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
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html xmlns:o="urn:schemas-microsoft-com:office:office"
xmlns:w="urn:schemas-microsoft-com:office:word"
xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=windows-1252">
<meta name=ProgId content=Word.Document>
<meta name=Generator content="Microsoft Word 9">
<meta name=Originator content="Microsoft Word 9">
<link rel=File-List href="./pool_bestanden/filelist.xml">
<!--[if gte mso 9]><xml>
<o:DocumentProperties>
<o:LastAuthor>Erik</o:LastAuthor>
<o:Revision>97</o:Revision>
<o:TotalTime>516</o:TotalTime>
<o:LastPrinted>2002-05-15T11:24:00Z</o:LastPrinted>
<o:Created>2002-04-16T19:32:00Z</o:Created>
<o:LastSaved>2002-05-15T11:27:00Z</o:LastSaved>
<o:Pages>6</o:Pages>
<o:Words>1767</o:Words>
<o:Characters>10077</o:Characters>
<o:Company>None</o:Company>
<o:Lines>83</o:Lines>
<o:Paragraphs>20</o:Paragraphs>
<o:CharactersWithSpaces>12375</o:CharactersWithSpaces>
<o:Version>9.2812</o:Version>
</o:DocumentProperties>
</xml><![endif]--><!--[if gte mso 9]><xml>
<w:WordDocument>
<w:View>Normal</w:View>
<w:HyphenationZone>21</w:HyphenationZone>
</w:WordDocument>
</xml><![endif]-->
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;
mso-font-charset:0;
mso-generic-font-family:swiss;
mso-font-pitch:variable;
mso-font-signature:553679495 -2147483648 8 0 66047 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0in;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:12.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";}
p.MsoDocumentMap, li.MsoDocumentMap, div.MsoDocumentMap
{margin:0in;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
background:navy;
font-size:12.0pt;
font-family:Tahoma;
mso-fareast-font-family:"Times New Roman";}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{margin:0in;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:"Courier New";
mso-fareast-font-family:"Times New Roman";}
@page Section1
{size:8.5in 11.0in;
margin:.8in .8in .7in .7in;
mso-header-margin:.2in;
mso-footer-margin:.2in;
mso-paper-source:0;}
div.Section1
{page:Section1;}
/* List Definitions */
@list l0
{mso-list-id:491943773;
mso-list-type:hybrid;
mso-list-template-ids:389161538 700215070 68354051 68354053 68354049 68354051 68354053 68354049 68354051 68354053;}
@list l0:level1
{mso-level-start-at:2;
mso-level-number-format:bullet;
mso-level-text:-;
mso-level-tab-stop:53.4pt;
mso-level-number-position:left;
margin-left:53.4pt;
text-indent:-.25in;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";}
@list l1
{mso-list-id:2044330862;
mso-list-type:hybrid;
mso-list-template-ids:1794557052 1241923622 68354073 68354075 68354063 68354073 68354075 68354063 68354073 68354075;}
@list l1:level1
{mso-level-tab-stop:106.15pt;
mso-level-number-position:left;
margin-left:106.15pt;
text-indent:-35.35pt;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
-->
</style>
<meta name=CVS content="$Id: pool.html,v 1.2 2004/01/15 06:36:14 andreas_kupries Exp $">
<meta name=CVS content="$Id: pool.html,v 1.2 2004/01/15 06:36:14 andreas_kupries Exp $">
<meta name=CVS content="\$Id: pool.html,v 1.2 2004/01/15 06:36:14 andreas_kupries Exp $">
</head>
<body lang=NL style='tab-interval:35.4pt'>
<div class=Section1>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText align=center style='text-align:center;mso-outline-level:
1'><b><span style='font-size:16.0pt;font-family:"Times New Roman"'>POOL 0.1<o:p></o:p></span></b></p>
<p class=MsoPlainText align=center style='text-align:center'><span
style='font-size:11.0pt;font-family:"Times New Roman"'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText align=center style='text-align:center;mso-outline-level:
1'><span style='font-size:11.0pt;font-family:"Times New Roman"'>Author: Erik
Leunissen<o:p></o:p></span></p>
<p class=MsoPlainText><span style='font-size:11.0pt;font-family:"Times New Roman"'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><span style='font-size:11.0pt;font-family:"Times New Roman"'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='mso-outline-level:1'><b><span lang=EN-GB
style='font-size:12.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>NAME<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>pool
- Managing a pool of discrete items.<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='mso-outline-level:1'><b><span lang=EN-GB
style='font-size:12.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>SYNOPSIS<o:p></o:p></span></b></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><span style='mso-tab-count:1'></span><b>pool
</b><i>?poolName? ?maxsize?</i><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='mso-outline-level:1'><b><span lang=EN-GB
style='font-size:12.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>DESCRIPTION</span></b><span lang=EN-GB
style='font-size:12.0pt;mso-bidi-font-size:11.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
<i>pool</i> command creates a new instance of a pool data structure. The command
takes the name of the new pool as its first argument. If no name is supplied,
then the new pool will be named pool<X>, where X is a positive integer.
The optional second argument <i>maxsize</i> is a positive integer indicating
the maximum size of the pool; this is the maximum number of items the pool may
hold.</span><span lang=EN-GB style='mso-ansi-language:EN-GB'><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='mso-outline-level:1'><b><span lang=EN-GB
style='font-size:12.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>POOLS AND ALLOCATION<o:p></o:p></span></b></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:12.0pt;mso-bidi-font-size:
11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
purpose of the <i>pool</i> command and the pool object command that it
generates, is to manage pools of discrete items.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Examples
of a pool of discrete items are:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:53.4pt;text-indent:-.25in;mso-list:
l0 level1 lfo2;tab-stops:list 53.4pt'><![if !supportLists]><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-<span
style='font:7.0pt "Times New Roman"'>
</span></span><![endif]><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'>the seats in a cinema, theatre,
train etc.. for which visitors/travellers can<span style="mso-spacerun: yes">
</span>make a reservation;<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:53.4pt;text-indent:-.25in;mso-list:
l0 level1 lfo2;tab-stops:list 53.4pt'><![if !supportLists]><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-<span
style='font:7.0pt "Times New Roman"'>
</span></span><![endif]><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'>the dynamic IP-addresses that an ISP
can dole out<span style="mso-spacerun: yes"></span>to subscribers;<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:53.4pt;text-indent:-.25in;mso-list:
l0 level1 lfo2;tab-stops:list 53.4pt'><![if !supportLists]><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-<span
style='font:7.0pt "Times New Roman"'>
</span></span><![endif]><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'>a car rental's collection of cars,
which can be rented by customers;<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:53.4pt;text-indent:-.25in;mso-list:
l0 level1 lfo2;tab-stops:list 53.4pt'><![if !supportLists]><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-<span
style='font:7.0pt "Times New Roman"'>
</span></span><![endif]><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'>the class rooms in a school
building, which need to be scheduled;<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:53.4pt;text-indent:-.25in;mso-list:
l0 level1 lfo2;tab-stops:list 53.4pt'><![if !supportLists]><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-<span
style='font:7.0pt "Times New Roman"'>
</span></span><![endif]><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'>the database connections available
to client-threads in a web-server application;<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:53.4pt;text-indent:-.25in;mso-list:
l0 level1 lfo2;tab-stops:list 53.4pt'><![if !supportLists]><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-<span
style='font:7.0pt "Times New Roman"'>
</span></span><![endif]><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'>the books in a library that
customers can borrow;<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:53.4pt;text-indent:-.25in'><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>etc ...<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
common denominator in the examples is that there is a more or less fixed number
of items (seats, IP-addresses, cars, ...) that are supposed to be allocated on
a more or less regular basis. An item can be allocated only once at a time. An
item that is allocated, must be released before it can be re-allocated. While
several items in a pool are being allocated and released continuously, the
total number of items in the pool remains constant.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Keeping
track of which items are allocated, and by whom, is the purpose of the <i>pool</i>
command and its subordinates.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Pool parlance<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>If
we say that an item is allocated, it means that the item is <i>busy</i>, <i>owned</i>
or <i>occupied</i>; it is not available anymore. If an item is free, it is
available. <i>Deallocating</i> an item is equivalent to <i>setting free</i> or <i>releasing</i>
an item. The person or entity to which the item has been allotted is said to <i>own</i>
the item.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><b><span lang=EN-GB style='font-size:12.0pt;mso-bidi-font-size:
11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>ITEMS<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Discrete items<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
<i>pool</i> command is designed for <b>discrete items only</b>. Note that there
are pools where allocation occurs on a non-discrete basis, for example computer
memory. There are also pools from which the shares that are doled out are not
expected to be returned, for example a charity fund or a pan of soup from which
you may receive a portion. Finally, there are even pools from which nothing is
ever allocated or returned, like a swimming pool or a cesspool.<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Unique item names<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>A pool cannot manage duplicate item names. Therefore, items in a pool
must have unique names.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><b><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><span
style="mso-spacerun: yes"></span><o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Item equivalence<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>From
the point of view of the manager of a pool, items are equivalent. The manager
of a pool is indifferent about which entity/person occupies a given item.
However, clients may have preferences for a particular item, based on some item
property they know.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Preferences<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>A
future owner may have a preference for a particular item. Preference based
allocation is supported (see the <b>-prefer</b> option to the <i>request</i>
subcommand). A preference for a particular item is most likely to result from
variability among features associated with the items. Note that the pool
commands themselves are not designed to manage such item properties. If item
properties play a role in an application, they should be<span
style="mso-spacerun: yes"></span>managed separately. <o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='mso-outline-level:1'><b><span lang=EN-GB
style='font-size:12.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>POOL OBJECT COMMAND<o:p></o:p></span></b></p>
<p class=MsoPlainText><b><span lang=EN-GB style='font-size:12.0pt;mso-bidi-font-size:
14.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
<i>pool</i> command creates a new Tcl command whose name is <i>poolName</i> .
This pool object command is used to manipulate or query the pool object. The
general syntax of a pool object command is:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><span
style='mso-tab-count:1'></span><i>poolName</i> <b>subcommand</b> <i>?arg
arg ...?</i><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
following subcommands and corresponding arguments are available:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>add</b> <i>itemName1 ?itemName2 itemName3 ...?</i><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>This
command adds the items on the command line to the pool. If duplicate item names
occur on the command line, an error is raised. If one or more of the items
already exist in the pool, this also is considered an error.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><span
style='mso-tab-count:1'></span><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>clear</b> <i>?-force?</i><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Removes
all items from the pool. If there are any allocated items at the time when the
command is invoked, an error is raised. This behaviour may be modified through
the <i>-force</i> argument. If it is supplied on the command line, the pool
will be cleared regardless the allocation state of its items.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>destroy</b> <i>?-force?<o:p></o:p></i></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Destroys
the pool data structure, all associated variables and the associated pool
object command. By default, the command checks whether any items are still
allocated and raises an error if such is the case. This behaviour may be
modified through the argument -<i>force</i>. If it is supplied on the command
line, the pool data structure will be destroyed regardless allocation state of
its items. <o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:
"Times New Roman";mso-ansi-language:EN-GB;mso-fareast-language:NL;mso-bidi-language:
AR-SA'><br clear=all style='page-break-before:always'>
</span>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>info</b> <i>type ?arg?<o:p></o:p></i></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:.5in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Returns
various information about the pool for further programmatic use. The type
argument indicates the type of information requested. Only the <i>allocID</i>
type uses an additional argument.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:.5in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>allocID </span></b><i><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>itemName<o:p></o:p></span></i></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>returns the allocID of the item whose name is <i>itemName.</i>
Free items have an allocation ID -1.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>allitems<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><span style='mso-tab-count:1'></span></span></b><span
lang=EN-GB style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>returns a list of all items in the pool.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>allocstate<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>Returns a list of key-value pairs, where the keys are
the items and the values are the corresponding allocation ID's. Free
items have an allocation ID -1.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>cursize<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>returns the current pool size, i.e. the
number of items in the pool.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>freeitems</span></b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.5in;margin-bottom:
0in;margin-left:107.4pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>returns
a list of items that currently are not allocated.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:71.4pt;margin-bottom:.0001pt'><b><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>maxsize<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>returns the maximum size of the pool.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:1.0in;margin-bottom:
0in;margin-left:105.6pt;margin-bottom:.0001pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>maxsize</b> <i>?maxsize?<o:p></o:p></i></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>Sets or queries the maximum size of the pool,
depending on whether the <i>maxsize</i> argument is supplied. If the optional
argument <i>maxsize</i> is supplied, the maximum size of the pool will<span
style="mso-spacerun: yes"></span>be set to that value. If no argument <i>maxsize</i>
is supplied, the current maximum size of the pool is returned. In this variant,
the command is an alias for: </span><span lang=EN-GB style='font-size:10.5pt;
mso-bidi-font-size:10.0pt;mso-ansi-language:EN-GB'>poolName info maxsize</span><span
lang=EN-GB style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>The <i>maxsize</i> argument needs to be a positive
integer.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><span style="mso-spacerun: yes"></span><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>release</b> <i>itemName<o:p></o:p></i></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>Releases the item whose name is <i>itemName</i> that
was allocated previously. An error is raised if the item was not allocated at
the time when the command was issued.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'><span style="mso-spacerun: yes"></span><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>remove</b> <i>itemName ?-force?</i><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Removes
the item whose name is <i>itemName</i><span style="mso-spacerun: yes">
</span>from the pool. If the item was allocated at the time when the command
was invoked, an error is raised. This behaviour may be modified through the
optional argument <i>-force</i>. If it is supplied on the command line, the
item will be removed regardless its allocation state.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:
"Times New Roman";mso-ansi-language:EN-GB;mso-fareast-language:NL;mso-bidi-language:
AR-SA'><br clear=all style='page-break-before:always'>
</span>
<p class=MsoPlainText style='margin-left:35.4pt'><i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>poolName</span></i><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <b>request</b> <i>itemVar ?options?</i><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Handles
a request for an item, taking into account a possible preference for a
particular item.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>There
are two possible outcomes depending on the availability of items:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:1.25in;text-indent:-19.2pt;mso-list:
l1 level1 lfo4'><![if !supportLists]><span lang=EN-GB style='font-size:11.0pt;
font-family:"Times New Roman";mso-ansi-language:EN-GB'>1.<span
style='font:7.0pt "Times New Roman"'> </span></span><![endif]><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>The request is honoured, an item is allocated and the variable whose
name is passed with the argument <i>itemVar</i> will be set to the name of the
item that was allocated. The command returns 1.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:1.25in;text-indent:-19.2pt;mso-list:
l1 level1 lfo4'><![if !supportLists]><span lang=EN-GB style='font-size:11.0pt;
font-family:"Times New Roman";mso-ansi-language:EN-GB'>2.<span
style='font:7.0pt "Times New Roman"'> </span></span><![endif]><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>The request is denied. No item is allocated. The variable whose name is <i>itemVar</i>
is not set. Attempts to read <i>itemVar</i><span style="mso-spacerun: yes">
</span>may raise an error if the variable was not defined before issuing the
request. The command returns 0.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
return values from this command are meant to be inspected. The examples below
show how to do this. Failure to check the return value may result in erroneous
behaviour.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>If
no preference for a particular item is supplied through the option <b>-prefer</b>
(see below), then all requests are honoured as long as items are available.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>The
following options are supported:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><b><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-allocID</span></b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'> <i>allocID</i><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:106.2pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>If
the request is honoured, an item will be allocated to the entity identified by <i>allocID</i>.
If the allocation state of an item is queried, it is this allocation ID that
will be returned. If the option <b>-allocID</b> is not supplied, the item will
be allocated to<span style="mso-spacerun: yes"></span><i>dummyID</i>.
Allocation ID's may be anything except the value -1, which is reserved for free
items.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:70.8pt'><b><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>-prefer
</span></b><i><span lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>preferredItem</span></i><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:106.2pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>This
option modifies the allocation strategy as follows:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:106.2pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>If
the item whose name is <i>preferredItem</i> is not allocated at the time when
the command is invoked, the request is honoured (return value is 1). If the item
was allocated at the time when the command was invoked, the request is denied
(return value is 0).<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:106.2pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:106.2pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='mso-outline-level:1'><b><span lang=EN-GB
style='font-size:12.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman";
mso-ansi-language:EN-GB'>EXAMPLES<o:p></o:p></span></b></p>
<p class=MsoPlainText><b><span lang=EN-GB style='font-size:12.0pt;mso-bidi-font-size:
14.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Two
examples are provided. The first one mimics a step by step interactive tclsh session,
where each step is explained. The second example shows the usage in a server
application that talks to a back-end application.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Example 1<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>This
example presents an interactive tclsh session which considers the case of a Car
rental's collection of cars. Ten steps explain its usage in chronological
order, from the creation of the pool, via the most important stages in the
usage of a pool, to the final destruction.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:63.0pt;margin-bottom:
0in;margin-left:81.0pt;margin-bottom:.0001pt'><span lang=EN-GB
style='mso-bidi-font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Note aside:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-top:0in;margin-right:63.0pt;margin-bottom:
0in;margin-left:81.0pt;margin-bottom:.0001pt'><span lang=EN-GB
style='mso-bidi-font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>In this example, brand names are used to label the various items.
However, a brand name could be regarded as a property of an item. Because the <i>pool</i>
command is not designed to manage properties of items, they need to be managed
separately. In the latter case the items should be labelled with more neutral
names such as: car1, car2, car3 , etc ... and a separate database or array
should hold the brand names associated with the car labels.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>1.
Load the package into an interpreter<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>%
package require pool<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;color:blue;mso-ansi-language:
EN-GB'>0.1<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>2.
Create a pool object called `CarPool' with a maximum size of 55 items (cars):<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>%
pool CarPool 55<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;color:blue;mso-ansi-language:
EN-GB'>CarPool<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>4.
Add items to the pool:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>%
CarPool add Toyota Trabant Chrysler1 Chrysler2 Volkswagen<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><span
style='mso-tab-count:1'></span><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>5.
Somebody crashed the Toyota? Remove it from the pool as follows:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>%
CarPool remove Toyota<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>6.
Acquired a new car for the pool? Add it as follows:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>%
CarPool add Nissan<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>7.
Check whether the pool was adjusted correctly:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'>% CarPool info allitems<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;color:blue;mso-ansi-language:
EN-GB'>Trabant Chrysler1 Chrysler2 Volkswagen Nissan<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Suspend
interactive session temporarily, and show the programmatic use of the <b>request</b>
subcommand:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>#
Mrs. Swift needs a car. She doesn't have a preference for a<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>#
particular car. We'll issue a request on her behalf as follows:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>if {
[CarPool request car -allocID "Mrs. Swift"] }<span
style="mso-spacerun: yes"></span>{<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;text-indent:35.4pt;mso-outline-level:
1'><span lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;
mso-ansi-language:EN-GB'># request was honoured, process the variable `car'<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;text-indent:35.4pt'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'>puts "$car has been allocated to [CarPool info allocID $car]."<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'>} else {<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;text-indent:35.4pt'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'># request was denied<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><span
style='mso-tab-count:1'></span>puts "No car available."<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>}<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;text-indent:35.4pt'><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>(note how the <b>if</b> command uses the value returned by the request
subcommand.)<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>#
Suppose mr. Wiggly has a preference for the Trabant:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>if {
[CarPool request car -allocID "Mr. Wiggly" -prefer Trabant] }<span
style="mso-spacerun: yes"></span>{<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;text-indent:35.4pt;mso-outline-level:
1'><span lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;
mso-ansi-language:EN-GB'># request was honoured, process the variable `car'<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;text-indent:35.4pt'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'>puts "$car has been allocated to [CarPool info allocID $car]."<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'>} else {<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;text-indent:35.4pt'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'># request was denied<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><span
style='mso-tab-count:1'></span>puts "The Trabant was not
available."<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>}<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Resume
interactive session:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>8.
When the car is returned then you can render it available by:<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>%
CarPool release Trabant<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>9.
When done, you delete the pool.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'>% CarPool destroy<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;color:#FF6600;mso-ansi-language:
EN-GB'>Couldn't destroy `CarPool' because some items are still allocated.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>Oops,
... forgot that Mrs. Swift still occupies a car.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>10.
We force the destruction of the pool as follows: <o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>%
CarPool destroy -force<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><b><span
lang=EN-GB style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:
EN-GB'>Example 2<o:p></o:p></span></b></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>This
example describes the case from which the author's need for pool management
originated. It is an example of a server application that receives requests
from client applications. The client requests are dispatched onto a back-end
application before being returned to the client application. In many cases
there are a few equivalent instances of back-end applications to which a client
request may be passed along. The file descriptors that identify the channels to
these back-end instances make up a pool of connections. A particular connection
may be allocated to just one client request at a time.<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'># Create
the pool of connections (pipes)<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>set
maxpipes 10<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>pool
Pipes $maxpipes<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>for
{set i 0} {$i < $maxpipes} {incr i} {<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:
11.0pt;mso-ansi-language:EN-GB'><span style='mso-tab-count:1'></span><span
style="mso-spacerun: yes"></span>set fd {open "|backendApplication" w+}<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:
11.0pt;mso-ansi-language:EN-GB'><span style='mso-tab-count:1'></span><span
style="mso-spacerun: yes"></span>Pipes add $fd<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:
11.0pt;mso-ansi-language:EN-GB'><span style='mso-tab-count:1'></span>}<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'># A
client request comes in. The request is identified as `clientX'.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'># Dispatch it onto an instance of a back-end application<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>if {
[Pipes request fd -allocID clientX] } {<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'><span style="mso-spacerun: yes"></span># a connection was allocated<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><span
style="mso-spacerun: yes"></span># communicate to the back-end application
via the variable `fd'<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><span
style="mso-spacerun: yes"></span>puts $fd "someInstruction"<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><span
style="mso-spacerun: yes"></span># ...... etc.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>}
else {<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt;mso-outline-level:1'><span
lang=EN-GB style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:
EN-GB'><span style="mso-spacerun: yes"></span># all connections are
currently occupied<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><span
style="mso-spacerun: yes"></span># store the client request in a queue for
later processing,<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'><span
style="mso-spacerun: yes"></span># or return a "Server busy" message to the
client.<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:10.5pt;mso-bidi-font-size:11.0pt;mso-ansi-language:EN-GB'>}<o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='margin-left:35.4pt'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=MsoPlainText style='mso-outline-level:1'><span lang=EN-GB
style='font-size:11.0pt;font-family:"Times New Roman";mso-ansi-language:EN-GB'>#
</span><span lang=EN-GB style='font-family:"Times New Roman";mso-ansi-language:
EN-GB'>CVS: $Id: pool.html,v 1.2 2004/01/15 06:36:14 andreas_kupries Exp $<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'># EOF pool.html<o:p></o:p></span></p>
<p class=MsoPlainText><span lang=EN-GB style='font-size:11.0pt;font-family:
"Times New Roman";mso-ansi-language:EN-GB'><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
</div>
</body>
</html>
|
