<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}

      // Call as const
      template<typename... _Args>
	result_type
	operator()(_Args&&... __args) const
	{
	  return this->__call<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}

      // Call as volatile
      template<typename... _Args>
	result_type
	operator()(_Args&&... __args) volatile
	{
	  return this->__call<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}

      // Call as const volatile
      template<typename... _Args>
	result_type
	operator()(_Args&&... __args) const volatile
	{
	  return this->__call<_Result>(
	      std::forward_as_tuple(std::forward<_Args>(__args)...),
	      _Bound_indexes());
	}
    };

  /**
   *  @brief Class template _Bind is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Signature>
    struct is_bind_expression<_Bind<_Signature> >
    : public true_type { };

  /**
   *  @brief Class template _Bind is always a bind expression.
   *  @ingroup binders
   */
  template<typename _Result, typename _Signature>
    struct is_bind_expression<_Bind_result<_Result, _Signature> >
    : public true_type { };

  template<typename _Functor, typename... _ArgTypes>
    struct _Bind_helper
    {
      typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
	__maybe_type;
      typedef typename __maybe_type::type __functor_type;
      typedef _Bind<__functor_type(typename decay<_ArgTypes>::type...)> type;
    };

  /**
   *  @brief Function template for std::bind.
   *  @ingroup binders
   */
  template<typename _Functor, typename... _ArgTypes>
    inline
    typename _Bind_helper<_Functor, _ArgTypes...>::type
    bind(_Functor&& __f, _ArgTypes&&... __args)
    {
      typedef _Bind_helper<_Functor, _ArgTypes...> __helper_type;
      typedef typename __helper_type::__maybe_type __maybe_type;
      typedef typename __helper_type::type __result_type;
      return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
			   std::forward<_ArgTypes>(__args)...);
    }

  template<typename _Result, typename _Functor, typename... _ArgTypes>
    struct _Bindres_helper
    {
      typedef _Maybe_wrap_member_pointer<typename decay<_Functor>::type>
	__maybe_type;
      typedef typename __maybe_type::type __functor_type;
      typedef _Bind_result<_Result,
			   __functor_type(typename decay<_ArgTypes>::type...)>
	type;
    };

  /**
   *  @brief Function template for std::bind<R>.
   *  @ingroup binders
   */
  template<typename _Result, typename _Functor, typename... _ArgTypes>
    inline
    typename _Bindres_helper<_Result, _Functor, _ArgTypes...>::type
    bind(_Functor&& __f, _ArgTypes&&... __args)
    {
      typedef _Bindres_helper<_Result, _Functor, _ArgTypes...> __helper_type;
      typedef typename __helper_type::__maybe_type __maybe_type;
      typedef typename __helper_type::type __result_type;
      return __result_type(__maybe_type::__do_wrap(std::forward<_Functor>(__f)),
			   std::forward<_ArgTypes>(__args)...);
    }

  /**
   *  @brief Exception class thrown when class template function's
   *  operator() is called with an empty target.
   *  @ingroup exceptions
   */
  class bad_function_call : public std::exception
  {
  public:
    virtual ~bad_function_call() throw();
  };

  /**
   *  Trait identifying "location-invariant" types, meaning that the
   *  address of the object (or any of its members) will not escape.
   *  Also implies a trivial copy constructor and assignment operator.
   */
  template<typename _Tp>
    struct __is_location_invariant
    : integral_constant<bool, (is_pointer<_Tp>::value
			       || is_member_pointer<_Tp>::value)>
    { };

  class _Undefined_class;

  union _Nocopy_types
  {
    void*       _M_object;
    const void* _M_const_object;
    void (*_M_function_pointer)();
    void (_Undefined_class::*_M_member_pointer)();
  };

  union _Any_data
  {
    void*       _M_access()       { return &_M_pod_data[0]; }
    const void* _M_access() const { return &_M_pod_data[0]; }

    template<typename _Tp>
      _Tp&
      _M_access()
      { return *static_cast<_Tp*>(_M_access()); }

    template<typename _Tp>
      const _Tp&
      _M_access() const
      { return *static_cast<const _Tp*>(_M_access()); }

    _Nocopy_types _M_unused;
    char _M_pod_data[sizeof(_Nocopy_types)];
  };

  enum _Manager_operation
  {
    __get_type_info,
    __get_functor_ptr,
    __clone_functor,
    __destroy_functor
  };

  // Simple type wrapper that helps avoid annoying const problems
  // when casting between void pointers and pointers-to-pointers.
  template<typename _Tp>
    struct _Simple_type_wrapper
    {
      _Simple_type_wrapper(_Tp __value) : __value(__value) { }

      _Tp __value;
    };

  template<typename _Tp>
    struct __is_location_invariant<_Simple_type_wrapper<_Tp> >
    : __is_location_invariant<_Tp>
    { };

  // Converts a reference to a function object into a callable
  // function object.
  template<typename _Functor>
    inline _Functor&
    __callable_functor(_Functor& __f)
    { return __f; }

  template<typename _Member, typename _Class>
    inline _Mem_fn<_Member _Class::*>
    __callable_functor(_Member _Class::* &__p)
    { return mem_fn(__p); }

  template<typename _Member, typename _Class>
    inline _Mem_fn<_Member _Class::*>
    __callable_functor(_Member _Class::* const &__p)
    { return mem_fn(__p); }

  template<typename _Signature>
    class function;

  /// Base class of all polymorphic function object wrappers.
  class _Function_base
  {
  public:
    static const std::size_t _M_max_size = sizeof(_Nocopy_types);
    static const std::size_t _M_max_align = __alignof__(_Nocopy_types);

    template<typename _Functor>
      class _Base_manager
      {
      protected:
	static const bool __stored_locally =
	(__is_location_invariant<_Functor>::value
	 && sizeof(_Functor) <= _M_max_size
	 && __alignof__(_Functor) <= _M_max_align
	 && (_M_max_align % __alignof__(_Functor) == 0));

	typedef integral_constant<bool, __stored_locally> _Local_storage;

	// Retrieve a pointer to the function object
	static _Functor*
	_M_get_pointer(const _Any_data& __source)
	{
	  const _Functor* __ptr =
	    __stored_locally? std::__addressof(__source._M_access<_Functor>())
	    /* have stored a pointer */ : __source._M_access<_Functor*>();
	  return const_cast<_Functor*>(__ptr);
	}

	// Clone a location-invariant function object that fits within
	// an _Any_data structure.
	static void
	_M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
	{
	  new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
	}

	// Clone a function object that is not location-invariant or
	// that cannot fit into an _Any_data structure.
	static void
	_M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
	{
	  __dest._M_access<_Functor*>() =
	    new _Functor(*__source._M_access<_Functor*>());
	}

	// Destroying a location-invariant object may still require
	// destruction.
	static void
	_M_destroy(_Any_data& __victim, true_type)
	{
	  __victim._M_access<_Functor>().~_Functor();
	}

	// Destroying an object located on the heap.
	static void
	_M_destroy(_Any_data& __victim, false_type)
	{
	  delete __victim._M_access<_Functor*>();
	}

      public:
	static bool
	_M_manager(_Any_data& __dest, const _Any_data& __source,
		   _Manager_operation __op)
	{
	  switch (__op)
	    {
#ifdef __GXX_RTTI
	    case __get_type_info:
	      __dest._M_access<const type_info*>() = &typeid(_Functor);
	      break;
#endif
	    case __get_functor_ptr:
	      __dest._M_access<_Functor*>() = _M_get_pointer(__source);
	      break;

	    case __clone_functor:
	      _M_clone(__dest, __source, _Local_storage());
	      break;

	    case __destroy_functor:
	      _M_destroy(__dest, _Local_storage());
	      break;
	    }
	  return false;
	}

	static void
	_M_init_functor(_Any_data& __functor, _Functor&& __f)
	{ _M_init_functor(__functor, std::move(__f), _Local_storage()); }

	template<typename _Signature>
	  static bool
	  _M_not_empty_function(const function<_Signature>& __f)
	  { return static_cast<bool>(__f); }

	template<typename _Tp>
	  static bool
	  _M_not_empty_function(const _Tp*& __fp)
	  { return __fp; }

	template<typename _Class, typename _Tp>
	  static bool
	  _M_not_empty_function(_Tp _Class::* const& __mp)
	  { return __mp; }

	template<typename _Tp>
	  static bool
	  _M_not_empty_function(const _Tp&)
	  { return true; }

      private:
	static void
	_M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
	{ new (__functor._M_access()) _Functor(std::move(__f)); }

	static void
	_M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
	{ __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
      };

    template<typename _Functor>
      class _Ref_manager : public _Base_manager<_Functor*>
      {
	typedef _Function_base::_Base_manager<_Functor*> _Base;

    public:
	static bool
	_M_manager(_Any_data& __dest, const _Any_data& __source,
		   _Manager_operation __op)
	{
	  switch (__op)
	    {
#ifdef __GXX_RTTI
	    case __get_type_info:
	      __dest._M_access<const type_info*>() = &typeid(_Functor);
	      break;
#endif
	    case __get_functor_ptr:
	      __dest._M_access<_Functor*>() = *_Base::_M_get_pointer(__source);
	      return is_const<_Functor>::value;
	      break;

	    default:
	      _Base::_M_manager(__dest, __source, __op);
	    }
	  return false;
	}

	static void
	_M_init_functor(_Any_data& __functor, reference_wrapper<_Functor> __f)
	{
	  // TBD: Use address_of function instead.
	  _Base::_M_init_functor(__functor, &__f.get());
	}
      };

    _Function_base() : _M_manager(0) { }

    ~_Function_base()
    {
      if (_M_manager)
	_M_manager(_M_functor, _M_functor, __destroy_functor);
    }


    bool _M_empty() const { return !_M_manager; }

    typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
				  _Manager_operation);

    _Any_data     _M_functor;
    _Manager_type _M_manager;
  };

  template<typename _Signature, typename _Functor>
    class _Function_handler;

  template<typename _Res, typename _Functor, typename... _ArgTypes>
    class _Function_handler<_Res(_ArgTypes...), _Functor>
    : public _Function_base::_Base_manager<_Functor>
    {
      typedef _Function_base::_Base_manager<_Functor> _Base;

    public:
      static _Res
      _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
      {
	return (*_Base::_M_get_pointer(__functor))(
	    std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Functor, typename... _ArgTypes>
    class _Function_handler<void(_ArgTypes...), _Functor>
    : public _Function_base::_Base_manager<_Functor>
    {
      typedef _Function_base::_Base_manager<_Functor> _Base;

     public:
      static void
      _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
      {
	(*_Base::_M_get_pointer(__functor))(
	    std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Res, typename _Functor, typename... _ArgTypes>
    class _Function_handler<_Res(_ArgTypes...), reference_wrapper<_Functor> >
    : public _Function_base::_Ref_manager<_Functor>
    {
      typedef _Function_base::_Ref_manager<_Functor> _Base;

     public:
      static _Res
      _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
      {
	return __callable_functor(**_Base::_M_get_pointer(__functor))(
	      std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Functor, typename... _ArgTypes>
    class _Function_handler<void(_ArgTypes...), reference_wrapper<_Functor> >
    : public _Function_base::_Ref_manager<_Functor>
    {
      typedef _Function_base::_Ref_manager<_Functor> _Base;

     public:
      static void
      _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
      {
	__callable_functor(**_Base::_M_get_pointer(__functor))(
	    std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Class, typename _Member, typename _Res,
	   typename... _ArgTypes>
    class _Function_handler<_Res(_ArgTypes...), _Member _Class::*>
    : public _Function_handler<void(_ArgTypes...), _Member _Class::*>
    {
      typedef _Function_handler<void(_ArgTypes...), _Member _Class::*>
	_Base;

     public:
      static _Res
      _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
      {
	return mem_fn(_Base::_M_get_pointer(__functor)->__value)(
	    std::forward<_ArgTypes>(__args)...);
      }
    };

  template<typename _Class, typename _Member, typename... _ArgTypes>
    class _Function_handler<void(_ArgTypes...), _Member _Class::*>
    : public _Function_base::_Base_manager<
		 _Simple_type_wrapper< _Member _Class::* > >
    {
      typedef _Member _Class::* _Functor;
      typedef _Simple_type_wrapper<_Functor> _Wrapper;
      typedef _Function_base::_Base_manager<_Wrapper> _Base;

     public:
      static bool
      _M_manager(_Any_data& __dest, const _Any_data& __source,
		 _Manager_operation __op)
      {
	switch (__op)
	  {
#ifdef __GXX_RTTI
	  case __get_type_info:
	    __dest._M_access<const type_info*>() = &typeid(_Functor);
	    break;
#endif
	  case __get_functor_ptr:
	    __dest._M_access<_Functor*>() =
	      &_Base::_M_get_pointer(__source)->__value;
	    break;

	  default:
	    _Base::_M_manager(__dest, __source, __op);
	  }
	return false;
      }

      static void
      _M_invoke(const _Any_data& __functor, _ArgTypes... __args)
      {
	mem_fn(_Base::_M_get_pointer(__functor)->__value)(
	    std::forward<_ArgTypes>(__args)...);
      }
    };

  /**
   *  @brief Primary class template for std::function.
   *  @ingroup functors
   *
   *  Polymorphic function wrapper.
   */
  template<typename _Res, typename... _ArgTypes>
    class function<_Res(_ArgTypes...)>
    : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
      private _Function_base
    {
      typedef _Res _Signature_type(_ArgTypes...);

      struct _Useless { };

    public:
      typedef _Res result_type;

      // [3.7.2.1] construct/copy/destroy

      /**
       *  @brief Default construct creates an empty function call wrapper.
       *  @post @c !(bool)*this
       */
      function() : _Function_base() { }

      /**
       *  @brief Creates an empty function call wrapper.
       *  @post @c !(bool)*this
       */
      function(nullptr_t) : _Function_base() { }

      /**
       *  @brief %Function copy constructor.
       *  @param x A %function object with identical call signature.
       *  @post @c (bool)*this == (bool)x
       *
       *  The newly-created %function contains a copy of the target of @a
       *  x (if it has one).
       */
      function(const function& __x);

      /**
       *  @brief %Function move constructor.
       *  @param x A %function object rvalue with identical call signature.
       *
       *  The newly-created %function contains the target of @a x
       *  (if it has one).
       */
      function(function&& __x) : _Function_base()
      {
	__x.swap(*this);
      }

      // TODO: needs allocator_arg_t

      /**
       *  @brief Builds a %function that targets a copy of the incoming
       *  function object.
       *  @param f A %function object that is callable with parameters of
       *  type @c T1, @c T2, ..., @c TN and returns a value convertible
       *  to @c Res.
       *
       *  The newly-created %function object will target a copy of @a
       *  f. If @a f is @c reference_wrapper<F>, then this function
       *  object will contain a reference to the function object @c
       *  f.get(). If @a f is a NULL function pointer or NULL
       *  pointer-to-member, the newly-created object will be empty.
       *
       *  If @a f is a non-NULL function pointer or an object of type @c
       *  reference_wrapper<F>, this function will not throw.
       */
      template<typename _Functor>
	function(_Functor __f,
		 typename enable_if<
			   !is_integral<_Functor>::value, _Useless>::type
		   = _Useless());

      /**
       *  @brief %Function assignment operator.
       *  @param x A %function with identical call signature.
       *  @post @c (bool)*this == (bool)x
       *  @returns @c *this
       *
       *  The target of @a x is copied to @c *this. If @a x has no
       *  target, then @c *this will be empty.
       *
       *  If @a x targets a function pointer or a reference to a function
       *  object, then this operation will not throw an %exception.
       */
      function&
      operator=(const function& __x)
      {
	function(__x).swap(*this);
	return *this;
      }

      /**
       *  @brief %Function move-assignment operator.
       *  @param x A %function rvalue with identical call signature.
       *  @returns @c *this
       *
       *  The target of @a x is moved to @c *this. If @a x has no
       *  target, then @c *this will be empty.
       *
       *  If @a x targets a function pointer or a reference to a function
       *  object, then this operation will not throw an %exception.
       */
      function&
      operator=(function&& __x)
      {
	function(std::move(__x)).swap(*this);
	return *this;
      }

      /**
       *  @brief %Function assignment to zero.
       *  @post @c !(bool)*this
       *  @returns @c *this
       *
       *  The target of @c *this is deallocated, leaving it empty.
       */
      function&
      operator=(nullptr_t)
      {
	if (_M_manager)
	  {
	    _M_manager(_M_functor, _M_functor, __destroy_functor);
	    _M_manager = 0;
	    _M_invoker = 0;
	  }
	return *this;
      }

      /**
       *  @brief %Function assignment to a new target.
       *  @param f A %function object that is callable with parameters of
       *  type @c T1, @c T2, ..., @c TN and returns a value convertible
       *  to @c Res.
       *  @return @c *this
       *
       *  This  %function object wrapper will target a copy of @a
       *  f. If @a f is @c reference_wrapper<F>, then this function
       *  object will contain a reference to the function object @c
       *  f.get(). If @a f is a NULL function pointer or NULL
       *  pointer-to-member, @c this object will be empty.
       *
       *  If @a f is a non-NULL function pointer or an object of type @c
       *  reference_wrapper<F>, this function will not throw.
       */
      template<typename _Functor>
	typename enable_if<!is_integral<_Functor>::value, function&>::type
	operator=(_Functor&& __f)
	{
	  function(std::forward<_Functor>(__f)).swap(*this);
	  return *this;
	}

      /// @overload
      template<typename _Functor>
	typename enable_if<!is_integral<_Functor>::value, function&>::type
	operator=(reference_wrapper<_Functor> __f)
	{
	  function(__f).swap(*this);
	  return *this;
	}

      // [3.7.2.2] function modifiers

      /**
       *  @brief Swap the targets of two %function objects.
       *  @param f A %function with identical call signature.
       *
       *  Swap the targets of @c this function object and @a f. This
       *  function will not throw an %exception.
       */
      void swap(function& __x)
      {
	std::swap(_M_functor, __x._M_functor);
	std::swap(_M_manager, __x._M_manager);
	std::swap(_M_invoker, __x._M_invoker);
      }

      // TODO: needs allocator_arg_t
      /*
      template<typename _Functor, typename _Alloc>
	void
	assign(_Functor&& __f, const _Alloc& __a)
	{
	  function(allocator_arg, __a,
		   std::forward<_Functor>(__f)).swap(*this);
	}
      */

      // [3.7.2.3] function capacity

      /**
       *  @brief Determine if the %function wrapper has a target.
       *
       *  @return @c true when this %function object contains a target,
       *  or @c false when it is empty.
       *
       *  This function will not throw an %exception.
       */
      explicit operator bool() const
      { return !_M_empty(); }

      // [3.7.2.4] function invocation

      /**
       *  @brief Invokes the function targeted by @c *this.
       *  @returns the result of the target.
       *  @throws bad_function_call when @c !(bool)*this
       *
       *  The function call operator invokes the target function object
       *  stored by @c this.
       */
      _Res operator()(_ArgTypes... __args) const;

#ifdef __GXX_RTTI
      // [3.7.2.5] function target access
      /**
       *  @brief Determine the type of the target of this function object
       *  wrapper.
       *
       *  @returns the type identifier of the target function object, or
       *  @c typeid(void) if @c !(bool)*this.
       *
       *  This function will not throw an %exception.
       */
      const type_info& target_type() const;

      /**
       *  @brief Access the stored target function object.
       *
       *  @return Returns a pointer to the stored target function object,
       *  if @c typeid(Functor).equals(target_type()); otherwise, a NULL
       *  pointer.
       *
       * This function will not throw an %exception.
       */
      template<typename _Functor>       _Functor* target();

      /// @overload
      template<typename _Functor> const _Functor* target() const;
#endif

    private:
      typedef _Res (*_Invoker_type)(const _Any_data&, _ArgTypes...);
      _Invoker_type _M_invoker;
  };

  // Out-of-line member definitions.
  template<typename _Res, typename... _ArgTypes>
    function<_Res(_ArgTypes...)>::
    function(const function& __x)
    : _Function_base()
    {
      if (static_cast<bool>(__x))
	{
	  _M_invoker = __x._M_invoker;
	  _M_manager = __x._M_manager;
	  __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
	}
    }

  template<typename _Res, typename... _ArgTypes>
    template<typename _Functor>
      function<_Res(_ArgTypes...)>::
      function(_Functor __f,
	       typename enable_if<
			!is_integral<_Functor>::value, _Useless>::type)
      : _Function_base()
      {
	typedef _Function_handler<_Signature_type, _Functor> _My_handler;

	if (_My_handler::_M_not_empty_function(__f))
	  {
	    _M_invoker = &_My_handler::_M_invoke;
	    _M_manager = &_My_handler::_M_manager;
	    _My_handler::_M_init_functor(_M_functor, std::move(__f));
	  }
      }

  template<typename _Res, typename... _ArgTypes>
    _Res
    function<_Res(_ArgTypes...)>::
    operator()(_ArgTypes... __args) const
    {
      if (_M_empty())
	__throw_bad_function_call();
      return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
    }

#ifdef __GXX_RTTI
  template<typename _Res, typename... _ArgTypes>
    const type_info&
    function<_Res(_ArgTypes...)>::
    target_type() const
    {
      if (_M_manager)
	{
	  _Any_data __typeinfo_result;
	  _M_manager(__typeinfo_result, _M_functor, __get_type_info);
	  return *__typeinfo_result._M_access<const type_info*>();
	}
      else
	return typeid(void);
    }

  template<typename _Res, typename... _ArgTypes>
    template<typename _Functor>
      _Functor*
      function<_Res(_ArgTypes...)>::
      target()
      {
	if (typeid(_Functor) == target_type() && _M_manager)
	  {
	    _Any_data __ptr;
	    if (_M_manager(__ptr, _M_functor, __get_functor_ptr)
		&& !is_const<_Functor>::value)
	      return 0;
	    else
	      return __ptr._M_access<_Functor*>();
	  }
	else
	  return 0;
      }

  template<typename _Res, typename... _ArgTypes>
    template<typename _Functor>
      const _Functor*
      function<_Res(_ArgTypes...)>::
      target() const
      {
	if (typeid(_Functor) == target_type() && _M_manager)
	  {
	    _Any_data __ptr;
	    _M_manager(__ptr, _M_functor, __get_functor_ptr);
	    return __ptr._M_access<const _Functor*>();
	  }
	else
	  return 0;
      }
#endif

  // [20.7.15.2.6] null pointer comparisons

  /**
   *  @brief Compares a polymorphic function object wrapper against 0
   *  (the NULL pointer).
   *  @returns @c true if the wrapper has no target, @c false otherwise
   *
   *  This function will not throw an %exception.
   */
  template<typename _Res, typename... _Args>
    inline bool
    operator==(const function<_Res(_Args...)>& __f, nullptr_t)
    { return !static_cast<bool>(__f); }

  /// @overload
  template<typename _Res, typename... _Args>
    inline bool
    operator==(nullptr_t, const function<_Res(_Args...)>& __f)
    { return !static_cast<bool>(__f); }

  /**
   *  @brief Compares a polymorphic function object wrapper against 0
   *  (the NULL pointer).
   *  @returns @c false if the wrapper has no target, @c true otherwise
   *
   *  This function will not throw an %exception.
   */
  template<typename _Res, typename... _Args>
    inline bool
    operator!=(const function<_Res(_Args...)>& __f, nullptr_t)
    { return static_cast<bool>(__f); }

  /// @overload
  template<typename _Res, typename... _Args>
    inline bool
    operator!=(nullptr_t, const function<_Res(_Args...)>& __f)
    { return static_cast<bool>(__f); }

  // [20.7.15.2.7] specialized algorithms

  /**
   *  @brief Swap the targets of two polymorphic function object wrappers.
   *
   *  This function will not throw an %exception.
   */
  template<typename _Res, typename... _Args>
    inline void
    swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y)
    { __x.swap(__y); }

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif // __GXX_EXPERIMENTAL_CXX0X__

#endif // _GLIBCXX_FUNCTIONAL