summaryrefslogtreecommitdiff
path: root/docs/ACE-subsets.html
blob: 199497afbe108d1597894bc8e5d8c24a1cb72319 (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
<!-- $Id$ -->

<html>
  <head>
    <title>ACE Subsets</title>
    <link rev=made href="mailto:ace-users@cs.wustl.edu">
  </head>

<body text = "#000000"
      link="#000fff"
      vlink="#ff0f0f"
      bgcolor="#ffffff">

<hr><p>
<font size=+2><strong>Contents</strong></font>
<ol>
  <li><a href="#Motivation">Motivation for Splitting ACE into Multiple
    Libraries</a>
  <li><a href="#Configuration Management">Configuration Management</a>
  <li><a href="#Classes">Classes in Each ACE Library Subset</a>
  <li><a href="#Status">Current ACE Subsetting Status</a>
  <li><a href="#ACE Library Size Breakdown">ACE Library Size Breakdown</a>
  <li><a href="#Building ACE Subsets">Building ACE Subsets</a>
  <li><a href="#ACE_OS Adaptation Layer">ACE_OS Adaptation Layer</a>
  <li><a href="#minimumTAO">Minimum TAO</a>
</ol><p>


<hr><p>
<h3><a name="Motivation">Motivation for Splitting ACE into Multiple
  Libraries</a></h3>

This document describes how we are splitting ACE into multiple
libraries, each of which will contain a smaller subset of the overall
ACE functionality.  The primary motivations for subsetting ACE are:

<UL>
<LI><EM>Principle of parsimony</EM> -- <EM>i.e.</EM>, developers
  should incur time/space overhead for components they use, rather
  than for all the components in the ACE framework. <P>

<LI><EM>Simplify the learning curve</EM> -- <EM>i.e.</EM>, developers
  only need to learn how to program components that they actually
  use. <P>
</UL>

The main design goals of our approach are as follows: <P>

<OL>
<LI>Support the original libACE as before.  Thus, for users who
want to use the existing ACE library as is, there will be
no changes, i.e., just link with <CODE>libACE</CODE> as usual. <P>

<LI>Allow ACE (and TAO) programmers to use smaller subsets of the
entire <CODE>libACE</CODE> library.  These subsets will include the
following libraries: <P>

<DL>
<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_OS</CODE> -- This library contains the OS adaptation
layer and its supporting classes.  All other ACE libraries will depend
on <CODE>libACE_OS</CODE> and it will depend on <EM>no</EM> other ACE
libraries. <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Utils</CODE> -- This library contains the various ACE
container classes and other miscellaneous classes, such as Singleton,
auto_ptr, timers, etc.  This library will depend only on
<CODE>libACE_OS</CODE>.<P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Logging</CODE> -- This library contains the various ACE
logging and tracing classes.  This library will depend only on
<CODE>libACE_OS</CODE>. <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Threads</CODE> -- This library contains the ACE
thread/process management and synchronization classes.  This library
will depend only on <CODE>libACE_OS</CODE>. <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Demux</CODE> -- This library contains the ACE Reactor and
Proactor classes.  This library will depend on <CODE>libACE_OS</CODE>
and <CODE>libACE_Thread</CODE>. <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Connection</CODE> -- This library contains the ACE
Connection components, i.e., Acceptor, Connector, and Svc_Handler.
This library will depend on <CODE>libACE_OS</CODE>,
<CODE>libACE_Thread</CODE>, and <CODE>libACE_Demux</CODE>.  <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Sockets</CODE> -- This library contains the ACE C++
wrappers for sockets.  This library will depend on
<CODE>libACE_OS</CODE>. <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_IPC</CODE> -- This library contains all the ACE C++
wrappers for the other types of IPC and FILE I/O other than sockets.
This library will depend on <CODE>libACE_OS</CODE> and
<CODE>libACE_Sockets</CODE>.  <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Svcconf</CODE> -- This library contains the ACE C++
wrappers for the Service Configurator.  This library will depend on
<CODE>libACE_OS</CODE>, <CODE>libACE_Demux</CODE>,
<CODE>libACE_Thread</CODE>, and <CODE>libACE_Sockets</CODE>.  <P>

<DT> <img alt="o" src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Streams</CODE> -- This library contains the ACE Streams
classes.  This library will depend on <CODE>libACE_OS</CODE>,
<CODE>libACE_Demux</CODE>, and <CODE>libACE_Thread</CODE>.  <P>

<DT> <img alt="o"
src="http://www.cs.wustl.edu/~schmidt/gifs/misc/redball.gif">
<CODE>libACE_Memory</CODE> -- This library contains the ACE C++
wrappers for shared memory and memory-mapped files.  This library will
depend on <CODE>libACE_OS</CODE>.<P>

</DL>
</OL>

In addition, we will create <CODE>libACE_TAO</CODE>, which contains
just the core set of components in ACE that are required to support
TAO.  This library is targeted at embedded systems developers who want
to minimize the footprint of ACE+TAO.  We are also planning to support
the OMG's <A
HREF="http://www.omg.org/cgi-bin/doc?orbos/98-08-04.pdf">Minimum
CORBA</A> specification as part of a separate effort.  Preliminary
results of prototypes for Minimum CORBA we've integrate to TAO have
been very promising, yielding a 40% reduction in ORB footprint. <P>

Note that the ACE library subsets described above are intended as a
guideline, <EM>not</EM> a complete specification.  The actual
partitioning of files in the final ACE library subsets may differ
somewhat to improve footprint and simplify common use-cases. <P>

<hr><p>
<h3><a name="Configuration Management">Configuration Management</a></h3>

Configuration management for the ACE library subsets described above
will be organized as follows:

<OL>
<LI>A single source tree with a single "version" for the source
    tree.<P>

<LI>Releases of libACE and its "subsets" will be atomic, <EM>i.e.</EM>,
    all or nothing.<P>
</OL>


<hr><p>
<h3><a name="Classes">Classes in Each ACE Library Subset</a></h3>

Below, we describe the classes in each ACE library subset.

<H4>libACE_OS</H4>

This library contains the OS adaptation layer and its supporting
classes.  The classes in this library should not depend on any other
ACE library subsets.  All of the other libraries will depend on this
library.  The following classes are included in this library.

<PRE><CODE>
config.h
Basic_Types
OS
Sched_Params
</code></pre>

<H4>libACE_Utils</H4>

This library contains the following ACE container classes and other
miscellaneous classes.

<PRE><CODE>
ACE 
Active_Map_Manager 
Arg_Shifter 
ARGV 
Containers 
Dirent 
Dynamic 
Filecache 
Functor 
Get_Opt 
Hash_Map_Manager 
High_Res_Timer 
Method_Request 
Object_Manager 
Profile_Timer 
Registry 
SString 
Stats 
System_Time 
Time_Request_Reply 
Timeprobe 
Timer_Hash 
Timer_Heap 
Timer_List 
Timer_Queue 
Timer_Wheel
LOGGING_FILES = 
Dump 
Log_Msg 
Log_Record 
Trace
</code></pre>

<H4>libACE_Logging</H4>

This library contains the various ACE logging and tracing classes.

<PRE><CODE>
Dump 
Log_Msg 
Log_Record 
Trace
</code></pre>

<H4>libACE_Threads</H4>

This library contains the ACE thread/process management and
synchronization classes.

<PRE><CODE>
Activation_Queue 
Process 
Process_Manager 
Synch 
Synch_Options 
Thread 
Thread_Manager 
Token
</code></pre>

<H4>libACE_Demux</H4>

This library contains the ACE Reactor and its associated classes,
including the ACE Connection components.

<PRE><CODE>
Event_Handler 
Handle_Set 
POSIX_Proactor 
Priority_Reactor 
Proactor 
Reactor 
Select_Reactor 
Select_Reactor_Base 
WFMO_Reactor
</code></pre>

<H4>libACE_Connection</H4>

This library contains the ACE Connection components, i.e., Acceptor,
Connector, and Svc_Handler.

<PRE><CODE>
Asynch_IO 
Asynch_IO_Impl 
POSIX_Asynch_IO 
Strategies
</code></pre>

<H4>libACE_Sockets</H4>

This library contains the ACE C++ wrappers for sockets.

<PRE><CODE>
IPC_SAP 
LSOCK 
LSOCK_Acceptor 
LSOCK_CODgram 
LSOCK_Connector 
LSOCK_Dgram 
LSOCK_Stream 
SOCK 
SOCK_Acceptor 
SOCK_CODgram 
SOCK_Connector 
SOCK_Dgram 
SOCK_Dgram_Bcast 
SOCK_Dgram_Mcast 
SOCK_IO 
SOCK_Stream
</code></pre>

<H4>libACE_IPC</H4>

This library contains all the ACE C++ wrappers for the other types of
IPC and FILE I/O other than sockets.  This library will depend on the
<CODE>libACE_Socket</CODE> library.

<PRE><CODE>
Addr 
DEV 
DEV_Addr 
DEV_Connector 
DEV_IO 
FIFO 
FIFO_Recv 
FIFO_Recv_Msg 
FIFO_Send 
FIFO_Send_Msg 
FILE_Addr 
FILE 
FILE_Connector 
FILE_IO 
INET_Addr 
IO_SAP 
IOStream 
Pipe 
Signal 
SPIPE_Addr 
SPIPE 
SPIPE_Acceptor 
SPIPE_Connector 
SPIPE_Stream 
SV_Message 
SV_Message_Queue 
SV_Semaphore_Complex 
SV_Semaphore_Simple 
SV_Shared_Memory 
TLI 
TLI_Acceptor 
TLI_Connector 
TLI_Stream 
TTY_IO 
UNIX_Addr 
UPIPE_Acceptor 
UPIPE_Connector 
UPIPE_Stream
</code></pre>

<H4>libACE_Svcconf</H4>

This library contains the ACE C++ wrappers for the Service
Configurator component.

<PRE><CODE>
DLL 
Parse_Node 
Service_Config 
Service_Manager 
Service_Object 
Service_Repository 
Service_Types 
Shared_Object 
Svc_Conf_l 
Svc_Conf_y
</code></pre>

<H4>libACE_Streams</H4>

This library contains the ACE Streams classes.

<PRE><CODE>
CDR_Stream 
Message_Block 
Message_Queue 
Task
</code></pre>

<H4>libACE_Memory</H4>

This library contains the ACE C++ wrappers for shared memory and
memory-mapped files.

<PRE><CODE>
Malloc 
Mem_Map 
Memory_Pool 
Obstack 
Read_Buffer 
Shared_Memory 
Shared_Memory_MM 
Shared_Memory_SV
</code></pre>

<H4>libACE_Token</H4>

This componenty contains the ACE C++ wrappers for Token classes.

<pre><code>
Local_Tokens 
Remote_Tokens 
Token_Collection 
Token_Invariants 
Token_Manager 
Token_Request_Reply
</code></pre>

<H4>libACE_Other</H4>

This component contains miscellaneous ACE C++ wrappers.

<pre><code>
CORBA_Handler 
CORBA_Ref 
Local_Name_Space 
Msg_WFMO_Reactor 
Name_Proxy 
Name_Request_Reply 
Name_Space 
Naming_Context 
Registry_Name_Space 
Remote_Name_Space 
TP_Reactor 
XtReactor
</code></pre>

<hr><p>
<h3><a name="Status">Current ACE Subsetting Status</a></h3>

The following are the remaining major subsetting issues: <P>

  <ul>
    <li>Remove remaining dependencies on higher layers from ACE_OS.
      (These can be seen by searching for ACE_HAS_MINIMAL_ACE_OS
       in OS.cpp, and by looking at the conditional #includes
       near the top of OS.cpp.)
    <ul>
      <li>ACE_Thread_Manager
      <li>ACE_Array
      <li>ACE_TSS: move all ACE_TSS support into separate .h,.i,cpp files
    </ul><p>

    <li>Log_Msg cleanup:  We have a good start on this, but it needs work
      to finish.  It might be easiest to make an abstract
      base class, then have ACE_Log_Msg derive from it.  That way
      we could remove the exposure of all the #includes in Log_Msg.cpp
      to applications that don't need it.<p>

    <li>Higher layer interdependencies:  we haven't been paying much
      attention to this.  We need to figure out what's there, and
      if/how to deal with the interdependencies.<p>

    <li>Remove use of multiple inheritance:  its only used in a few
      places, in one of the SOCK classes and service config.<p>
  </ul><P>

Please let us know if you're able to contribute to this effort.<p>


<hr><p>
<h3><a name="ACE Library Size Breakdown">ACE Library Size Breakdown</a></h3>

Here is an example size breakdown, by ACE library component.  It is
for ACE 4.6.25, statically built with these <a
href="../ACE-INSTALL.html#flags">make flags</a>:

<pre><code>
    debug=0 optimize=1 static_libs_only=1 DEFFLAGS=-DACE_USE_RCSID=0
</code></pre><p>

To build an ACE static library, if shared libraries are the default, use
<code>make static_libs_only=1</code>.<p>

<center><table cellpadding=4 border=4>
  <tr>
    <th>Platform
    <th>Component
    <th>Total
    <th>For TAO<br>subset
    <th>OS
    <th>Utils
    <th>Logging
    <th>Threads
    <th>Demux
    <th>Con-<br>nection
    <th>Sockets
    <th>IPC
    <th>Svcconf
    <th>Streams
    <th>Memory
    <th>Token
    <th>Other
  <tr>
    <th rowspan=2>Linux (RedHat 5.2)<br>egcs 1.0.3
    <th>Size, bytes
    <td align=center>527445
    <td align=center>395541
    <td align=center>10645
    <td align=center>111542
    <td align=center>13783
    <td align=center>54239
    <td align=center>33880
    <td align=center>650
    <td align=center>12565
    <td align=center>32391
    <td align=center>91919
    <td align=center>16773
    <td align=center>17154
    <td align=center>69346
    <td align=center>62558
  <tr>
    <th>Percentage of<br>total size
    <td align=center>100
    <td align=center>75
    <td align=center>2
    <td align=center>21
    <td align=center>3
    <td align=center>10
    <td align=center>6
    <td align=center>0
    <td align=center>2
    <td align=center>6
    <td align=center>17
    <td align=center>3
    <td align=center>3
    <td align=center>13
    <td align=center>12

  <tr>
    <th rowspan=2>LynxOS 3.0.0<br>g++ 2.7-97r1
    <th>Size, bytes
    <td align=center>547004
    <td align=center>429944
    <td align=center>17056
    <td align=center>100712
    <td align=center>11104
    <td align=center>44548
    <td align=center>45780
    <td align=center>52888
    <td align=center>11468
    <td align=center>29184
    <td align=center>84236
    <td align=center>15664
    <td align=center>17304
    <td align=center>62312
    <td align=center>54748
  <tr>
    <th>Percentage of<br>total size
    <td align=center>100
    <td align=center>78
    <td align=center>3
    <td align=center>18
    <td align=center>2
    <td align=center>8
    <td align=center>8
    <td align=center>10
    <td align=center>2
    <td align=center>5
    <td align=center>15
    <td align=center>3
    <td align=center>3
    <td align=center>11
    <td align=center>10

  <tr>
    <th rowspan=2>SunOS5.7<br>egcs 1.1.1
    <th>Size, bytes
    <td align=center>587059
    <td align=center>446609
    <td align=center>21651
    <td align=center>116410
    <td align=center>14005
    <td align=center>58063
    <td align=center>39620
    <td align=center>770
    <td align=center>13719
    <td align=center>40362
    <td align=center>101543
    <td align=center>19611
    <td align=center>20855
    <td align=center>75806
    <td align=center>64644
  <tr>
    <th>Percentage of<br>total size
    <td align=center>100
    <td align=center>76
    <td align=center>4
    <td align=center>20
    <td align=center>2
    <td align=center>10
    <td align=center>7
    <td align=center>0
    <td align=center>2
    <td align=center>7
    <td align=center>17
    <td align=center>3
    <td align=center>4
    <td align=center>13
    <td align=center>11

  <tr>
    <th rowspan=2>SunOS 5.5.1<br>GreenHills 1.8.9
    <th>Size, bytes
    <td align=center>677237
    <td align=center>527133
    <td align=center>15232
    <td align=center>147857
    <td align=center>18336
    <td align=center>64732
    <td align=center>49220
    <td align=center>976
    <td align=center>19084
    <td align=center>56662
    <td align=center>109686
    <td align=center>19652
    <td align=center>25696
    <td align=center>78792
    <td align=center>71312
  <tr>
    <th>Percentage of<br>total size
    <td align=center>100
    <td align=center>77
    <td align=center>2
    <td align=center>22
    <td align=center>3
    <td align=center>10
    <td align=center>7
    <td align=center>0
    <td align=center>3
    <td align=center>8
    <td align=center>16
    <td align=center>3
    <td align=center>4
    <td align=center>12
    <td align=center>11

  <tr>
    <th rowspan=2>SunOS 5.7<br>Sun C++ 4.2
    <th>Size, bytes
    <td align=center>512538
    <td align=center>344815
    <td align=center>13433
    <td align=center>63314
    <td align=center>15570
    <td align=center>61947
    <td align=center>58158
    <td align=center>864
    <td align=center>16609
    <td align=center>71484
    <td align=center>50155
    <td align=center>17747
    <td align=center>22279
    <td align=center>70771
    <td align=center>96952
  <tr>
    <th>Percentage of<br>total size
    <td align=center>100
    <td align=center>67
    <td align=center>3
    <td align=center>12
    <td align=center>3
    <td align=center>12
    <td align=center>11
    <td align=center>0
    <td align=center>3
    <td align=center>14
    <td align=center>10
    <td align=center>3
    <td align=center>4
    <td align=center>14
    <td align=center>19

  <tr>
    <th rowspan=2>VxWorks 5.3.1<br>GreenHills 1.8.8
    <th>Size, bytes
    <td align=center>669176
    <td align=center>519284
    <td align=center>26248
    <td align=center>143632
    <td align=center>16860
    <td align=center>60468
    <td align=center>49964
    <td align=center>868
    <td align=center>18660
    <td align=center>42512
    <td align=center>120384
    <td align=center>21444
    <td align=center>19252
    <td align=center>79112
    <td align=center>70780
  <tr>
    <th>Percentage of<br>total size
    <td align=center>100
    <td align=center>77
    <td align=center>4
    <td align=center>21
    <td align=center>3
    <td align=center>9
    <td align=center>7
    <td align=center>0
    <td align=center>3
    <td align=center>6
    <td align=center>18
    <td align=center>3
    <td align=center>3
    <td align=center>12
    <td align=center>11

  <tr>
    <th rowspan=2>VxWorks 5.3.1<br>g++ cygnus-<br>2.7.2-960126<br>
      (with implicit templates)
    <th>Size, bytes
    <td align=center>999608
    <td align=center>742832
    <td align=center>21232
    <td align=center>164948
    <td align=center>14752
    <td align=center>66728
    <td align=center>138008
    <td align=center>9788
    <td align=center>13116
    <td align=center>108128
    <td align=center>146528
    <td align=center>39552
    <td align=center>20052
    <td align=center>108140
    <td align=center>148636
  <tr>
    <th>Percentage of<br>total size
    <td align=center>100
    <td align=center>74
    <td align=center>2
    <td align=center>17
    <td align=center>1
    <td align=center>7
    <td align=center>14
    <td align=center>1
    <td align=center>1
    <td align=center>11
    <td align=center>15
    <td align=center>4
    <td align=center>2
    <td align=center>11
    <td align=center>15
</table></center><p>


<hr><p>
<h3><a name="Building ACE Subsets">Building ACE Subsets</a></h3>

By default, the ACE library contains all of the components that ACE
currently supports.  To reduce build time and library size, you can
exclude unused components.  To do that, define an
<code>ACE_COMPONENTS</code> variable using one of these approaches:<p>

<ol>
  <li>In your <code>$(ACE_ROOT)/include/makeinclude/platform_macros.GNU</code>
    file, <em>e.g.</em>, add:
    <pre><code>ACE_COMPONENTS = OS</code></pre>or<p>

  <li>On the make command line, <em>e.g.</em>,
    <pre><code>make ACE_COMPONENTS=OS</code></pre>or<p>

  <li>Set (and export) the <code>ACE_COMPONENTS</code> environment variable
    to contain the components that you want to build.<p>
</ol><p>

Please see <code><a href="../ace/Makefile">../ace/Makefile</a></code>
for the default contents of <code>ACE_COMPONENTS</code>.<p>

A special value of <code>ACE_COMPONENTS</code> can be used to
build an ACE library that supports
<a href="http://www.cs.wustl.edu/~schmidt/TAO.html">TAO</a>.  The
special value is <code>FOR_TAO</code>.  So, for example, you can
add this to your
<code>$(ACE_ROOT)/include/makeinclude/platform_macros.GNU</code>
to restrict ACE support to just that which is needed for TAO:
<pre><code>
ACE_COMPONENTS = FOR_TAO
</code></pre><p>

Please note the current limitations:<p>

<ol>
  <li>We currently don't check for interdependencies between components.
    For example, if you build any component beside <code>OS</code>, you
    must explicitly include <code>OS</code> in your
    <code>ACE_COMPONENTS</code>.<p>

  <li>We currently don't check this macro in other ACE or TAO Makefiles, or
    in their tests. We'll add those checks as time allows.</li>
</ol>


<hr><p>
<h3><a name="ACE_OS Adaptation Layer">ACE_OS Adaptation Layer</a></h3>

The lowest-level component, <code>OS</code>, is also called the
<em>ACE_OS adaption layer</em>.  It provides the ACE interface to
the underlying operating system, but little else.  It can be used
standalone.<p>

To create the ACE_OS adaptation layer, build your <code>libACE</code>
with <code>ACE_COMPONENTS</code> set to <code>OS</code>.  In addition,
add <code>#include "ace/config-minimal.h"</code> to your
<code>ACE_wrappers/ace/config.h</code> file.<p>

When using the ACE_OS adaptation layer, you'll be limited to the
the <code>ACE_OS</code> member functions, ACE's
<a href="../ace/Basic_Types.h">Basic_Types</a> and
<a href="../ace/Sched_Params.h">Sched_Params</a>, and macros defined in
<a href="../ace/OS.h"><code>ace/OS.h</code></a>.  See ACE's
<a href="../tests/Basic_Types_Test.cpp">Basic_Types_Test.cpp</a>
for an example of usage.<p>

<HR><P>

<a name="minimumTAO"><!--
  #include virtual="/~schmidt/ACE_wrappers/TAO/docs/minimumTAO.html" -->
</a>

Back to the <A HREF="http://www.cs.wustl.edu/~schmidt/ACE.html">ACE</A>
home page.

<!--#include virtual="/~schmidt/cgi-sig.html" -->
</BODY>
</HTML>