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
|
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.3.8: http://docutils.sourceforge.net/" />
<title>The Boost Parameter Library Reference Documentation</title>
<link rel="stylesheet" href="rst.css" type="text/css" />
</head>
<body>
<div class="document" id="the-boost-parameter-library-reference-documentation">
<h1 class="title">The Boost Parameter Library Reference Documentation</h1>
<p><a class="reference" href="../../../../index.htm"><img alt="Boost" src="../../../../boost.png" /></a></p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Authors:</th><td class="field-body">David Abrahams, Daniel Wallin</td>
</tr>
<tr class="field"><th class="field-name">Contact:</th><td class="field-body"><a class="reference" href="mailto:dave@boost-consulting.com">dave@boost-consulting.com</a>, <a class="reference" href="mailto:dalwan01@student.umu.se">dalwan01@student.umu.se</a></td>
</tr>
<tr class="field"><th class="field-name">organization:</th><td class="field-body"><a class="reference" href="http://www.boost-consulting.com">Boost Consulting</a></td>
</tr>
<tr class="field"><th class="field-name">date:</th><td class="field-body">$Date: 2005/07/17 19:53:01 $</td>
</tr>
<tr class="field"><th class="field-name">copyright:</th><td class="field-body">Copyright David Abrahams, Daniel Wallin
2005. Distributed under the Boost Software License,
Version 1.0. (See accompanying file LICENSE_1_0.txt
or copy at <a class="reference" href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</td>
</tr>
</tbody>
</table>
<hr class="docutils" />
<div class="contents topic" id="contents">
<p class="topic-title first"><a name="contents">Contents</a></p>
<ul class="auto-toc simple">
<li><a class="reference" href="#preliminaries" id="id23" name="id23">1 Preliminaries</a><ul class="auto-toc">
<li><a class="reference" href="#namespaces" id="id24" name="id24">1.1 Namespaces</a></li>
<li><a class="reference" href="#exceptions" id="id25" name="id25">1.2 Exceptions</a></li>
<li><a class="reference" href="#thread-safety" id="id26" name="id26">1.3 Thread Safety</a></li>
<li><a class="reference" href="#typography" id="id27" name="id27">1.4 Typography</a></li>
</ul>
</li>
<li><a class="reference" href="#terminology" id="id28" name="id28">2 Terminology</a></li>
<li><a class="reference" href="#concepts" id="id29" name="id29">3 Concepts</a><ul class="auto-toc">
<li><a class="reference" href="#argumentpack" id="id30" name="id30">3.1 <span class="concept">ArgumentPack</span></a></li>
<li><a class="reference" href="#id4" id="id31" name="id31">3.2 <span class="concept">ParameterSpec</span></a></li>
</ul>
</li>
<li><a class="reference" href="#class-templates" id="id32" name="id32">4 Class Templates</a><ul class="auto-toc">
<li><a class="reference" href="#id6" id="id33" name="id33">4.1 <tt class="docutils literal"><span class="pre">keyword</span></tt></a></li>
<li><a class="reference" href="#parameters" id="id34" name="id34">4.2 <tt class="docutils literal"><span class="pre">parameters</span></tt></a></li>
<li><a class="reference" href="#optional-required" id="id35" name="id35">4.3 <tt class="docutils literal"><span class="pre">optional</span></tt>, <tt class="docutils literal"><span class="pre">required</span></tt></a></li>
</ul>
</li>
<li><a class="reference" href="#metafunctions" id="id36" name="id36">5 Metafunctions</a><ul class="auto-toc">
<li><a class="reference" href="#binding" id="id37" name="id37">5.1 <tt class="docutils literal"><span class="pre">binding</span></tt></a></li>
<li><a class="reference" href="#lazy-binding" id="id38" name="id38">5.2 <tt class="docutils literal"><span class="pre">lazy_binding</span></tt></a></li>
</ul>
</li>
<li><a class="reference" href="#code-generation-macros" id="id39" name="id39">6 Code Generation Macros</a><ul class="auto-toc">
<li><a class="reference" href="#boost-parameter-fun-r-n-l-h-p" id="id40" name="id40">6.1 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_FUN(r,n,l,h,p)</span></tt></a></li>
<li><a class="reference" href="#boost-parameter-keyword-n-k" id="id41" name="id41">6.2 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_KEYWORD(n,k)</span></tt></a></li>
<li><a class="reference" href="#boost-parameter-match-p-a-x" id="id42" name="id42">6.3 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_MATCH(p,a,x)</span></tt></a></li>
</ul>
</li>
<li><a class="reference" href="#configuration-macros" id="id43" name="id43">7 Configuration Macros</a><ul class="auto-toc">
<li><a class="reference" href="#boost-parameter-max-arity" id="id44" name="id44">7.1 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_MAX_ARITY</span></tt></a></li>
</ul>
</li>
<li><a class="reference" href="#tutorial" id="id45" name="id45">8 Tutorial</a></li>
</ul>
</div>
<hr class="docutils" />
<div class="section" id="preliminaries">
<h1><a class="toc-backref" href="#id23" name="preliminaries">1 Preliminaries</a></h1>
<p>This section covers some basic information you'll need to know in
order to understand this reference</p>
<div class="section" id="namespaces">
<h2><a class="toc-backref" href="#id24" name="namespaces">1.1 Namespaces</a></h2>
<p>In this document, all unqualified identifiers should be assumed to
be defined in namespace <tt class="docutils literal"><span class="pre">boost::parameter</span></tt> unless otherwise
specified.</p>
</div>
<div class="section" id="exceptions">
<h2><a class="toc-backref" href="#id25" name="exceptions">1.2 Exceptions</a></h2>
<p>No operation described in this document
throws an exception unless otherwise specified.</p>
</div>
<div class="section" id="thread-safety">
<h2><a class="toc-backref" href="#id26" name="thread-safety">1.3 Thread Safety</a></h2>
<p>All components of this library can be used safely from multiple
threads without synchronization.<a class="footnote-reference" href="#thread" id="id2" name="id2"><sup>1</sup></a></p>
</div>
<div class="section" id="typography">
<h2><a class="toc-backref" href="#id27" name="typography">1.4 Typography</a></h2>
<p>Names written in <span class="concept">sans serif type</span> represent <a class="reference" href="../../../../more/generic_programming.html#concept">concepts</a>.</p>
<p>In code blocks, <em>italic type</em> represents unspecified text that
satisfies the requirements given in the detailed description that
follows the code block.</p>
<p>In a specification of the tokens generated by a macro, <strong>bold
type</strong> is used to highlight the position of the expanded macro
argument in the result.</p>
<p>The special character β represents the value of <a class="reference" href="#boost-parameter-max-arity"><tt class="docutils literal"><span class="pre">BOOST_PARAMETER_MAX_ARITY</span></tt></a>.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="terminology">
<h1><a class="toc-backref" href="#id28" name="terminology">2 Terminology</a></h1>
<span class="target" id="kw"></span><dl class="docutils">
<dt>keyword</dt>
<dd>The name of a function parameter.</dd>
</dl>
<span class="target" id="keyword-tag-type"></span><dl class="docutils">
<dt>keyword tag type</dt>
<dd>A type used to uniquely identify a function parameter. Typically
its name will be the same as that of the parameter.</dd>
</dl>
<span class="target" id="positional"></span><dl class="docutils">
<dt>positional argument</dt>
<dd>An argument passed with no explicit keyword. Its parameter is
determined in the usual C++ way: by position with respect to a
parameter list.</dd>
</dl>
<span class="target" id="tag-type"></span><dl class="docutils">
<dt>tag type</dt>
<dd>Shorthand for “<a class="reference" href="#keyword-tag-type">keyword tag type</a>.”</dd>
</dl>
<span class="target" id="keyword-object"></span><dl class="docutils">
<dt>keyword object</dt>
<dd>An instance of <a class="reference" href="#keyword"><tt class="docutils literal"><span class="pre">keyword</span></tt></a> <tt class="docutils literal"><span class="pre"><T></span></tt> for some <a class="reference" href="#tag-type">tag type</a> <tt class="docutils literal"><span class="pre">T</span></tt>.</dd>
</dl>
<span class="target" id="tagged-reference"></span><dl class="docutils">
<dt>tagged reference</dt>
<dd><p class="first">An object whose type is associated with a <a class="reference" href="#keyword-tag-type">keyword tag type</a> (the
object's <em>keyword</em>), and that holds a reference (to the object's
<em>value</em>).</p>
<p class="last">As a shorthand, a “tagged reference to <tt class="docutils literal"><span class="pre">x</span></tt>” means a tagged
reference whose <em>value</em> is <tt class="docutils literal"><span class="pre">x</span></tt>.</p>
</dd>
</dl>
<span class="target" id="tagged-default"></span><dl class="docutils">
<dt>tagged default </dt>
<dd>A <a class="reference" href="#tagged-reference">tagged reference</a> whose <em>value</em> represents the value of a
default argument.</dd>
</dl>
<span class="target" id="tagged-lazy-default"></span><dl class="docutils">
<dt>tagged lazy default </dt>
<dd>A <a class="reference" href="#tagged-reference">tagged reference</a> whose <em>value</em>, when invoked with no
arguments, computes a default argument value.</dd>
</dl>
<span class="target" id="intended-argument-type"></span><dl class="docutils">
<dt>intended argument type</dt>
<dd>The <em>intended argument type</em> of a single-element <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> is the
type of its element's <em>value</em>. The intended argument type of any other
type <tt class="docutils literal"><span class="pre">X</span></tt> is <tt class="docutils literal"><span class="pre">X</span></tt> itself.</dd>
</dl>
<div class="note">
<p class="first admonition-title">Note</p>
<p class="last">In this reference, we will use concept names (and other names)
to describe both types and objects, depending on context. So
for example, “an <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a>” can refer to a type that
models <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> <em>or</em> an object of such a type.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="concepts">
<h1><a class="toc-backref" href="#id29" name="concepts">3 Concepts</a></h1>
<p>This section describes the generic type <a class="reference" href="../../../../more/generic_programming.html#concept">concepts</a> used by the Parameter library.</p>
<div class="section" id="argumentpack">
<h2><a class="toc-backref" href="#id30" name="argumentpack">3.1 <span class="concept">ArgumentPack</span></a></h2>
<p>An <span class="concept">ArgumentPack</span> is a collection of <a class="reference" href="#tagged-reference">tagged reference</a>s to the
actual arguments passed to a function.</p>
<div class="section" id="requirements">
<h3><a name="requirements">Requirements</a></h3>
<p>In the table below,</p>
<ul class="simple">
<li><tt class="docutils literal"><span class="pre">A</span></tt> is a model of <span class="concept">ArgumentPack</span></li>
<li><tt class="docutils literal"><span class="pre">x</span></tt> is an instance of <tt class="docutils literal"><span class="pre">A</span></tt></li>
<li><tt class="docutils literal"><span class="pre">u</span></tt> is a <a class="reference" href="#keyword-object">keyword object</a> of type <tt class="docutils literal"><span class="pre">K</span></tt></li>
<li><tt class="docutils literal"><span class="pre">v</span></tt> is a <a class="reference" href="#tagged-default">tagged default</a> with <a class="reference" href="#tag-type">tag type</a> <tt class="docutils literal"><span class="pre">L</span></tt> and <em>value</em> of type <tt class="docutils literal"><span class="pre">D</span></tt></li>
<li><tt class="docutils literal"><span class="pre">w</span></tt> is a <a class="reference" href="#tagged-lazy-default">tagged lazy default</a> with <a class="reference" href="#tag-type">tag type</a> <tt class="docutils literal"><span class="pre">M</span></tt> and <em>value</em> of type <tt class="docutils literal"><span class="pre">E</span> <span class="pre">const</span></tt></li>
<li><tt class="docutils literal"><span class="pre">z</span></tt> is an <span class="concept">ArgumentPack</span> containing a single element (as created by <a class="reference" href="#keyword"><tt class="docutils literal"><span class="pre">keyword</span></tt></a><tt class="docutils literal"><span class="pre"><…>::operator=</span></tt>)</li>
</ul>
<p>Any exceptions are thrown from the invocation of <tt class="docutils literal"><span class="pre">w</span></tt>'s <em>value</em>
will be propagated to the caller.</p>
<table border="1" class="docutils">
<caption><span class="concept">ArgumentPack</span> requirements</caption>
<colgroup>
<col width="11%" />
<col width="31%" />
<col width="19%" />
<col width="40%" />
</colgroup>
<thead valign="bottom">
<tr><th>Expression</th>
<th>Type</th>
<th>Requirements</th>
<th>Semantics/Notes</th>
</tr>
</thead>
<tbody valign="top">
<tr><td><tt class="docutils literal"><span class="pre">x[u]</span></tt></td>
<td><tt class="docutils literal"><span class="pre">binding<A,K>::type</span></tt></td>
<td><tt class="docutils literal"><span class="pre">x</span></tt> contains an
element <em>b</em> whose
<a class="reference" href="#kw">keyword</a> is <tt class="docutils literal"><span class="pre">K</span></tt></td>
<td>Returns <em>b</em>'s <em>value</em> (by
reference).</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">x[u]</span></tt></td>
<td><tt class="docutils literal"><span class="pre">binding<A,L,D>::type</span></tt></td>
<td><em>none</em></td>
<td>If <tt class="docutils literal"><span class="pre">x</span></tt> contains an element <em>b</em> whose
<a class="reference" href="#kw">keyword</a> is the same as <tt class="docutils literal"><span class="pre">u</span></tt>'s,
returns <em>b</em>'s <em>value</em> (by
reference). Otherwise, returns <tt class="docutils literal"><span class="pre">u</span></tt>'s <em>value</em>.</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">x[w]</span></tt></td>
<td><tt class="docutils literal"><span class="pre">lazy_binding<A,M,E>::type</span></tt></td>
<td><em>none</em></td>
<td>If <tt class="docutils literal"><span class="pre">x</span></tt> contains an element <em>b</em> whose
<a class="reference" href="#kw">keyword</a> is the same as <tt class="docutils literal"><span class="pre">w</span></tt>'s,
returns <em>b</em>'s <em>value</em> (by
reference). Otherwise, invokes <tt class="docutils literal"><span class="pre">w</span></tt>'s <em>value</em> and returns the result.</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">x,</span> <span class="pre">z</span></tt></td>
<td>Model of <span class="concept">ArgumentPack</span></td>
<td><em>none</em></td>
<td>Returns an <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> containing
all the elements of both <tt class="docutils literal"><span class="pre">x</span></tt> and
<tt class="docutils literal"><span class="pre">z</span></tt>.</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="section" id="id4">
<h2><a class="toc-backref" href="#id31" name="id4">3.2 <span class="target" id="parameterspec"></span><span class="concept">ParameterSpec</span></a></h2>
<p>A <span class="concept">ParameterSpec</span> describes the type requirements for arguments
corresponding to a given <a class="reference" href="#kw">keyword</a> and indicates whether the argument
is optional or required. The table below details the allowed forms
and describes their condition for satisfaction by an actual
argument type. In each row,</p>
<span class="target" id="conditions"></span><ul class="simple">
<li><tt class="docutils literal"><span class="pre">K</span></tt> is the <span class="concept">ParameterSpec</span>'s <a class="reference" href="#keyword-tag-type">keyword tag type</a></li>
<li><tt class="docutils literal"><span class="pre">A</span></tt> is an <a class="reference" href="#intended-argument-type">intended argument type</a> associated with <tt class="docutils literal"><span class="pre">K</span></tt>, if any</li>
<li><tt class="docutils literal"><span class="pre">F</span></tt> is a unary <a class="reference" href="../../../mpl/doc/refmanual/lambda-expression.html">MPL lambda expression</a></li>
</ul>
<table border="1" class="docutils">
<caption><span class="concept">ParameterSpec</span> allowed forms and conditions of satisfaction</caption>
<colgroup>
<col width="32%" />
<col width="21%" />
<col width="47%" />
</colgroup>
<thead valign="bottom">
<tr><th>Type</th>
<th><tt class="docutils literal"><span class="pre">A</span></tt> required</th>
<th>Condition <tt class="docutils literal"><span class="pre">A</span></tt> must satisfy</th>
</tr>
</thead>
<tbody valign="top">
<tr><td><a class="reference" href="#keyword"><tt class="docutils literal"><span class="pre">keyword</span></tt></a><tt class="docutils literal"><span class="pre"><K></span></tt></td>
<td>no</td>
<td><em>n/a</em></td>
</tr>
<tr><td><a class="reference" href="#optional"><tt class="docutils literal"><span class="pre">optional</span></tt></a><tt class="docutils literal"><span class="pre"><K,F></span></tt></td>
<td>no</td>
<td><tt class="docutils literal"><span class="pre">mpl::apply<F,A>::type::value</span></tt>
is <tt class="docutils literal"><span class="pre">true</span></tt>.</td>
</tr>
<tr><td><a class="reference" href="#required"><tt class="docutils literal"><span class="pre">required</span></tt></a><tt class="docutils literal"><span class="pre"><K,F></span></tt></td>
<td>yes</td>
<td><tt class="docutils literal"><span class="pre">mpl::apply<F,A>::type::value</span></tt>
is <tt class="docutils literal"><span class="pre">true</span></tt>.</td>
</tr>
</tbody>
</table>
<p>The information in a <span class="concept">ParameterSpec</span> is used to <a class="reference" href="index.html#controlling-overload-resolution">limit</a> the
arguments that will be matched by <a class="reference" href="index.html#forwarding-functions">forwarding functions</a>.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="class-templates">
<h1><a class="toc-backref" href="#id32" name="class-templates">4 Class Templates</a></h1>
<div class="section" id="id6">
<h2><a class="toc-backref" href="#id33" name="id6">4.1 <span class="target" id="keyword"></span><tt class="docutils literal"><span class="pre">keyword</span></tt></a></h2>
<p>The type of every <a class="reference" href="#keyword-object">keyword object</a> is a specialization of <tt class="docutils literal"><span class="pre">keyword</span></tt>.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/keyword.hpp">boost/parameter/keyword.hpp</a></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template <class Tag>
struct keyword
{
template <class T> <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> <a class="reference" href="#operator">operator=</a>(T& value) const;
template <class T> <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> <a class="reference" href="#operator">operator=</a>(T const& value) const;
template <class T> <em>tagged default</em> <a class="reference" href="#id8">operator|</a>(T& x) const;
template <class T> <em>tagged default</em> <a class="reference" href="#id8">operator|</a>(T const& x) const;
template <class F> <em>tagged lazy default</em> <a class="reference" href="#id9">operator||</a>(F const&) const;
static keyword<Tag>& <a class="reference" href="#get">get</a>();
};
</pre>
<span class="target" id="operator"></span><dl class="docutils">
<dt><tt class="docutils literal"><span class="pre">operator=</span></tt></dt>
<dd><pre class="first literal-block">
template <class T> <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> operator=(T& value) const;
template <class T> <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> operator=(T const& value) const;
</pre>
<table class="last docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body">nothing</td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">an <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> containing a single <a class="reference" href="#tagged-reference">tagged reference</a> to
<tt class="docutils literal"><span class="pre">value</span></tt> with <a class="reference" href="#kw">keyword</a> <tt class="docutils literal"><span class="pre">Tag</span></tt></td>
</tr>
</tbody>
</table>
</dd>
</dl>
<span class="target" id="id8"></span><dl class="docutils">
<dt><tt class="docutils literal"><span class="pre">operator|</span></tt></dt>
<dd><pre class="first literal-block">
template <class T> <em>tagged default</em> operator|(T& x) const;
template <class T> <em>tagged default</em> operator|(T const& x) const;
</pre>
<table class="last docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">a <a class="reference" href="#tagged-default">tagged default</a> with <em>value</em> <tt class="docutils literal"><span class="pre">x</span></tt> and <a class="reference" href="#kw">keyword</a> <tt class="docutils literal"><span class="pre">Tag</span></tt>.</td>
</tr>
</tbody>
</table>
</dd>
</dl>
<span class="target" id="id9"></span><dl class="docutils">
<dt><tt class="docutils literal"><span class="pre">operator||</span></tt></dt>
<dd><pre class="first literal-block">
template <class F> <em>tagged lazy default</em> operator||(F const& g) const;
</pre>
<table class="last docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="docutils literal"><span class="pre">g()</span></tt> is valid, with type <tt class="docutils literal"><span class="pre">boost::</span></tt><a class="reference" href="../../../utility/utility.htm#result_of"><tt class="docutils literal"><span class="pre">result_of</span></tt></a><tt class="docutils literal"><span class="pre"><F()>::type</span></tt>.<a class="footnote-reference" href="#no-result-of" id="id10" name="id10"><sup>2</sup></a></td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">a <a class="reference" href="#tagged-lazy-default">tagged lazy default</a> with <em>value</em> <tt class="docutils literal"><span class="pre">g</span></tt> and <a class="reference" href="#kw">keyword</a> <tt class="docutils literal"><span class="pre">Tag</span></tt>.</td>
</tr>
</tbody>
</table>
</dd>
</dl>
<span class="target" id="get"></span><dl class="docutils">
<dt><tt class="docutils literal"><span class="pre">get</span></tt></dt>
<dd><pre class="first literal-block">
static keyword<Tag>& get();
</pre>
<table class="last docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">a “singleton instance”: the same object will be
returned on each invocation of <tt class="docutils literal"><span class="pre">get()</span></tt>.</td>
</tr>
<tr class="field"><th class="field-name">Thread Safety:</th><td class="field-body"><tt class="docutils literal"><span class="pre">get()</span></tt> can be called from multiple threads
simultaneously.</td>
</tr>
</tbody>
</table>
</dd>
</dl>
</div>
<div class="section" id="parameters">
<h2><a class="toc-backref" href="#id34" name="parameters">4.2 <tt class="docutils literal"><span class="pre">parameters</span></tt></a></h2>
<p>Provides an interface for assembling the actual arguments to a
<cite>forwarding function</cite> into an <span class="concept">ArgumentPack</span>, in which any
<a class="reference" href="#positional">positional</a> arguments will be tagged according to the
corresponding template argument to <tt class="docutils literal"><span class="pre">parameters</span></tt>.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/parameters.hpp">boost/parameter/parameters.hpp</a></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template <class P0 = <em>unspecified</em>, class P1 = <em>unspecified</em>, …class Pβ = <em>unspecified</em>>
struct parameters
{
template <class A0, class A1 = <em>unspecified</em>, …class Aβ = <em>unspecified</em>>
struct <a class="reference" href="#match">match</a>
{
typedef … type;
};
template <class A0>
<a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> <a class="reference" href="#id12">operator()</a>(A0 const& a0) const;
template <class A0, class A1>
<a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> <a class="reference" href="#id12">operator()</a>(A0 const& a0, A1 const& a1) const; <span class="vellipsis">
.
.
.
</span>
template <class A0, class A1, …class Aβ>
<a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> <a class="reference" href="#id12">operator()</a>(A0 const& a0, A1 const& a1, …Aβ const& aβ) const;
};
</pre>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="docutils literal"><span class="pre">P0</span></tt>, <tt class="docutils literal"><span class="pre">P1</span></tt>, … <tt class="docutils literal"><span class="pre">P</span></tt>β are models of <a class="reference" href="#parameterspec"><span class="concept">ParameterSpec</span></a>.</td>
</tr>
</tbody>
</table>
<div class="note">
<p class="first admonition-title">Note</p>
<p>In this section, <tt class="docutils literal"><span class="pre">R</span></tt><em>i</em> and <tt class="docutils literal"><span class="pre">K</span></tt><em>i</em> are defined as
follows, for any argument type <tt class="docutils literal"><span class="pre">A</span></tt><em>i</em>:</p>
<blockquote class="last">
<div class="line-block">
<div class="line"><tt class="docutils literal"><span class="pre">R</span></tt><em>i</em> is <tt class="docutils literal"><span class="pre">A</span></tt><em>i</em>'s <a class="reference" href="#intended-argument-type">intended argument type</a></div>
<div class="line"><br /></div>
<div class="line-block">
<div class="line">if <tt class="docutils literal"><span class="pre">A</span></tt><em>i</em> is a result type of <tt class="docutils literal"><span class="pre">keyword<T>::</span></tt><a class="reference" href="#operator"><tt class="docutils literal"><span class="pre">operator=</span></tt></a></div>
<div class="line">then </div>
<div class="line-block">
<div class="line"><tt class="docutils literal"><span class="pre">K</span></tt><em>i</em> is <tt class="docutils literal"><span class="pre">T</span></tt></div>
</div>
<div class="line">else </div>
<div class="line-block">
<div class="line"><tt class="docutils literal"><span class="pre">K</span></tt><em>i</em> is <tt class="docutils literal"><span class="pre">P</span></tt><em>i</em>'s <a class="reference" href="#keyword-tag-type">keyword tag type</a>.</div>
</div>
</div>
</div>
</blockquote>
</div>
<span class="target" id="match"></span><dl class="docutils">
<dt><tt class="docutils literal"><span class="pre">match</span></tt></dt>
<dd><p class="first">A <a class="reference" href="../../../mpl/doc/refmanual/metafunction.html"><span class="concept">Metafunction</span></a> used to remove a <a class="reference" href="index.html#forwarding-functions">forwarding function</a> from overload resolution.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">if <tt class="docutils literal"><span class="pre">P0</span></tt>, <tt class="docutils literal"><span class="pre">P1</span></tt>, …<tt class="docutils literal"><span class="pre">P</span></tt>β are <em>satisfied</em> (see
below), then <tt class="docutils literal"><span class="pre">parameters<P0,P1,…Pβ></span></tt>. Otherwise,
<tt class="docutils literal"><span class="pre">match<A0,A1,…Aβ>::type</span></tt> is not defined.</td>
</tr>
</tbody>
</table>
<p><tt class="docutils literal"><span class="pre">P0</span></tt>, <tt class="docutils literal"><span class="pre">P1</span></tt>, …<tt class="docutils literal"><span class="pre">P</span></tt>β are <strong>satisfied</strong> if, for
every <em>j</em> in 0…β, either:</p>
<ul class="last simple">
<li><tt class="docutils literal"><span class="pre">P</span></tt><em>j</em> is the <em>unspecified</em> default</li>
<li><strong>or</strong>, <tt class="docutils literal"><span class="pre">P</span></tt><em>j</em> is a specialization of <a class="reference" href="#keyword"><tt class="docutils literal"><span class="pre">keyword</span></tt></a>,</li>
<li><strong>or</strong>, <tt class="docutils literal"><span class="pre">P</span></tt><em>j</em> is <a class="reference" href="#optional"><tt class="docutils literal"><span class="pre">optional</span></tt></a> <tt class="docutils literal"><span class="pre"><X,F></span></tt> and either<ul>
<li><tt class="docutils literal"><span class="pre">X</span></tt> is not <tt class="docutils literal"><span class="pre">K</span></tt><em>i</em> for any <em>i</em>,</li>
<li><strong>or</strong> <tt class="docutils literal"><span class="pre">X</span></tt> is some <tt class="docutils literal"><span class="pre">K</span></tt><em>i</em> and <tt class="docutils literal"><span class="pre">mpl::apply<F,R</span></tt><em>i</em><tt class="docutils literal"><span class="pre">>::type::value</span></tt> is <tt class="docutils literal"><span class="pre">true</span></tt></li>
</ul>
</li>
<li><strong>or</strong>, <tt class="docutils literal"><span class="pre">P</span></tt><em>j</em> is <a class="reference" href="#required"><tt class="docutils literal"><span class="pre">required</span></tt></a> <tt class="docutils literal"><span class="pre"><X,F></span></tt>, and<ul>
<li><tt class="docutils literal"><span class="pre">X</span></tt> is some <tt class="docutils literal"><span class="pre">K</span></tt><em>i</em>, <strong>and</strong></li>
<li><tt class="docutils literal"><span class="pre">mpl::apply<F,R</span></tt><em>i</em><tt class="docutils literal"><span class="pre">>::type::value</span></tt> is <tt class="docutils literal"><span class="pre">true</span></tt></li>
</ul>
</li>
</ul>
</dd>
</dl>
<span class="target" id="id12"></span><dl class="docutils">
<dt><tt class="docutils literal"><span class="pre">operator()</span></tt></dt>
<dd><pre class="first literal-block">
template <class A0> <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> operator()(A0 const& a0) const; <span class="vellipsis">
.
.
.
</span>
template <class A0, …class Aβ> <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> <a class="reference" href="#id12">operator()</a>(A0 const& a0, …Aβ const& aβ) const;
</pre>
<table class="last docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">An <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a> containing, for each <tt class="docutils literal"><span class="pre">a</span></tt><em>i</em>,</p>
<ul class="last simple">
<li>if <tt class="docutils literal"><span class="pre">a</span></tt><em>i</em>, is a single-element <span class="concept">ArgumentPack</span>, its element</li>
<li>Otherwise, a <a class="reference" href="#tagged-reference">tagged reference</a> with <a class="reference" href="#kw">keyword</a> <tt class="docutils literal"><span class="pre">K</span></tt><em>i</em> and <em>value</em> <tt class="docutils literal"><span class="pre">a</span></tt><em>i</em></li>
</ul>
</td>
</tr>
</tbody>
</table>
</dd>
</dl>
</div>
<div class="section" id="optional-required">
<h2><a class="toc-backref" href="#id35" name="optional-required">4.3 <span class="target" id="required"></span><span class="target" id="optional"></span><tt class="docutils literal"><span class="pre">optional</span></tt>, <tt class="docutils literal"><span class="pre">required</span></tt></a></h2>
<p>These templates describe the requirements on a function parameter.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/parameters.hpp">boost/parameter/parameters.hpp</a></td>
</tr>
</tbody>
</table>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name" colspan="2">Specializations model:</th></tr>
<tr><td> </td><td class="field-body"><a class="reference" href="#parameterspec"><span class="concept">ParameterSpec</span></a></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template <class Tag, class Predicate = <em>unspecified</em>>
struct optional;
template <class Tag, class Predicate = <em>unspecified</em>>
struct required;
</pre>
<p>The default value of <tt class="docutils literal"><span class="pre">Predicate</span></tt> is an unspecified <a class="reference" href="../../../mpl/doc/refmanual/metafunction.html"><span class="concept">Metafunction</span></a> that returns
<tt class="docutils literal"><span class="pre">mpl::true_</span></tt> for any argument.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="metafunctions">
<h1><a class="toc-backref" href="#id36" name="metafunctions">5 Metafunctions</a></h1>
<p>A <a class="reference" href="../../../mpl/doc/refmanual/metafunction.html"><span class="concept">Metafunction</span></a> is conceptually a function that operates on, and
returns, C++ types.</p>
<div class="section" id="binding">
<h2><a class="toc-backref" href="#id37" name="binding">5.1 <tt class="docutils literal"><span class="pre">binding</span></tt></a></h2>
<p>Returns the result type of indexing an argument pack with a
<a class="reference" href="#keyword-tag-type">keyword tag type</a> or with a <a class="reference" href="#tagged-default">tagged default</a>.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined n:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/binding.hpp">boost/parameter/binding.hpp</a></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template <class A, class K, class D = void>
struct binding
{
typedef … type;
};
</pre>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="docutils literal"><span class="pre">A</span></tt> is a model of <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a>.</td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">the reference type of the <a class="reference" href="#tagged-reference">tagged reference</a> in <tt class="docutils literal"><span class="pre">A</span></tt>
having <a class="reference" href="#keyword-tag-type">keyword tag type</a> <tt class="docutils literal"><span class="pre">K</span></tt>, if any. If no such <a class="reference" href="#tagged-reference">tagged reference</a> exists, returns <tt class="docutils literal"><span class="pre">D</span></tt>.</td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="lazy-binding">
<h2><a class="toc-backref" href="#id38" name="lazy-binding">5.2 <tt class="docutils literal"><span class="pre">lazy_binding</span></tt></a></h2>
<p>Returns the result type of indexing an argument pack with a <a class="reference" href="#tagged-lazy-default">tagged lazy default</a>.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/binding.hpp">boost/parameter/binding.hpp</a></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
template <class A, class K, class F>
struct lazy_binding
{
typedef … type;
};
</pre>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="docutils literal"><span class="pre">A</span></tt> is a model of <a class="reference" href="#argumentpack"><span class="concept">ArgumentPack</span></a>.</td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">the reference type of the <a class="reference" href="#tagged-reference">tagged reference</a> in <tt class="docutils literal"><span class="pre">A</span></tt>
having <a class="reference" href="#keyword-tag-type">keyword tag type</a> <tt class="docutils literal"><span class="pre">K</span></tt>, if any. If no such <a class="reference" href="#tagged-reference">tagged reference</a> exists, returns <tt class="docutils literal"><span class="pre">boost::</span></tt><a class="reference" href="../../../utility/utility.htm#result_of"><tt class="docutils literal"><span class="pre">result_of</span></tt></a><tt class="docutils literal"><span class="pre"><F()>::type</span></tt>.<a class="footnote-reference" href="#no-result-of" id="id16" name="id16"><sup>2</sup></a></td>
</tr>
</tbody>
</table>
</div>
</div>
<hr class="docutils" />
<div class="section" id="code-generation-macros">
<h1><a class="toc-backref" href="#id39" name="code-generation-macros">6 Code Generation Macros</a></h1>
<p>Macros in this section can be used to ease the writing of code
using the Parameter libray by eliminating repetitive boilerplate.</p>
<div class="section" id="boost-parameter-fun-r-n-l-h-p">
<h2><a class="toc-backref" href="#id40" name="boost-parameter-fun-r-n-l-h-p">6.1 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_FUN(r,n,l,h,p)</span></tt></a></h2>
<p>Generates a sequence of <a class="reference" href="index.html#forwarding-functions">forwarding function</a> templates named
<tt class="docutils literal"><span class="pre">n</span></tt>, with arities ranging from <tt class="docutils literal"><span class="pre">l</span></tt> to <tt class="docutils literal"><span class="pre">h</span></tt> , returning <tt class="docutils literal"><span class="pre">r</span></tt>,
and using <tt class="docutils literal"><span class="pre">p</span></tt> to control overload resolution and assign tags to
positional arguments.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/macros.hpp">boost/parameter/macros.hpp</a></td>
</tr>
</tbody>
</table>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="docutils literal"><span class="pre">l</span></tt> and <tt class="docutils literal"><span class="pre">h</span></tt> are nonnegative integer tokens such
that <tt class="docutils literal"><span class="pre">l</span></tt> < <tt class="docutils literal"><span class="pre">h</span></tt></td>
</tr>
</tbody>
</table>
<dl class="docutils">
<dt>Generates</dt>
<dd><pre class="first last literal-block">
template <class A1, class A2, …class A##<strong>l</strong>>
r name(
A1 const& a1, A2 const& a2, …A<strong>l</strong> const& x<strong>l</strong>
, typename <strong>p</strong>::match<A1,A2,…A<strong>l</strong>>::type p = <strong>p</strong>())
{
return <strong>name</strong>_with_named_params(<strong>p</strong>(x1,x2,…x<strong>l</strong>));
}
template <class A1, class A2, …class A<strong>l</strong>, class A##<a class="reference" href="../../../preprocessor/doc/ref/inc.html">BOOST_PP_INC</a>(<strong>l</strong>)>
r name(
A1 const& a1, A2 const& a2, …A<strong>l</strong> const& x<strong>l</strong>
, A##<a class="reference" href="../../../preprocessor/doc/ref/inc.html">BOOST_PP_INC</a>(<strong>l</strong>) const& x##<a class="reference" href="../../../preprocessor/doc/ref/inc.html">BOOST_PP_INC</a>(<strong>l</strong>)
, typename <strong>p</strong>::match<A1,A2,…A<strong>l</strong>,A##<a class="reference" href="../../../preprocessor/doc/ref/inc.html">BOOST_PP_INC</a>(<strong>l</strong>)>::type p = <strong>p</strong>())
{
return <strong>name</strong>_with_named_params(<strong>p</strong>(x1,x2,…x<strong>l</strong>,x##<a class="reference" href="../../../preprocessor/doc/ref/inc.html">BOOST_PP_INC</a>(<strong>l</strong>)));
} <span class="vellipsis">
.
.
.
</span>
template <class A1, class A2, …class A<strong>h</strong>>
r name(
A1 const& a1, A2 const& a2, …A<strong>h</strong> const& x<strong>h</strong>
, typename <strong>p</strong>::match<A1,A2,…A<strong>h</strong>>::type p = <strong>p</strong>())
{
return <strong>name</strong>_with_named_params(<strong>p</strong>(a1,a2,…a<strong>h</strong>));
}
</pre>
</dd>
</dl>
</div>
<div class="section" id="boost-parameter-keyword-n-k">
<h2><a class="toc-backref" href="#id41" name="boost-parameter-keyword-n-k">6.2 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_KEYWORD(n,k)</span></tt></a></h2>
<p>Generates the declaration of a <a class="reference" href="#keyword-tag-type">keyword tag type</a> named <tt class="docutils literal"><span class="pre">k</span></tt> in
namespace <tt class="docutils literal"><span class="pre">n</span></tt>, and a corresponding <a class="reference" href="#keyword-object">keyword object</a> definition in
the enclosing namespace.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/keyword.hpp">boost/parameter/keyword.hpp</a></td>
</tr>
</tbody>
</table>
<dl class="docutils">
<dt>Generates</dt>
<dd><pre class="first last literal-block">
namespace <strong>n</strong> { struct <strong>k</strong>; }
namespace {
boost::parameter::keyword<<em>tag-namespace</em>::<strong>k</strong>>& <strong>k</strong>
= boost::parameter::keyword<<em>tag-namespace</em>::<strong>k</strong>>::get();
}
</pre>
</dd>
</dl>
</div>
<div class="section" id="boost-parameter-match-p-a-x">
<h2><a class="toc-backref" href="#id42" name="boost-parameter-match-p-a-x">6.3 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_MATCH(p,a,x)</span></tt></a></h2>
<p>Generates a defaulted parameter declaration for a <a class="reference" href="index.html#forwarding-functions">forwarding
function</a>.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/match.hpp">boost/parameter/match.hpp</a></td>
</tr>
</tbody>
</table>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><p class="first"><tt class="docutils literal"><span class="pre">a</span></tt> is a <a class="reference" href="http://www.boost.org/libs/preprocessor/doc/data.html">Boost.Preprocessor sequence</a>
of the form</p>
<pre class="last literal-block">
(A0)(A1)…(A<em>n</em>)
</pre>
</td>
</tr>
</tbody>
</table>
<dl class="docutils">
<dt>Generates</dt>
<dd><pre class="first last literal-block">
typename <strong>p</strong>::match<<strong>A0</strong>,<strong>A1</strong>…,<strong>A</strong><em>n</em>>::type <strong>x</strong> = <strong>p</strong>()
</pre>
</dd>
</dl>
</div>
</div>
<div class="section" id="configuration-macros">
<h1><a class="toc-backref" href="#id43" name="configuration-macros">7 Configuration Macros</a></h1>
<div class="section" id="boost-parameter-max-arity">
<h2><a class="toc-backref" href="#id44" name="boost-parameter-max-arity">7.1 <tt class="docutils literal"><span class="pre">BOOST_PARAMETER_MAX_ARITY</span></tt></a></h2>
<p>Determines the maximum number of arguments supported by the
library. Will only be <tt class="docutils literal"><span class="pre">#defined</span></tt> by the library if it is not
already <tt class="docutils literal"><span class="pre">#defined</span></tt>.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Defined in:</th><td class="field-body"><a class="reference" href="../../../../boost/parameter/config.hpp">boost/parameter/config.hpp</a></td>
</tr>
</tbody>
</table>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Default Value:</th><td class="field-body"><tt class="docutils literal"><span class="pre">5</span></tt></td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="section" id="tutorial">
<h1><a class="toc-backref" href="#id45" name="tutorial">8 Tutorial</a></h1>
<p>Follow <a class="reference" href="index.html#tutorial">this link</a> to the Boost.Parameter tutorial
documentation.</p>
<hr class="docutils" />
<table class="docutils footnote" frame="void" id="thread" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a class="fn-backref" href="#id2" name="thread">[1]</a></td><td>References to tag objects may be initialized multiple
times. This scenario can only occur in the presence of
threading. Because the C++ standard doesn't consider threading,
it doesn't explicitly allow or forbid multiple initialization of
references. That said, it's hard to imagine an implementation
where it could make a difference.</td></tr>
</tbody>
</table>
<table class="docutils footnote" frame="void" id="no-result-of" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label"><a name="no-result-of">[2]</a></td><td><em>(<a class="fn-backref" href="#id10">1</a>, <a class="fn-backref" href="#id16">2</a>)</em> Where <a class="reference" href="../../../utility/utility.htm#BOOST_NO_RESULT_OF"><tt class="docutils literal"><span class="pre">BOOST_NO_RESULT_OF</span></tt></a> is <tt class="docutils literal"><span class="pre">#defined</span></tt>,
<tt class="docutils literal"><span class="pre">boost::</span></tt><a class="reference" href="../../../utility/utility.htm#result_of"><tt class="docutils literal"><span class="pre">result_of</span></tt></a><tt class="docutils literal"><span class="pre"><F()>::type</span></tt> is replaced by
<tt class="docutils literal"><span class="pre">F::result_type</span></tt>.</td></tr>
</tbody>
</table>
</div>
</div>
<hr class="docutils footer" />
<div class="footer">
Generated on: 2005-08-05 14:58 UTC.
Generated by <a class="reference" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
</div>
</body>
</html>
|
