summaryrefslogtreecommitdiffstats
path: root/win/tclWinPipe.c
blob: 4c8bc479e30726bb094faf0c48dfd8000645e55d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
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
/* 
 * tclWinPipe.c --
 *
 *	This file implements the Windows-specific exec pipeline functions,
 *	the "pipe" channel driver, and the "pid" Tcl command.
 *
 * Copyright (c) 1996-1997 by Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclWinPipe.c,v 1.34 2003/03/12 19:21:26 dgp Exp $
 */

#define PREFIX_IDENT ""
#define DEBUG_IDENT TCL_DBGX

#include "tclWinInt.h"

#include <fcntl.h>
#include <io.h>
#include <sys/stat.h>

/*
 * The following variable is used to tell whether this module has been
 * initialized.
 */

static int initialized = 0;

/*
 * The pipeMutex locks around access to the initialized and procList variables,
 * and it is used to protect background threads from being terminated while
 * they are using APIs that hold locks.
 */

TCL_DECLARE_MUTEX(pipeMutex)

/*
 * The following defines identify the various types of applications that 
 * run under windows.  There is special case code for the various types.
 */

#define APPL_NONE	0
#define APPL_DOS	1
#define APPL_WIN3X	2
#define APPL_WIN32	3

/*
 * The following constants and structures are used to encapsulate the state
 * of various types of files used in a pipeline.
 * This used to have a 1 && 2 that supported Win32s.
 */

#define WIN_FILE 3		/* Basic Win32 file. */

/*
 * This structure encapsulates the common state associated with all file
 * types used in a pipeline.
 */

typedef struct WinFile {
    int type;			/* One of the file types defined above. */
    HANDLE handle;		/* Open file handle. */
} WinFile;

/*
 * This list is used to map from pids to process handles.
 */

typedef struct ProcInfo {
    HANDLE hProcess;
    DWORD dwProcessId;
    struct ProcInfo *nextPtr;
} ProcInfo;

static ProcInfo *procList;

/*
 * Bit masks used in the flags field of the PipeInfo structure below.
 */

#define PIPE_PENDING	(1<<0)	/* Message is pending in the queue. */
#define PIPE_ASYNC	(1<<1)	/* Channel is non-blocking. */

/*
 * Bit masks used in the sharedFlags field of the PipeInfo structure below.
 */

#define PIPE_EOF	(1<<2)	/* Pipe has reached EOF. */
#define PIPE_EXTRABYTE	(1<<3)	/* The reader thread has consumed one byte. */

/*
 * This structure describes per-instance data for a pipe based channel.
 */

typedef struct PipeInfo {
    struct PipeInfo *nextPtr;	/* Pointer to next registered pipe. */
    Tcl_Channel channel;	/* Pointer to channel structure. */
    int validMask;		/* OR'ed combination of TCL_READABLE,
				 * TCL_WRITABLE, or TCL_EXCEPTION: indicates
				 * which operations are valid on the file. */
    int watchMask;		/* OR'ed combination of TCL_READABLE,
				 * TCL_WRITABLE, or TCL_EXCEPTION: indicates
				 * which events should be reported. */
    int flags;			/* State flags, see above for a list. */
    TclFile readFile;		/* Output from pipe. */
    TclFile writeFile;		/* Input from pipe. */
    TclFile errorFile;		/* Error output from pipe. */
    int numPids;		/* Number of processes attached to pipe. */
    Tcl_Pid *pidPtr;		/* Pids of attached processes. */
    Tcl_ThreadId threadId;	/* Thread to which events should be reported.
				 * This value is used by the reader/writer
				 * threads. */
    HANDLE writeThread;		/* Handle to writer thread. */
    HANDLE readThread;		/* Handle to reader thread. */
    HANDLE writable;		/* Manual-reset event to signal when the
				 * writer thread has finished waiting for
				 * the current buffer to be written. */
    HANDLE readable;		/* Manual-reset event to signal when the
				 * reader thread has finished waiting for
				 * input. */
    HANDLE startWriter;		/* Auto-reset event used by the main thread to
				 * signal when the writer thread should attempt
				 * to write to the pipe. */
    HANDLE stopWriter;		/* Manual-reset event used to alert the reader
				 * thread to fall-out and exit */
    HANDLE startReader;		/* Auto-reset event used by the main thread to
				 * signal when the reader thread should attempt
				 * to read from the pipe. */
    HANDLE stopReader;		/* Manual-reset event used to alert the reader
				 * thread to fall-out and exit */
    DWORD writeError;		/* An error caused by the last background
				 * write.  Set to 0 if no error has been
				 * detected.  This word is shared with the
				 * writer thread so access must be
				 * synchronized with the writable object.
				 */
    char *writeBuf;		/* Current background output buffer.
				 * Access is synchronized with the writable
				 * object. */
    int writeBufLen;		/* Size of write buffer.  Access is
				 * synchronized with the writable
				 * object. */
    int toWrite;		/* Current amount to be written.  Access is
				 * synchronized with the writable object. */
    int readFlags;		/* Flags that are shared with the reader
				 * thread.  Access is synchronized with the
				 * readable object.  */
    char extraByte;		/* Buffer for extra character consumed by
				 * reader thread.  This byte is shared with
				 * the reader thread so access must be
				 * synchronized with the readable object. */
} PipeInfo;

typedef struct ThreadSpecificData {
    /*
     * The following pointer refers to the head of the list of pipes
     * that are being watched for file events.
     */
    
    PipeInfo *firstPipePtr;
} ThreadSpecificData;

static Tcl_ThreadDataKey dataKey;

/*
 * The following structure is what is added to the Tcl event queue when
 * pipe events are generated.
 */

typedef struct PipeEvent {
    Tcl_Event header;		/* Information that is standard for
				 * all events. */
    PipeInfo *infoPtr;		/* Pointer to pipe info structure.  Note
				 * that we still have to verify that the
				 * pipe exists before dereferencing this
				 * pointer. */
} PipeEvent;

/*
 * Declarations for functions used only in this file.
 */

static int		ApplicationType(Tcl_Interp *interp,
			    const char *fileName, char *fullName);
static void		BuildCommandLine(const char *executable, int argc, 
			    CONST char **argv, Tcl_DString *linePtr);
static BOOL		HasConsole(void);
static int		PipeBlockModeProc(ClientData instanceData, int mode);
static void		PipeCheckProc(ClientData clientData, int flags);
static int		PipeClose2Proc(ClientData instanceData,
			    Tcl_Interp *interp, int flags);
static int		PipeEventProc(Tcl_Event *evPtr, int flags);
static void		PipeExitHandler(ClientData clientData);
static int		PipeGetHandleProc(ClientData instanceData,
			    int direction, ClientData *handlePtr);
static void		PipeInit(void);
static int		PipeInputProc(ClientData instanceData, char *buf,
			    int toRead, int *errorCode);
static int		PipeOutputProc(ClientData instanceData,
			    CONST char *buf, int toWrite, int *errorCode);
static DWORD WINAPI	PipeReaderThread(LPVOID arg);
static void		PipeSetupProc(ClientData clientData, int flags);
static void		PipeWatchProc(ClientData instanceData, int mask);
static DWORD WINAPI	PipeWriterThread(LPVOID arg);
static void		ProcExitHandler(ClientData clientData);
static int		TempFileName(WCHAR name[MAX_PATH]);
static int		WaitForRead(PipeInfo *infoPtr, int blocking);

/*
 * This structure describes the channel type structure for command pipe
 * based IO.
 */

static Tcl_ChannelType pipeChannelType = {
    "pipe",			/* Type name. */
    TCL_CHANNEL_VERSION_2,	/* v2 channel */
    TCL_CLOSE2PROC,		/* Close proc. */
    PipeInputProc,		/* Input proc. */
    PipeOutputProc,		/* Output proc. */
    NULL,			/* Seek proc. */
    NULL,			/* Set option proc. */
    NULL,			/* Get option proc. */
    PipeWatchProc,		/* Set up notifier to watch the channel. */
    PipeGetHandleProc,		/* Get an OS handle from channel. */
    PipeClose2Proc,		/* close2proc */
    PipeBlockModeProc,		/* Set blocking or non-blocking mode.*/
    NULL,			/* flush proc. */
    NULL,			/* handler proc. */
};

/*
 *----------------------------------------------------------------------
 *
 * PipeInit --
 *
 *	This function initializes the static variables for this file.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Creates a new event source.
 *
 *----------------------------------------------------------------------
 */

static void
PipeInit()
{
    ThreadSpecificData *tsdPtr;

    /*
     * Check the initialized flag first, then check again in the mutex.
     * This is a speed enhancement.
     */

    if (!initialized) {
	Tcl_MutexLock(&pipeMutex);
	if (!initialized) {
	    initialized = 1;
	    procList = NULL;
	    Tcl_CreateExitHandler(ProcExitHandler, NULL);
	}
	Tcl_MutexUnlock(&pipeMutex);
    }

    tsdPtr = (ThreadSpecificData *)TclThreadDataKeyGet(&dataKey);
    if (tsdPtr == NULL) {
	tsdPtr = TCL_TSD_INIT(&dataKey);
	tsdPtr->firstPipePtr = NULL;
	Tcl_CreateEventSource(PipeSetupProc, PipeCheckProc, NULL);
	Tcl_CreateThreadExitHandler(PipeExitHandler, NULL);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * PipeExitHandler --
 *
 *	This function is called to cleanup the pipe module before
 *	Tcl is unloaded.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Removes the pipe event source.
 *
 *----------------------------------------------------------------------
 */

static void
PipeExitHandler(
    ClientData clientData)	/* Old window proc */
{
    Tcl_DeleteEventSource(PipeSetupProc, PipeCheckProc, NULL);
}

/*
 *----------------------------------------------------------------------
 *
 * ProcExitHandler --
 *
 *	This function is called to cleanup the process list before
 *	Tcl is unloaded.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Resets the process list.
 *
 *----------------------------------------------------------------------
 */

static void
ProcExitHandler(
    ClientData clientData)	/* Old window proc */
{
    Tcl_MutexLock(&pipeMutex);
    initialized = 0;
    Tcl_MutexUnlock(&pipeMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * PipeSetupProc --
 *
 *	This procedure is invoked before Tcl_DoOneEvent blocks waiting
 *	for an event.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Adjusts the block time if needed.
 *
 *----------------------------------------------------------------------
 */

void
PipeSetupProc(
    ClientData data,		/* Not used. */
    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
{
    PipeInfo *infoPtr;
    Tcl_Time blockTime = { 0, 0 };
    int block = 1;
    WinFile *filePtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!(flags & TCL_FILE_EVENTS)) {
	return;
    }
    
    /*
     * Look to see if any events are already pending.  If they are, poll.
     */

    for (infoPtr = tsdPtr->firstPipePtr; infoPtr != NULL; 
	    infoPtr = infoPtr->nextPtr) {
	if (infoPtr->watchMask & TCL_WRITABLE) {
	    filePtr = (WinFile*) infoPtr->writeFile;
	    if (WaitForSingleObject(infoPtr->writable, 0) != WAIT_TIMEOUT) {
		block = 0;
	    }
	}
	if (infoPtr->watchMask & TCL_READABLE) {
	    filePtr = (WinFile*) infoPtr->readFile;
	    if (WaitForRead(infoPtr, 0) >= 0) {
		block = 0;
	    }
	}
    }
    if (!block) {
	Tcl_SetMaxBlockTime(&blockTime);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * PipeCheckProc --
 *
 *	This procedure is called by Tcl_DoOneEvent to check the pipe
 *	event source for events. 
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May queue an event.
 *
 *----------------------------------------------------------------------
 */

static void
PipeCheckProc(
    ClientData data,		/* Not used. */
    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
{
    PipeInfo *infoPtr;
    PipeEvent *evPtr;
    WinFile *filePtr;
    int needEvent;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!(flags & TCL_FILE_EVENTS)) {
	return;
    }
    
    /*
     * Queue events for any ready pipes that don't already have events
     * queued.
     */

    for (infoPtr = tsdPtr->firstPipePtr; infoPtr != NULL; 
	    infoPtr = infoPtr->nextPtr) {
	if (infoPtr->flags & PIPE_PENDING) {
	    continue;
	}
	
	/*
	 * Queue an event if the pipe is signaled for reading or writing.
	 */

	needEvent = 0;
	filePtr = (WinFile*) infoPtr->writeFile;
	if ((infoPtr->watchMask & TCL_WRITABLE) &&
		(WaitForSingleObject(infoPtr->writable, 0) != WAIT_TIMEOUT)) {
	    needEvent = 1;
	}
	
	filePtr = (WinFile*) infoPtr->readFile;
	if ((infoPtr->watchMask & TCL_READABLE) &&
		(WaitForRead(infoPtr, 0) >= 0)) {
	    needEvent = 1;
	}

	if (needEvent) {
	    infoPtr->flags |= PIPE_PENDING;
	    evPtr = (PipeEvent *) ckalloc(sizeof(PipeEvent));
	    evPtr->header.proc = PipeEventProc;
	    evPtr->infoPtr = infoPtr;
	    Tcl_QueueEvent((Tcl_Event *) evPtr, TCL_QUEUE_TAIL);
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclWinMakeFile --
 *
 *	This function constructs a new TclFile from a given data and
 *	type value.
 *
 * Results:
 *	Returns a newly allocated WinFile as a TclFile.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

TclFile
TclWinMakeFile(
    HANDLE handle)		/* Type-specific data. */
{
    WinFile *filePtr;

    filePtr = (WinFile *) ckalloc(sizeof(WinFile));
    filePtr->type = WIN_FILE;
    filePtr->handle = handle;

    return (TclFile)filePtr;
}

/*
 *----------------------------------------------------------------------
 *
 * TempFileName --
 *
 *	Gets a temporary file name and deals with the fact that the
 *	temporary file path provided by Windows may not actually exist
 *	if the TMP or TEMP environment variables refer to a 
 *	non-existent directory.
 *
 * Results:    
 *	0 if error, non-zero otherwise.  If non-zero is returned, the
 *	name buffer will be filled with a name that can be used to 
 *	construct a temporary file.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
TempFileName(name)
    WCHAR name[MAX_PATH];	/* Buffer in which name for temporary 
				 * file gets stored. */
{
    TCHAR *prefix;

    prefix = (tclWinProcs->useWide) ? (TCHAR *) L"TCL" : (TCHAR *) "TCL";
    if ((*tclWinProcs->getTempPathProc)(MAX_PATH, name) != 0) {
	if ((*tclWinProcs->getTempFileNameProc)((TCHAR *) name, prefix, 0, 
		name) != 0) {
	    return 1;
	}
    }
    if (tclWinProcs->useWide) {
	((WCHAR *) name)[0] = '.';
	((WCHAR *) name)[1] = '\0';
    } else {
	((char *) name)[0] = '.';
	((char *) name)[1] = '\0';
    }
    return (*tclWinProcs->getTempFileNameProc)((TCHAR *) name, prefix, 0, 
	    name);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpMakeFile --
 *
 *	Make a TclFile from a channel.
 *
 * Results:
 *	Returns a new TclFile or NULL on failure.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

TclFile
TclpMakeFile(channel, direction)
    Tcl_Channel channel;	/* Channel to get file from. */
    int direction;		/* Either TCL_READABLE or TCL_WRITABLE. */
{
    HANDLE handle;

    if (Tcl_GetChannelHandle(channel, direction, 
	    (ClientData *) &handle) == TCL_OK) {
	return TclWinMakeFile(handle);
    } else {
	return (TclFile) NULL;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclpOpenFile --
 *
 *	This function opens files for use in a pipeline.
 *
 * Results:
 *	Returns a newly allocated TclFile structure containing the
 *	file handle.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

TclFile
TclpOpenFile(path, mode)
    CONST char *path;		/* The name of the file to open. */
    int mode;			/* In what mode to open the file? */
{
    HANDLE handle;
    DWORD accessMode, createMode, shareMode, flags;
    Tcl_DString ds;
    CONST TCHAR *nativePath;
    
    /*
     * Map the access bits to the NT access mode.
     */

    switch (mode & (O_RDONLY | O_WRONLY | O_RDWR)) {
	case O_RDONLY:
	    accessMode = GENERIC_READ;
	    break;
	case O_WRONLY:
	    accessMode = GENERIC_WRITE;
	    break;
	case O_RDWR:
	    accessMode = (GENERIC_READ | GENERIC_WRITE);
	    break;
	default:
	    TclWinConvertError(ERROR_INVALID_FUNCTION);
	    return NULL;
    }

    /*
     * Map the creation flags to the NT create mode.
     */

    switch (mode & (O_CREAT | O_EXCL | O_TRUNC)) {
	case (O_CREAT | O_EXCL):
	case (O_CREAT | O_EXCL | O_TRUNC):
	    createMode = CREATE_NEW;
	    break;
	case (O_CREAT | O_TRUNC):
	    createMode = CREATE_ALWAYS;
	    break;
	case O_CREAT:
	    createMode = OPEN_ALWAYS;
	    break;
	case O_TRUNC:
	case (O_TRUNC | O_EXCL):
	    createMode = TRUNCATE_EXISTING;
	    break;
	default:
	    createMode = OPEN_EXISTING;
	    break;
    }

    nativePath = Tcl_WinUtfToTChar(path, -1, &ds);

    /*
     * If the file is not being created, use the existing file attributes.
     */

    flags = 0;
    if (!(mode & O_CREAT)) {
	flags = (*tclWinProcs->getFileAttributesProc)(nativePath);
	if (flags == 0xFFFFFFFF) {
	    flags = 0;
	}
    }

    /*
     * Set up the file sharing mode.  We want to allow simultaneous access.
     */

    shareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;

    /*
     * Now we get to create the file.
     */

    handle = (*tclWinProcs->createFileProc)(nativePath, accessMode, 
	    shareMode, NULL, createMode, flags, NULL);
    Tcl_DStringFree(&ds);

    if (handle == INVALID_HANDLE_VALUE) {
	DWORD err;
	
	err = GetLastError();
	if ((err & 0xffffL) == ERROR_OPEN_FAILED) {
	    err = (mode & O_CREAT) ? ERROR_FILE_EXISTS : ERROR_FILE_NOT_FOUND;
	}
        TclWinConvertError(err);
        return NULL;
    }

    /*
     * Seek to the end of file if we are writing.
     */

    if (mode & O_WRONLY) {
	SetFilePointer(handle, 0, NULL, FILE_END);
    }

    return TclWinMakeFile(handle);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreateTempFile --
 *
 *	This function opens a unique file with the property that it
 *	will be deleted when its file handle is closed.  The temporary
 *	file is created in the system temporary directory.
 *
 * Results:
 *	Returns a valid TclFile, or NULL on failure.
 *
 * Side effects:
 *	Creates a new temporary file.
 *
 *----------------------------------------------------------------------
 */

TclFile
TclpCreateTempFile(contents)
    CONST char *contents;	/* String to write into temp file, or NULL. */
{
    WCHAR name[MAX_PATH];
    CONST char *native;
    Tcl_DString dstring;
    HANDLE handle;

    if (TempFileName(name) == 0) {
	return NULL;
    }

    handle = (*tclWinProcs->createFileProc)((TCHAR *) name, 
	    GENERIC_READ | GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 
	    FILE_ATTRIBUTE_TEMPORARY|FILE_FLAG_DELETE_ON_CLOSE, NULL);
    if (handle == INVALID_HANDLE_VALUE) {
	goto error;
    }

    /*
     * Write the file out, doing line translations on the way.
     */

    if (contents != NULL) {
	DWORD result, length;
	CONST char *p;

	/*
	 * Convert the contents from UTF to native encoding
	 */
	native = Tcl_UtfToExternalDString(NULL, contents, -1, &dstring);
	
	for (p = native; *p != '\0'; p++) {
	    if (*p == '\n') {
		length = p - native;
		if (length > 0) {
		    if (!WriteFile(handle, native, length, &result, NULL)) {
			goto error;
		    }
		}
		if (!WriteFile(handle, "\r\n", 2, &result, NULL)) {
		    goto error;
		}
		native = p+1;
	    }
	}
	length = p - native;
	if (length > 0) {
	    if (!WriteFile(handle, native, length, &result, NULL)) {
		goto error;
	    }
	}
	Tcl_DStringFree(&dstring);
	if (SetFilePointer(handle, 0, NULL, FILE_BEGIN) == 0xFFFFFFFF) {
	    goto error;
	}
    }

    return TclWinMakeFile(handle);

  error:
    /* Free the native representation of the contents if necessary */
    if (contents != NULL) {
	Tcl_DStringFree(&dstring);
    }

    TclWinConvertError(GetLastError());
    CloseHandle(handle);
    (*tclWinProcs->deleteFileProc)((TCHAR *) name);
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpTempFileName --
 *
 *	This function returns a unique filename.
 *
 * Results:
 *	Returns a valid Tcl_Obj* with refCount 0, or NULL on failure.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_Obj* 
TclpTempFileName()
{
    WCHAR fileName[MAX_PATH];

    if (TempFileName(fileName) == 0) {
	return NULL;
    }

    return TclpNativeToNormalized((ClientData) fileName);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreatePipe --
 *
 *      Creates an anonymous pipe.
 *
 * Results:
 *      Returns 1 on success, 0 on failure. 
 *
 * Side effects:
 *      Creates a pipe.
 *
 *----------------------------------------------------------------------
 */

int
TclpCreatePipe(
    TclFile *readPipe,	/* Location to store file handle for
				 * read side of pipe. */
    TclFile *writePipe)	/* Location to store file handle for
				 * write side of pipe. */
{
    HANDLE readHandle, writeHandle;

    if (CreatePipe(&readHandle, &writeHandle, NULL, 0) != 0) {
	*readPipe = TclWinMakeFile(readHandle);
	*writePipe = TclWinMakeFile(writeHandle);
	return 1;
    }

    TclWinConvertError(GetLastError());
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCloseFile --
 *
 *	Closes a pipeline file handle.  These handles are created by
 *	TclpOpenFile, TclpCreatePipe, or TclpMakeFile.
 *
 * Results:
 *	0 on success, -1 on failure.
 *
 * Side effects:
 *	The file is closed and deallocated.
 *
 *----------------------------------------------------------------------
 */

int
TclpCloseFile(
    TclFile file)	/* The file to close. */
{
    WinFile *filePtr = (WinFile *) file;

    switch (filePtr->type) {
	case WIN_FILE:
	    /*
	     * Don't close the Win32 handle if the handle is a standard channel
	     * during the thread exit process.  Otherwise, one thread may kill
	     * the stdio of another.
	     */

	    if (!TclInThreadExit() 
		    || ((GetStdHandle(STD_INPUT_HANDLE) != filePtr->handle)
			    && (GetStdHandle(STD_OUTPUT_HANDLE) != filePtr->handle)
			    && (GetStdHandle(STD_ERROR_HANDLE) != filePtr->handle))) {
		if (filePtr->handle != NULL &&
			CloseHandle(filePtr->handle) == FALSE) {
		    TclWinConvertError(GetLastError());
		    ckfree((char *) filePtr);
		    return -1;
		}
	    }
	    break;

	default:
	    panic("TclpCloseFile: unexpected file type");
    }

    ckfree((char *) filePtr);
    return 0;
}

/*
 *--------------------------------------------------------------------------
 *
 * TclpGetPid --
 *
 *	Given a HANDLE to a child process, return the process id for that
 *	child process.
 *
 * Results:
 *	Returns the process id for the child process.  If the pid was not 
 *	known by Tcl, either because the pid was not created by Tcl or the 
 *	child process has already been reaped, -1 is returned.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------------------
 */

unsigned long
TclpGetPid(
    Tcl_Pid pid)		/* The HANDLE of the child process. */
{
    ProcInfo *infoPtr;

    Tcl_MutexLock(&pipeMutex);
    for (infoPtr = procList; infoPtr != NULL; infoPtr = infoPtr->nextPtr) {
	if (infoPtr->hProcess == (HANDLE) pid) {
	    Tcl_MutexUnlock(&pipeMutex);
	    return infoPtr->dwProcessId;
	}
    }
    Tcl_MutexUnlock(&pipeMutex);
    return (unsigned long) -1;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreateProcess --
 *
 *	Create a child process that has the specified files as its 
 *	standard input, output, and error.  The child process runs
 *	asynchronously under Windows NT and Windows 9x, and runs
 *	with the same environment variables as the creating process.
 *
 *	The complete Windows search path is searched to find the specified 
 *	executable.  If an executable by the given name is not found, 
 *	automatically tries appending ".com", ".exe", and ".bat" to the 
 *	executable name.
 *
 * Results:
 *	The return value is TCL_ERROR and an error message is left in
 *	the interp's result if there was a problem creating the child 
 *	process.  Otherwise, the return value is TCL_OK and *pidPtr is
 *	filled with the process id of the child process.
 * 
 * Side effects:
 *	A process is created.
 *	
 *----------------------------------------------------------------------
 */

int
TclpCreateProcess(
    Tcl_Interp *interp,		/* Interpreter in which to leave errors that
				 * occurred when creating the child process.
				 * Error messages from the child process
				 * itself are sent to errorFile. */
    int argc,			/* Number of arguments in following array. */
    CONST char **argv,		/* Array of argument strings.  argv[0]
				 * contains the name of the executable
				 * converted to native format (using the
				 * Tcl_TranslateFileName call).  Additional
				 * arguments have not been converted. */
    TclFile inputFile,		/* If non-NULL, gives the file to use as
				 * input for the child process.  If inputFile
				 * file is not readable or is NULL, the child
				 * will receive no standard input. */
    TclFile outputFile,		/* If non-NULL, gives the file that
				 * receives output from the child process.  If
				 * outputFile file is not writeable or is
				 * NULL, output from the child will be
				 * discarded. */
    TclFile errorFile,		/* If non-NULL, gives the file that
				 * receives errors from the child process.  If
				 * errorFile file is not writeable or is NULL,
				 * errors from the child will be discarded.
				 * errorFile may be the same as outputFile. */
    Tcl_Pid *pidPtr)		/* If this procedure is successful, pidPtr
				 * is filled with the process id of the child
				 * process. */
{
    int result, applType, createFlags;
    Tcl_DString cmdLine;	/* Complete command line (TCHAR). */
    STARTUPINFOA startInfo;
    PROCESS_INFORMATION procInfo;
    SECURITY_ATTRIBUTES secAtts;
    HANDLE hProcess, h, inputHandle, outputHandle, errorHandle;
    char execPath[MAX_PATH * TCL_UTF_MAX];
    WinFile *filePtr;

    PipeInit();

    applType = ApplicationType(interp, argv[0], execPath);
    if (applType == APPL_NONE) {
	return TCL_ERROR;
    }

    result = TCL_ERROR;
    Tcl_DStringInit(&cmdLine);
    hProcess = GetCurrentProcess();

    /*
     * STARTF_USESTDHANDLES must be used to pass handles to child process.
     * Using SetStdHandle() and/or dup2() only works when a console mode 
     * parent process is spawning an attached console mode child process.
     */

    ZeroMemory(&startInfo, sizeof(startInfo));
    startInfo.cb = sizeof(startInfo);
    startInfo.dwFlags   = STARTF_USESTDHANDLES;
    startInfo.hStdInput	= INVALID_HANDLE_VALUE;
    startInfo.hStdOutput= INVALID_HANDLE_VALUE;
    startInfo.hStdError = INVALID_HANDLE_VALUE;

    secAtts.nLength = sizeof(SECURITY_ATTRIBUTES);
    secAtts.lpSecurityDescriptor = NULL;
    secAtts.bInheritHandle = TRUE;

    /*
     * We have to check the type of each file, since we cannot duplicate 
     * some file types.  
     */

    inputHandle = INVALID_HANDLE_VALUE;
    if (inputFile != NULL) {
	filePtr = (WinFile *)inputFile;
	if (filePtr->type == WIN_FILE) {
	    inputHandle = filePtr->handle;
	}
    }
    outputHandle = INVALID_HANDLE_VALUE;
    if (outputFile != NULL) {
	filePtr = (WinFile *)outputFile;
	if (filePtr->type == WIN_FILE) {
	    outputHandle = filePtr->handle;
	}
    }
    errorHandle = INVALID_HANDLE_VALUE;
    if (errorFile != NULL) {
	filePtr = (WinFile *)errorFile;
	if (filePtr->type == WIN_FILE) {
	    errorHandle = filePtr->handle;
	}
    }

    /*
     * Duplicate all the handles which will be passed off as stdin, stdout
     * and stderr of the child process. The duplicate handles are set to
     * be inheritable, so the child process can use them.
     */

    if (inputHandle == INVALID_HANDLE_VALUE) {
	/* 
	 * If handle was not set, stdin should return immediate EOF.
	 * Under Windows95, some applications (both 16 and 32 bit!) 
	 * cannot read from the NUL device; they read from console
	 * instead.  When running tk, this is fatal because the child 
	 * process would hang forever waiting for EOF from the unmapped 
	 * console window used by the helper application.
	 *
	 * Fortunately, the helper application detects a closed pipe 
	 * as an immediate EOF and can pass that information to the 
	 * child process.
	 */

	if (CreatePipe(&startInfo.hStdInput, &h, &secAtts, 0) != FALSE) {
	    CloseHandle(h);
	}
    } else {
	DuplicateHandle(hProcess, inputHandle, hProcess, &startInfo.hStdInput,
		0, TRUE, DUPLICATE_SAME_ACCESS);
    }
    if (startInfo.hStdInput == INVALID_HANDLE_VALUE) {
	TclWinConvertError(GetLastError());
	Tcl_AppendResult(interp, "couldn't duplicate input handle: ",
		Tcl_PosixError(interp), (char *) NULL);
	goto end;
    }

    if (outputHandle == INVALID_HANDLE_VALUE) {
	/*
	 * If handle was not set, output should be sent to an infinitely 
	 * deep sink.  Under Windows 95, some 16 bit applications cannot
	 * have stdout redirected to NUL; they send their output to
	 * the console instead.  Some applications, like "more" or "dir /p", 
	 * when outputting multiple pages to the console, also then try and
	 * read from the console to go the next page.  When running tk, this
	 * is fatal because the child process would hang forever waiting
	 * for input from the unmapped console window used by the helper
	 * application.
	 *
	 * Fortunately, the helper application will detect a closed pipe
	 * as a sink.
	 */

	if ((TclWinGetPlatformId() == VER_PLATFORM_WIN32_WINDOWS) 
		&& (applType == APPL_DOS)) {
	    if (CreatePipe(&h, &startInfo.hStdOutput, &secAtts, 0) != FALSE) {
		CloseHandle(h);
	    }
	} else {
	    startInfo.hStdOutput = CreateFileA("NUL:", GENERIC_WRITE, 0,
		    &secAtts, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	}
    } else {
	DuplicateHandle(hProcess, outputHandle, hProcess, &startInfo.hStdOutput, 
		0, TRUE, DUPLICATE_SAME_ACCESS);
    }
    if (startInfo.hStdOutput == INVALID_HANDLE_VALUE) {
	TclWinConvertError(GetLastError());
	Tcl_AppendResult(interp, "couldn't duplicate output handle: ",
		Tcl_PosixError(interp), (char *) NULL);
	goto end;
    }

    if (errorHandle == INVALID_HANDLE_VALUE) {
	/*
	 * If handle was not set, errors should be sent to an infinitely
	 * deep sink.
	 */

	startInfo.hStdError = CreateFileA("NUL:", GENERIC_WRITE, 0,
		&secAtts, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    } else {
	DuplicateHandle(hProcess, errorHandle, hProcess, &startInfo.hStdError, 
		0, TRUE, DUPLICATE_SAME_ACCESS);
    } 
    if (startInfo.hStdError == INVALID_HANDLE_VALUE) {
	TclWinConvertError(GetLastError());
	Tcl_AppendResult(interp, "couldn't duplicate error handle: ",
		Tcl_PosixError(interp), (char *) NULL);
	goto end;
    }
    /* 
     * If we do not have a console window, then we must run DOS and
     * WIN32 console mode applications as detached processes. This tells
     * the loader that the child application should not inherit the
     * console, and that it should not create a new console window for
     * the child application.  The child application should get its stdio 
     * from the redirection handles provided by this application, and run
     * in the background.
     *
     * If we are starting a GUI process, they don't automatically get a 
     * console, so it doesn't matter if they are started as foreground or
     * detached processes.  The GUI window will still pop up to the
     * foreground.
     */

    if (TclWinGetPlatformId() == VER_PLATFORM_WIN32_NT) {
	if (HasConsole()) {
	    createFlags = 0;
	} else if (applType == APPL_DOS) {
	    /*
	     * Under NT, 16-bit DOS applications will not run unless they
	     * can be attached to a console.  If we are running without a
	     * console, run the 16-bit program as an normal process inside
	     * of a hidden console application, and then run that hidden
	     * console as a detached process.
	     */

	    startInfo.wShowWindow = SW_HIDE;
	    startInfo.dwFlags |= STARTF_USESHOWWINDOW;
	    createFlags = CREATE_NEW_CONSOLE;
	    Tcl_DStringAppend(&cmdLine, "cmd.exe /c ", -1);
	} else {
	    createFlags = DETACHED_PROCESS;
	} 
    } else {
	if (HasConsole()) {
	    createFlags = 0;
	} else {
	    createFlags = DETACHED_PROCESS;
	}
	
	if (applType == APPL_DOS) {
	    /*
	     * Under Windows 95, 16-bit DOS applications do not work well 
	     * with pipes:
	     *
	     * 1. EOF on a pipe between a detached 16-bit DOS application 
	     * and another application is not seen at the other
	     * end of the pipe, so the listening process blocks forever on 
	     * reads.  This inablity to detect EOF happens when either a 
	     * 16-bit app or the 32-bit app is the listener.  
	     *
	     * 2. If a 16-bit DOS application (detached or not) blocks when 
	     * writing to a pipe, it will never wake up again, and it
	     * eventually brings the whole system down around it.
	     *
	     * The 16-bit application is run as a normal process inside
	     * of a hidden helper console app, and this helper may be run
	     * as a detached process.  If any of the stdio handles is
	     * a pipe, the helper application accumulates information 
	     * into temp files and forwards it to or from the DOS 
	     * application as appropriate.  This means that DOS apps 
	     * must receive EOF from a stdin pipe before they will actually
	     * begin, and must finish generating stdout or stderr before 
	     * the data will be sent to the next stage of the pipe.
	     *
	     * The helper app should be located in the same directory as
	     * the tcl dll.
	     */

	    if (createFlags != 0) {
		startInfo.wShowWindow = SW_HIDE;
		startInfo.dwFlags |= STARTF_USESHOWWINDOW;
		createFlags = CREATE_NEW_CONSOLE;
	    }

	    {
		Tcl_Obj *tclExePtr, *pipeDllPtr;
		int i, fileExists;
		char *start,*end;
		Tcl_DString pipeDll;
		Tcl_DStringInit(&pipeDll);
		Tcl_DStringAppend(&pipeDll, PREFIX_IDENT "tclpip"
		    STRINGIFY(TCL_MAJOR_VERSION) STRINGIFY(TCL_MINOR_VERSION)
		    STRINGIFY(DEBUG_IDENT) ".dll ", -1);
		tclExePtr = Tcl_NewStringObj(TclpFindExecutable(""), -1);
		start = Tcl_GetStringFromObj(tclExePtr, &i);
		for (end = start + (i-1); end > start; end--) {
		    if (*end == '/')
		        break;
		}
		if (*end != '/')
		    panic("no / in executable path name");
		i = (end - start) + 1;
		pipeDllPtr = Tcl_NewStringObj(start, i);
		Tcl_AppendToObj(pipeDllPtr, Tcl_DStringValue(&pipeDll), -1);
		Tcl_IncrRefCount(pipeDllPtr);
		if (Tcl_FSConvertToPathType(interp, pipeDllPtr) != TCL_OK)
		    panic("Tcl_FSConvertToPathType failed");
		fileExists = (Tcl_FSAccess(pipeDllPtr, F_OK) == 0);
		if (!fileExists) {
		    panic("Tcl pipe dll \"%s\" not found",
		        Tcl_DStringValue(&pipeDll));
		}
		Tcl_DStringAppend(&cmdLine, Tcl_DStringValue(&pipeDll), -1);
		Tcl_DecrRefCount(tclExePtr);
		Tcl_DecrRefCount(pipeDllPtr);
		Tcl_DStringFree(&pipeDll);
	    }
	}
    }
    
    /*
     * cmdLine gets the full command line used to invoke the executable,
     * including the name of the executable itself.  The command line
     * arguments in argv[] are stored in cmdLine separated by spaces. 
     * Special characters in individual arguments from argv[] must be 
     * quoted when being stored in cmdLine.
     *
     * When calling any application, bear in mind that arguments that 
     * specify a path name are not converted.  If an argument contains 
     * forward slashes as path separators, it may or may not be 
     * recognized as a path name, depending on the program.  In general,
     * most applications accept forward slashes only as option 
     * delimiters and backslashes only as paths.
     *
     * Additionally, when calling a 16-bit dos or windows application, 
     * all path names must use the short, cryptic, path format (e.g., 
     * using ab~1.def instead of "a b.default").  
     */

    BuildCommandLine(execPath, argc, argv, &cmdLine);

    if ((*tclWinProcs->createProcessProc)(NULL, 
	    (TCHAR *) Tcl_DStringValue(&cmdLine), NULL, NULL, TRUE, 
	    (DWORD) createFlags, NULL, NULL, &startInfo, &procInfo) == 0) {
	TclWinConvertError(GetLastError());
	Tcl_AppendResult(interp, "couldn't execute \"", argv[0],
		"\": ", Tcl_PosixError(interp), (char *) NULL);
	goto end;
    }

    /*
     * This wait is used to force the OS to give some time to the DOS
     * process.
     */

    if (applType == APPL_DOS) {
	WaitForSingleObject(procInfo.hProcess, 50);
    }

    /* 
     * "When an application spawns a process repeatedly, a new thread 
     * instance will be created for each process but the previous 
     * instances may not be cleaned up.  This results in a significant 
     * virtual memory loss each time the process is spawned.  If there 
     * is a WaitForInputIdle() call between CreateProcess() and
     * CloseHandle(), the problem does not occur." PSS ID Number: Q124121
     */

    WaitForInputIdle(procInfo.hProcess, 5000);
    CloseHandle(procInfo.hThread);

    *pidPtr = (Tcl_Pid) procInfo.hProcess;
    if (*pidPtr != 0) {
	TclWinAddProcess(procInfo.hProcess, procInfo.dwProcessId);
    }
    result = TCL_OK;

    end:
    Tcl_DStringFree(&cmdLine);
    if (startInfo.hStdInput != INVALID_HANDLE_VALUE) {
        CloseHandle(startInfo.hStdInput);
    }
    if (startInfo.hStdOutput != INVALID_HANDLE_VALUE) {
        CloseHandle(startInfo.hStdOutput);
    }
    if (startInfo.hStdError != INVALID_HANDLE_VALUE) {
	CloseHandle(startInfo.hStdError);
    }
    return result;
}


/*
 *----------------------------------------------------------------------
 *
 * HasConsole --
 *
 *	Determines whether the current application is attached to a
 *	console.
 *
 * Results:
 *	Returns TRUE if this application has a console, else FALSE.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static BOOL
HasConsole()
{
    HANDLE handle;
    
    handle = CreateFileA("CONOUT$", GENERIC_WRITE, FILE_SHARE_WRITE,
	    NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

    if (handle != INVALID_HANDLE_VALUE) {
        CloseHandle(handle);
	return TRUE;
    } else {
        return FALSE;
    }
}

/*
 *--------------------------------------------------------------------
 *
 * ApplicationType --
 *
 *	Search for the specified program and identify if it refers to a DOS,
 *	Windows 3.X, or Win32 program.  Used to determine how to invoke 
 *	a program, or if it can even be invoked.
 *
 *	It is possible to almost positively identify DOS and Windows 
 *	applications that contain the appropriate magic numbers.  However, 
 *	DOS .com files do not seem to contain a magic number; if the program 
 *	name ends with .com and could not be identified as a Windows .com
 *	file, it will be assumed to be a DOS application, even if it was
 *	just random data.  If the program name does not end with .com, no 
 *	such assumption is made.
 *
 *	The Win32 procedure GetBinaryType incorrectly identifies any 
 *	junk file that ends with .exe as a dos executable and some 
 *	executables that don't end with .exe as not executable.  Plus it 
 *	doesn't exist under win95, so I won't feel bad about reimplementing
 *	functionality.
 *
 * Results:
 *	The return value is one of APPL_DOS, APPL_WIN3X, or APPL_WIN32
 *	if the filename referred to the corresponding application type.
 *	If the file name could not be found or did not refer to any known 
 *	application type, APPL_NONE is returned and an error message is 
 *	left in interp.  .bat files are identified as APPL_DOS.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
ApplicationType(interp, originalName, fullName)
    Tcl_Interp *interp;		/* Interp, for error message. */
    const char *originalName;	/* Name of the application to find. */
    char fullName[];		/* Filled with complete path to 
				 * application. */
{
    int applType, i, nameLen, found;
    HANDLE hFile;
    TCHAR *rest;
    char *ext;
    char buf[2];
    DWORD attr, read;
    IMAGE_DOS_HEADER header;
    Tcl_DString nameBuf, ds;
    CONST TCHAR *nativeName;
    WCHAR nativeFullPath[MAX_PATH];
    static char extensions[][5] = {"", ".com", ".exe", ".bat"};

    /* Look for the program as an external program.  First try the name
     * as it is, then try adding .com, .exe, and .bat, in that order, to
     * the name, looking for an executable.
     *
     * Using the raw SearchPath() procedure doesn't do quite what is 
     * necessary.  If the name of the executable already contains a '.' 
     * character, it will not try appending the specified extension when
     * searching (in other words, SearchPath will not find the program 
     * "a.b.exe" if the arguments specified "a.b" and ".exe").   
     * So, first look for the file as it is named.  Then manually append 
     * the extensions, looking for a match.  
     */

    applType = APPL_NONE;
    Tcl_DStringInit(&nameBuf);
    Tcl_DStringAppend(&nameBuf, originalName, -1);
    nameLen = Tcl_DStringLength(&nameBuf);

    for (i = 0; i < (int) (sizeof(extensions) / sizeof(extensions[0])); i++) {
	Tcl_DStringSetLength(&nameBuf, nameLen);
	Tcl_DStringAppend(&nameBuf, extensions[i], -1);
        nativeName = Tcl_WinUtfToTChar(Tcl_DStringValue(&nameBuf), 
		Tcl_DStringLength(&nameBuf), &ds);
	found = (*tclWinProcs->searchPathProc)(NULL, nativeName, NULL, 
		MAX_PATH, nativeFullPath, &rest);
	Tcl_DStringFree(&ds);
	if (found == 0) {
	    continue;
	}

	/*
	 * Ignore matches on directories or data files, return if identified
	 * a known type.
	 */

	attr = (*tclWinProcs->getFileAttributesProc)((TCHAR *) nativeFullPath);
	if ((attr == 0xffffffff) || (attr & FILE_ATTRIBUTE_DIRECTORY)) {
	    continue;
	}
	strcpy(fullName, Tcl_WinTCharToUtf((TCHAR *) nativeFullPath, -1, &ds));
	Tcl_DStringFree(&ds);

	ext = strrchr(fullName, '.');
	if ((ext != NULL) && (stricmp(ext, ".bat") == 0)) {
	    applType = APPL_DOS;
	    break;
	}
	
	hFile = (*tclWinProcs->createFileProc)((TCHAR *) nativeFullPath, 
		GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 
		FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile == INVALID_HANDLE_VALUE) {
	    continue;
	}

	header.e_magic = 0;
	ReadFile(hFile, (void *) &header, sizeof(header), &read, NULL);
	if (header.e_magic != IMAGE_DOS_SIGNATURE) {
	    /* 
	     * Doesn't have the magic number for relocatable executables.  If 
	     * filename ends with .com, assume it's a DOS application anyhow.
	     * Note that we didn't make this assumption at first, because some
	     * supposed .com files are really 32-bit executables with all the
	     * magic numbers and everything.  
	     */

	    CloseHandle(hFile);
	    if ((ext != NULL) && (stricmp(ext, ".com") == 0)) {
		applType = APPL_DOS;
		break;
	    }
	    continue;
	}
	if (header.e_lfarlc != sizeof(header)) {
	    /* 
	     * All Windows 3.X and Win32 and some DOS programs have this value
	     * set here.  If it doesn't, assume that since it already had the 
	     * other magic number it was a DOS application.
	     */

	    CloseHandle(hFile);
	    applType = APPL_DOS;
	    break;
	}

	/* 
	 * The DWORD at header.e_lfanew points to yet another magic number.
	 */

	buf[0] = '\0';
	SetFilePointer(hFile, header.e_lfanew, NULL, FILE_BEGIN);
	ReadFile(hFile, (void *) buf, 2, &read, NULL);
	CloseHandle(hFile);

	if ((buf[0] == 'N') && (buf[1] == 'E')) {
	    applType = APPL_WIN3X;
	} else if ((buf[0] == 'P') && (buf[1] == 'E')) {
	    applType = APPL_WIN32;
	} else {
	    /*
	     * Strictly speaking, there should be a test that there
	     * is an 'L' and 'E' at buf[0..1], to identify the type as 
	     * DOS, but of course we ran into a DOS executable that 
	     * _doesn't_ have the magic number -- specifically, one
	     * compiled using the Lahey Fortran90 compiler.
	     */

	    applType = APPL_DOS;
	}
	break;
    }
    Tcl_DStringFree(&nameBuf);

    if (applType == APPL_NONE) {
	TclWinConvertError(GetLastError());
	Tcl_AppendResult(interp, "couldn't execute \"", originalName,
		"\": ", Tcl_PosixError(interp), (char *) NULL);
	return APPL_NONE;
    }

    if ((applType == APPL_DOS) || (applType == APPL_WIN3X)) {
	/* 
	 * Replace long path name of executable with short path name for 
	 * 16-bit applications.  Otherwise the application may not be able
	 * to correctly parse its own command line to separate off the 
	 * application name from the arguments.
	 */

	(*tclWinProcs->getShortPathNameProc)((TCHAR *) nativeFullPath, 
		nativeFullPath, MAX_PATH);
	strcpy(fullName, Tcl_WinTCharToUtf((TCHAR *) nativeFullPath, -1, &ds));
	Tcl_DStringFree(&ds);
    }
    return applType;
}

/*    
 *----------------------------------------------------------------------
 *
 * BuildCommandLine --
 *
 *	The command line arguments are stored in linePtr separated
 *	by spaces, in a form that CreateProcess() understands.  Special 
 *	characters in individual arguments from argv[] must be quoted 
 *	when being stored in cmdLine.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
BuildCommandLine(
    CONST char *executable,	/* Full path of executable (including 
				 * extension).  Replacement for argv[0]. */
    int argc,			/* Number of arguments. */
    CONST char **argv,		/* Argument strings in UTF. */
    Tcl_DString *linePtr)	/* Initialized Tcl_DString that receives the
				 * command line (TCHAR). */
{
    CONST char *arg, *start, *special;
    int quote, i;
    Tcl_DString ds;

    Tcl_DStringInit(&ds);

    /*
     * Prime the path.
     */
    
    Tcl_DStringAppend(&ds, Tcl_DStringValue(linePtr), -1);
    
    for (i = 0; i < argc; i++) {
	if (i == 0) {
	    arg = executable;
	} else {
	    arg = argv[i];
	    Tcl_DStringAppend(&ds, " ", 1);
	}

	quote = 0;
	if (arg[0] == '\0') {
	    quote = 1;
	} else {
	    for (start = arg; *start != '\0'; start++) {
		if (isspace(*start)) { /* INTL: ISO space. */
		    quote = 1;
		    break;
		}
	    }
	}
	if (quote) {
	    Tcl_DStringAppend(&ds, "\"", 1);
	}

	start = arg;	    
	for (special = arg; ; ) {
	    if ((*special == '\\') && 
		    (special[1] == '\\' || special[1] == '"')) {
		Tcl_DStringAppend(&ds, start, special - start);
		start = special;
		while (1) {
		    special++;
		    if (*special == '"') {
			/* 
			 * N backslashes followed a quote -> insert 
			 * N * 2 + 1 backslashes then a quote.
			 */

			Tcl_DStringAppend(&ds, start, special - start);
			break;
		    }
		    if (*special != '\\') {
			break;
		    }
		}
		Tcl_DStringAppend(&ds, start, special - start);
		start = special;
	    }
	    if (*special == '"') {
		Tcl_DStringAppend(&ds, start, special - start);
		Tcl_DStringAppend(&ds, "\\\"", 2);
		start = special + 1;
	    }
	    if (*special == '{') {
		Tcl_DStringAppend(&ds, start, special - start);
		Tcl_DStringAppend(&ds, "\\{", 2);
		start = special + 1;
	    }
	    if (*special == '\0') {
		break;
	    }
	    special++;
	}
	Tcl_DStringAppend(&ds, start, special - start);
	if (quote) {
	    Tcl_DStringAppend(&ds, "\"", 1);
	}
    }
    Tcl_DStringFree(linePtr);
    Tcl_WinUtfToTChar(Tcl_DStringValue(&ds), Tcl_DStringLength(&ds), linePtr);
    Tcl_DStringFree(&ds);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreateCommandChannel --
 *
 *	This function is called by Tcl_OpenCommandChannel to perform
 *	the platform specific channel initialization for a command
 *	channel.
 *
 * Results:
 *	Returns a new channel or NULL on failure.
 *
 * Side effects:
 *	Allocates a new channel.
 *
 *----------------------------------------------------------------------
 */

Tcl_Channel
TclpCreateCommandChannel(
    TclFile readFile,		/* If non-null, gives the file for reading. */
    TclFile writeFile,		/* If non-null, gives the file for writing. */
    TclFile errorFile,		/* If non-null, gives the file where errors
				 * can be read. */
    int numPids,		/* The number of pids in the pid array. */
    Tcl_Pid *pidPtr)		/* An array of process identifiers. */
{
    char channelName[16 + TCL_INTEGER_SPACE];
    int channelId;
    DWORD id;
    PipeInfo *infoPtr = (PipeInfo *) ckalloc((unsigned) sizeof(PipeInfo));

    PipeInit();

    infoPtr->watchMask = 0;
    infoPtr->flags = 0;
    infoPtr->readFlags = 0;
    infoPtr->readFile = readFile;
    infoPtr->writeFile = writeFile;
    infoPtr->errorFile = errorFile;
    infoPtr->numPids = numPids;
    infoPtr->pidPtr = pidPtr;
    infoPtr->writeBuf = 0;
    infoPtr->writeBufLen = 0;
    infoPtr->writeError = 0;

    /*
     * Use one of the fds associated with the channel as the
     * channel id.
     */

    if (readFile) {
	channelId = (int) ((WinFile*)readFile)->handle;
    } else if (writeFile) {
	channelId = (int) ((WinFile*)writeFile)->handle;
    } else if (errorFile) {
	channelId = (int) ((WinFile*)errorFile)->handle;
    } else {
	channelId = 0;
    }

    infoPtr->validMask = 0;

    infoPtr->threadId = Tcl_GetCurrentThread();

    if (readFile != NULL) {
	/*
	 * Start the background reader thread.
	 */

	infoPtr->readable = CreateEvent(NULL, TRUE, TRUE, NULL);
	infoPtr->startReader = CreateEvent(NULL, FALSE, FALSE, NULL);
	infoPtr->stopReader = CreateEvent(NULL, TRUE, FALSE, NULL);
	infoPtr->readThread = CreateThread(NULL, 256, PipeReaderThread,
		infoPtr, 0, &id);
	SetThreadPriority(infoPtr->readThread, THREAD_PRIORITY_HIGHEST); 
        infoPtr->validMask |= TCL_READABLE;
    } else {
	infoPtr->readThread = 0;
    }
    if (writeFile != NULL) {
	/*
	 * Start the background writer thread.
	 */

	infoPtr->writable = CreateEvent(NULL, TRUE, TRUE, NULL);
	infoPtr->startWriter = CreateEvent(NULL, FALSE, FALSE, NULL);
	infoPtr->stopWriter = CreateEvent(NULL, TRUE, FALSE, NULL);
	infoPtr->writeThread = CreateThread(NULL, 256, PipeWriterThread,
		infoPtr, 0, &id);
	SetThreadPriority(infoPtr->readThread, THREAD_PRIORITY_HIGHEST); 
        infoPtr->validMask |= TCL_WRITABLE;
    }

    /*
     * For backward compatibility with previous versions of Tcl, we
     * use "file%d" as the base name for pipes even though it would
     * be more natural to use "pipe%d".
     * Use the pointer to keep the channel names unique, in case
     * channels share handles (stdin/stdout).
     */

    wsprintfA(channelName, "file%lx", infoPtr);
    infoPtr->channel = Tcl_CreateChannel(&pipeChannelType, channelName,
            (ClientData) infoPtr, infoPtr->validMask);

    /*
     * Pipes have AUTO translation mode on Windows and ^Z eof char, which
     * means that a ^Z will be appended to them at close. This is needed
     * for Windows programs that expect a ^Z at EOF.
     */

    Tcl_SetChannelOption((Tcl_Interp *) NULL, infoPtr->channel,
	    "-translation", "auto");
    Tcl_SetChannelOption((Tcl_Interp *) NULL, infoPtr->channel,
	    "-eofchar", "\032 {}");
    return infoPtr->channel;
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetAndDetachPids --
 *
 *	Stores a list of the command PIDs for a command channel in
 *	the interp's result.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Modifies the interp's result.
 *
 *----------------------------------------------------------------------
 */

void
TclGetAndDetachPids(
    Tcl_Interp *interp,
    Tcl_Channel chan)
{
    PipeInfo *pipePtr;
    Tcl_ChannelType *chanTypePtr;
    int i;
    char buf[TCL_INTEGER_SPACE];

    /*
     * Punt if the channel is not a command channel.
     */

    chanTypePtr = Tcl_GetChannelType(chan);
    if (chanTypePtr != &pipeChannelType) {
        return;
    }

    pipePtr = (PipeInfo *) Tcl_GetChannelInstanceData(chan);
    for (i = 0; i < pipePtr->numPids; i++) {
        wsprintfA(buf, "%lu", TclpGetPid(pipePtr->pidPtr[i]));
        Tcl_AppendElement(interp, buf);
        Tcl_DetachPids(1, &(pipePtr->pidPtr[i]));
    }
    if (pipePtr->numPids > 0) {
        ckfree((char *) pipePtr->pidPtr);
        pipePtr->numPids = 0;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * PipeBlockModeProc --
 *
 *	Set blocking or non-blocking mode on channel.
 *
 * Results:
 *	0 if successful, errno when failed.
 *
 * Side effects:
 *	Sets the device into blocking or non-blocking mode.
 *
 *----------------------------------------------------------------------
 */

static int
PipeBlockModeProc(
    ClientData instanceData,	/* Instance data for channel. */
    int mode)			/* TCL_MODE_BLOCKING or
                                 * TCL_MODE_NONBLOCKING. */
{
    PipeInfo *infoPtr = (PipeInfo *) instanceData;
    
    /*
     * Pipes on Windows can not be switched between blocking and nonblocking,
     * hence we have to emulate the behavior. This is done in the input
     * function by checking against a bit in the state. We set or unset the
     * bit here to cause the input function to emulate the correct behavior.
     */

    if (mode == TCL_MODE_NONBLOCKING) {
	infoPtr->flags |= PIPE_ASYNC;
    } else {
	infoPtr->flags &= ~(PIPE_ASYNC);
    }
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeClose2Proc --
 *
 *	Closes a pipe based IO channel.
 *
 * Results:
 *	0 on success, errno otherwise.
 *
 * Side effects:
 *	Closes the physical channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeClose2Proc(
    ClientData instanceData,	/* Pointer to PipeInfo structure. */
    Tcl_Interp *interp,		/* For error reporting. */
    int flags)			/* Flags that indicate which side to close. */
{
    PipeInfo *pipePtr = (PipeInfo *) instanceData;
    Tcl_Channel errChan;
    int errorCode, result;
    PipeInfo *infoPtr, **nextPtrPtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    DWORD exitCode;

    errorCode = 0;
    if ((!flags || (flags == TCL_CLOSE_READ))
	    && (pipePtr->readFile != NULL)) {
	/*
	 * Clean up the background thread if necessary.  Note that this
	 * must be done before we can close the file, since the 
	 * thread may be blocking trying to read from the pipe.
	 */

	if (pipePtr->readThread) {
	    /*
	     * The thread may already have closed on it's own.  Check it's
	     * exit code.
	     */

	    GetExitCodeThread(pipePtr->readThread, &exitCode);

	    if (exitCode == STILL_ACTIVE) {
		/*
		 * Set the stop event so that if the reader thread is blocked
		 * in PipeReaderThread on WaitForMultipleEvents, it will exit
		 * cleanly.
		 */

		SetEvent(pipePtr->stopReader);

		/*
		 * Wait at most 20 milliseconds for the reader thread to close.
		 */

		if (WaitForSingleObject(pipePtr->readThread, 20)
			== WAIT_TIMEOUT) {
		    /*
		     * The thread must be blocked waiting for the pipe to
		     * become readable in ReadFile().  There isn't a clean way
		     * to exit the thread from this condition.  We should
		     * terminate the child process instead to get the reader
		     * thread to fall out of ReadFile with a FALSE.  (below) is
		     * not the correct way to do this, but will stay here until
		     * a better solution is found.
		     *
		     * Note that we need to guard against terminating the
		     * thread while it is in the middle of Tcl_ThreadAlert
		     * because it won't be able to release the notifier lock.
		     */

		    Tcl_MutexLock(&pipeMutex);

		    /* BUG: this leaks memory */
		    TerminateThread(pipePtr->readThread, 0);
		    Tcl_MutexUnlock(&pipeMutex);
		}
	    }

	    CloseHandle(pipePtr->readThread);
	    CloseHandle(pipePtr->readable);
	    CloseHandle(pipePtr->startReader);
	    CloseHandle(pipePtr->stopReader);
	    pipePtr->readThread = NULL;
	}
	if (TclpCloseFile(pipePtr->readFile) != 0) {
	    errorCode = errno;
	}
	pipePtr->validMask &= ~TCL_READABLE;
	pipePtr->readFile = NULL;
    }
    if ((!flags || (flags & TCL_CLOSE_WRITE))
	    && (pipePtr->writeFile != NULL)) {

	if (pipePtr->writeThread) {
	    /*
	     * Wait for the writer thread to finish the current buffer,
	     * then terminate the thread and close the handles.  If the
	     * channel is nonblocking, there should be no pending write
	     * operations.
	     */

	    WaitForSingleObject(pipePtr->writable, INFINITE);

	    /*
	     * The thread may already have closed on it's own.  Check it's
	     * exit code.
	     */

	    GetExitCodeThread(pipePtr->writeThread, &exitCode);

	    if (exitCode == STILL_ACTIVE) {
		/*
		 * Set the stop event so that if the reader thread is blocked
		 * in PipeReaderThread on WaitForMultipleEvents, it will exit
		 * cleanly.
		 */

		SetEvent(pipePtr->stopWriter);

		/*
		 * Wait at most 20 milliseconds for the reader thread to close.
		 */

		if (WaitForSingleObject(pipePtr->writeThread, 20)
			== WAIT_TIMEOUT) {
		    /*
		     * The thread must be blocked waiting for the pipe to
		     * consume input in WriteFile().  There isn't a clean way
		     * to exit the thread from this condition.  We should
		     * terminate the child process instead to get the writer
		     * thread to fall out of WriteFile with a FALSE.  (below) is
		     * not the correct way to do this, but will stay here until
		     * a better solution is found.
		     *
		     * Note that we need to guard against terminating the
		     * thread while it is in the middle of Tcl_ThreadAlert
		     * because it won't be able to release the notifier lock.
		     */

		    Tcl_MutexLock(&pipeMutex);

		    /* BUG: this leaks memory */
		    TerminateThread(pipePtr->writeThread, 0);
		    Tcl_MutexUnlock(&pipeMutex);
		}
	    }

	    CloseHandle(pipePtr->writeThread);
	    CloseHandle(pipePtr->writable);
	    CloseHandle(pipePtr->startWriter);
	    CloseHandle(pipePtr->stopWriter);
	    pipePtr->writeThread = NULL;
	}
	if (TclpCloseFile(pipePtr->writeFile) != 0) {
	    if (errorCode == 0) {
		errorCode = errno;
	    }
	}
	pipePtr->validMask &= ~TCL_WRITABLE;
	pipePtr->writeFile = NULL;
    }

    pipePtr->watchMask &= pipePtr->validMask;

    /*
     * Don't free the channel if any of the flags were set.
     */

    if (flags) {
	return errorCode;
    }

    /*
     * Remove the file from the list of watched files.
     */

    for (nextPtrPtr = &(tsdPtr->firstPipePtr), infoPtr = *nextPtrPtr;
	    infoPtr != NULL;
	    nextPtrPtr = &infoPtr->nextPtr, infoPtr = *nextPtrPtr) {
	if (infoPtr == (PipeInfo *)pipePtr) {
	    *nextPtrPtr = infoPtr->nextPtr;
	    break;
	}
    }

    /*
     * Wrap the error file into a channel and give it to the cleanup
     * routine.
     */

    if (pipePtr->errorFile) {
	WinFile *filePtr;

	filePtr = (WinFile*)pipePtr->errorFile;
	errChan = Tcl_MakeFileChannel((ClientData) filePtr->handle,
		TCL_READABLE);
	ckfree((char *) filePtr);
    } else {
        errChan = NULL;
    }

    result = TclCleanupChildren(interp, pipePtr->numPids, pipePtr->pidPtr,
            errChan);

    if (pipePtr->numPids > 0) {
        ckfree((char *) pipePtr->pidPtr);
    }

    if (pipePtr->writeBuf != NULL) {
	ckfree(pipePtr->writeBuf);
    }

    ckfree((char*) pipePtr);

    if (errorCode == 0) {
        return result;
    }
    return errorCode;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeInputProc --
 *
 *	Reads input from the IO channel into the buffer given. Returns
 *	count of how many bytes were actually read, and an error indication.
 *
 * Results:
 *	A count of how many bytes were read is returned and an error
 *	indication is returned in an output argument.
 *
 * Side effects:
 *	Reads input from the actual channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeInputProc(
    ClientData instanceData,		/* Pipe state. */
    char *buf,				/* Where to store data read. */
    int bufSize,			/* How much space is available
                                         * in the buffer? */
    int *errorCode)			/* Where to store error code. */
{
    PipeInfo *infoPtr = (PipeInfo *) instanceData;
    WinFile *filePtr = (WinFile*) infoPtr->readFile;
    DWORD count, bytesRead = 0;
    int result;

    *errorCode = 0;
    /*
     * Synchronize with the reader thread.
     */

    result = WaitForRead(infoPtr, (infoPtr->flags & PIPE_ASYNC) ? 0 : 1);

    /*
     * If an error occurred, return immediately.
     */

    if (result == -1) {
	*errorCode = errno;
	return -1;
    }

    if (infoPtr->readFlags & PIPE_EXTRABYTE) {
	/*
	 * The reader thread consumed 1 byte as a side effect of
	 * waiting so we need to move it into the buffer.
	 */

	*buf = infoPtr->extraByte;
	infoPtr->readFlags &= ~PIPE_EXTRABYTE;
	buf++;
	bufSize--;
	bytesRead = 1;

	/*
	 * If further read attempts would block, return what we have.
	 */

	if (result == 0) {
	    return bytesRead;
	}
    }

    /*
     * Attempt to read bufSize bytes.  The read will return immediately
     * if there is any data available.  Otherwise it will block until
     * at least one byte is available or an EOF occurs.
     */

    if (ReadFile(filePtr->handle, (LPVOID) buf, (DWORD) bufSize, &count,
	    (LPOVERLAPPED) NULL) == TRUE) {
	return bytesRead + count;
    } else if (bytesRead) {
	/*
	 * Ignore errors if we have data to return.
	 */

	return bytesRead;
    }

    TclWinConvertError(GetLastError());
    if (errno == EPIPE) {
	infoPtr->readFlags |= PIPE_EOF;
	return 0;
    }
    *errorCode = errno;
    return -1;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeOutputProc --
 *
 *	Writes the given output on the IO channel. Returns count of how
 *	many characters were actually written, and an error indication.
 *
 * Results:
 *	A count of how many characters were written is returned and an
 *	error indication is returned in an output argument.
 *
 * Side effects:
 *	Writes output on the actual channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeOutputProc(
    ClientData instanceData,		/* Pipe state. */
    CONST char *buf,			/* The data buffer. */
    int toWrite,			/* How many bytes to write? */
    int *errorCode)			/* Where to store error code. */
{
    PipeInfo *infoPtr = (PipeInfo *) instanceData;
    WinFile *filePtr = (WinFile*) infoPtr->writeFile;
    DWORD bytesWritten, timeout;
    
    *errorCode = 0;
    timeout = (infoPtr->flags & PIPE_ASYNC) ? 0 : INFINITE;
    if (WaitForSingleObject(infoPtr->writable, timeout) == WAIT_TIMEOUT) {
	/*
	 * The writer thread is blocked waiting for a write to complete
	 * and the channel is in non-blocking mode.
	 */

	errno = EAGAIN;
	goto error;
    }
    
    /*
     * Check for a background error on the last write.
     */

    if (infoPtr->writeError) {
	TclWinConvertError(infoPtr->writeError);
	infoPtr->writeError = 0;
	goto error;
    }

    if (infoPtr->flags & PIPE_ASYNC) {
	/*
	 * The pipe is non-blocking, so copy the data into the output
	 * buffer and restart the writer thread.
	 */

	if (toWrite > infoPtr->writeBufLen) {
	    /*
	     * Reallocate the buffer to be large enough to hold the data.
	     */

	    if (infoPtr->writeBuf) {
		ckfree(infoPtr->writeBuf);
	    }
	    infoPtr->writeBufLen = toWrite;
	    infoPtr->writeBuf = ckalloc((unsigned int) toWrite);
	}
	memcpy(infoPtr->writeBuf, buf, (size_t) toWrite);
	infoPtr->toWrite = toWrite;
	ResetEvent(infoPtr->writable);
	SetEvent(infoPtr->startWriter);
	bytesWritten = toWrite;
    } else {
	/*
	 * In the blocking case, just try to write the buffer directly.
	 * This avoids an unnecessary copy.
	 */

	if (WriteFile(filePtr->handle, (LPVOID) buf, (DWORD) toWrite,
		&bytesWritten, (LPOVERLAPPED) NULL) == FALSE) {
	    TclWinConvertError(GetLastError());
	    goto error;
	}
    }
    return bytesWritten;

    error:
    *errorCode = errno;
    return -1;

}

/*
 *----------------------------------------------------------------------
 *
 * PipeEventProc --
 *
 *	This function is invoked by Tcl_ServiceEvent when a file event
 *	reaches the front of the event queue.  This procedure invokes
 *	Tcl_NotifyChannel on the pipe.
 *
 * Results:
 *	Returns 1 if the event was handled, meaning it should be removed
 *	from the queue.  Returns 0 if the event was not handled, meaning
 *	it should stay on the queue.  The only time the event isn't
 *	handled is if the TCL_FILE_EVENTS flag bit isn't set.
 *
 * Side effects:
 *	Whatever the notifier callback does.
 *
 *----------------------------------------------------------------------
 */

static int
PipeEventProc(
    Tcl_Event *evPtr,		/* Event to service. */
    int flags)			/* Flags that indicate what events to
				 * handle, such as TCL_FILE_EVENTS. */
{
    PipeEvent *pipeEvPtr = (PipeEvent *)evPtr;
    PipeInfo *infoPtr;
    WinFile *filePtr;
    int mask;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!(flags & TCL_FILE_EVENTS)) {
	return 0;
    }

    /*
     * Search through the list of watched pipes for the one whose handle
     * matches the event.  We do this rather than simply dereferencing
     * the handle in the event so that pipes can be deleted while the
     * event is in the queue.
     */

    for (infoPtr = tsdPtr->firstPipePtr; infoPtr != NULL;
	    infoPtr = infoPtr->nextPtr) {
	if (pipeEvPtr->infoPtr == infoPtr) {
	    infoPtr->flags &= ~(PIPE_PENDING);
	    break;
	}
    }

    /*
     * Remove stale events.
     */

    if (!infoPtr) {
	return 1;
    }

    /*
     * Check to see if the pipe is readable.  Note
     * that we can't tell if a pipe is writable, so we always report it
     * as being writable unless we have detected EOF.
     */

    filePtr = (WinFile*) ((PipeInfo*)infoPtr)->writeFile;
    mask = 0;
    if ((infoPtr->watchMask & TCL_WRITABLE) &&
	    (WaitForSingleObject(infoPtr->writable, 0) != WAIT_TIMEOUT)) {
	mask = TCL_WRITABLE;
    }

    filePtr = (WinFile*) ((PipeInfo*)infoPtr)->readFile;
    if ((infoPtr->watchMask & TCL_READABLE) &&
	    (WaitForRead(infoPtr, 0) >= 0)) {
	if (infoPtr->readFlags & PIPE_EOF) {
	    mask = TCL_READABLE;
	} else {
	    mask |= TCL_READABLE;
	}
    }

    /*
     * Inform the channel of the events.
     */

    Tcl_NotifyChannel(infoPtr->channel, infoPtr->watchMask & mask);
    return 1;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeWatchProc --
 *
 *	Called by the notifier to set up to watch for events on this
 *	channel.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
PipeWatchProc(
    ClientData instanceData,		/* Pipe state. */
    int mask)				/* What events to watch for, OR-ed
                                         * combination of TCL_READABLE,
                                         * TCL_WRITABLE and TCL_EXCEPTION. */
{
    PipeInfo **nextPtrPtr, *ptr;
    PipeInfo *infoPtr = (PipeInfo *) instanceData;
    int oldMask = infoPtr->watchMask;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    /*
     * Since most of the work is handled by the background threads,
     * we just need to update the watchMask and then force the notifier
     * to poll once. 
     */

    infoPtr->watchMask = mask & infoPtr->validMask;
    if (infoPtr->watchMask) {
	Tcl_Time blockTime = { 0, 0 };
	if (!oldMask) {
	    infoPtr->nextPtr = tsdPtr->firstPipePtr;
	    tsdPtr->firstPipePtr = infoPtr;
	}
	Tcl_SetMaxBlockTime(&blockTime);
    } else {
	if (oldMask) {
	    /*
	     * Remove the pipe from the list of watched pipes.
	     */

	    for (nextPtrPtr = &(tsdPtr->firstPipePtr), ptr = *nextPtrPtr;
		 ptr != NULL;
		 nextPtrPtr = &ptr->nextPtr, ptr = *nextPtrPtr) {
		if (infoPtr == ptr) {
		    *nextPtrPtr = ptr->nextPtr;
		    break;
		}
	    }
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * PipeGetHandleProc --
 *
 *	Called from Tcl_GetChannelHandle to retrieve OS handles from
 *	inside a command pipeline based channel.
 *
 * Results:
 *	Returns TCL_OK with the fd in handlePtr, or TCL_ERROR if
 *	there is no handle for the specified direction. 
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
PipeGetHandleProc(
    ClientData instanceData,	/* The pipe state. */
    int direction,		/* TCL_READABLE or TCL_WRITABLE */
    ClientData *handlePtr)	/* Where to store the handle.  */
{
    PipeInfo *infoPtr = (PipeInfo *) instanceData;
    WinFile *filePtr; 

    if (direction == TCL_READABLE && infoPtr->readFile) {
	filePtr = (WinFile*) infoPtr->readFile;
	*handlePtr = (ClientData) filePtr->handle;
	return TCL_OK;
    }
    if (direction == TCL_WRITABLE && infoPtr->writeFile) {
	filePtr = (WinFile*) infoPtr->writeFile;
	*handlePtr = (ClientData) filePtr->handle;
	return TCL_OK;
    }
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_WaitPid --
 *
 *	Emulates the waitpid system call.
 *
 * Results:
 *	Returns 0 if the process is still alive, -1 on an error, or
 *	the pid on a clean close.  
 *
 * Side effects:
 *	Unless WNOHANG is set and the wait times out, the process
 *	information record will be deleted and the process handle
 *	will be closed.
 *
 *----------------------------------------------------------------------
 */

Tcl_Pid
Tcl_WaitPid(
    Tcl_Pid pid,
    int *statPtr,
    int options)
{
    ProcInfo *infoPtr, **prevPtrPtr;
    DWORD flags;
    Tcl_Pid result;
    DWORD ret, exitCode;

    PipeInit();

    /*
     * If no pid is specified, do nothing.
     */
    
    if (pid == 0) {
	*statPtr = 0;
	return 0;
    }

    /*
     * Find the process on the process list.
     */

    Tcl_MutexLock(&pipeMutex);
    prevPtrPtr = &procList;
    for (infoPtr = procList; infoPtr != NULL;
	    prevPtrPtr = &infoPtr->nextPtr, infoPtr = infoPtr->nextPtr) {
	 if (infoPtr->hProcess == (HANDLE) pid) {
	    break;
	}
    }
    Tcl_MutexUnlock(&pipeMutex);

    /*
     * If the pid is not one of the processes we know about (we started it)
     * then do nothing.
     */
    		     
    if (infoPtr == NULL) {
        *statPtr = 0;
	return 0;
    }

    /*
     * Officially "wait" for it to finish. We either poll (WNOHANG) or
     * wait for an infinite amount of time.
     */
    
    if (options & WNOHANG) {
	flags = 0;
    } else {
	flags = INFINITE;
    }
    ret = WaitForSingleObject(infoPtr->hProcess, flags);
    if (ret == WAIT_TIMEOUT) {
	*statPtr = 0;
	if (options & WNOHANG) {
	    return 0;
	} else {
	    result = 0;
	}
    } else if (ret == WAIT_OBJECT_0) {
	GetExitCodeProcess(infoPtr->hProcess, &exitCode);
	if (exitCode & 0xC0000000) {
	    /*
	     * A fatal exception occured.
	     */
	    switch (exitCode) {
		case EXCEPTION_FLT_DENORMAL_OPERAND:
		case EXCEPTION_FLT_DIVIDE_BY_ZERO:
		case EXCEPTION_FLT_INEXACT_RESULT:
		case EXCEPTION_FLT_INVALID_OPERATION:
		case EXCEPTION_FLT_OVERFLOW:
		case EXCEPTION_FLT_STACK_CHECK:
		case EXCEPTION_FLT_UNDERFLOW:
		case EXCEPTION_INT_DIVIDE_BY_ZERO:
		case EXCEPTION_INT_OVERFLOW:
		    *statPtr = SIGFPE;
		    break;

		case EXCEPTION_PRIV_INSTRUCTION:
		case EXCEPTION_ILLEGAL_INSTRUCTION:
		    *statPtr = SIGILL;
		    break;

		case EXCEPTION_ACCESS_VIOLATION:
		case EXCEPTION_DATATYPE_MISALIGNMENT:
		case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
		case EXCEPTION_STACK_OVERFLOW:
		case EXCEPTION_NONCONTINUABLE_EXCEPTION:
		case EXCEPTION_INVALID_DISPOSITION:
		case EXCEPTION_GUARD_PAGE:
		case EXCEPTION_INVALID_HANDLE:
		    *statPtr = SIGSEGV;
		    break;

		case CONTROL_C_EXIT:
		    *statPtr = SIGINT;
		    break;

		default:
		    *statPtr = SIGABRT;
		    break;
	    }
	} else {
	    /*
	     * Non exception, normal, exit code.  Note that the exit code
	     * is truncated to a byte range.
	     */
	    *statPtr = ((exitCode << 8) & 0xff00);
	}
	result = pid;
    } else {
	errno = ECHILD;
        *statPtr = ECHILD;
	result = (Tcl_Pid) -1;
    }

    /*
     * Remove the process from the process list and close the process handle.
     */

    CloseHandle(infoPtr->hProcess);
    *prevPtrPtr = infoPtr->nextPtr;
    ckfree((char*)infoPtr);

    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * TclWinAddProcess --
 *
 *     Add a process to the process list so that we can use
 *     Tcl_WaitPid on the process.
 *
 * Results:
 *     None
 *
 * Side effects:
 *	Adds the specified process handle to the process list so
 *	Tcl_WaitPid knows about it.
 *
 *----------------------------------------------------------------------
 */

void
TclWinAddProcess(hProcess, id)
    HANDLE hProcess;           /* Handle to process */
    DWORD id;                  /* Global process identifier */
{
    ProcInfo *procPtr = (ProcInfo *) ckalloc(sizeof(ProcInfo));
    procPtr->hProcess = hProcess;
    procPtr->dwProcessId = id;
    Tcl_MutexLock(&pipeMutex);
    procPtr->nextPtr = procList;
    procList = procPtr;
    Tcl_MutexUnlock(&pipeMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_PidObjCmd --
 *
 *	This procedure is invoked to process the "pid" Tcl command.
 *	See the user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
int
Tcl_PidObjCmd(
    ClientData dummy,		/* Not used. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *CONST *objv)	/* Argument strings. */
{
    Tcl_Channel chan;
    Tcl_ChannelType *chanTypePtr;
    PipeInfo *pipePtr;
    int i;
    Tcl_Obj *resultPtr;
    char buf[TCL_INTEGER_SPACE];

    if (objc > 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "?channelId?");
	return TCL_ERROR;
    }
    if (objc == 1) {
	resultPtr = Tcl_GetObjResult(interp);
	wsprintfA(buf, "%lu", (unsigned long) getpid());
	Tcl_SetStringObj(resultPtr, buf, -1);
    } else {
        chan = Tcl_GetChannel(interp, Tcl_GetStringFromObj(objv[1], NULL),
		NULL);
        if (chan == (Tcl_Channel) NULL) {
	    return TCL_ERROR;
	}
	chanTypePtr = Tcl_GetChannelType(chan);
	if (chanTypePtr != &pipeChannelType) {
	    return TCL_OK;
	}

        pipePtr = (PipeInfo *) Tcl_GetChannelInstanceData(chan);
	resultPtr = Tcl_GetObjResult(interp);
        for (i = 0; i < pipePtr->numPids; i++) {
	    wsprintfA(buf, "%lu", TclpGetPid(pipePtr->pidPtr[i]));
	    Tcl_ListObjAppendElement(/*interp*/ NULL, resultPtr,
		    Tcl_NewStringObj(buf, -1));
	}
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * WaitForRead --
 *
 *	Wait until some data is available, the pipe is at
 *	EOF or the reader thread is blocked waiting for data (if the
 *	channel is in non-blocking mode).
 *
 * Results:
 *	Returns 1 if pipe is readable.  Returns 0 if there is no data
 *	on the pipe, but there is buffered data.  Returns -1 if an
 *	error occurred.  If an error occurred, the threads may not
 *	be synchronized.
 *
 * Side effects:
 *	Updates the shared state flags and may consume 1 byte of data
 *	from the pipe.  If no error occurred, the reader thread is
 *	blocked waiting for a signal from the main thread.
 *
 *----------------------------------------------------------------------
 */

static int
WaitForRead(
    PipeInfo *infoPtr,		/* Pipe state. */
    int blocking)		/* Indicates whether call should be
				 * blocking or not. */
{
    DWORD timeout, count;
    HANDLE *handle = ((WinFile *) infoPtr->readFile)->handle;

    while (1) {
	/*
	 * Synchronize with the reader thread.
	 */
       
	timeout = blocking ? INFINITE : 0;
	if (WaitForSingleObject(infoPtr->readable, timeout) == WAIT_TIMEOUT) {
	    /*
	     * The reader thread is blocked waiting for data and the channel
	     * is in non-blocking mode.
	     */

	    errno = EAGAIN;
	    return -1;
	}

	/*
	 * At this point, the two threads are synchronized, so it is safe
	 * to access shared state.
	 */


	/*
	 * If the pipe has hit EOF, it is always readable.
	 */

	if (infoPtr->readFlags & PIPE_EOF) {
	    return 1;
	}
    
	/*
	 * Check to see if there is any data sitting in the pipe.
	 */

	if (PeekNamedPipe(handle, (LPVOID) NULL, (DWORD) 0,
		(LPDWORD) NULL, &count, (LPDWORD) NULL) != TRUE) {
	    TclWinConvertError(GetLastError());
	    /*
	     * Check to see if the peek failed because of EOF.
	     */

	    if (errno == EPIPE) {
		infoPtr->readFlags |= PIPE_EOF;
		return 1;
	    }

	    /*
	     * Ignore errors if there is data in the buffer.
	     */

	    if (infoPtr->readFlags & PIPE_EXTRABYTE) {
		return 0;
	    } else {
		return -1;
	    }
	}

	/*
	 * We found some data in the pipe, so it must be readable.
	 */

	if (count > 0) {
	    return 1;
	}

	/*
	 * The pipe isn't readable, but there is some data sitting
	 * in the buffer, so return immediately.
	 */

	if (infoPtr->readFlags & PIPE_EXTRABYTE) {
	    return 0;
	}

	/*
	 * There wasn't any data available, so reset the thread and
	 * try again.
	 */
    
	ResetEvent(infoPtr->readable);
	SetEvent(infoPtr->startReader);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * PipeReaderThread --
 *
 *	This function runs in a separate thread and waits for input
 *	to become available on a pipe.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Signals the main thread when input become available.  May
 *	cause the main thread to wake up by posting a message.  May
 *	consume one byte from the pipe for each wait operation.  Will
 *	cause a memory leak of ~4k, if forcefully terminated with
 *	TerminateThread().
 *
 *----------------------------------------------------------------------
 */

static DWORD WINAPI
PipeReaderThread(LPVOID arg)
{
    PipeInfo *infoPtr = (PipeInfo *)arg;
    HANDLE *handle = ((WinFile *) infoPtr->readFile)->handle;
    DWORD count, err;
    int done = 0;
    HANDLE wEvents[2];
    DWORD waitResult;

    wEvents[0] = infoPtr->stopReader;
    wEvents[1] = infoPtr->startReader;

    while (!done) {
	/*
	 * Wait for the main thread to signal before attempting to wait
	 * on the pipe becoming readable.
	 */

	waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE);

	if (waitResult != (WAIT_OBJECT_0 + 1)) {
	    /*
	     * The start event was not signaled.  It might be the stop event
	     * or an error, so exit.
	     */

	    break;
	}

	/*
	 * Try waiting for 0 bytes.  This will block until some data is
	 * available on NT, but will return immediately on Win 95.  So,
	 * if no data is available after the first read, we block until
	 * we can read a single byte off of the pipe.
	 */

	if ((ReadFile(handle, NULL, 0, &count, NULL) == FALSE)
		|| (PeekNamedPipe(handle, NULL, 0, NULL, &count,
			NULL) == FALSE)) {
	    /*
	     * The error is a result of an EOF condition, so set the
	     * EOF bit before signalling the main thread.
	     */

	    err = GetLastError();
	    if (err == ERROR_BROKEN_PIPE) {
		infoPtr->readFlags |= PIPE_EOF;
		done = 1;
	    } else if (err == ERROR_INVALID_HANDLE) {
		break;
	    }
	} else if (count == 0) {
	    if (ReadFile(handle, &(infoPtr->extraByte), 1, &count, NULL)
		    != FALSE) {
		/*
		 * One byte was consumed as a side effect of waiting
		 * for the pipe to become readable.
		 */

		infoPtr->readFlags |= PIPE_EXTRABYTE;
	    } else {
		err = GetLastError();
		if (err == ERROR_BROKEN_PIPE) {
		    /*
		     * The error is a result of an EOF condition, so set the
		     * EOF bit before signalling the main thread.
		     */

		    infoPtr->readFlags |= PIPE_EOF;
		    done = 1;
		} else if (err == ERROR_INVALID_HANDLE) {
		    break;
		}
	    }
	}

		
	/*
	 * Signal the main thread by signalling the readable event and
	 * then waking up the notifier thread.
	 */

	SetEvent(infoPtr->readable);
	
	/*
	 * Alert the foreground thread.  Note that we need to treat this like
	 * a critical section so the foreground thread does not terminate
	 * this thread while we are holding a mutex in the notifier code.
	 */

	Tcl_MutexLock(&pipeMutex);
	Tcl_ThreadAlert(infoPtr->threadId);
	Tcl_MutexUnlock(&pipeMutex);
    }

    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeWriterThread --
 *
 *	This function runs in a separate thread and writes data
 *	onto a pipe.
 *
 * Results:
 *	Always returns 0.
 *
 * Side effects:
 *	Signals the main thread when an output operation is completed.
 *	May cause the main thread to wake up by posting a message.  
 *
 *----------------------------------------------------------------------
 */

static DWORD WINAPI
PipeWriterThread(LPVOID arg)
{

    PipeInfo *infoPtr = (PipeInfo *)arg;
    HANDLE *handle = ((WinFile *) infoPtr->writeFile)->handle;
    DWORD count, toWrite;
    char *buf;
    int done = 0;
    HANDLE wEvents[2];
    DWORD waitResult;

    wEvents[0] = infoPtr->stopWriter;
    wEvents[1] = infoPtr->startWriter;

    while (!done) {
	/*
	 * Wait for the main thread to signal before attempting to write.
	 */

	waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE);

	if (waitResult != (WAIT_OBJECT_0 + 1)) {
	    /*
	     * The start event was not signaled.  It might be the stop event
	     * or an error, so exit.
	     */

	    break;
	}

	buf = infoPtr->writeBuf;
	toWrite = infoPtr->toWrite;

	/*
	 * Loop until all of the bytes are written or an error occurs.
	 */

	while (toWrite > 0) {
	    if (WriteFile(handle, buf, toWrite, &count, NULL) == FALSE) {
		infoPtr->writeError = GetLastError();
		done = 1; 
		break;
	    } else {
		toWrite -= count;
		buf += count;
	    }
	}
	
	/*
	 * Signal the main thread by signalling the writable event and
	 * then waking up the notifier thread.
	 */

	SetEvent(infoPtr->writable);

	/*
	 * Alert the foreground thread.  Note that we need to treat this like
	 * a critical section so the foreground thread does not terminate
	 * this thread while we are holding a mutex in the notifier code.
	 */

	Tcl_MutexLock(&pipeMutex);
	Tcl_ThreadAlert(infoPtr->threadId);
	Tcl_MutexUnlock(&pipeMutex);
    }

    return 0;
}