Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

   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
// -*- C++ -*- C forwarding header.

// Copyright (C) 1997-2020 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/>.

/** @file include/cmath
 *  This is a Standard C++ Library file.  You should @c \#include this file
 *  in your programs, rather than any of the @a *.h implementation files.
 *
 *  This is the C++ version of the Standard C Library header @c math.h,
 *  and its contents are (mostly) the same as that header, but are all
 *  contained in the namespace @c std (except for names which are defined
 *  as macros in C).
 */

//
// ISO C++ 14882: 26.5  C library
//

#pragma GCC system_header

#include <bits/c++config.h>
#include <bits/cpp_type_traits.h>
#include <ext/type_traits.h>
#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
#include_next <math.h>
#undef _GLIBCXX_INCLUDE_NEXT_C_HEADERS
#include <bits/std_abs.h>

#ifndef _GLIBCXX_CMATH
#define _GLIBCXX_CMATH 1

// Get rid of those macros defined in <math.h> in lieu of real functions.
#undef div
#undef acos
#undef asin
#undef atan
#undef atan2
#undef ceil
#undef cos
#undef cosh
#undef exp
#undef fabs
#undef floor
#undef fmod
#undef frexp
#undef ldexp
#undef log
#undef log10
#undef modf
#undef pow
#undef sin
#undef sinh
#undef sqrt
#undef tan
#undef tanh

extern "C++"
{
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  using ::acos;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  acos(float __x)
  { return __builtin_acosf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  acos(long double __x)
  { return __builtin_acosl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    acos(_Tp __x)
    { return __builtin_acos(__x); }

  using ::asin;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  asin(float __x)
  { return __builtin_asinf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  asin(long double __x)
  { return __builtin_asinl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    asin(_Tp __x)
    { return __builtin_asin(__x); }

  using ::atan;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  atan(float __x)
  { return __builtin_atanf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  atan(long double __x)
  { return __builtin_atanl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    atan(_Tp __x)
    { return __builtin_atan(__x); }

  using ::atan2;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  atan2(float __y, float __x)
  { return __builtin_atan2f(__y, __x); }

  inline _GLIBCXX_CONSTEXPR long double
  atan2(long double __y, long double __x)
  { return __builtin_atan2l(__y, __x); }
#endif

  template<typename _Tp, typename _Up>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    atan2(_Tp __y, _Up __x)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return atan2(__type(__y), __type(__x));
    }

  using ::ceil;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  ceil(float __x)
  { return __builtin_ceilf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  ceil(long double __x)
  { return __builtin_ceill(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    ceil(_Tp __x)
    { return __builtin_ceil(__x); }

  using ::cos;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  cos(float __x)
  { return __builtin_cosf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  cos(long double __x)
  { return __builtin_cosl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    cos(_Tp __x)
    { return __builtin_cos(__x); }

  using ::cosh;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  cosh(float __x)
  { return __builtin_coshf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  cosh(long double __x)
  { return __builtin_coshl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    cosh(_Tp __x)
    { return __builtin_cosh(__x); }

  using ::exp;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  exp(float __x)
  { return __builtin_expf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  exp(long double __x)
  { return __builtin_expl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    exp(_Tp __x)
    { return __builtin_exp(__x); }

  using ::fabs;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  fabs(float __x)
  { return __builtin_fabsf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  fabs(long double __x)
  { return __builtin_fabsl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    fabs(_Tp __x)
    { return __builtin_fabs(__x); }

  using ::floor;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  floor(float __x)
  { return __builtin_floorf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  floor(long double __x)
  { return __builtin_floorl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    floor(_Tp __x)
    { return __builtin_floor(__x); }

  using ::fmod;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  fmod(float __x, float __y)
  { return __builtin_fmodf(__x, __y); }

  inline _GLIBCXX_CONSTEXPR long double
  fmod(long double __x, long double __y)
  { return __builtin_fmodl(__x, __y); }
#endif

  template<typename _Tp, typename _Up>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fmod(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fmod(__type(__x), __type(__y));
    }

  using ::frexp;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline float
  frexp(float __x, int* __exp)
  { return __builtin_frexpf(__x, __exp); }

  inline long double
  frexp(long double __x, int* __exp)
  { return __builtin_frexpl(__x, __exp); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    frexp(_Tp __x, int* __exp)
    { return __builtin_frexp(__x, __exp); }

  using ::ldexp;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  ldexp(float __x, int __exp)
  { return __builtin_ldexpf(__x, __exp); }

  inline _GLIBCXX_CONSTEXPR long double
  ldexp(long double __x, int __exp)
  { return __builtin_ldexpl(__x, __exp); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    ldexp(_Tp __x, int __exp)
    { return __builtin_ldexp(__x, __exp); }

  using ::log;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  log(float __x)
  { return __builtin_logf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  log(long double __x)
  { return __builtin_logl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    log(_Tp __x)
    { return __builtin_log(__x); }

  using ::log10;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  log10(float __x)
  { return __builtin_log10f(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  log10(long double __x)
  { return __builtin_log10l(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                    double>::__type
    log10(_Tp __x)
    { return __builtin_log10(__x); }

  using ::modf;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline float
  modf(float __x, float* __iptr)
  { return __builtin_modff(__x, __iptr); }

  inline long double
  modf(long double __x, long double* __iptr)
  { return __builtin_modfl(__x, __iptr); }
#endif

  using ::pow;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  pow(float __x, float __y)
  { return __builtin_powf(__x, __y); }

  inline _GLIBCXX_CONSTEXPR long double
  pow(long double __x, long double __y)
  { return __builtin_powl(__x, __y); }

#if __cplusplus < 201103L
  // _GLIBCXX_RESOLVE_LIB_DEFECTS
  // DR 550. What should the return type of pow(float,int) be?
  inline double
  pow(double __x, int __i)
  { return __builtin_powi(__x, __i); }

  inline float
  pow(float __x, int __n)
  { return __builtin_powif(__x, __n); }

  inline long double
  pow(long double __x, int __n)
  { return __builtin_powil(__x, __n); }
#endif
#endif

  template<typename _Tp, typename _Up>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    pow(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return pow(__type(__x), __type(__y));
    }

  using ::sin;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  sin(float __x)
  { return __builtin_sinf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  sin(long double __x)
  { return __builtin_sinl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    sin(_Tp __x)
    { return __builtin_sin(__x); }

  using ::sinh;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  sinh(float __x)
  { return __builtin_sinhf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  sinh(long double __x)
  { return __builtin_sinhl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    sinh(_Tp __x)
    { return __builtin_sinh(__x); }

  using ::sqrt;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  sqrt(float __x)
  { return __builtin_sqrtf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  sqrt(long double __x)
  { return __builtin_sqrtl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    sqrt(_Tp __x)
    { return __builtin_sqrt(__x); }

  using ::tan;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  tan(float __x)
  { return __builtin_tanf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  tan(long double __x)
  { return __builtin_tanl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    tan(_Tp __x)
    { return __builtin_tan(__x); }

  using ::tanh;

#ifndef __CORRECT_ISO_CPP_MATH_H_PROTO
  inline _GLIBCXX_CONSTEXPR float
  tanh(float __x)
  { return __builtin_tanhf(__x); }

  inline _GLIBCXX_CONSTEXPR long double
  tanh(long double __x)
  { return __builtin_tanhl(__x); }
#endif

  template<typename _Tp>
    inline _GLIBCXX_CONSTEXPR
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    double>::__type
    tanh(_Tp __x)
    { return __builtin_tanh(__x); }

#if _GLIBCXX_USE_C99_MATH
#if !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC

// These are possible macros imported from C99-land.
#undef fpclassify
#undef isfinite
#undef isinf
#undef isnan
#undef isnormal
#undef signbit
#undef isgreater
#undef isgreaterequal
#undef isless
#undef islessequal
#undef islessgreater
#undef isunordered

#if __cplusplus >= 201103L

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr int
  fpclassify(float __x)
  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
				FP_SUBNORMAL, FP_ZERO, __x); }

  constexpr int
  fpclassify(double __x)
  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
				FP_SUBNORMAL, FP_ZERO, __x); }

  constexpr int
  fpclassify(long double __x)
  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
				FP_SUBNORMAL, FP_ZERO, __x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              int>::__type
    fpclassify(_Tp __x)
    { return __x != 0 ? FP_NORMAL : FP_ZERO; }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isfinite(float __x)
  { return __builtin_isfinite(__x); }

  constexpr bool
  isfinite(double __x)
  { return __builtin_isfinite(__x); }

  constexpr bool
  isfinite(long double __x)
  { return __builtin_isfinite(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isfinite(_Tp __x)
    { return true; }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isinf(float __x)
  { return __builtin_isinf(__x); }

#if _GLIBCXX_HAVE_OBSOLETE_ISINF \
  && !_GLIBCXX_NO_OBSOLETE_ISINF_ISNAN_DYNAMIC
  using ::isinf;
#else
  constexpr bool
  isinf(double __x)
  { return __builtin_isinf(__x); }
#endif

  constexpr bool
  isinf(long double __x)
  { return __builtin_isinf(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isinf(_Tp __x)
    { return false; }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isnan(float __x)
  { return __builtin_isnan(__x); }

#if _GLIBCXX_HAVE_OBSOLETE_ISNAN \
  && !_GLIBCXX_NO_OBSOLETE_ISINF_ISNAN_DYNAMIC
  using ::isnan;
#else
  constexpr bool
  isnan(double __x)
  { return __builtin_isnan(__x); }
#endif

  constexpr bool
  isnan(long double __x)
  { return __builtin_isnan(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isnan(_Tp __x)
    { return false; }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isnormal(float __x)
  { return __builtin_isnormal(__x); }

  constexpr bool
  isnormal(double __x)
  { return __builtin_isnormal(__x); }

  constexpr bool
  isnormal(long double __x)
  { return __builtin_isnormal(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    isnormal(_Tp __x)
    { return __x != 0 ? true : false; }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  // Note: middle-end/36757 is fixed, __builtin_signbit is type-generic.
  constexpr bool
  signbit(float __x)
  { return __builtin_signbit(__x); }

  constexpr bool
  signbit(double __x)
  { return __builtin_signbit(__x); }

  constexpr bool
  signbit(long double __x)
  { return __builtin_signbit(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value,
                                              bool>::__type
    signbit(_Tp __x)
    { return __x < 0 ? true : false; }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isgreater(float __x, float __y)
  { return __builtin_isgreater(__x, __y); }

  constexpr bool
  isgreater(double __x, double __y)
  { return __builtin_isgreater(__x, __y); }

  constexpr bool
  isgreater(long double __x, long double __y)
  { return __builtin_isgreater(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
			    && __is_arithmetic<_Up>::__value), bool>::__type
    isgreater(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isgreater(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isgreaterequal(float __x, float __y)
  { return __builtin_isgreaterequal(__x, __y); }

  constexpr bool
  isgreaterequal(double __x, double __y)
  { return __builtin_isgreaterequal(__x, __y); }

  constexpr bool
  isgreaterequal(long double __x, long double __y)
  { return __builtin_isgreaterequal(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
			    && __is_arithmetic<_Up>::__value), bool>::__type
    isgreaterequal(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isgreaterequal(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isless(float __x, float __y)
  { return __builtin_isless(__x, __y); }

  constexpr bool
  isless(double __x, double __y)
  { return __builtin_isless(__x, __y); }

  constexpr bool
  isless(long double __x, long double __y)
  { return __builtin_isless(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
			    && __is_arithmetic<_Up>::__value), bool>::__type
    isless(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isless(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  islessequal(float __x, float __y)
  { return __builtin_islessequal(__x, __y); }

  constexpr bool
  islessequal(double __x, double __y)
  { return __builtin_islessequal(__x, __y); }

  constexpr bool
  islessequal(long double __x, long double __y)
  { return __builtin_islessequal(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
			    && __is_arithmetic<_Up>::__value), bool>::__type
    islessequal(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_islessequal(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  islessgreater(float __x, float __y)
  { return __builtin_islessgreater(__x, __y); }

  constexpr bool
  islessgreater(double __x, double __y)
  { return __builtin_islessgreater(__x, __y); }

  constexpr bool
  islessgreater(long double __x, long double __y)
  { return __builtin_islessgreater(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
			    && __is_arithmetic<_Up>::__value), bool>::__type
    islessgreater(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_islessgreater(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr bool
  isunordered(float __x, float __y)
  { return __builtin_isunordered(__x, __y); }

  constexpr bool
  isunordered(double __x, double __y)
  { return __builtin_isunordered(__x, __y); }

  constexpr bool
  isunordered(long double __x, long double __y)
  { return __builtin_isunordered(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename
    __gnu_cxx::__enable_if<(__is_arithmetic<_Tp>::__value
			    && __is_arithmetic<_Up>::__value), bool>::__type
    isunordered(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return __builtin_isunordered(__type(__x), __type(__y));
    }
#endif

#else

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    fpclassify(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
				  FP_SUBNORMAL, FP_ZERO, __type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isfinite(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isfinite(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isinf(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isinf(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isnan(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isnan(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isnormal(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isnormal(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    signbit(_Tp __f)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_signbit(__type(__f));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isgreater(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isgreater(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isgreaterequal(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isgreaterequal(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isless(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isless(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    islessequal(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_islessequal(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    islessgreater(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_islessgreater(__type(__f1), __type(__f2));
    }

  template<typename _Tp>
    inline typename __gnu_cxx::__enable_if<__is_arithmetic<_Tp>::__value,
					   int>::__type
    isunordered(_Tp __f1, _Tp __f2)
    {
      typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
      return __builtin_isunordered(__type(__f1), __type(__f2));
    }

#endif // C++11
#endif /* _GLIBCXX_USE_C99_FP_MACROS_DYNAMIC */
#endif /* _GLIBCXX_USE_C99_MATH */

#if __cplusplus >= 201103L

#ifdef _GLIBCXX_USE_C99_MATH_TR1

#undef acosh
#undef acoshf
#undef acoshl
#undef asinh
#undef asinhf
#undef asinhl
#undef atanh
#undef atanhf
#undef atanhl
#undef cbrt
#undef cbrtf
#undef cbrtl
#undef copysign
#undef copysignf
#undef copysignl
#undef erf
#undef erff
#undef erfl
#undef erfc
#undef erfcf
#undef erfcl
#undef exp2
#undef exp2f
#undef exp2l
#undef expm1
#undef expm1f
#undef expm1l
#undef fdim
#undef fdimf
#undef fdiml
#undef fma
#undef fmaf
#undef fmal
#undef fmax
#undef fmaxf
#undef fmaxl
#undef fmin
#undef fminf
#undef fminl
#undef hypot
#undef hypotf
#undef hypotl
#undef ilogb
#undef ilogbf
#undef ilogbl
#undef lgamma
#undef lgammaf
#undef lgammal
#ifndef _GLIBCXX_NO_C99_ROUNDING_FUNCS
#undef llrint
#undef llrintf
#undef llrintl
#undef llround
#undef llroundf
#undef llroundl
#endif
#undef log1p
#undef log1pf
#undef log1pl
#undef log2
#undef log2f
#undef log2l
#undef logb
#undef logbf
#undef logbl
#undef lrint
#undef lrintf
#undef lrintl
#undef lround
#undef lroundf
#undef lroundl
#undef nan
#undef nanf
#undef nanl
#undef nearbyint
#undef nearbyintf
#undef nearbyintl
#undef nextafter
#undef nextafterf
#undef nextafterl
#undef nexttoward
#undef nexttowardf
#undef nexttowardl
#undef remainder
#undef remainderf
#undef remainderl
#undef remquo
#undef remquof
#undef remquol
#undef rint
#undef rintf
#undef rintl
#undef round
#undef roundf
#undef roundl
#undef scalbln
#undef scalblnf
#undef scalblnl
#undef scalbn
#undef scalbnf
#undef scalbnl
#undef tgamma
#undef tgammaf
#undef tgammal
#undef trunc
#undef truncf
#undef truncl

  // types
  using ::double_t;
  using ::float_t;

  // functions
  using ::acosh;
  using ::acoshf;
  using ::acoshl;

  using ::asinh;
  using ::asinhf;
  using ::asinhl;

  using ::atanh;
  using ::atanhf;
  using ::atanhl;

  using ::cbrt;
  using ::cbrtf;
  using ::cbrtl;

  using ::copysign;
  using ::copysignf;
  using ::copysignl;

  using ::erf;
  using ::erff;
  using ::erfl;

  using ::erfc;
  using ::erfcf;
  using ::erfcl;

  using ::exp2;
  using ::exp2f;
  using ::exp2l;

  using ::expm1;
  using ::expm1f;
  using ::expm1l;

  using ::fdim;
  using ::fdimf;
  using ::fdiml;

  using ::fma;
  using ::fmaf;
  using ::fmal;

  using ::fmax;
  using ::fmaxf;
  using ::fmaxl;

  using ::fmin;
  using ::fminf;
  using ::fminl;

  using ::hypot;
  using ::hypotf;
  using ::hypotl;

  using ::ilogb;
  using ::ilogbf;
  using ::ilogbl;

  using ::lgamma;
  using ::lgammaf;
  using ::lgammal;

#ifndef _GLIBCXX_NO_C99_ROUNDING_FUNCS
  using ::llrint;
  using ::llrintf;
  using ::llrintl;

  using ::llround;
  using ::llroundf;
  using ::llroundl;
#endif

  using ::log1p;
  using ::log1pf;
  using ::log1pl;

  using ::log2;
  using ::log2f;
  using ::log2l;

  using ::logb;
  using ::logbf;
  using ::logbl;

  using ::lrint;
  using ::lrintf;
  using ::lrintl;

  using ::lround;
  using ::lroundf;
  using ::lroundl;

  using ::nan;
  using ::nanf;
  using ::nanl;

  using ::nearbyint;
  using ::nearbyintf;
  using ::nearbyintl;

  using ::nextafter;
  using ::nextafterf;
  using ::nextafterl;

  using ::nexttoward;
  using ::nexttowardf;
  using ::nexttowardl;

  using ::remainder;
  using ::remainderf;
  using ::remainderl;

  using ::remquo;
  using ::remquof;
  using ::remquol;

  using ::rint;
  using ::rintf;
  using ::rintl;

  using ::round;
  using ::roundf;
  using ::roundl;

  using ::scalbln;
  using ::scalblnf;
  using ::scalblnl;

  using ::scalbn;
  using ::scalbnf;
  using ::scalbnl;

  using ::tgamma;
  using ::tgammaf;
  using ::tgammal;

  using ::trunc;
  using ::truncf;
  using ::truncl;

  /// Additional overloads.
#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  acosh(float __x)
  { return __builtin_acoshf(__x); }

  constexpr long double
  acosh(long double __x)
  { return __builtin_acoshl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    acosh(_Tp __x)
    { return __builtin_acosh(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  asinh(float __x)
  { return __builtin_asinhf(__x); }

  constexpr long double
  asinh(long double __x)
  { return __builtin_asinhl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    asinh(_Tp __x)
    { return __builtin_asinh(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  atanh(float __x)
  { return __builtin_atanhf(__x); }

  constexpr long double
  atanh(long double __x)
  { return __builtin_atanhl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    atanh(_Tp __x)
    { return __builtin_atanh(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  cbrt(float __x)
  { return __builtin_cbrtf(__x); }

  constexpr long double
  cbrt(long double __x)
  { return __builtin_cbrtl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    cbrt(_Tp __x)
    { return __builtin_cbrt(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  copysign(float __x, float __y)
  { return __builtin_copysignf(__x, __y); }

  constexpr long double
  copysign(long double __x, long double __y)
  { return __builtin_copysignl(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    copysign(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return copysign(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  erf(float __x)
  { return __builtin_erff(__x); }

  constexpr long double
  erf(long double __x)
  { return __builtin_erfl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    erf(_Tp __x)
    { return __builtin_erf(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  erfc(float __x)
  { return __builtin_erfcf(__x); }

  constexpr long double
  erfc(long double __x)
  { return __builtin_erfcl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    erfc(_Tp __x)
    { return __builtin_erfc(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  exp2(float __x)
  { return __builtin_exp2f(__x); }

  constexpr long double
  exp2(long double __x)
  { return __builtin_exp2l(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    exp2(_Tp __x)
    { return __builtin_exp2(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  expm1(float __x)
  { return __builtin_expm1f(__x); }

  constexpr long double
  expm1(long double __x)
  { return __builtin_expm1l(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    expm1(_Tp __x)
    { return __builtin_expm1(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  fdim(float __x, float __y)
  { return __builtin_fdimf(__x, __y); }

  constexpr long double
  fdim(long double __x, long double __y)
  { return __builtin_fdiml(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fdim(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fdim(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  fma(float __x, float __y, float __z)
  { return __builtin_fmaf(__x, __y, __z); }

  constexpr long double
  fma(long double __x, long double __y, long double __z)
  { return __builtin_fmal(__x, __y, __z); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up, typename _Vp>
    constexpr typename __gnu_cxx::__promote_3<_Tp, _Up, _Vp>::__type
    fma(_Tp __x, _Up __y, _Vp __z)
    {
      typedef typename __gnu_cxx::__promote_3<_Tp, _Up, _Vp>::__type __type;
      return fma(__type(__x), __type(__y), __type(__z));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  fmax(float __x, float __y)
  { return __builtin_fmaxf(__x, __y); }

  constexpr long double
  fmax(long double __x, long double __y)
  { return __builtin_fmaxl(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fmax(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fmax(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  fmin(float __x, float __y)
  { return __builtin_fminf(__x, __y); }

  constexpr long double
  fmin(long double __x, long double __y)
  { return __builtin_fminl(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    fmin(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return fmin(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  hypot(float __x, float __y)
  { return __builtin_hypotf(__x, __y); }

  constexpr long double
  hypot(long double __x, long double __y)
  { return __builtin_hypotl(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    hypot(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return hypot(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr int
  ilogb(float __x)
  { return __builtin_ilogbf(__x); }

  constexpr int
  ilogb(long double __x)
  { return __builtin_ilogbl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr
    typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                    int>::__type
    ilogb(_Tp __x)
    { return __builtin_ilogb(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  lgamma(float __x)
  { return __builtin_lgammaf(__x); }

  constexpr long double
  lgamma(long double __x)
  { return __builtin_lgammal(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    lgamma(_Tp __x)
    { return __builtin_lgamma(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr long long
  llrint(float __x)
  { return __builtin_llrintf(__x); }

  constexpr long long
  llrint(long double __x)
  { return __builtin_llrintl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long long>::__type
    llrint(_Tp __x)
    { return __builtin_llrint(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr long long
  llround(float __x)
  { return __builtin_llroundf(__x); }

  constexpr long long
  llround(long double __x)
  { return __builtin_llroundl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long long>::__type
    llround(_Tp __x)
    { return __builtin_llround(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  log1p(float __x)
  { return __builtin_log1pf(__x); }

  constexpr long double
  log1p(long double __x)
  { return __builtin_log1pl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    log1p(_Tp __x)
    { return __builtin_log1p(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  // DR 568.
  constexpr float
  log2(float __x)
  { return __builtin_log2f(__x); }

  constexpr long double
  log2(long double __x)
  { return __builtin_log2l(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    log2(_Tp __x)
    { return __builtin_log2(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  logb(float __x)
  { return __builtin_logbf(__x); }

  constexpr long double
  logb(long double __x)
  { return __builtin_logbl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    logb(_Tp __x)
    { return __builtin_logb(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr long
  lrint(float __x)
  { return __builtin_lrintf(__x); }

  constexpr long
  lrint(long double __x)
  { return __builtin_lrintl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long>::__type
    lrint(_Tp __x)
    { return __builtin_lrint(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr long
  lround(float __x)
  { return __builtin_lroundf(__x); }

  constexpr long
  lround(long double __x)
  { return __builtin_lroundl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              long>::__type
    lround(_Tp __x)
    { return __builtin_lround(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  nearbyint(float __x)
  { return __builtin_nearbyintf(__x); }

  constexpr long double
  nearbyint(long double __x)
  { return __builtin_nearbyintl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    nearbyint(_Tp __x)
    { return __builtin_nearbyint(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  nextafter(float __x, float __y)
  { return __builtin_nextafterf(__x, __y); }

  constexpr long double
  nextafter(long double __x, long double __y)
  { return __builtin_nextafterl(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    nextafter(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return nextafter(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  nexttoward(float __x, long double __y)
  { return __builtin_nexttowardf(__x, __y); }

  constexpr long double
  nexttoward(long double __x, long double __y)
  { return __builtin_nexttowardl(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    nexttoward(_Tp __x, long double __y)
    { return __builtin_nexttoward(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  remainder(float __x, float __y)
  { return __builtin_remainderf(__x, __y); }

  constexpr long double
  remainder(long double __x, long double __y)
  { return __builtin_remainderl(__x, __y); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    remainder(_Tp __x, _Up __y)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return remainder(__type(__x), __type(__y));
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  inline float
  remquo(float __x, float __y, int* __pquo)
  { return __builtin_remquof(__x, __y, __pquo); }

  inline long double
  remquo(long double __x, long double __y, int* __pquo)
  { return __builtin_remquol(__x, __y, __pquo); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp, typename _Up>
    inline typename __gnu_cxx::__promote_2<_Tp, _Up>::__type
    remquo(_Tp __x, _Up __y, int* __pquo)
    {
      typedef typename __gnu_cxx::__promote_2<_Tp, _Up>::__type __type;
      return remquo(__type(__x), __type(__y), __pquo);
    }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  rint(float __x)
  { return __builtin_rintf(__x); }

  constexpr long double
  rint(long double __x)
  { return __builtin_rintl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    rint(_Tp __x)
    { return __builtin_rint(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  round(float __x)
  { return __builtin_roundf(__x); }

  constexpr long double
  round(long double __x)
  { return __builtin_roundl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    round(_Tp __x)
    { return __builtin_round(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  scalbln(float __x, long __ex)
  { return __builtin_scalblnf(__x, __ex); }

  constexpr long double
  scalbln(long double __x, long __ex)
  { return __builtin_scalblnl(__x, __ex); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    scalbln(_Tp __x, long __ex)
    { return __builtin_scalbln(__x, __ex); }
#endif
 
#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  scalbn(float __x, int __ex)
  { return __builtin_scalbnf(__x, __ex); }

  constexpr long double
  scalbn(long double __x, int __ex)
  { return __builtin_scalbnl(__x, __ex); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    scalbn(_Tp __x, int __ex)
    { return __builtin_scalbn(__x, __ex); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  tgamma(float __x)
  { return __builtin_tgammaf(__x); }

  constexpr long double
  tgamma(long double __x)
  { return __builtin_tgammal(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    tgamma(_Tp __x)
    { return __builtin_tgamma(__x); }
#endif
 
#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
  constexpr float
  trunc(float __x)
  { return __builtin_truncf(__x); }

  constexpr long double
  trunc(long double __x)
  { return __builtin_truncl(__x); }
#endif

#ifndef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
  template<typename _Tp>
    constexpr typename __gnu_cxx::__enable_if<__is_integer<_Tp>::__value, 
                                              double>::__type
    trunc(_Tp __x)
    { return __builtin_trunc(__x); }
#endif

#endif // _GLIBCXX_USE_C99_MATH_TR1
#endif // C++11

#if __cplusplus >= 201703L

  // [c.math.hypot3], three-dimensional hypotenuse
#define __cpp_lib_hypot 201603

  template<typename _Tp>
    inline _Tp
    __hypot3(_Tp __x, _Tp __y, _Tp __z)
    {
      __x = std::abs(__x);
      __y = std::abs(__y);
      __z = std::abs(__z);
      if (_Tp __a = __x < __y ? __y < __z ? __z : __y : __x < __z ? __z : __x)
	return __a * std::sqrt((__x / __a) * (__x / __a)
			       + (__y / __a) * (__y / __a)
			       + (__z / __a) * (__z / __a));
      else
	return {};
    }

  inline float
  hypot(float __x, float __y, float __z)
  { return std::__hypot3<float>(__x, __y, __z); }

  inline double
  hypot(double __x, double __y, double __z)
  { return std::__hypot3<double>(__x, __y, __z); }

  inline long double
  hypot(long double __x, long double __y, long double __z)
  { return std::__hypot3<long double>(__x, __y, __z); }

  template<typename _Tp, typename _Up, typename _Vp>
    __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>
    hypot(_Tp __x, _Up __y, _Vp __z)
    {
      using __type = __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>;
      return std::__hypot3<__type>(__x, __y, __z);
    }
#endif // C++17

#if __cplusplus > 201703L
  // linear interpolation
# define __cpp_lib_interpolate 201902L

  template<typename _Fp>
    constexpr _Fp
    __lerp(_Fp __a, _Fp __b, _Fp __t) noexcept
    {
      if (__a <= 0 && __b >= 0 || __a >= 0 && __b <= 0)
	return __t * __b + (1 - __t) * __a;

      if (__t == 1)
	return __b;                        // exact

      // Exact at __t=0, monotonic except near __t=1,
      // bounded, determinate, and consistent:
      const _Fp __x = __a + __t * (__b - __a);
      return __t > 1 == __b > __a
	? (__b < __x ? __x : __b)
	: (__b > __x ? __x : __b);  // monotonic near __t=1
    }

  constexpr float
  lerp(float __a, float __b, float __t) noexcept
  { return std::__lerp(__a, __b, __t); }

  constexpr double
  lerp(double __a, double __b, double __t) noexcept
  { return std::__lerp(__a, __b, __t); }

  constexpr long double
  lerp(long double __a, long double __b, long double __t) noexcept
  { return std::__lerp(__a, __b, __t); }

  template<typename _Tp, typename _Up, typename _Vp>
    constexpr __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>
    lerp(_Tp __x, _Up __y, _Vp __z) noexcept
    {
      using __type = __gnu_cxx::__promoted_t<_Tp, _Up, _Vp>;
      return std::__lerp<__type>(__x, __y, __z);
    }
#endif // C++20

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#if _GLIBCXX_USE_STD_SPEC_FUNCS
#  include <bits/specfun.h>
#endif

} // extern "C++"

#endif