Source

SCons / doc / man / scons.1

   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
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
.\" __COPYRIGHT__
.\"
.\" Permission is hereby granted, free of charge, to any person obtaining
.\" a copy of this software and associated documentation files (the
.\" "Software"), to deal in the Software without restriction, including
.\" without limitation the rights to use, copy, modify, merge, publish,
.\" distribute, sublicense, and/or sell copies of the Software, and to
.\" permit persons to whom the Software is furnished to do so, subject to
.\" the following conditions:
.\"
.\" The above copyright notice and this permission notice shall be included
.\" in all copies or substantial portions of the Software.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
.\" KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
.\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
.\" NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
.\" LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
.\" OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
.\" WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
.\"
.\" __FILE__ __REVISION__ __DATE__ __DEVELOPER__
.\"
.\" ES - Example Start - indents and turns off line fill
.de ES
.RS
.nf
..
.\" EE - Example End - ends indent and turns line fill back on
.de EE
.RE
.fi
..
.TH SCONS 1 "November 2002"
.SH NAME
scons \- a software construction tool
.SH SYNOPSIS
.B scons
[
.IR options ...
]
[
.IR name = val ...
]
[
.IR targets ...
]
.SH DESCRIPTION

The 
.B scons 
utility builds software (or other files) by determining which
component pieces must be rebuilt and executing the necessary commands to
rebuild them.

By default, 
.B scons 
searches for a file named 
.IR SConstruct ,
.IR Sconstruct ,
or
.I sconstruct
(in that order) in the current directory and reads its
configuration from the first file found.
An alternate file name may be
specified via the 
.B -f
option. If the specified file is not
in the local directory, 
.B scons 
will internally change its working
directory (chdir) to the directory containing the file.

The
.I SConstruct
file can specify subsidiary
configuration files using the
.B SConscript()
function.
By convention,
these subsidiary files are named
.IR SConscript ,
although any name may be used.
(Because of this naming convention,
the term "SConscript files"
is sometimes used to refer
generically to all
.B scons
configuration files,
regardless of actual file name.)

The configuration files
specify the target files to be built, and
(optionally) the rules to build those targets.  Reasonable default
rules exist for building common software components (executable
programs, object files, libraries), so that for most software
projects, only the target and input files need be specified.

.B scons
reads and executes the SConscript files as Python scripts,
so you may use normal Python scripting capabilities
(such as flow control, data manipulation, and imported Python libraries)
to handle complicated build situations.
.BR scons ,
however, reads all of the SConscript files
.I before
it begins building any targets.
To make this obvious,
.B scons
prints the following messages about what it is doing:

.ES
$ scons foo.out
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets  ...
cp foo.in foo.out
scons: done building targets.
$
.EE

These status messages may be suppressed using the
.B -Q
option.

.B scons
can scan known input files automatically for dependency
information (for example, #include statements
in C or C++ files) and will rebuild dependent files appropriately
whenever any "included" input file changes. 
.B scons
supports the
ability to define new scanners for unknown input file types.

.B scons
is normally executed in a top-level directory containing a
.I SConstruct
file, specifying the target or targets to be built as
command-line arguments.  The command

.ES
scons .
.EE

will build all target files in or below the current directory 
.RI ( . ")."

.ES
scons /
.EE

will build all target files in or below the root directory (i.e.,
all files).  Specific targets may be supplied:

.ES
scons foo bar
.EE

Targets may be omitted from the command line,
in which case the targets specified
in the SConscript file(s) as
.B Default
targets will be built:

.ES
scons
.EE

Specifying "cleanup" targets in SConscript files is not
necessary.  The 
.B -c
flag removes all files
necessary to build the specified target:

.ES
scons -c .
.EE

to remove all target files, or:

.ES
scons -c build export
.EE

to remove target files under build and export.
Additional files or directories to remove can be specified using the
Clean() function.

A subset of a hierarchical tree may be built by
remaining at the top-level directory (where the 
.I SConstruct
file lives) and specifying the subdirectory as the target to be
built:

.ES
scons src/subdir
.EE

or by changing directory and invoking scons with the
.B -u
option, which traverses up the directory
hierarchy until it finds the 
.I SConstruct
file, and then builds
targets relatively to the current subdirectory:

.ES
cd src/subdir
scons -u .
.EE

.B scons
supports building multiple targets in parallel via a
.B -j
option that takes, as its argument, the number
of simultaneous tasks that may be spawned:

.ES
scons -j 4
.EE

builds four targets in parallel, for example.

Values of variables to be passed to the SConscript file(s)
may be specified on the command line:

.ES
scons debug=1 .
.EE

These variables are available in SConscript files
through the ARGUMENTS dictionary,
and can be used in the SConscript file(s) to modify
the build in any way:

.ES
if ARGUMENTS.get('debug', 0):
    env = Environment(CCFLAGS = '-g')
else:
    env = Environment()
.EE

.\" .B scons
.\" can maintain a cache of target (derived) files that can
.\" be shared between multiple builds.  When caching is enabled in a
.\" SConscript file, any target files built by 
.\" .B scons
.\" will be copied
.\" to the cache.  If an up-to-date target file is found in the cache, it
.\" will be retrieved from the cache instead of being rebuilt locally.
.\" Caching behavior may be disabled and controlled in other ways by the
.\" .BR --cache-force , 
.\" .BR --cache-disable ,
.\" and
.\" .B --cache-show
.\" command-line options.  The
.\" .B --random
.\" option is useful whenever multiple builds may be
.\" trying to update the cache simultaneously.

.B scons
requires Python version 1.5.2 or later.
There should be no other dependencies or requirements to run
.B scons.

The default
.B scons
configuration assumes
use of the Microsoft Visual C++ compiler suite on WIN32 systems,
and assumes a C compiler named
.B cc
and a C++ compiler named
.B c++
(such as found in the GNU C compiler suite)
on any other type of system.
You may, of course, override these default values
by appropriate configuration of
Environment construction variables.

.SH OPTIONS
In general, 
.B scons 
supports the same command-line options as GNU
.BR make , 
and many of those supported by 
.BR cons .

.TP
-b
Ignored for compatibility with non-GNU versions of
.BR make.

.TP
-c, --clean, --remove
Clean up by removing all target files for which a construction
command is specified.
Also remove any files or directories associated to the construction command
using the Clean() function.

.\" .TP
.\" --cache-disable, --no-cache
.\" Disable caching.  Will neither retrieve files from cache nor flush
.\" files to cache.  Has no effect if use of caching is not specified
.\" in an SConscript file.
.\"
.\" .TP
.\" --cache-force, --cache-populate
.\" Populate a cache by forcing any already-existing up-to-date
.\" target files to the cache, in addition to files built by this
.\" invocation.  This is useful to populate a new cache with
.\" appropriate target files, or to make available in the cache
.\" any target files recently built with caching disabled via the
.\" .B --cache-disable
.\" option.
.\"
.\" .TP
.\" --cache-show
.\" When retrieving a target file from a cache, show the command
.\" that would have been executed to build the file.  This produces
.\" consistent output for build logs, regardless of whether a target
.\" file was rebuilt or retrieved from cache.

.TP 
.RI "-C" " directory" ",  --directory=" directory
Change to the specified 
.I directory
before searching for the 
.IR SConstruct ,
.IR Sconstruct ,
or
.I sconstruct
file, or doing anything
else.  Multiple 
.B -C
options are interpreted
relative to the previous one, and the right-most
.B -C
option wins. (This option is nearly
equivalent to 
.BR "-f directory/SConstruct" ,
except that it will search for
.IR SConstruct ,
.IR Sconstruct , 
or
.I sconstruct
in the specified directory.)

.\" .TP
.\" -d
.\" Display dependencies while building target files.  Useful for
.\" figuring out why a specific file is being rebuilt, as well as
.\" general debugging of the build process.

.TP
-D
Works exactly the same way as the
.B -u
option except for the way default targets are handled.
When this option is used and no targets are specified on the command line,
all default targets are built, whether or not they are below the current
directory.

.TP
.RI --debug= type
Debug the build process.
.I type
specifies what type of debugging:

.TP
.RI --debug=pdb
Re-run SCons under the control of the
.RI pdb
Python debugger.
The
.RI --debug=pdb
argument will be stripped from the command-line,
but all other arguments will be passed in-order
to the SCons invocation run by the debugger.

.TP
.RI --debug=tree
Print the dependency tree
after each top-level target is built. This prints out the complete
dependency tree including implicit dependencies and ignored
dependencies.

.TP
.RI --debug=dtree
Print the dependency tree
after each top-level target is built. This prints out only derived files.

.TP
.RI --debug=time
Prints various time profiling information: the time spent
executing each build command, the total build time, the total time spent
executing build commands, the total time spent executing SConstruct and
SConscript files, and the total time spent executing SCons itself.

.TP
.RI --debug=includes
Print the include tree after each top-level target is built. 
This is generally used to find out what files are included by the sources
of a given derived file:

.ES
$ scons --debug=includes foo.o
.EE

.TP
-e, --environment-overrides
Variables from the execution environment override construction
variables from the SConscript files.

.TP
.RI -f " file" ", --file=" file ", --makefile=" file ", --sconstruct=" file
Use 
.I file 
as the initial SConscript file.
If 
.I file
is in another directory,
.B scons 
will change to that directory before building targets.

.TP 
-h, --help
Print a local help message for this build, if one is defined in
the SConscript file(s), plus a line that describes the 
.B -H
option for command-line option help.  If no local help message
is defined, prints the standard help message about command-line
options.  Exits after displaying the appropriate message.

.TP
-H, --help-options
Print the standard help message about command-line options and
exit.

.TP
-i, --ignore-errors
Ignore all errors from commands executed to rebuild files.

.TP 
.RI -I " directory" ", --include-dir=" directory
Specifies a 
.I directory
to search for
imported Python modules.  If several 
.B -I
options
are used, the directories are searched in the order specified.

.TP
--implicit-cache
Cache implicit dependencies. This can cause 
.B scons
to miss changes in the implicit dependencies in cases where a new implicit
dependency is added earlier in the implicit dependency search path
(e.g. CPPPATH) than a current implicit dependency with the same name.

.TP
--implicit-deps-changed
Force SCons to ignore the cached implicit dependencies. This causes the
implicit dependencies to be rescanned and recached. This implies
.BR --implicit-cache .

.TP
--implicit-deps-unchanged
Force SCons to ignore changes in the implicit dependencies.
This causes cached implicit dependencies to always be used.
This implies 
.BR --implicit-cache .

.TP
.RI -j " N" ", --jobs=" N
Specifies the number of jobs (commands) to run simultaneously.
If there is more than one 
.B -j 
option, the last one is effective.
.\" ??? If the 
.\" .B -j 
.\" option
.\" is specified without an argument,
.\" .B scons 
.\" will not limit the number of
.\" simultaneous jobs.

.TP
-k, --keep-going
Continue as much as possible after an error.  The target that
failed and those that depend on it will not be remade, but other
targets specified on the command line will still be processed.

.\" .TP
.\" .RI  -l " N" ", --load-average=" N ", --max-load=" N
.\" No new jobs (commands) will be started if
.\" there are other jobs running and the system load
.\" average is at least 
.\" .I N
.\" (a floating-point number).
.\"
.\" .TP
.\" --list-derived
.\" List derived files (targets, dependencies) that would be built,
.\" but do not build them.
.\" [XXX This can probably go away with the right
.\" combination of other options.  Revisit this issue.]
.\"
.\" .TP
.\" --list-actions
.\" List derived files that would be built, with the actions
.\" (commands) that build them.  Does not build the files.
.\" [XXX This can probably go away with the right
.\" combination of other options.  Revisit this issue.]
.\"
.\" .TP
.\" --list-where
.\" List derived files that would be built, plus where the file is
.\" defined (file name and line number).  Does not build the files.
.\" [XXX This can probably go away with the right
.\" combination of other options.  Revisit this issue.]

.TP
-m
Ignored for compatibility with non-GNU versions of
.BR make .

.TP
.RI --max-drift= SECONDS
Set the maximum expected drift in the modification time of files to 
.IR SECONDS .
This value determines how old a file must be before its content signature
is cached. The default value is 2 days, which means a file must have a
modification time of at least two days ago in order to have its content
signature cached. A negative value means to never cache the content
signature and to ignore the cached value if there already is one. A value
of 0 means to always cache the signature, no matter how old the file is.

.TP
-n, --just-print, --dry-run, --recon
No execute.  Print the commands that would be executed to build
any out-of-date target files, but do not execute the commands.

.\" .TP
.\" .RI -o " file" ", --old-file=" file ", --assume-old=" file
.\" Do not rebuild 
.\" .IR file ,
.\" and do
.\" not rebuild anything due to changes in the contents of
.\" .IR file .
.\" .TP 
.\" .RI --override " file"
.\" Read values to override specific build environment variables
.\" from the specified 
.\" .IR file .
.\" .TP
.\" -p
.\" Print the data base (construction environments,
.\" Builder and Scanner objects) that are defined
.\" after reading the SConscript files.
.\" After printing, a normal build is performed
.\" as usual, as specified by other command-line options.
.\" This also prints version information
.\" printed by the 
.\" .B -v
.\" option.
.\"
.\" To print the database without performing a build do:
.\"
.\" .ES
.\" scons -p -q
.\" .EE

.TP
.RI --profile= file
Run SCons under the Python profiler
and save the results in the specified
.IR file .
The results may be analyzed using the Python
pstats module.
.TP
-q, --question
Do not run any commands, or print anything.  Just return an exit
status that is zero if the specified targets are already up to
date, non-zero otherwise.
.TP
-Q
Quiets SCons status messages about
reading SConscript files,
building targets
and entering directories.
Commands that are executed
to rebuild target files are still printed.

.\" .TP
.\" -r, -R, --no-builtin-rules, --no-builtin-variables
.\" Clear the default construction variables.  Construction
.\" environments that are created will be completely empty.
.\"
.\" .TP
.\" --random
.\" Build dependencies in a random order.  This is useful when
.\" building multiple trees simultaneously with caching enabled as a
.\" way to prevent multiple builds from simultaneously trying to build
.\" or retrieve the same target files.

.TP
-s, --silent, --quiet
Silent.  Do not print commands that are executed to rebuild
target files.
Also suppresses SCons status messages.

.TP
-S, --no-keep-going, --stop
Ignored for compatibility with GNU 
.BR make .

.TP
-t, --touch
Ignored for compatibility with GNU
.BR make .  
(Touching a file to make it
appear up-to-date is unnecessary when using 
.BR scons .)

.TP
-u, --up, --search-up
Walks up the directory structure until an 
.I SConstruct ,
.I Sconstruct
or 
.I sconstruct
file is found, and uses that
as the top of the directory tree. Only targets at or below the
current directory will be built.

.TP
-U
Works exactly the same way as the
.B -u
option except for the way default targets are handled.
When this option is used and no targets are specified on the command line,
all default targets that are defined in the SConscript(s) in the current
directory are built, regardless of what directory the resultant targets end
up in.

.TP
-v, --version
Print the 
.B scons
version, copyright information,
list of authors, and any other relevant information.
Then exit.

.TP
-w, --print-directory
Print a message containing the working directory before and
after other processing.

.TP
.RI --warn= type ", --warn=no-" type
Enable or disable warnings.
.I type
specifies the type of warnings to be enabled or disabled:

.TP
.RI --warn=all ", " --warn=no-all
Enables or disables all warnings.

.TP
.RI --warn=dependency ", " --warn=no-dependency
Enables or disables warnings about dependencies.
These warnings are disabled by default.

.TP
.RI --warn=deprecated ", " --warn=no-deprecated
Enables or disables warnings about use of deprecated features.
These warnings are enabled by default.

.TP
--no-print-directory
Turn off -w, even if it was turned on implicitly.

.\" .TP
.\" .RI --write-filenames= file
.\" Write all filenames considered into
.\" .IR file .
.\"
.\" .TP
.\" .RI -W " file" ", --what-if=" file ", --new-file=" file ", --assume-new=" file
.\" Pretend that the target 
.\" .I file 
.\" has been
.\" modified.  When used with the 
.\" .B -n
.\" option, this
.\" show you what would be rebuilt if you were to modify that file.
.\" Without 
.\" .B -n
.\" ... what? XXX
.\"
.\" .TP
.\" --warn-undefined-variables
.\" Warn when an undefined variable is referenced.

.TP 
.RI -Y " repository" ", --repository=" repository
Search the specified repository for any input and target
files not found in the local directory hierarchy.  Multiple
.B -Y
options may specified, in which case the
repositories are searched in the order specified.

.SH CONFIGURATION FILE REFERENCE
.\" .SS Python Basics
.\" XXX Adding this in the future would be a help.
.SS Construction Environments
A construction environment is the basic means by which the SConscript
files communicate build information to 
.BR scons .
A new construction environment is created using the 
.B Environment 
function:

.ES
env = Environment()
.EE

By default, a new construction environment is
initialized with a set of builder methods
and construction variables that are appropriate
for the current platform.
An optional platform keyword argument may be
used to specify that an environment should
be initialized for a different platform:

.ES
env = Environment(platform = 'cygwin')
env = Environment(platform = 'os2')
env = Environment(platform = 'posix')
env = Environment(platform = 'win32')
.EE

Specifying a platform initializes the appropriate
construction variables in the environment
to use and generate file names with prefixes
and suffixes appropriate for the platform.

The platform argument may be function or callable object,
in which case the Environment() method
will call the specified argument to update
the new construction environment:

.ES
def my_platform(env):
    env['VAR'] = 'xyzzy'

env = Environment(platform = my_platform)
.EE

Additionally, a specific set of tools
with which to initialize the environment
may specified as an optional keyword argument:

.ES
env = Environment(tools = ['msvc', 'lex'])
.EE

The elements of the tools list may also
be functions or callable objects,
in which case the Environment() method
will call the specified elements
to update the new construction environment:

.ES
def my_tool(env):
    env['XYZZY'] = 'xyzzy'

env = Environment(tools = [my_tool])
.EE

If no tool list is specified, then SCons will auto-detect the installed
tools using the PATH variable in the ENV construction variable and the
platform name when the Environment is constructed. Changing the PATH
variable after the Environment is constructed will not cause the tools to
be redetected.

SCons supports the following tool specifications
out of the box on all platforms:
.ES
ar
dvipdf
dvips
g++
g77
icc
ifl
ilink
gas
gcc
gnulink
latex
lex
masm
mingw
mslib
mslink
msvc
nasm
pdflatex
pdftex
tar
tex
yacc
.EE

On posix and cygwin platforms
the GNU tools (e.g. gcc) are preferred by SCons,
on win32 the Microsoft tools (e.g. msvc)
followed by MinGW are preferred by SCons,
and in OS/2 the IBM tools (e.g. icc) are preferred by SCons.

.SS Builder Methods

Build rules are specified by calling a construction
environment's builder methods.
The arguments to the builder methods are
.B target
(a list of target files)
and
.B source
(a list of source files).

Because long lists of file names
can lead to a lot of quoting,
.B scons
supplies a
.B Split()
function that splits a single string
into a list, separated on
strings of white-space characters.
(This is similar to the
string.split() method
from the standard Python library.)

Like all Python arguments,
the target and source arguments to a builder
can be specified either with or without
the "target" and "source" keywords.
When the keywords are omitted,
the target is first,
followed by the source.
The following are equivalent examples of calling the Program builder:

.ES
env.Program('bar', ['bar.c', 'foo.c'])
env.Program('bar', Split('bar.c foo.c'))
env.Program(source =  ['bar.c', 'foo.c'], target = 'bar')
env.Program(target = 'bar', Split('bar.c foo.c'))
env.Program('bar', source = string.split('bar.c foo.c'))
.EE

When the target shares the same base name
as the source and only the suffix varies,
and if the builder has a suffix defined for the target file type,
then the target argument may be omitted completely,
and
.B scons
will deduce the target file name from
the source file name.
The following examples all build the
executable program
.B bar
(on POSIX systems)
or 
.B bar.exe
(on Windows systems)
from the bar.c source file:

.ES
env.Program(target = 'bar', source = 'bar.c')
env.Program('bar', source = 'bar.c')
env.Program(source = 'bar.c')
env.Program('bar.c')
.EE

It is possible to override or add construction variables when calling a
builder by passing additional keyword arguments. These overriden or added
variables will only be in effect when building the target, so they will not
effect other parts of the build. For example, if you want to add additional
libraries for just one program:

.ES
env.Program('hello', 'hello.c', LIBS=['gl', 'glut'])
.EE

or generate a shared library with a nonstandard suffix:

.ES
env.SharedLibrary('word', 'word.cpp', SHLIBSUFFIX='.ocx')
.EE

All Builders return a Node or a list of Nodes,
representing the target or targets that will be built.
A list of Nodes is returned if there is more than one target,
and a single Node is returned if there is only one target.
A
.I Node
is an internal SCons object
which represents
build targets or sources.

The returned Node(s)
can be passed to other builder methods as source(s)
or passed into to any SCons function or method
where a filename would normally be accepted.
For example, if it were necessary
to add a specific
.B -D
flag when compiling one specific object file:

.ES
bar_obj = env.StaticObject('bar.c', CCFLAGS='-DBAR')
env.Program(source = ['foo.c', bar_obj, 'main.c'])
.EE

Using a Node in this way
makes for a more portable build
by avoiding having to specify
a platform-specific object suffix
when calling the Program() builder.

The path name for a Node's file may be used
by passing the Node to the Python-builtin
.B str()
function:

.ES
bar_obj = env.StaticObject('bar.c', CCFLAGS='-DBAR')
print "The path to bar_obj is:", str(bar_obj)
.EE

.B scons
provides the following builders:

.IP StaticObject
Builds a static object file
from one or more C, C++, or Fortran source files.
Source files must have one of the following extensions:
.ES
  .asm    assembly language file
  .ASM    assembly language file
  .c      C file
  .C      WIN32:  C file
          POSIX:  C++ file
  .cc     C++ file
  .cpp    C++ file
  .cxx    C++ file
  .cxx    C++ file
  .c++    C++ file
  .C++    C++ file
  .f      Fortran file
  .F      WIN32:  Fortran file
          POSIX:  Fortran file + C pre-processor
  .for    Fortran file
  .FOR    Fortran file
  .fpp    Fortran file + C pre-processor
  .FPP    Fortran file + C pre-processor
  .s      assembly language file
  .S      WIN32:  assembly language file
          POSIX:  assembly language file + C pre-processor
  .spp    assembly language file + C pre-processor
  .SPP    assembly language file + C pre-processor
.EE
.IP
The target object file prefix
(specified by the $OBJPREFIX construction variable; nothing by default)
and suffix
(specified by the $OBJSUFFIX construction variable;
\.obj on Windows systems, .o on POSIX systems)
are automatically added to the target if not already present.
Examples:

.ES
env.StaticObject(target = 'aaa', source = 'aaa.c')
env.StaticObject(target = 'bbb.o', source = 'bbb.c++')
env.StaticObject(target = 'ccc.obj', source = 'ccc.f')
.EE
.IP SharedObject
Builds an object file for
inclusion in a shared library.
Source files must have one of the same set of extensions
specified above for the
.B StaticObject
builder. On some platforms building a shared object requires additional
compiler options (e.g. -fPIC for gcc) in addition to those needed to build a
normal (static) object, but on some platforms there is no difference between a
shared object and a normal (static) one. When there is a difference, SCons
will only allow shared objects to be linked into a shared library, and will
use a different suffix for shared objects. On platforms where there is no
difference, SCons will allow both normal (static)
and shared objects to be linked into a
shared library, and will use the same suffix for shared and normal
(static) objects.
The target object file prefix
(specified by the $SHOBJPREFIX construction variable;
by default, the same as $OBJPREFIX)
and suffix
(specified by the $SHOBJSUFFIX construction variable)
are automatically added to the target if not already present. 
Examples:

.ES
env.SharedObject(target = 'ddd', source = 'ddd.c')
env.SharedObject(target = 'eee.o', source = 'eee.cpp')
env.SharedObject(target = 'fff.obj', source = 'fff.for')
.EE

.IP Object
A synonym for the
.B StaticObject
builder.

.IP PCH
Builds a Microsoft Visual C++ precompiled header. Calling this builder
returns a list of two targets: the PCH as the first element, and the object
file as the second element. Normally the object file is ignored. This builder is only
provided when Microsoft Visual C++ is being used as the compiler. 
The PCH builder is generally used in
conjuction with the PCH construction variable to force object files to use
the precompiled header:

.ES
env['PCH'] = env.PCH('StdAfx.cpp')[0]
.EE

.IP Program
Builds an executable given one or more object files or C, C++
or Fortran source files.
If any C, C++ or Fortran source files are specified,
then they will be automatically
compiled to object files using the
.B Object
builder;
see that builder's description for
a list of legal source file suffixes
and how they are interpreted.
The target executable file prefix
(specified by the $PROGPREFIX construction variable; nothing by default)
and suffix
(specified by the $PROGSUFFIX construction variable;
by default, .exe on Windows systems, nothing on POSIX systems)
are automatically added to the target if not already present.
Example:

.ES
env.Program(target = 'foo', source = ['foo.o', 'bar.c', 'baz.f'])
.EE

.IP RES
Builds a Microsoft Visual C++ resource file.
This builder is only provided
when Microsoft Visual C++ or MinGW is being used as the compiler. The
.I .res
(or 
.I .o 
for MinGW) suffix is added to the target name if no other suffix is given. The source
file is scanned for implicit dependencies as though it were a C file. Example:

.ES
env.RES('resource.rc')
.EE

.IP StaticLibrary
Builds a static library given one or more object files
or C, C++ or Fortran source files.
If any source files are given,
then they will be automatically
compiled to object files.
The static library prefix and suffix (if any)
are automatically added to the target.
The target library file prefix
(specified by the $LIBPREFIX construction variable;
by default, lib on POSIX systems, nothing on Windows systems)
and suffix
(specified by the $LIBSUFFIX construction variable;
by default, .lib on Windows systems, .a on POSIX systems)
are automatically added to the target if not already present.
Example:

.ES
env.StaticLibrary(target = 'bar', source = ['bar.c', 'foo.o'])
.EE

.IP
Any object files listed in the
.B source
must have been built for a static library
(that is, using the
.B StaticObject
builder).
.B scons
will raise an error if there is any mismatch.

.IP SharedLibrary
Builds a shared library
(.so on a POSIX system, .dll on WIN32)
given one or more object files
or C, C++ or Fortran source files.
If any source files are given,
then they will be automatically
compiled to object files.
The static library prefix and suffix (if any)
are automatically added to the target.
The target library file prefix
(specified by the $SHLIBPREFIX construction variable;
by default, lib on POSIX systems, nothing on Windows systems)
and suffix
(specified by the $SHLIBSUFFIX construction variable;
by default, .dll on Windows systems, .so on POSIX systems)
are automatically added to the target if not already present.
Example:

.ES
env.SharedLibrary(target = 'bar', source = ['bar.c', 'foo.o'])
.EE
.IP
On WIN32 systems, the
.B SharedLibrary
builder will always build an import (.lib) library
in addition to the shared (.dll) library,
adding a .lib library with the same basename
if there is not already a .lib file explicitly
listed in the targets.

Any object files listed in the
.B source
must have been built for a shared library
(that is, using the
.B SharedObject
builder).
.B scons
will raise an error if there is any mismatch.

.IP Library
A synonym for the
.B StaticLibrary
builder.

.IP CFile
Builds a C source file given a lex (.l) or yacc (.y) input file.
The suffix specified by the $CFILESUFFIX construction variable
(.c by default)
is automatically added to the target
if it is not already present. Example:

.ES
# builds foo.c
env.CFile(target = 'foo.c', source = 'foo.l')
# builds bar.c
env.CFile(target = 'bar', source = 'bar.y')
.EE

.IP CXXFile
Builds a C++ source file given a lex (.ll) or yacc (.yy) input file.
The suffix specified by the $CXXFILESUFFIX construction variable
(.cc by default)
is automatically added to the target
if it is not already present. Example:

.ES
# builds foo.cc
env.CXXFile(target = 'foo.cc', source = 'foo.ll')
# builds bar.cc
env.CXXFile(target = 'bar', source = 'bar.yy')
.EE

.IP DVI
Builds a .dvi file from a .tex, .ltx or .latex input file.
The suffix .dvi
(hard-coded within TeX itself)
is automatically added to the target
if it is not already present. Example:

.ES
# builds from aaa.tex
env.DVI(target = 'aaa.dvi', source = 'aaa.tex')
# builds bbb.dvi
env.DVI(target = 'bbb', source = 'bbb.ltx')
# builds from ccc.latex
env.DVI(target = 'ccc.dvi', source = 'ccc.latex')
.EE

.IP PDF
Builds a .pdf file from a .dvi input file
(or, by extension, a .tex, .ltx, or .latex input file).
The suffix specified by the $PDFSUFFIX construction variable
(.pdf by default)
is added automatically to the target
if it is not already present.  Example:

.ES
# builds from aaa.tex
env.PDF(target = 'aaa.pdf', source = 'aaa.tex')
# builds bbb.pdf from bbb.dvi
env.PDF(target = 'bbb', source = 'bbb.dvi')
.EE

.IP PostScript
Builds a .ps file from a .dvi input file
(or, by extension, a .tex, .ltx, or .latex input file).
The suffix specified by the $PSSUFFIX construction variable
(.ps by default)
is added automatically to the target
if it is not already present.  Example:

.ES
# builds from aaa.tex
env.PostScript(target = 'aaa.ps', source = 'aaa.tex')
# builds bbb.ps from bbb.dvi
env.PostScript(target = 'bbb', source = 'bbb.dvi')
.EE
.LP
.B scons
automatically scans
C source files, C++ source files,
Fortran source files with
.B .F
(POSIX systems only),
.B .fpp,
or
.B .FPP
file extensions,
and assembly language files with
.B .S
(POSIX systems only),
.B .spp,
or
.B .SPP
files extensions
for C preprocessor dependencies,
so the dependencies do not need to be specified explicitly.
In addition, all builder
targets automatically depend on their sources.
An explicit dependency can
be specified using the 
.B Depends 
method of a construction environment (see below).

.SS Other Construction Environment Methods
Additional construction environment methods include:

.TP
.RI Alias( alias ", " targets )
Creates a phony target that
expands to one or more other targets.
Returns the Node object representing the alias,
which exists outside of any file system.
This Node object, or the alias name,
may be used as a dependency of any other target,
including another alias. Alias can be called multiple times for the same
alias to add additional targets to the alias.

.ES
env.Alias('install', ['/usr/local/bin', '/usr/local/lib'])
env.Alias('install', ['/usr/local/man'])
.EE

.TP
.RI Append( key = val ", [...])"
Appends the specified keyword arguments
to the end of construction variables in the environment.
If the Environment does not have
the specified construction variable,
it is simply added to the environment.
If the values of the construction variable
and the keyword argument are the same type,
then the two values will be simply added together.
Otherwise, the construction variable
and the value of the keyword argument
are both coerced to lists,
and the lists are added together.
(See also the Prepend method, below.)

.ES
env.Append(CCFLAGS = ' -g', FOO = ['foo.yyy'])
.EE

.TP
.RI Command( target ", " source ", " commands )
Executes a specific action
(or list of actions)
to build a target file or files.
This is more convenient
than defining a separate Builder object
for a single special-case build.

Note that an action can be an external command,
specified as a string,
or a callable Python object;
see "Action Objects," below.
Examples:

.ES
env.Command('foo.out', 'foo.in',
            "$FOO_BUILD < $SOURCES > $TARGET")

env.Command('bar.out', 'bar.in',
            ["rm -f $TARGET",
             "$BAR_BUILD < $SOURCES > $TARGET"])

def rename(env, target, source):
    import os
    os.rename('.tmp', str(target[0]))

env.Command('baz.out', 'baz.in',
            ["$BAZ_BUILD < $SOURCES > .tmp",
	     rename ])
.EE

.TP
.RI Copy([ key = val ", ...])"
Return a separate copy of a construction environment.
If there are any keyword arguments specified,
they are added to the returned copy,
overwriting any existing values
for the keywords.

.ES
env2 = env.Copy()
env3 = env.Copy(CCFLAGS = '-g')
.EE

.TP
.RI Depends( target ", " dependency )
Specifies an explicit dependency;
the target file(s) will be rebuilt
whenever the dependency file(s) has changed.
This should only be necessary
for cases where the dependency
is not caught by a Scanner
for the file.

.ES
env.Depends('foo', 'other-input-file-for-foo')
.EE

.TP
.RI Dictionary([ vars ])
Returns a dictionary object
containing copies of all of the
construction variables in the environment.
If there are any variable names specified,
only the specified construction
variables are returned in the dictionary.

.ES
dict = env.Dictionary()
cc_dict = env.Dictionary('CC', 'CCFLAGS', 'CCCOM')
.EE

.TP
.RI Ignore( target ", " dependency )
The specified dependency file(s)
will be ignored when deciding if
the target file(s) need to be rebuilt.

.ES
env.Ignore('foo', 'foo.c')
env.Ignore('bar', ['bar1.h', 'bar2.h'])
.EE

.TP
.RI Install( dir ", " source )
Installs one or more files in a destination directory.
The file names remain the same.

.ES
env.Install(dir = '/usr/local/bin', source = 'foo bar')
.EE

.TP
.RI InstallAs( target ", " source )
Installs one or more files as specific file names,
allowing changing a file name as part of the
installation.
It is an error if the target and source
list different numbers of files.

.ES
env.InstallAs(target = '/usr/local/bin/foo',
              source = 'foo_debug')
env.InstallAs(target = '../lib/libfoo.a ../lib/libbar.a',
              source = 'libFOO.a libBAR.a')
.EE

.TP
.RI Precious( target ", ...)"
Marks each given
.I target
as precious so it is not deleted before it is rebuilt. Normally
.B scons
deletes a target before building it.
Multiple targets can be passed in to a single call to
.BR Precious ().

.TP
.RI Prepend( key = val ", [...])"
Appends the specified keyword arguments
to the beginning of construction variables in the environment.
If the Environment does not have
the specified construction variable,
it is simply added to the environment.
If the values of the construction variable
and the keyword argument are the same type,
then the two values will be simply added together.
Otherwise, the construction variable
and the value of the keyword argument
are both coerced to lists,
and the lists are added together.
(See also the Append method, above.)

.ES
env.Prepend(CCFLAGS = '-g ', FOO = ['foo.yyy'])
.EE

.TP
.RI Replace( key = val ", [...])"
Replaces construction variables in the Environment
with the specified keyword arguments.
(Note:  "Update()" is a deprecated synonym for this method.)

.ES
env.Replace(CCFLAGS = '-g', FOO = 'foo.xxx')
.EE

.TP
.RI SideEffect( side_effect , target )
Declares
.I side_effect
as a side effect of building
.IR target . 
Both 
.I side_effect 
and
.I target
can be a list, a file name, or a node.
A side effect is a target that is created
as a side effect of building other targets.
For example, a Windows PDB
file is created as a side effect of building the .obj
files for a static library.
If a target is a side effect of multiple build commands,
.B scons
will ensure that only one set of commands
is executed at a time.
Consequently, you only need to use this method
for side-effect targets that are built as a result of
multiple build commands.

.SS Construction Variables
.\" XXX From Gary Ruben, 23 April 2002:
.\" I think it would be good to have an example with each construction
.\" variable description in the documentation.
.\" eg.
.\" CC     The C compiler
.\"    Example: env["CC"] = "c68x"
.\"    Default: env["CC"] = "cc"
.\" 
.\" CCCOM  The command line ...
.\"    Example:
.\"        To generate the compiler line c68x -ps -qq -mr -o $TARGET $SOURCES
.\"        env["CC"] = "c68x"
.\"        env["CFLAGS"] = "-ps -qq -mr"
.\"        env["CCCOM"] = "$CC $CFLAGS -o $TARGET $SOURCES
.\"    Default:
.\"        (I dunno what this is ;-)
A construction environment has an associated dictionary of construction
variables that are used by built-in or user-supplied build rules. A number
of useful construction variables are automatically defined by scons for
each supported platform, and additional construction variables can be defined
by the user. The following is a list of the automatically defined construction
variables:

.IP AR
The static library archiver.

.IP ARCOM
The command line used to generate a static library from object files.

.IP ARFLAGS
General options passed to the static library archiver.

.IP AS
The assembler.

.IP ASCOM
The command line used to generate an object file
from an assembly-language source file.

.IP ASFLAGS
General options passed to the assembler.

.IP ASPPCOM
The command line used to assemble an assembly-language
source file into an object file
after first running the file through the C preprocessor.
Any options specified in the $ASFLAGS and $CPPFLAGS construction variables
are included on this command line.

.IP BUILDERS
A dictionary mapping the names of the builders
available through this environment
to underlying Builder objects.
Builders named
Alias, CFile, CXXFile, DVI, Library, Object, PDF, PostScript, and Program
are available by default.

.IP CC 
The C compiler.

.IP CCCOM 
The command line used to compile a C source file to a (static) object file.
Any options specified in the $CCFLAGS and $CPPFLAGS construction variables
are included on this command line.

.IP CCFLAGS 
General options that are passed to the C compiler.

.IP CFILESUFFIX
The suffix for C source files.
This is used by the internal CFile builder
when generating C files from Lex (.l) or YACC (.y) input files.
The default suffix, of course, is
.I .c
(lower case).
On case-insensitive systems (like Win32),
SCons also treats
.I .C
(upper case) files
as C files.

.IP _concat
A function used to produce variables like $_CPPINCFLAGS. It takes six
arguments: a prefix to concatenate onto each element, a list of elements, a
suffix to concatenate onto each element, a dictionary of global variables
for variable interpolation, a list of local variables for variable
interpolation, and an optional function that will be called to transform the list
before concatenation.

.ES
env['_CPPINCFLAGS'] = '$( ${_concat(INCPREFIX, CPPPATH, INCSUFFIX, locals(), globals(), RDirs)} $)',
.EE


.IP CPPFLAGS
C preprocessor options.
These will be included in any command that uses the C preprocessor,
including not just compilation of C and C++ source files
via the $CCCOM, $SHCCCOM, $CXXCOM and $SHCXXCOM command lines,
but also the $F77PPCOM command line
used to compile a Fortran source file,
and the $ASPPCOM command line
used to assemble an assembly language source file,
after first running each file through the C preprocessor.

.IP _CPPINCFLAGS
An automatically-generated construction variable
containing the C preprocessor command-line options
for specifying directories to be searched for include files.
The value of $_CPPINCFLAGS is created
by appending $INCPREFIX and $INCSUFFIX
to the beginning and end
of each directory in $CPPPATH.

.IP CPPPATH
The list of directories that the C preprocessor will search for include
directories. The C/C++ implicit dependency scanner will search these
directories for include files. Don't explicitly put include directory
arguments in CCFLAGS or CXXFLAGS because the result will be non-portable
and the directories will not be searched by the dependency scanner. Note:
directory names in CPPPATH will be looked-up relative to the SConscript
directory when they are used in a command. To force 
.B scons
to look-up a directory relative to the root of the source tree use #:

.ES
env = Environment(CPPPATH='#/include')
.EE

.IP
The directory look-up can also be forced using the 
.BR Dir ()
function:

.ES
include = Dir('include')
env = Environment(CPPPATH=include)
.EE

.IP
The directory list will be added to command lines
through the automatically-generated
$_CPPINCFLAGS
construction variable,
which is constructed by
appending the values of the
$INCPREFIX and $INCSUFFIX
construction variables
to the beginning and end
of each directory in $CPPPATH.
Any command lines you define that need
the CPPPATH directory list should
include $_CPPINCFLAGS:

.ES
env = Environment(CCCOM="my_compiler $_CPPINCFLAGS -c -o $TARGET $SOURCE")
.EE

.IP CXX
The C++ compiler.

.IP CXXFILESUFFIX
The suffix for C++ source files.
This is used by the internal CXXFile builder
when generating C++ files from Lex (.ll) or YACC (.yy) input files.
The default suffix is
.IR .cc .
SCons also treats files with the suffixes
.IR .cpp ,
.IR .cxx ,
.IR .c++ ,
and
.I .C++
as C++ files.
On case-sensitive systems (Linux, UNIX, and other POSIX-alikes),
SCons also treats
.I .C
(upper case) files
as C++ files.

.IP CXXCOM
The command line used to compile a C++ source file to an object file.
Any options specified in the $CXXFLAGS and $CPPFLAGS construction variables
are included on this command line.

.IP CXXFLAGS 
General options that are passed to the C++ compiler.

.IP Dir
A function that converts a file name into a Dir instance relative to the
target being built. 

.IP DVIPDF
The TeX DVI file to PDF file converter.

.IP DVIPDFFLAGS
General options passed to the TeX DVI file to PDF file converter.

.IP DVIPS
The TeX DVI file to PostScript converter.

.IP DVIPSFLAGS
General options passed to the TeX DVI file to PostScript converter.

.IP ENV
A dictionary of environment variables
to use when invoking commands.
Note that, by default,
.B scons
does
.I not
propagate the environment in force when you
execute
.B scons
to the commands used to build target files.
This is so that builds will be guaranteed
repeatable regardless of the environment
variables set at the time
.B scons
is invoked.

If you want to propagate your
environment variables
to the commands executed
to build target files,
you must do so explicitly:

.ES
import os
env = Environment(ENV = os.environ)
.EE

.RS
Note that you can choose only to propagate
certain environment variables.
A common example is
the system
.B PATH
environment variable,
so that
.B scons
uses the same utilities
as the invoking shell (or other process):
.RE

.ES
import os
env = Environment(ENV = {'PATH' : os.environ['PATH']})
.EE

.IP ESCAPE
A function that will be called to escape shell special characters in
command lines. The function should take one argument: the command line
string to escape; and should return the escaped command line.

.IP F77
The Fortran compiler.

.IP F77COM 
The command line used to compile a Fortran source file to an object file.

.IP F77FLAGS
General options that are passed to the Fortran compiler.

.IP _F77INCFLAGS
An automatically-generated construction variable
containing the Fortran compiler command-line options
for specifying directories to be searched for include files.
The value of $_F77INCFLAGS is created
by appending $INCPREFIX and $INCSUFFIX
to the beginning and end
of each directory in $F77PATH.

.IP F77PATH
The list of directories that the Fortran compiler will search for include
directories. The Fortran implicit dependency scanner will search these
directories for include files. Don't explicitly put include directory
arguments in F77FLAGS because the result will be non-portable
and the directories will not be searched by the dependency scanner. Note:
directory names in F77PATH will be looked-up relative to the SConscript
directory when they are used in a command. To force 
.B scons
to look-up a directory relative to the root of the source tree use #:

.ES
env = Environment(F77PATH='#/include')
.EE

.IP
The directory look-up can also be forced using the 
.BR Dir ()
function:

.ES
include = Dir('include')
env = Environment(F77PATH=include)
.EE

.IP
The directory list will be added to command lines
through the automatically-generated
$_F77INCFLAGS
construction variable,
which is constructed by
appending the values of the
$INCPREFIX and $INCSUFFIX
construction variables
to the beginning and end
of each directory in $F77PATH.
Any command lines you define that need
the F77PATH directory list should
include $_F77INCFLAGS:

.ES
env = Environment(F77COM="my_compiler $_F77INCFLAGS -c -o $TARGET $SOURCE")
.EE

.IP F77PPCOM 
The command line used to compile a Fortran source file to an object file
after first running the file through the C preprocessor.
Any options specified in the $F77FLAGS and $CPPFLAGS construction variables
are included on this command line.

.IP File
A function that converts a file name into a File instance relative to the
target being built. 

.IP INCPREFIX
The prefix used to specify an include directory on the C compiler command
line.
This will be appended to the beginning of each directory
in the $CPPPATH and $F77PATH construction variables
when the $_CPPINCFLAGS and $_F77INCFLAGS
variables are automatically generated.

.IP INCSUFFIX
The suffix used to specify an include directory on the C compiler command
line.
This will be appended to the end of each directory
in the $CPPPATH and $F77PATH construction variables
when the $_CPPINCFLAGS and $_F77INCFLAGS
variables are automatically generated.

.IP LATEX
The LaTeX structured formatter and typesetter.

.IP LATEXCOM
The command line used to call the LaTeX structured formatter and typesetter.

.IP LATEXFLAGS
General options passed to the LaTeX structured formatter and typesetter.

.IP LEX
The lexical analyzer generator.

.IP LEXFLAGS
General options passed to the lexical analyzer generator.

.IP LEXCOM
The command line used to call the lexical analyzer generator
to generate a source file.

.IP _LIBDIRFLAGS
An automatically-generated construction variable
containing the linker command-line options
for specifying directories to be searched for library.
The value of $_LIBDIRFLAGS is created
by appending $LIBDIRPREFIX and $LIBDIRSUFFIX
to the beginning and end
of each directory in $LIBPATH.

.IP LIBDIRPREFIX
The prefix used to specify a library directory on the linker command line.
This will be appended to the beginning of each directory
in the $LIBPATH construction variable
when the $_LIBDIRFLAGS variable is automatically generated.

.IP LIBDIRSUFFIX
The suffix used to specify a library directory on the linker command line.
This will be appended to the end of each directory
in the $LIBPATH construction variable
when the $_LIBDIRFLAGS variable is automatically generated.

.IP _LIBFLAGS
An automatically-generated construction variable
containing the linker command-line options
for specifying libraries to be linked with the resulting target.
The value of $_LIBFLAGS is created
by appending $LIBLINKPREFIX and $LIBLINKSUFFIX
to the beginning and end
of each directory in $LIBS.

.IP LIBLINKPREFIX
The prefix used to specify a library to link on the linker command line.
This will be appended to the beginning of each library
in the $LIBS construction variable
when the $_LIBFLAGS variable is automatically generated.

.IP LIBLINKSUFFIX
The suffix used to specify a library to link on the linker command line.
This will be appended to the end of each library
in the $LIBS construction variable
when the $_LIBFLAGS variable is automatically generated.

.IP LIBPATH
The list of directories that will be searched for libraries.
The implicit dependency scanner will search these
directories for include files. Don't explicitly put include directory
arguments in LINKFLAGS because the result will be non-portable
and the directories will not be searched by the dependency scanner. Note:
directory names in LIBPATH will be looked-up relative to the SConscript
directory when they are used in a command. To force 
.B scons
to look-up a directory relative to the root of the source tree use #:

.ES
env = Environment(LIBPATH='#/libs')
.EE

.IP
The directory look-up can also be forced using the 
.BR Dir ()
function:

.ES
libs = Dir('libs')
env = Environment(LIBPATH=libs)
.EE

.IP
The directory list will be added to command lines
through the automatically-generated
$_LIBDIRFLAGS
construction variable,
which is constructed by
appending the values of the
$LIBDIRPREFIX and $LIBDIRSUFFIX
construction variables
to the beginning and end
of each directory in $LIBPATH.
Any command lines you define that need
the LIBPATH directory list should
include $_LIBDIRFLAGS:

.ES
env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")
.EE

.IP LIBPREFIX
The prefix used for (static) library file names.

.IP LIBPREFIXES
An array of legal prefixes for library file names.

.IP LIBS
A list of one or more libraries
that will be linked with
any executable programs
created by this environment.

.IP
The library list will be added to command lines
through the automatically-generated
$_LIBFLAGS
construction variable,
which is constructed by
appending the values of the
$LIBLINKPREFIX and $LIBLINKSUFFIX
construction variables
to the beginning and end
of each directory in $LIBS.
Any command lines you define that need
the LIBS library list should
include $_LIBFLAGS:

.ES
env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")
.EE

.IP LIBSUFFIX 
The suffix used for (static) library file names.

.IP LIBSUFFIXES
An array of legal suffixes for library file names.

.IP LINK
The linker.

.IP LINKFLAGS
General options passed to the linker.

.IP LINKCOM
The command line used to link object files into an executable.

.IP OBJPREFIX 
The prefix used for (static) object file names.

.IP OBJSUFFIX 
The suffix used for (static) object file names.

.IP PCH
The Microsoft Visual C++ precompiled header that will be used when compiling
object files. This variable is ignored by tools other than Microsoft Visual C++.
When this variable is
defined SCons will add options to the compiler command line to
cause it to use the precompiled header, and will also set up the
dependencies for the PCH file. Example: 

.ES
env['PCH'] = 'StdAfx.pch'
.EE

.IP PCHSTOP
This variable specifies how much of a source file is precompiled. This
variable is ignored by tools other than Microsoft Visual C++, or when
the PCH variable is not being used. When this variable is define it
must be a string that is the name of the header that
is included at the end of the precompiled portion of the source files, or
the empty string if the "#pragma hrdstop" construct is being used:

.ES
env['PCHSTOP'] = 'StdAfx.h'
.EE

.IP PDB
The Microsoft Visual C++ PDB file that will store debugging information for
object files, shared libraries, and programs. This variable is ignored by
tools other than Microsoft Visual C++.
When this variable is
defined SCons will add options to the compiler and linker command line to
cause them to generate external debugging information, and will also set up the
dependencies for the PDB file. Example:

.ES
env['PDB'] = 'hello.pdb'
.EE

.IP PDFCOM
The command line used to convert TeX DVI files into a PDF file.

.IP PDFPREFIX
The prefix used for PDF file names.

.IP PDFSUFFIX
The suffix used for PDF file names.

.IP PROGPREFIX
The prefix used for executable file names.

.IP PROGSUFFIX
The suffix used for executable file names.

.IP PSCOM
The command line used to convert TeX DVI files into a PostScript file.

.IP PSPREFIX
The prefix used for PostScript file names.

.IP PSSUFFIX
The prefix used for PostScript file names.

.IP RANLIB
The archive indexer.

.IP RANLIBFLAGS
General options passed to the archive indexer.

.IP RC
The resource compiler used by the RES builder.

.IP RCCOM
The command line used by the RES builder.

.IP RCFLAGS
The flags passed to the resource compiler by the RES builder.

.IP RDirs
A function that converts a file name into a list of Dir instances by
searching the repositories. 

.IP SCANNERS
A list of the available implicit dependency scanners. [CScan] by default.

.IP SHCC
The C compiler used for generating shared-library objects.

.IP SHCCCOM
The command line used to compile a C source file
to a shared-library object file.
Any options specified in the $SHCCFLAGS and $CPPFLAGS construction variables
are included on this command line.

.IP SHCCFLAGS
Options that are passed to the C compiler
to generate shared-library objects.

.IP SHCXX
The C++ compiler used for generating shared-library objects.

.IP SHCXXCOM
The command line used to compile a C++ source file
to a shared-library object file.
Any options specified in the $SHCXXFLAGS and $CPPFLAGS construction variables
are included on this command line.

.IP SHCXXFLAGS
Options that are passed to the C++ compiler
to generate shared-library objects.

.IP SHELL
A string naming the shell program that will be passed to the 
.I SPAWN 
function. 
See the 
.I SPAWN 
construction variable for more information.

.IP SHF77
The Fortran compiler used for generating shared-library objects.

.IP SHF77COM
The command line used to compile a Fortran source file
to a shared-library object file.

.IP SHF77FLAGS
Options that are passed to the Fortran compiler
to generated shared-library objects.

.IP SHF77PPCOM
The command line used to compile a Fortran source file to a
shared-library object file
after first running the file through the C preprocessor.
Any options specified in the $SHF77FLAGS and $CPPFLAGS construction variables
are included on this command line.

.IP SHLIBPREFIX
The prefix used for shared library file names.

.IP SHLIBSUFFIX
The suffix used for shared library file names.

.IP SHLINK
The linker for programs that use shared libraries.

.IP SHLINKFLAGS
General options passed to the linker for programs using shared libraries.

.IP SHOBJPREFIX 
The prefix used for shared object file names.

.IP SHOBJSUFFIX 
The suffix used for shared object file names.

.IP SPAWN
A command interpreter function that will be called to execute command line
strings. The function must expect 4 arguments:

.ES
def spawn(shell, escape, cmd, args, env):
.EE
.IP
.I sh
is a string naming the shell program to use.
.I escape
is a function that can be called to escape shell special characters in
the command line. 
.I cmd
is the path to the command to be executed.
.I args
is that arguments to the command.
.I env
is a dictionary of the environment variables
in which the command should be executed.

.IP TAR
The tar archiver.

.IP TARCOM
The command line used to call the tar archiver.

.IP TARFLAGS
General options passed to the tar archiver.

.IP TARSUFFIX 
The suffix used for tar file names.

.IP TEX
The TeX formatter and typesetter.

.IP TEXCOM
The command line used to call the TeX formatter and typesetter.

.IP TEXFLAGS
General options passed to the TeX formatter and typesetter.

.IP WIN32_INSERT_DEF
When this is set to true,
a library build of a WIN32 shared library (.dll file)
will also build a corresponding .def file at the same time,
if a .def file is not already listed as a build target.
The default is 0 (do not build a .def file).

.IP WIN32DEFPREFIX
The prefix used for WIN32 .def file names.

.IP WIN32DEFSUFFIX
The suffix used for WIN32 .def file names.

.IP YACC
The parser generator.

.IP YACCCOM
The command line used to call the parser generator
to generate a source file.

.IP YACCFLAGS
General options passed to the parser generator.

.LP
Construction variables can be retrieved and set using the 
.B Dictionary 
method of the construction environment:

.ES
dict = env.Dictionary()
dict["CC"] = "cc"
.EE

or using the [] operator:

.ES
env["CC"] = "cc"
.EE

Construction variables can also be passed to the construction environment
constructor:

.ES
env = Environment(CC="cc")
.EE

or when copying a construction environment using the 
.B Copy 
method:

.ES
env2 = env.Copy(CC="cl.exe")
.EE

.SS Costruction Variable Options

Often when building software, various options need to be specified at build
time that are not known when the SConstruct/SConscript files are
written. For example, libraries needed for the build may be in non-standard
locations, or site-specific compiler options may need to be passed to the
compiler. 
.B scons
provides a mechanism for overridding construction variables from the
command line or a text-based SConscript file through an Options
object. To create an Options object, call the Options() function:

.TP
.RI Options([ file ])
This creates an Options object that will read construction variables from
the filename based in the 
.I file
argument. If no filename is given, then no file will be read. Example:

.ES
opts = Options('custom.py')
.EE

Options objects have the following methods:

.TP
.RI Add( key ", [" help ", " default ", " validater ", " converter ])
This adds a customizable construction variable to the Options object. 
.I key
is the name of the variable. 
.I help 
is the help text for the variable.
.I default 
is the default value of the variable.
.I validater
is called to validate the value of the variable, and should take two
arguments: key and value.
.I converter
is called to convert the value before putting it in the environment, and
should take a single argument: value. Example:

.ES
opts.Add('CC', 'The C compiler')
.EE

.TP
.RI Update( env )
This updates a construction environment
.I env
with the customized construction variables. Normally this method is not
called directly, but is called indirectly by passing the Options object to
the Environment() function:

.ES
env = Environment(options=opts)
.EE

.TP
.RI GenerateHelpText( env )
This generates help text documenting the customizable construction
variables suitable to passing in to the Help() function. 
.I env
is the construction environment that will be used to get the actual values
of customizable variables. Example:

.ES
Help(opts.GenerateHelpText(env))
.EE

The text based SConscript file is executed as a Python script, and the
global variables are queried for customizable construction
variables. Example:

.ES
CC = 'my_cc'
.EE

.SS Other Functions

.B scons
also provides various additional functions,
not associated with a construction environment,
that SConscript files can use:

.TP
.RI BuildDir( build_dir ", " src_dir ", [" duplicate ])
This specifies a build directory to use for all derived files.  
.I build_dir
specifies the build directory to be used for all derived files that would
normally be built under
.IR src_dir .
Multiple build directories can be set up for multiple build variants, for
example. 
.I src_dir
must be underneath the SConstruct file's directory,
and
.I build_dir
may not be underneath the
.I src_dir .

.B scons
will link or copy (depending on the platform) all the source files into the
build directory if 
.I duplicate
is set to 1 (the default). If 
.I duplicate
is set to 0, then 
.B scons 
will not copy or link any source files, which may cause build problems in
certain situations (e.g. C source files that are generated by the
build). 
.IR duplicate =0
is usually safe, and is always more efficient than 
.IR duplicate =1.

.TP 
.RI Clean ( target, files_or_dirs )
This specifies a list of files or directories which should be removed
whenever the target is specified with the
.B -c
command line option.
Multiple calls to
.BR Clean ()
are legal,
and create a new target or add files and directories to the
clean list for the specified target.

Multiple files or directories should be specified
either as separate arguments to the
.BR Clean ()
method, or as a list.
.BR Clean ()
will also accept the return value of any of the construction environment
Builder methods.
Examples:

.ES
Clean('foo', ['bar', 'baz'])
Clean('dist', env.Program('hello', 'hello.c'))
.EE

.TP 
.RI Default( targets )
This specifies a list of default targets,
which will be built by
.B scons
if no explicit targets are given on the command line.
Multiple calls to
.BR Default ()
are legal,
and add to the list of default targets.

Multiple targets should be specified as
separate arguments to the
.BR Default ()
method or as a list.
.BR Default ()
will also accept the return value of any of the construction environment
builder methods.
Examples:

.ES
Default('foo', 'bar', 'baz')
Default(['a', 'b', 'c'])
Default(env.Program('hello', 'hello.c'))
.EE

.TP
.RI Dir( name ", [" directory ])
This returns an object that represents a given directory 
.IR name . 
.I name
can be a relative or absolute path. 
.I directory
is an optional directory that will be used as the parent directory. 

.TP
.RI EnsurePythonVersion( major ", " minor )
Ensure that the Python version is at least 
.IR major . minor . 
This function will
print out an error message and exit SCons with a non-zero exit code if the
actual Python version is not late enough.

.ES
EnsurePythonVersion(2,2)
.EE

.TP
.RI EnsureSConsVersion( major ", " minor )
Ensure that the SCons version is at least 
.IR major . minor . 
This function will
print out an error message and exit SCons with a non-zero exit code if the
actual SCons version is not late enough.

.ES
EnsureSConsVersion(0,9)
.EE

.TP
.RI Export( vars )
This tells 
.B scons
to export a list of variables from the current
SConscript file to all other SConscript files. The exported variables
are kept in a global collection, so subsequent exports
will over-write previous exports that have the same name. 
Multiple variable names should be passed to
.BR Export ()
as separate arguments. Examples:

.ES
Export("env")
Export("env", "variable")
.EE

.TP 
.RI File( name ", [" directory ])
This returns an object that represents a given file 
.IR name . 
.I name
can be a relative or absolute path. 
.I directory
is an optional directory that will be used as the parent directory. 

.TP
.RI FindFile( file ", " dirs )
Search for 
.I file 
in the path specified by 
.IR dirs .
.I file
may be a list of file names or a single file name. In addition to searching
for files that exist in the filesytem, this function also searches for
derived files that have not yet been built.

.ES
foo = FindFile('foo', ['dir1', 'dir2'])
.EE
.\"
.\".TP
.\".RI GetBuildPath( XXX )
.\"XXX
.\"
.\".TP
.\".RI GetLaunchDir( XXX )
.\"XXX

.TP
.RI GetJobs()
Get the number of jobs (commands) that will be run simultaneously. See also 
.I -j
and
.IR SetJobs() .

.TP
.RI Help( text )
This specifies help text to be printed if the 
.B -h 
argument is given to
.BR scons .
.B scons
will exit after printing out the help text.

.TP 
.RI Import( vars )
This tells 
.B scons
to import a list of variables into the current SConscript file. This
will import variables that were exported with
.BR Export ()
or in the 
.I exports
argument to 
.BR SConscript ().
Variables exported by 
.BR SConscript ()
have precedence.
Multiple variable names should be passed to 
.BR Import ()
as separate arguments.
Examples:

.ES
Import("env")
Import("env", "variable")
.EE

.TP
.RI Literal( string )
The specified
.I string
will be preserved as-is
and not have construction variables expanded.

.TP
.RI Local( targets )
The specified
.I targets
will have copies made in the local tree,
even if an already up-to-date copy
exists in a repository.

.TP
.RI ParseConfig( env , command ", [" function ])
Calls the specified
.I function
to modify the specified environment
.I env
as specified by the output of
.I command .
The default
.I function
expects the output of a typical
.I *-config command
(for example,
.BR gtk-config )
and parses the returned
.BR -L ,
.BR -l ,
.B -I
and other options
into the
.BR LIBPATH ,
.BR LIBS ,
.B CPPPATH
and
.B CCFLAGS
variables,
respectively.

.TP
.RI Platform( string )
Returns a callable object
that can be used to initialize
a construction environment using the
platform keyword of the Environment() method.

.ES
env = Environment(platform = Platform('win32'))
.EE

.TP
.RI Repository( directory )
Specifies that
.I directory
is a repository to be searched for files.
Multiple calls to
.BR Repository ()
are legal,
and each one adds to the list of
repositories that will be searched.

To
.BR scons ,
a repository is a copy of the source tree,
from the top-level directory on down,
which may contain
both source files and derived files
that can be used to build targets in
the local source tree.
The canonical example would be an
official source tree maintained by an integrator.
If the repository contains derived files,
then the derived files should have been built using
.BR scons ,
so that the repository contains the necessary
signature information to allow
.B scons
to figure out when it is appropriate to
use the repository copy of a derived file,
instead of building one locally.

Note that if an up-to-date derived file
already exists in a repository,
.B scons
will
.I not
make a copy in the local directory tree.
In order to guarantee that a local copy
will be made,
use the
.B Local()
method.

.TP
.RI Return( vars )
This tells
.B scons
what variable(s) to use as the return value(s) of the current SConscript
file. These variables will be returned to the "calling" SConscript file
as the return value(s) of 
.BR SConscript ().
Multiple variable names should be passed to 
.BR Return ()
as a list. Example:

.ES
Return("foo")
Return(["foo", "bar"])
.EE

.TP
.RI SConscript( script ", [" exports ])
This tells
.B scons
to execute
.I script
as a SConscript (configuration) file. The optional 
.I exports
argument provides a list of variable names to export to
.IR script ". "
.I script
must use the
.BR Import ()
function to import the variables. Any variables returned by 
.I script 
using 
.BR Return ()
will be returned by the call to
.BR SConscript (). 
Examples:

.ES
SConscript('dir/SConscript')
foo = SConscript('subdir/SConscript', "env")
.EE

.TP
.RI SConscriptChdir( value )
When a non-zero
.I value
is specified,
this instructs
.B scons
to change its working directory (chdir)
to the directory in which each subsidiary
SConscript file lives.
Note that you may enable and disable
this ability by calling
SConscriptChdir()
multiple times:

.ES
SConscriptChdir(1)
SConscript('foo/SConscript')	# will chdir to foo
SConscriptChdir(0)
SConscript('bar/SConscript')	# will not chdir to bar
.EE

.TP 
.RI SetBuildSignatureType( type )

This function tells SCons what type of build signature to use: "build" or
"content". "build" means to concatenate the signatures of all source files
of a derived file to make its signature, and "content" means to use
the derived files content signature as its signature. "build" signatures
are usually faster to compute, but "content" signatures can prevent
redundant rebuilds. The default is "build".

.TP
.RI SetContentSignatureType( type )

This function tells SCons what type of content signature to use: "MD5" or
"timestamp". "MD5" means to use the MD5 checksum of a files contents as
its signature, and "timestamp" means to use a files timestamp as its
signature. When using "timestamp" signatures, changes in the
command line will not cause files to be rebuilt. "MD5" signatures take
longer to compute, but "timestamp" signatures are less accurate. The
default is "MD5".

.TP
.RI SetJobs( num )
Specifies the number of jobs (commands) to run simultaneously. 
.I -j
overrides this function. See also 
.I -j
and 
.IR GetJobs() .

.TP
.RI Split( arg )
Returns a list of file names or other objects.
If arg is a string,
it will be split on strings of white-space characters
within the string,
making it easier to write long lists of file names.
If arg is already a list,
the list will be returned untouched.
If arg is any other type of object,
it will be returned as a list
containing just the object.

.ES
files = Split("f1.c f2.c f3.c")
files = Split("""
	f4.c
	f5.c
	f6.c
""")
.EE

.TP
.RI Tool( string )
Returns a callable object
that can be used to initialize
a construction environment using the
tools keyword of the Environment() method.

.ES
env = Environment(tools = [ Tool('msvc') ])
.EE

.TP
.RI WhereIs( program ", [" path  ", [" pathext ]])

Searches for the specified executable
.I program,
returning the full path name to the program
if it is found,
and returning None if not.
Searches the specified
.I path,
or the user's current PATH
(os.environ['PATH'])
by default.
On Win32 systems, searches for executable
programs with any of the file extensions
listed in the specified
.I pathext,
or the user's current PATHEXT
(os.environ['PATHEXT'])
by default.

.SH EXTENDING SCONS
.SS Builder Objects
.B scons
can be extended by adding new builders to a construction
environment using the 
.B Builder 
function.
The
.B Builder
function accepts the following arguments:

.IP name
The name of the builder. This will be the
name of the construction environment method
used to create an instance of the builder.

.IP action
The command line string used to build the target from the source. 
.B action
can also be:
a list of strings representing the command
to be executed and its arguments
(suitable for enclosing white space in an argument),
a dictionary
mapping source file name suffixes to
any combination of command line strings
(if the builder should accept multiple source file extensions),
a Python function;
an Action object
(see the next section);
or a list of any of the above.

An action function
takes three arguments:
.I source 
- a list of source nodes, 
.I target
- a list of target nodes,
.I env
- the construction environment.

.IP multi
Specifies whether this builder is allowed to be called multiple times for
the same target file(s). The default is 0, which means the builder
can not be called multiple times for the same target file(s). Calling a
builder multiple times for the same target simply adds additional source
files to the target; it is not allowed to change the environment associated
with the target, specify addition environment overrides, or associate a different
builder with the target. 

.IP prefix 
The prefix that will be prepended to the target file name.

.IP suffix
The suffix that will be appended to the target file name.

.IP src_suffix
The expected source file name suffix.

.IP src_builder
Specifies a builder to use when a source file name suffix does not match
any of the suffixes of the builder. Using this argument produces a
multi-stage builder.

.IP emitter
A function that is passed the target, source, and environment,
and which returns a tuple containing two lists,
the list of targets to be built by this builder,
and the list of sources for this builder.
This allows the target and source lists to
be manipulated before the target(s) are actually built.

The emitter function
takes three arguments:
.I source 
- a list of source nodes, 
.I target
- a list of target nodes,
.I env
- the construction environment.

Example:

.ES
def e(target, source, env):
    return (target + ['foo.foo'], source + ['foo.src'])

b = Builder(emitter=e)
.EE

.IP generator
A function that returns a list of actions that will be executed to build
the target(s) from the source(s).
The returned action(s) may be
an Action object, or anything that
can be converted into an Action object
(see the next section).

The generator function
takes four arguments:
.I source 
- a list of source nodes, 
.I target
- a list of target nodes,
.I env
- the construction environment.
.I for_signature
- a Boolean value that specifies
whether the generator is being called
for generating a build signature
(as opposed to actually executing the command).
Example:

.ES
def g(source, target, env, for_signature):
    return [["gcc", "-c", "-o"] + target + source] 

b = Builder(generator=g)
.EE

The 
.I generator
and
.I action
arguments must not both be used for the same Builder.

Any additional keyword arguments supplied
when a Builder object is called
will be associated with the target
(and any other files built as a
result of the call).

.ES
b = Builder(action="build < $SOURCE > $TARGET")
env = Environment(BUILDERS = {'MyBuild' : b})
env.MyBuild('foo.out', 'foo.in', my_arg = 'xyzzy')
.EE

These extra keyword arguments are passed to the
following functions:
command generator functions,
function Actions,
and emitter functions.

.SS Action Objects

The Builder function will turn its
.B action
keyword argument into an appropriate
internal Action object.
Occasionally, it may be more efficient
to create an explicit Action object
and use it to initialize multiple
Builder objects,
rather than let each separate Builder object
create a separate Action.

The Action method takes one or two arguments
and returns an appropriate object for the action
represented by the type of the first argument:

.IP Action
If the first argument is already an Action object,
the object is simply returned.

.IP String
If the first argument is a string,
a command-line Action is returned.

.ES
Action('$CC -c -o $TARGET $SOURCES')
.EE

.\" XXX From Gary Ruben, 23 April 2002:
.\" What would be useful is a discussion of how you execute command
.\" shell commands ie. what is the process used to spawn the shell, pass
.\" environment variables to it etc., whether there is one shell per
.\" environment or one per command etc.  It might help to look at the Gnu
.\" make documentation to see what they think is important to discuss about
.\" a build system. I'm sure you can do a better job of organising the
.\" documentation than they have :-)


.IP List
If the first argument is a list,
then a list of Action objects is returned.
An Action object is created as necessary
for each element in the list.
If an element
.I within
the list is itself a list,
the internal list is the
command and arguments to be executed via
the command line.
This allows white space to be enclosed
in an argument by defining
a command in a list within a list:
.ES
Action([['cc', '-c', '-DWHITE SPACE', '-o', '$TARGET', '$SOURCES']])
.EE

.IP Function
If the first argument is a Python function,
a function Action is returned.
The Python function takes three keyword arguments,
.B target
(a Node object representing the target file),
.B source
(a Node object representing the source file)
and
.BR env
(the construction environment
used for building the target file).
The
.B target
and
.B source
arguments may be lists of Node objects if there is
more than one target file or source file.
The actual target and source file name(s) may
be retrieved from their Node objects
via the built-in Python str() function:
.ES
target_file_name = str(target)
source_file_names = map(lambda x: str(x), source)
.EE
.IP
The function should return
.B 0
or
.B None
to indicate a successful build of the target file(s).
The function may raise an exception
or return a non-zero exit status
to indicate an unsuccessful build.

.ES
def build_it(target = None, source = None, env = None):
    # build the target from the source
    return 0
 
a = Action(build_it)
.EE

The second, optional argument
is a Python function that returns
a string to be printed describing the action being executed.
This function takes two arguments,
an array of targets to be created by the function action,
and an array of sources used to create the target(s):

.ES
def build_it(target, source, env):
    # build the target from the source
    return 0

def string_it(target, source):
    return "building '%s' from '%s'" % (target[0], source[0])

# Use a positional argument.
a = Action(build_it, string_it)

# Alternatively, use a keyword argument.
a = Action(build_it, strfunction=string_it)
.EE

The third, also optional argument
is a list of construction variables
whose values will be included
in the signature of the Action
when deciding whether a target should
be rebuilt because the action changed.
This is necessary whenever you want a target to
be rebuilt by an action when a specific
construction variable changes,
because the underlying Python code for a function
will not change when the value of the construction variable does.

.ES
def build_it(target, source, env):
    # build the target from the 'XXX' construction variable
    open(target[0], 'w').write(env['XXX'])
    return 0

def string_it(target, source):
    return "building '%s' from '%s'" % (target[0], source[0])

# Use positional arguments.
a = Action(build_it, string_it, ['XXX'])

# Alternatively, use a keyword argument.
a = Action(build_it, varlist=['XXX'])
.EE
.PP
If the action argument is not one of the above,
None is returned.

.SS Variable Substitution

Before executing a command,
.B scons
performs construction variable interpolation on the strings that make up
the command line of builders.
Variables are introduced by a
.B $
prefix.
Besides construction variables, scons provides the following
variables for each command execution:

.IP TARGET
The file name of the target being built, or the file name of the first 
target if multiple targets are being built.

.IP TARGETS
The file names of all targets being built.

.IP SOURCE
The file name of the source of the build command, or the file name of the
first source if multiple sources are being built.

.IP SOURCES
The file names of the sources of the build command.

.LP 
For example, given the construction variable CC='cc', targets=['foo'], and
sources=['foo.c', 'bar.c']:

.ES
action='$CC -c -o $TARGET $SOURCES'
.EE

would produce the command line:

.ES
cc -c -o foo foo.c bar.c
.EE

Variable names may be surrounded by curly braces ({})
to separate the name from the trailing characters.
Within the curly braces, a variable name may have
a Python slice subscript appended to select one
or more items from a list.
In the previous example, the string:

.ES
${SOURCES[1]}
.EE

would produce:

.ES
bar.c
.EE

Additionally, a variable name may
have the following special
modifiers appended within the enclosing curly braces
to modify the interpolated string:

.IP base
The base path of the file name,
including the directory path
but excluding any suffix.

.IP dir
The name of the directory in which the file exists.

.IP file
The file name,
minus any directory portion.

.IP filebase
Just the basename of the file,
minus any suffix
and minus the directory.

.IP suffix
Just the file suffix.

.IP abspath
The absolute path name of the file.

.LP
For example, the specified target will
expand as follows for the corresponding modifiers:

.ES
$TARGET              => sub/dir/file.x
${TARGET.base}       => sub/dir/file
${TARGET.dir}        => sub/dir
${TARGET.file}       => file.x
${TARGET.filebase}   => file
${TARGET.suffix}     => .x
${TARGET.abspath}    => /top/dir/sub/dir/file.x
.EE

.LP
The special pseudo-variables
.R $(
and
.R $)
may be used to surround parts of a command line
that may change
.I without
causing a rebuild--that is,
which are not included in the signature
of target files built with this command.
All text between
.R $(
and
.R $)
will be removed from the command line
before it is added to file signatures,
and the
.R $(
and
.R $)
will be removed before the command is executed.
For example, the command line:

.ES
echo Last build occurred $( $TODAY $). > $TARGET
.EE

.LP
would execute the command:

.ES
echo Last build occurred $TODAY. > $TARGET
.EE

.LP
but the command signature added to any target files would be:

.ES
echo Last build occurred  . > $TARGET
.EE

SCons uses the following rules when converting construction variables into
command lines:

.IP String
When the value is a string it is interpreted as a space delimited list of
command line arguments. 

.IP List
When the value is a list it is interpreted as a list of command line
arguments. Each element of the list is converted to a string.

.IP Other
Anything that is not a list or string is converted to a string and
interpreted as a single command line argument.

.IP Newline
Newline characters (\\n) delimit lines. The newline parsing is done after
all other parsing, so it is not possible for arguments (e.g. file names) to
contain embedded newline characters. This limitation will likely go away in
a future version of SCons.

.SS Scanner Objects

You can use the
.B Scanner
function to define
objects to scan
new file types for implicit dependencies.
Scanner accepts the following arguments:

.IP function
A Python function that will process
the Node (file)
and return a list of strings (file names)
representing the implicit
dependencies found in the contents.
The function takes three or four arguments:

    def scanner_function(node, env, path):

    def scanner_function(node, env, path, arg):

The
.B node
argument is the internal
SCons node representing the file.
Use
.B str(node)
to fetch the name of the file, and
.B node.get_contents()
to fetch contents of the file.

The
.B env
argument is the construction environment for the scan.
Fetch values from it using the
.B env.Dictionary()
method.

The
.B path
argument is a tuple (or list)
of directories that can be searched
for files.
This will usually be the tuple returned by the
.B path_function
argument (see below).

The
.B arg
argument is the argument supplied
when the scanner was created, if any.

.IP name
The name of the Scanner.
This is mainly used
to identify the Scanner internally.

.IP argument
An optional argument that, if specified,
will be passed to the scanner function
(described above)
and the path function
(specified below).

.IP skeys
An optional list that can be used to
determine which scanner should be used for
a given Node.
In the usual case of scanning for file names,
this array will be a list of suffixes
for the different file types that this
Scanner knows how to scan.

.IP path_function
A Python function that takes
two or three arguments:
a construction environment, directory Node,
and optional argument supplied
when the scanner was created.
The
.B path_function
returns a tuple of directories
that can be searched for files to be returned
by this Scanner object.

.IP node_class
The class of Node that should be returned
by this Scanner object.
Any strings or other objects returned
by the scanner function
that are not of this class
will be run through the
.B node_factory
function.

.IP node_factory
A Python function that will take a string
or other object
and turn it into the appropriate class of Node
to be returned by this Scanner object.

.IP scan_check
An optional Python function that takes a Node (file)
as an argument and returns whether the
Node should, in fact,
be scanned for dependencies.
This check can be used to eliminate unnecessary
calls to the scanner function when,
for example, the underlying file
represented by a Node does not yet exist.

.IP recursive
An optional flag that
specifies whether this scanner should be re-invoked
on the dependency files returned by the scanner.
When this flag is not set,
the Node subsystem will
only invoke the scanner on the file being scanned,
and not (for example) also on the files
specified by the #include lines
in the file being scanned.

.SH SYSTEM-SPECIFIC BEHAVIOR
SCons and its configuration files are very portable,
due largely to its implementation in Python.
There are, however, a few portability
issues waiting to trap the unwary.
.SS .C file suffix
SCons handles the upper-case
.B .C
file suffix differently,
depending on the capabilities of
the underlying system.
On a case-sensitive system
such as Linux or UNIX,
SCons treats a file with a 
.B .C
suffix as a C++ source file.
On a case-insensitive system
such as Windows,
SCons treats a file with a 
.B .C
suffix as a C source file.
.SS .F file suffix
SCons handles the upper-case
.B .F
file suffix differently,
depending on the capabilities of
the underlying system.
On a case-sensitive system
such as Linux or UNIX,
SCons treats a file with a 
.B .F
suffix as a Fortran source file
that is to be first run through
the standard C preprocessor.
On a case-insensitive system
such as Windows,
SCons treats a file with a 
.B .F
suffix as a Fortran source file that should
.I not
be run through the C preprocessor.
.SS WIN32:  Cygwin Tools and Cygwin Python vs. Windows Pythons
Cygwin supplies a set of tools and utilities
that let users work on a
Windows system using a more POSIX-like environment.
The Cygwin tools, including Cygwin Python,
do this, in part,
by sharing an ability to interpret UNIX-like path names.
For example, the Cygwin tools
will internally translate a Cygwin path name
like /cygdrive/c/mydir
to an equivalent Windows pathname
of C:/mydir (equivalent to C:\\mydir).

Versions of Python
that are built for native Windows execution,
such as the python.org and ActiveState versions,
do not have the Cygwin path name semantics.
This means that using a native Windows version of Python
to build compiled programs using Cygwin tools
(such as gcc, bison, and flex)
may yield unpredictable results.
"Mixing and matching" in this way
can be made to work,
but it requires careful attention to the use of path names
in your SConscript files.

In practice, users can sidestep
the issue by adopting the following rules:
When using gcc,
use the Cygwin-supplied Python interpreter
to run SCons;
when using Microsoft Visual C/C++
(or some other Windows compiler)
use the python.org or ActiveState version of Python
to run SCons.
.SS WIN32:  scons.bat file
On WIN32 systems,
SCons is executed via a wrapper
.B scons.bat
file.
This has (at least) two ramifications:

First, Windows command-line users
that want to use variable assignment
on the command line
may have to put double quotes
around the assignments:

.ES
scons "FOO=BAR" "BAZ=BLEH"
.EE

Second, the Cygwin shell does not
recognize this file as being the same
as an
.B scons
command issued at the command-line prompt.
You can work around this either by
executing
.B scons.bat
from the Cygwin command line,
or by creating a wrapper shell
script named
.B scons .

.SS MinGW

The MinGW bin directory must be in your PATH environment variable or the
PATH variable under the ENV construction variable for SCons
to detect and use the MinGW tools. When running under the native Windows
Python interpreter, SCons will prefer the MinGW tools over the Cygwin
tools, if they are both installed, regardless of the order of the bin
directories in the PATH variable. If you have both MSVC and MinGW
installed and you want to use MinGW instead of MSVC,
then you must explictly tell SCons to use MinGW by passing 

.ES
tools=['mingw']
.EE

to the Environment() function, because SCons will prefer the MSVC tools
over the MinGW tools.

.SH EXAMPLES

To help you get started using SCons,
this section contains a brief overview of some common tasks.

NOTE:  SCons does
.I not
build all of its targets by default,
like other build tools do.
The canonical way to invoke SCons
is with a target of '.' (dot)
to represent all targets in and below the current directory:

.ES
scons .
.EE

One or more default targets may be specified
via the Default() method
in the SConstruct file.

.SS Basic Compilation From a Single Source File

.ES
env = Environment()
env.Program(target = 'foo', source = 'foo.c')
.EE

Note:  Build the file by specifying
the target as an argument
("scons foo" or "scons foo.exe").
or by specifying a dot ("scons .").

.SS Basic Compilation From Multiple Source Files

.ES
env = Environment()
env.Program(target = 'foo', source = 'f1.c f2.c f3.c')
.EE

.SS Setting a Compilation Flag

.ES
env = Environment(CCFLAGS = '-g')
env.Program(target = 'foo', source = 'foo.c')
.EE

.SS Search The Local Directory For .h Files

Note:  You do
.I not
need to set CCFLAGS to specify -I options by hand.
SCons will construct the right -I options from CPPPATH.

.ES
env = Environment(CPPPATH = ['.'])
env.Program(target = 'foo', source = 'foo.c')
.EE

.SS Search Multiple Directories For .h Files

.ES
env = Environment(CPPPATH = ['include1', 'include2'])
env.Program(target = 'foo', source = 'foo.c')
.EE

.SS Building a Static Library

.ES
env = Environment()
env.StaticLibrary(target = 'foo', source = 'l1.c l2.c')
.EE

.SS Building a Shared Library

.ES
env = Environment()
env.SharedLibrary(target = 'foo', source = 'l3.c l4.c')
.EE

.SS Linking a Local Library Into a Program

.ES
env = Environment(LIBS = 'mylib', LIBPATH = ['.'])
env.Library(target = 'mylib', source = 'l1.c l2.c')
env.Program(target = 'prog', source = 'p1.c p2.c')
.EE

.SS Defining Your Own Builder Object

Notice that when you invoke the Builder,
you can leave off the target file suffix,
and SCons will add it automatically.

.ES
bld = Builder(action = 'pdftex < $SOURCES > $TARGET'
              suffix = '.pdf',
              src_suffix = '.tex')
env = Environment(BUILDERS = {'PDFBuilder' : bld})
env.PDFBuilder(target = 'foo.pdf', source = 'foo.tex')

# The following creates "bar.pdf" from "bar.tex"
env.PDFBuilder(target = 'bar', source = 'bar')
.EE

.SS Defining Your Own Scanner Object

.ES
import re

include_re = re.compile(r'^include\\s+(\\S+)$', re.M)

def kfile_scan(node, env, path, arg):
    contents = node.get_contents()
    includes = include_re.findall(contents)
    return includes

kscan = Scanner(name = 'kfile',
                function = kfile_scan,
                argument = None,
                skeys = ['.k'])
scanners = Environment().Dictionary('SCANNERS')
env = Environment(SCANNERS = scanners + [kscan])

env.Command('foo', 'foo.k', 'kprocess < $SOURCES > $TARGET')

bar_in = File('bar.in')
env.Command('bar', bar_in, 'kprocess $SOURCES > $TARGET')
bar_in.target_scanner = kscan
.EE

.SS Creating a Hierarchical Build

Notice that the file names specified in a subdirectory's
SConscript
file are relative to that subdirectory.

.ES
SConstruct:

    env = Environment()
    env.Program(target = 'foo', source = 'foo.c')

    SConscript('sub/SConscript')

sub/SConscript:

    env = Environment()
    # Builds sub/foo from sub/foo.c
    env.Program(target = 'foo', source = 'foo.c')

    SConscript('dir/SConscript')

sub/dir/SConscript:

    env = Environment()
    # Builds sub/dir/foo from sub/dir/foo.c
    env.Program(target = 'foo', source = 'foo.c')
.EE

.SS Sharing Variables Between SConscript Files

You must explicitly Export() and Import() variables that
you want to share between SConscript files.

.ES
SConstruct:

    env = Environment()
    env.Program(target = 'foo', source = 'foo.c')

    Export("env")
    SConscript('subdirectory/SConscript')

subdirectory/SConscript:

    Import("env")
    env.Program(target = 'foo', source = 'foo.c')
.EE

.SS Building Multiple Variants From the Same Source

Use the BuildDir() method to establish
one or more separate build directories for
a given source directory,
then use the SConscript() method
to specify the SConscript files
in the build directories:

.ES
SConstruct:

    ccflags = '-DFOO'
    Export("ccflags")
    BuildDir('foo', 'src')
    SConscript('foo/SConscript')

    ccflags = '-DBAR'
    Export("ccflags")
    BuildDir('bar', 'src')
    SConscript('bar/SConscript')

src/SConscript:

    Import("ccflags")
    env = Environment(CCFLAGS = ccflags)
    env.Program(target = 'src', source = 'src.c')
.EE

Note the use of the Export() method
to set the "ccflags" variable to a different
value for each variant build.

.SS Hierarchical Build of Two Libraries Linked With a Program

.ES
SConstruct:

    env = Environment(LIBPATH = ['#libA', '#libB'])
    Export('env')
    SConscript('libA/SConscript')
    SConscript('libB/SConscript')
    SConscript('Main/SConscript')

libA/SConscript:

    Import('env')
    env.Library('a', 'a1.c a2.c a3.c')

libB/SConscript:                                                  

    Import('env')
    env.Library('b', 'b1.c b2.c b3.c')

Main/SConscript:

    Import('env')
    e = env.Copy(LIBS = ['a', ','b'])
    e.Program('foo', 'm1.c m2.c m3.c')
.EE

The '#' in the LIBPATH directories specify that they're relative to the
top-level directory, so they don't turn into "Main/libA" when they're
used in Main/SConscript.

Specifying only 'a' and 'b' for the library names
allows SCons to append the appropriate library
prefix and suffix for the current platform
(for example, 'liba.a' on POSIX systems,
'a.lib' on Windows).

.SS Customizing contruction variables from the command line.

The following would allow the C compiler to be specified on the command
line or in the file custom.py. 

.ES
opts = Options('custom.py')
opts.Add('CC', 'The C compiler.')
env = Environment(options=opts)
Help(opts.GenerateHelpText(env))
.EE

The user could specify the C compiler on the command line:

.ES
scons "CC=my_cc"
.EE

or in the custom.py file:

.ES
CC = 'my_cc'
.EE

or get documentation on the options:

.ES
$ scons -h

CC: The C compiler.
    default: None
    actual: cc

.EE

.SS Using Microsoft Visual C++ precompiled headers

Since windows.h includes everything and the kitchen sink, it can take quite
some time to compile it over and over again for a bunch of object files, so
Microsoft provides a mechanism to compile a set of headers once and then
include the previously compiled headers in any object file. This
technology is called precompiled headers. The general recipe is to create a
file named "StdAfx.cpp" that includes a single header named "StdAfx.h", and
then include every header you want to precompile in "StdAfx.h", and finally
include "StdAfx.h" as the first header in all the source files you are
compiling to object files. For example:

StdAfx.h:
.ES
#include <windows.h>
#include <my_big_header.h>
.EE

StdAfx.cpp:
.ES
#include <StdAfx.h>
.EE

Foo.cpp:
.ES
#include <StdAfx.h>

/* do some stuff */
.EE

Bar.cpp:
.ES
#include <StdAfx.h>

/* do some other stuff */
.EE

SConstruct:
.ES
env=Environment()
env['PCHSTOP'] = StdAfx.h
env['PCH'] = env.PCH('StdAfx.cpp')[0]
env.Program('MyApp', ['Foo.cpp', 'Bar.cpp'])
.EE

For more information see the document for the PCH builder, and the PCH and
PCHSTOP construction variables. To learn about the details of precompiled
headers consult the MSDN documention for /Yc, /Yu, and /Yp.

.SS Using Microsoft Visual C++ external debugging information

Since including debugging information in programs and shared libraries can
cause their size to increase significantly, Microsoft provides a mechanism
for including the debugging information in an external file called a PDB
file. SCons supports PDB files through the PDB construction
variable. 

SConstruct:
.ES
env=Environment()
env['PDB'] = 'MyApp.pdb'
env.Program('MyApp', ['Foo.cpp', 'Bar.cpp'])
.EE

For more information see the document for the PDB construction variable.

.SH ENVIRONMENT

.IP SCONS_LIB_DIR
Specifies the directory that contains the SCons Python module directory
(e.g. /home/aroach/scons-src-0.01/src/engine).

.IP SCONSFLAGS
A string of options that will be used by scons in addition to those passed
on the command line.

.SH "SEE ALSO"
.B scons
User Manual,
.B scons
Design Document,
.B scons
source code.

.SH AUTHORS
Steven Knight <knight@baldmt.com>
.br
Anthony Roach <aroach@electriceyeball.com>
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.