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1<?xml version="1.0" encoding="utf-8"?>
2<!DOCTYPE header PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
3  "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
4<!--
5Copyright Douglas Gregor 2001-2004
6Copyright Frank Mori Hess 2007-2009
7
8Distributed under the Boost Software License, Version 1.0. (See accompanying
9file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
10-->
11<header name="boost/signals2/signal.hpp" last-revision="$Date: 2007-03-06 16:51:55 -0500 (Tue, 06 Mar 2007) $">
12  <using-namespace name="boost::signals2"/>
13  <using-namespace name="boost"/>
14  <namespace name="boost">
15    <namespace name="signals2">
16      <enum name="connect_position">
17        <enumvalue name="at_front"/>
18        <enumvalue name="at_back"/>
19      </enum>
20      <class name="signal">
21        <template>
22          <template-type-parameter name="Signature">
23            <purpose>Function type R (T1, T2, ..., TN)</purpose>
24          </template-type-parameter>
25          <template-type-parameter name="Combiner">
26            <default><classname>boost::signals2::optional_last_value</classname>&lt;R&gt;</default>
27          </template-type-parameter>
28          <template-type-parameter name="Group">
29            <default>int</default>
30          </template-type-parameter>
31          <template-type-parameter name="GroupCompare">
32            <default><classname>std::less</classname>&lt;Group&gt;</default>
33          </template-type-parameter>
34          <template-type-parameter name="SlotFunction">
35            <default><classname>boost::function</classname>&lt;Signature&gt;</default>
36          </template-type-parameter>
37          <template-type-parameter name="ExtendedSlotFunction">
38            <default><classname>boost::function</classname>&lt;R (const <classname alt="signals2::connection">connection</classname> &amp;, T1, T2, ..., TN)&gt;</default>
39          </template-type-parameter>
40          <template-type-parameter name="Mutex">
41            <default><classname>boost::signals2::mutex</classname></default>
42          </template-type-parameter>
43        </template>
44        <inherit access="public">
45          <type><classname>boost::signals2::signal_base</classname></type>
46        </inherit>
47
48        <purpose>Safe multicast callback.</purpose>
49
50        <description>
51          <para>
52            See the <link linkend="signals2.tutorial">tutorial</link>
53            for more information on how to use the signal class.
54          </para>
55        </description>
56
57        <typedef name="signature_type"><type>Signature</type></typedef>
58        <typedef name="result_type">
59          <type>typename Combiner::result_type</type>
60        </typedef>
61        <typedef name="combiner_type"><type>Combiner</type></typedef>
62        <typedef name="group_type"><type>Group</type></typedef>
63        <typedef name="group_compare_type"><type>GroupCompare</type></typedef>
64        <typedef name="slot_function_type"><type>SlotFunction</type></typedef>
65        <typedef name="slot_type">
66          <type>typename <classname>signals2::slot</classname>&lt;Signature, SlotFunction&gt;</type>
67        </typedef>
68        <typedef name="extended_slot_function_type"><type>ExtendedSlotFunction</type></typedef>
69        <typedef name="extended_slot_type">
70          <type>typename <classname>signals2::slot</classname>&lt;R (const <classname alt="signals2::connection">connection</classname> &amp;, T1, ..., TN), ExtendedSlotFunction&gt;</type>
71          <description>
72            <para>Slots of the <code>extended_slot_type</code> may be connected to the signal using the
73              <methodname>connect_extended</methodname> methods.  The <code>extended_slot_type</code>
74              has an additional <classname>signals2::connection</classname> argument in its signature,
75              which gives slot functions access to their connection to the signal
76              invoking them.
77            </para>
78          </description>
79        </typedef>
80        <typedef name="slot_result_type">
81          <type>typename SlotFunction::result_type</type>
82          <description>
83            <para>
84              This is the type returned when dereferencing the input iterators passed to the signal's
85              combiner.
86            </para>
87          </description>
88        </typedef>
89        <typedef name="slot_call_iterator">
90          <type><emphasis>unspecified</emphasis></type>
91          <description>
92            <para>
93              The input iterator type passed to the combiner when the signal is invoked.
94            </para>
95          </description>
96        </typedef>
97        <typedef name="argument_type">
98          <type>T1</type>
99          <purpose>Exists iff arity == 1</purpose>
100        </typedef>
101        <typedef name="first_argument_type">
102          <type>T1</type>
103          <purpose>Exists iff arity == 2</purpose>
104        </typedef>
105        <typedef name="second_argument_type">
106          <type>T2</type>
107          <purpose>Exists iff arity == 2</purpose>
108        </typedef>
109
110        <class name="arg">
111          <template>
112            <template-nontype-parameter name="n">
113              <type>unsigned</type>
114            </template-nontype-parameter>
115          </template>
116          <typedef name="type">
117            <type>Tn</type>
118            <purpose>The type of the <classname alt="signals2::signal">signal</classname>'s (n+1)th argument</purpose>
119          </typedef>
120        </class>
121
122        <static-constant name="arity">
123          <type>int</type>
124          <default>N</default>
125          <purpose>The number of arguments taken by the signal.</purpose>
126        </static-constant>
127
128        <constructor>
129          <parameter name="combiner">
130            <paramtype>const combiner_type&amp;</paramtype>
131            <default>combiner_type()</default>
132          </parameter>
133          <parameter name="compare">
134            <paramtype>const group_compare_type&amp;</paramtype>
135            <default>group_compare_type()</default>
136          </parameter>
137
138          <effects><para>Initializes the signal to contain no slots, copies the given combiner into internal storage, and stores the given group comparison function object to compare groups.</para></effects>
139
140          <postconditions><para><computeroutput>this-&gt;<methodname>empty</methodname>()</computeroutput></para></postconditions>
141        </constructor>
142
143        <constructor>
144          <parameter name="other">
145            <paramtype>signal &amp;&amp;</paramtype>
146          </parameter>
147          <description><para>Move constructor.</para></description>
148          <postconditions><para>The signal <computeroutput>other</computeroutput>
149            is in a "moved-from" state where it may only be destroyed, swapped, or move assigned.
150            Any other operation on a "moved-from" signal is invalid.</para></postconditions>
151
152          <throws><para>Will not throw.</para></throws>
153        </constructor>
154
155        <copy-assignment>
156          <parameter name="rhs">
157            <paramtype>signal &amp;&amp;</paramtype>
158          </parameter>
159          <description><para>Move assignment.</para></description>
160          <postconditions><para>The signal <computeroutput>rhs</computeroutput>
161            is in a "moved-from" state where it may only be destroyed, swapped, or move assigned.
162            Any other operation on a "moved-from" signal is invalid.</para></postconditions>
163
164          <throws><para>Will not throw.</para></throws>
165        </copy-assignment>
166
167        <method-group name="connection management">
168          <overloaded-method name="connect">
169            <signature>
170              <type><classname alt="signals2::connection">connection</classname></type>
171              <parameter name="slot">
172                <paramtype>const slot_type&amp;</paramtype>
173              </parameter>
174              <parameter name="at">
175                <paramtype>connect_position</paramtype>
176                <default>at_back</default>
177              </parameter>
178            </signature>
179
180            <signature>
181              <type><classname alt="signals2::connection">connection</classname></type>
182              <parameter name="group">
183                <paramtype>const group_type&amp;</paramtype>
184              </parameter>
185              <parameter name="slot">
186                <paramtype>const slot_type&amp;</paramtype>
187              </parameter>
188              <parameter name="at">
189                <paramtype>connect_position</paramtype>
190                <default>at_back</default>
191              </parameter>
192            </signature>
193
194            <effects><para>Connects the signal this to the incoming
195            slot. If the slot is inactive, i.e., any of the slots's tracked
196            objects have been destroyed, then the
197            call to connect is a no-op. If the second version of
198            <computeroutput>connect</computeroutput> is invoked, the
199            slot is associated with the given group. The <code>at</code>
200            parameter specifies where the slot should be connected:
201            <code>at_front</code> indicates that the slot will be
202            connected at the front of the list or group of slots and
203            <code>at_back</code> indicates that the slot will be
204            connected at the back of the list or group of
205            slots.</para></effects>
206
207            <returns><para>A
208            <computeroutput><classname>signals2::connection</classname></computeroutput>
209            object that references the newly-created connection between
210            the signal and the slot; if the slot is inactive, returns a
211            disconnected connection.</para></returns>
212
213            <throws><para>This routine meets the strong exception guarantee,
214            where any exception thrown will cause the slot to not be
215            connected to the signal.</para></throws>
216
217            <complexity><para>Constant time when connecting a slot
218            without a group name or logarithmic in the number of groups
219            when connecting to a particular
220            group.</para></complexity>
221
222            <notes><para>It is unspecified whether connecting a slot while the
223            signal is calling will result in the slot being called
224            immediately.</para></notes>
225          </overloaded-method>
226          <overloaded-method name="connect_extended">
227            <signature>
228              <type><classname alt="signals2::connection">connection</classname></type>
229              <parameter name="slot">
230                <paramtype>const extended_slot_type&amp;</paramtype>
231              </parameter>
232              <parameter name="at">
233                <paramtype>connect_position</paramtype>
234                <default>at_back</default>
235              </parameter>
236            </signature>
237
238            <signature>
239              <type><classname alt="signals2::connection">connection</classname></type>
240              <parameter name="group">
241                <paramtype>const group_type&amp;</paramtype>
242              </parameter>
243              <parameter name="slot">
244                <paramtype>const extended_slot_type&amp;</paramtype>
245              </parameter>
246              <parameter name="at">
247                <paramtype>connect_position</paramtype>
248                <default>at_back</default>
249              </parameter>
250            </signature>
251            <description>
252              <para>
253                The <code>connect_extended</code> methods work the same as the <methodname>connect</methodname>
254                methods, except they take slots of type <classname>extended_slot_type</classname>.
255                This is useful if a slot needs to access the connection between it and the
256                signal invoking it, for example if it wishes to disconnect or block its own connection.
257              </para>
258            </description>
259          </overloaded-method>
260
261          <overloaded-method name="disconnect">
262            <signature>
263              <type>void</type>
264              <parameter name="group">
265                <paramtype>const group_type&amp;</paramtype>
266              </parameter>
267            </signature>
268            <signature>
269              <template>
270                <template-type-parameter name="S"/>
271              </template>
272              <type>void</type>
273              <parameter name="slot_func">
274                <paramtype>const S&amp;</paramtype>
275              </parameter>
276            </signature>
277
278            <effects><para>If the parameter is (convertible to) a
279            group name, any slots in the given group are
280            disconnected. Otherwise, any slots equal to the
281            given slot function
282            are disconnected.
283            </para>
284            <para>Note, the <code>slot_func</code>
285            argument should not be an actual <classname>signals2::slot</classname>
286            object (which does not even support <code>operator==</code>), but rather
287            the functor you wrapped inside a <classname>signals2::slot</classname>
288            when you initially made the connection.
289            </para></effects>
290
291            <throws><para>Will not throw unless a user destructor or
292            equality operator <code>==</code> throws. If either throws,
293            not all slots may be disconnected.</para></throws>
294
295            <complexity><para>If a group is given, O(lg g) + k where
296            g is the number of groups in the signal and k is the
297            number of slots in the group. Otherwise, linear in the
298            number of slots connected to the
299            signal.</para></complexity>
300          </overloaded-method>
301
302          <method name="disconnect_all_slots">
303            <type>void</type>
304            <effects><para>Disconnects all slots connected to the signal.</para></effects>
305
306            <postconditions><para><computeroutput>this-&gt;<methodname>empty</methodname>()</computeroutput>.</para></postconditions>
307
308            <throws><para>If disconnecting a slot causes an exception to be
309            thrown, not all slots may be disconnected.</para></throws>
310
311            <complexity><para>Linear in the number of slots known to the
312            signal.</para></complexity>
313
314            <notes><para>May be called at any time within the lifetime of the
315            signal, including during calls to the signal's slots.</para></notes>
316          </method>
317
318          <method name="empty" cv="const">
319            <type>bool</type>
320            <returns><para><computeroutput>true</computeroutput> if no slots
321            are connected to the signal, and
322            <computeroutput>false</computeroutput> otherwise.</para></returns>
323
324            <throws><para>Will not throw.</para></throws>
325
326            <complexity><para>Linear in the number of slots known to the
327            signal.</para></complexity>
328
329            <rationale><para>Slots can disconnect at any point in time,
330            including while those same slots are being invoked. It is
331            therefore possible that the implementation must search
332            through a list of disconnected slots to determine if any
333            slots are still connected.</para></rationale>
334          </method>
335
336          <method name="num_slots" cv="const">
337            <type>std::size_t</type>
338            <returns><para>The number of slots connected to the signal</para></returns>
339
340            <throws><para>Will not throw.</para></throws>
341
342            <complexity><para>Linear in the number of slots known to the
343            signal.</para></complexity>
344
345            <rationale><para>Slots can disconnect at any point in time,
346            including while those same slots are being invoked. It is
347            therefore possible that the implementation must search
348            through a list of disconnected slots to determine how many
349            slots are still connected.</para></rationale>
350          </method>
351        </method-group>
352
353        <method-group name="invocation">
354          <overloaded-method name="operator()">
355            <signature>
356              <type>result_type</type>
357              <parameter name="a1"><paramtype>arg&lt;0&gt;::type</paramtype></parameter>
358              <parameter name="a2"><paramtype>arg&lt;1&gt;::type</paramtype></parameter>
359              <parameter><paramtype>...</paramtype></parameter>
360              <parameter name="aN"><paramtype>arg&lt;N-1&gt;::type</paramtype></parameter>
361            </signature>
362
363            <signature cv="const">
364              <type>result_type</type>
365              <parameter name="a1"><paramtype>arg&lt;0&gt;::type</paramtype></parameter>
366              <parameter name="a2"><paramtype>arg&lt;1&gt;::type</paramtype></parameter>
367              <parameter><paramtype>...</paramtype></parameter>
368              <parameter name="aN"><paramtype>arg&lt;N-1&gt;::type</paramtype></parameter>
369            </signature>
370
371            <effects><para>Invokes the combiner with a
372            <computeroutput>slot_call_iterator</computeroutput> range
373            [first, last) corresponding to the sequence of calls to the
374            slots connected to signal
375            <computeroutput>*this</computeroutput>. Dereferencing an
376            iterator in this range causes a slot call with the given set
377            of parameters <computeroutput>(a1, a2, ...,
378            aN)</computeroutput>, the result of which is returned from
379            the iterator dereference operation.</para></effects>
380
381            <returns><para>The result returned by the combiner.</para></returns>
382
383            <throws><para>If an exception is thrown by a slot call, or if the
384            combiner does not dereference any slot past some given slot,
385            all slots after that slot in the internal list of connected
386            slots will not be invoked.</para></throws>
387
388            <notes><para>Only the slots associated with iterators that are
389            actually dereferenced will be invoked. Multiple dereferences
390            of the same iterator will not result in multiple slot
391            invocations, because the return value of the slot will be
392            cached.</para>
393
394            <para>The <computeroutput>const</computeroutput> version of
395            the function call operator will invoke the combiner as
396            <computeroutput>const</computeroutput>, whereas the
397            non-<computeroutput>const</computeroutput> version will
398            invoke the combiner as
399            non-<computeroutput>const</computeroutput>.</para>
400            </notes>
401          </overloaded-method>
402        </method-group>
403
404        <method-group name="combiner access">
405          <method name="combiner" cv="const">
406            <type>combiner_type</type>
407
408            <returns><para>A copy of the stored combiner.</para></returns>
409            <throws><para>Will not throw.</para></throws>
410          </method>
411          <method name="set_combiner">
412            <type>void</type>
413            <parameter name="combiner"><paramtype>const combiner_type&amp;</paramtype></parameter>
414
415            <effects><para>Copies a new combiner into the signal for use with
416            future signal invocations.</para></effects>
417            <throws><para>Will not throw.</para></throws>
418          </method>
419        </method-group>
420
421        <method-group name="modifiers">
422          <method name="swap">
423            <type>void</type>
424            <parameter name="other">
425              <paramtype><classname alt="signals2::signal">signal</classname>&amp;</paramtype>
426            </parameter>
427            <effects><para>Swaps the signal referenced in
428            <computeroutput>this</computeroutput> and
429            <computeroutput>other</computeroutput>.</para></effects>
430
431            <throws><para>Will not throw.</para></throws>
432          </method>
433        </method-group>
434
435        <free-function-group name="specialized algorithms">
436          <function name="swap">
437            <template>
438              <template-type-parameter name="Signature"/>
439              <template-type-parameter name="Combiner"/>
440              <template-type-parameter name="Group"/>
441              <template-type-parameter name="GroupCompare"/>
442              <template-type-parameter name="SlotFunction"/>
443              <template-type-parameter name="ExtendedSlotFunction"/>
444              <template-type-parameter name="Mutex"/>
445            </template>
446            <type>void</type>
447            <parameter name="x">
448              <paramtype><classname alt="signals2::signal">signal</classname>&lt;Signature, Combiner, Group, GroupCompare, SlotFunction, ExtendedSlotFunction, Mutex&gt;&amp;</paramtype>
449            </parameter>
450            <parameter name="y">
451              <paramtype><classname alt="signals2::signal">signal</classname>&lt;Signature, Combiner, Group, GroupCompare, SlotFunction, ExtendedSlotFunction, Mutex&gt;&amp;</paramtype>
452            </parameter>
453
454            <effects><para><computeroutput>x.swap(y)</computeroutput></para></effects>
455            <throws><para>Will not throw.</para></throws>
456          </function>
457        </free-function-group>
458      </class>
459    </namespace>
460  </namespace>
461</header>
462