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<h3><a href="../../../index.htm"><img alt="C++ Boost" src=
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<h1 align="center">The Boost Statechart Library</h1>
<h2 align="center">Reference</h2>
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<hr>
<h2>Contents</h2>
<dl class="page-index">
<dt><a href="#Concepts">Concepts</a></dt>
<dd><a href="#Scheduler">Scheduler</a></dd>
<dd><a href="#FifoWorker">FifoWorker</a></dd>
<dd><a href="#ExceptionTranslator">ExceptionTranslator</a></dd>
<dd><a href="#StateBase">StateBase</a></dd>
<dd><a href="#SimpleState">SimpleState</a></dd>
<dd><a href="#State">State</a></dd>
<dd><a href="#Event">Event</a></dd>
<dt><a href="#state_machine.hpp">state_machine.hpp</a></dt>
<dd><a href="#ClassTemplatestate_machine">Class template
<code>state_machine</code></a></dd>
<dt><a href=
"#asynchronous_state_machine.hpp">asynchronous_state_machine.hpp</a></dt>
<dd><a href="#ClassTemplateasynchronous_state_machine">Class template
<code>asynchronous_state_machine</code></a></dd>
<dt><a href="#event_processor.hpp">event_processor.hpp</a></dt>
<dd><a href="#ClassTemplateevent_processor">Class template
<code>event_processor</code></a></dd>
<dt><a href="#fifo_scheduler.hpp">fifo_scheduler.hpp</a></dt>
<dd><a href="#ClassTemplatefifo_scheduler">Class template
<code>fifo_scheduler</code></a></dd>
<dt><a href="#exception_translator.hpp">exception_translator.hpp</a></dt>
<dd><a href="#ClassTemplateexception_translator">Class template
<code>exception_translator</code></a></dd>
<dt><a href=
"#null_exception_translator.hpp">null_exception_translator.hpp</a></dt>
<dd><a href="#Classnull_exception_translator">Class
<code>null_exception_translator</code></a></dd>
<dt>&nbsp;</dt>
<dt><a href="#simple_state.hpp">simple_state.hpp</a></dt>
<dd><a href="#Enumhistory_mode">Enum <code>history_mode</code></a></dd>
<dd><a href="#ClassTemplatesimple_state">Class template
<code>simple_state</code></a></dd>
<dt><a href="#state.hpp">state.hpp</a></dt>
<dd><a href="#ClassTemplatestate">Class template
<code>state</code></a></dd>
<dt><a href="#shallow_history.hpp">shallow_history.hpp</a></dt>
<dd><a href="#ClassTemplateshallow_history">Class template
<code>shallow_history</code></a></dd>
<dt><a href="#deep_history.hpp">deep_history.hpp</a></dt>
<dd><a href="#ClassTemplatedeep_history">Class template
<code>deep_history</code></a></dd>
<dt>&nbsp;</dt>
<dt><a href="#event_base.hpp">event_base.hpp</a></dt>
<dd><a href="#Classevent_base">Class <code>event_base</code></a></dd>
<dt><a href="#event.hpp">event.hpp</a></dt>
<dd><a href="#ClassTemplateevent">Class template
<code>event</code></a></dd>
<dt>&nbsp;</dt>
<dt><a href="#transition.hpp">transition.hpp</a></dt>
<dd><a href="#ClassTemplatetransition">Class template
<code>transition</code></a></dd>
<dt><a href="#in_state_reaction.hpp">in_state_reaction.hpp</a></dt>
<dd><a href="#ClassTemplatein_state_reaction">Class template
in_state_reaction</a></dd>
<dt><a href="#termination.hpp">termination.hpp</a></dt>
<dd><a href="#ClassTemplatetermination">Class template
<code>termination</code></a></dd>
<dt><a href="#deferral.hpp">deferral.hpp</a></dt>
<dd><a href="#ClassTemplatedeferral">Class template
<code>deferral</code></a></dd>
<dt><a href="#custom_reaction.hpp">custom_reaction.hpp</a></dt>
<dd><a href="#ClassTemplatecustom_reaction">Class template
<code>custom_reaction</code></a></dd>
<dt><a href="#result.hpp">result.hpp</a></dt>
<dd><a href="#Classresult">Class <code>result</code></a></dd>
</dl>
<hr>
<h1><a name="Concepts" id="Concepts">Concepts</a></h1>
<h2><a name="Scheduler" id="Scheduler">Scheduler</a> concept</h2>
<p>A Scheduler type defines the following:</p>
<ul>
<li>What is passed to the constructors of <code><a href=
"#ClassTemplateevent_processor">event_processor&lt;&gt;</a></code>
subtypes and how the lifetime of such objects is managed</li>
<li>Whether or not multiple <code>event_processor&lt;&gt;</code> subtype
objects can share the same queue and scheduler thread</li>
<li>How events are added to the schedulers' queue</li>
<li>Whether and how to wait for new events when the schedulers' queue
runs empty</li>
<li>Whether and what type of locking is used to ensure thread-safety</li>
<li>Whether it is possible to queue events for no longer existing
<code>event_processor&lt;&gt;</code> subtype objects and what happens
when such an event is processed</li>
<li>What happens when one of the serviced
<code>event_processor&lt;&gt;</code> subtype objects propagates an
exception</li>
</ul>
<p>For a Scheduler type <code>S</code> and an object <code>cpc</code> of
type <code>const S::processor_context</code> the following expressions must
be well-formed and have the indicated results:</p>
<table border="3" cellpadding="2" width="100%" summary="Scheduler concept">
<tr>
<td><b>Expression</b></td>
<td><b>Type</b></td>
<td><b>Result</b></td>
</tr>
<tr>
<td><code>cpc.my_scheduler()</code></td>
<td><code>S &amp;</code></td>
<td>A reference to the scheduler</td>
</tr>
<tr>
<td><code>cpc.my_handle()</code></td>
<td><code>S::processor_handle</code></td>
<td>The handle identifying the
<code>event_processor&lt;&gt;</code> subtype object</td>
</tr>
</table>
<p>To protect against abuse, all members of
<code>S::processor_context</code> should be declared private. As a result,
<code>event_processor&lt;&gt;</code> must be a friend of
<code>S::processor_context</code>.</p>
<h2><a name="FifoWorker" id="FifoWorker">FifoWorker</a> concept</h2>
<p>A FifoWorker type defines the following:</p>
<ul>
<li>Whether and how to wait for new work items when the internal work
queue runs empty</li>
<li>Whether and what type of locking is used to ensure thread-safety</li>
</ul>
<p>For a FifoWorker type <code>F</code>, an object <code>f</code> of that
type, a <code>const</code> object <code>cf</code> of that type, a
parameterless function object <code>w</code> of arbitrary type and an
<code>unsigned long</code> value <code>n</code> the following
expressions/statements must be well-formed and have the indicated
results:</p>
<table border="3" cellpadding="2" width="100%" summary=
"FifoWorker concept">
<tr>
<td><b>Expression/Statement</b></td>
<td><b>Type</b></td>
<td><b>Effects/Result</b></td>
</tr>
<tr>
<td><code>F::work_item</code></td>
<td><code>boost::function0&lt; void &gt;</code></td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>F()</code> or <code>F( false )</code></td>
<td><code>F</code></td>
<td>Constructs a <b>non-blocking</b> (see below) object of
the FifoWorker type. In single-threaded builds the second expression is
not well-formed</td>
</tr>
<tr>
<td><code>F( true )</code></td>
<td><code>F</code></td>
<td>Constructs a <b>blocking</b> (see below) object of the
FifoWorker type. Not well-formed in single-threaded builds</td>
</tr>
<tr>
<td><code>f.queue_work_item( w );</code></td>
<td>&nbsp;</td>
<td>Constructs and queues an object of type
<code>F::work_item</code>, passing <code>w</code> as the only
argument</td>
</tr>
<tr>
<td><code>f.terminate();</code></td>
<td>&nbsp;</td>
<td>Creates and queues an object of type
<code>F::work_item</code> that, when later executed in
<code>operator()()</code>, leads to a modification of internal state so
that <code>terminated()</code> henceforth returns
<code>true</code></td>
</tr>
<tr>
<td><code>cf.terminated();</code></td>
<td><code>bool</code></td>
<td><code>true</code> if <code>terminate()</code> has been
called and the resulting work item has been executed in
<code>operator()()</code>. Returns <code>false</code> otherwise<br>
<br>
<b>Must only be called from the thread that also calls
<code>operator()()</code></b></td>
</tr>
<tr>
<td><code>f( n );</code></td>
<td><code>unsigned long</code></td>
<td>
Enters a loop that, with each cycle, dequeues and calls
<code>operator()()</code> on the oldest work item in the queue.
<p>The loop is left and the number of executed work items returned if
one or more of the following conditions are met:</p>
<ul>
<li><code>f.terminated() == true</code></li>
<li>The application is single-threaded and the internal queue is
empty</li>
<li>The application is multi-threaded and the internal queue is
empty and the worker was created as non-blocking</li>
<li><code>n != 0</code> and the number of work items that have been
processed since <code>operator()()</code> was called equals
<code>n</code></li>
</ul>
<p>If the queue is empty and none of the above conditions are met
then the thread calling <code>operator()()</code> is put into a wait
state until <code>f.queue_work_item()</code> is called from another
thread.<br>
<br>
<b>Must only be called from exactly one thread</b></p>
</td>
</tr>
<tr>
<td><code>f();</code></td>
<td><code>unsigned long</code></td>
<td>Has exactly the same semantics as <code>f( n );</code>
with <code>n == 0</code> (see above)</td>
</tr>
</table>
<h2><a name="ExceptionTranslator" id=
"ExceptionTranslator">ExceptionTranslator</a> concept</h2>
<p>An ExceptionTranslator type defines how C++ exceptions occurring during
state machine operation are translated to exception events.</p>
<p>For an ExceptionTranslator object <code>et</code>, a parameterless
function object <code>a</code> of arbitrary type returning <code><a href=
"#Classresult">result</a></code> and a function object <code>eh</code> of
arbitrary type taking a <code>const <a href=
"#Classevent_base">event_base</a> &amp;</code> parameter and returning
<code><a href="#Classresult">result</a></code> the following expression
must be well-formed and have the indicated results:</p>
<table border="3" cellpadding="2" width="100%" summary=
"ExceptionTranslator concept">
<tr>
<td><b>Expression</b></td>
<td><b>Type</b></td>
<td><b>Effects/Result</b></td>
</tr>
<tr>
<td><code>et(&nbsp;a,&nbsp;eh&nbsp;);</code></td>
<td><code>result</code></td>
<td>
<ol>
<li>Attempts to execute <code>return a();</code></li>
<li>If <code>a()</code> propagates an exception, the exception is
caught</li>
<li>Inside the catch block calls <code>eh</code>, passing a
suitable stack-allocated model of the <a href="#Event">Event</a>
concept</li>
<li>Returns the result returned by <code>eh</code></li>
</ol>
</td>
</tr>
</table>
<h2><a name="StateBase" id="StateBase">StateBase</a> concept</h2>
<p>A StateBase type is the common base of all states of a given state
machine type. <code>state_machine&lt;&gt;::state_base_type</code> is a
model of the StateBase concept.</p>
<p>For a StateBase type <code>S</code> and a <code>const</code> object
<code>cs</code> of that type the following expressions must be well-formed
and have the indicated results:</p>
<table border="3" cellpadding="2" width="100%" summary="StateBase concept">
<tr>
<td><b>Expression</b></td>
<td><b>Type</b></td>
<td><b>Result</b></td>
</tr>
<tr>
<td><code>cs.outer_state_ptr()</code></td>
<td><code>const S *</code></td>
<td><code>0</code> if <code>cs</code> is an <a href=
"definitions.html#OutermostState">outermost state</a>, a pointer to the
direct outer state of <code>cs</code> otherwise</td>
</tr>
<tr>
<td><code>cs.dynamic_type()</code></td>
<td><code>S::id_type</code></td>
<td>A value unambiguously identifying the most-derived type
of <code>cs</code>. <code>S::id_type</code> values are comparable with
<code>operator==()</code> and <code>operator!=()</code>. An unspecified
collating order can be established with <code>std::less&lt; S::id_type
&gt;</code>. In contrast to <code>typeid( cs )</code>, this function is
available even on platforms that do not support C++ RTTI (or have been
configured to not support it)</td>
</tr>
<tr>
<td><code>cs.custom_dynamic_type_ptr&lt;<br>
&nbsp; Type &gt;()</code></td>
<td><code>const Type *</code></td>
<td>A pointer to the custom type identifier or
<code>0</code>. If <code>!= 0</code>, <code>Type</code> must match the
type of the previously set pointer. This function is only available if
<a href=
"configuration.html#ApplicationDefinedMacros">BOOST_STATECHART_USE_NATIVE_RTTI</a>
is not defined</td>
</tr>
</table>
<h2><a name="SimpleState" id="SimpleState">SimpleState</a> concept</h2>
<p>A SimpleState type defines one state of a particular state machine.</p>
<p>For a SimpleState type <code>S</code> and a pointer <code>pS</code>
pointing to an object of type <code>S</code> allocated with
<code>new</code> the following expressions/statements must be well-formed
and have the indicated effects/results:</p>
<table border="3" cellpadding="2" width="100%" summary=
"SimpleState concept">
<tr>
<td><b>Expression/Statement</b></td>
<td><b>Type</b></td>
<td><b>Effects/Result/Notes</b></td>
</tr>
<tr>
<td><code><a href=
"#ClassTemplatesimple_state">simple_state</a>&lt;<br>
&nbsp;&nbsp;S,&nbsp;C,&nbsp;I,&nbsp;h&nbsp;&gt;&nbsp;*&nbsp;pB&nbsp;=<br>
&nbsp;&nbsp;&nbsp;&nbsp;pS;</code></td>
<td>&nbsp;</td>
<td><code>simple_state&lt; S, C, I, h &gt;</code> must be
an unambiguous public base of <code>S</code>. See <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code>
documentation for the requirements and semantics of <code>C</code>,
<code>I</code> and <code>h</code></td>
</tr>
<tr>
<td><code>new S()</code></td>
<td><code>S *</code></td>
<td>Enters the state <code>S</code>. Certain functions must
not be called from <code>S::S()</code>, see <a href=
"#ClassTemplatesimple_state"><code>simple_state&lt;&gt;</code></a>
documentation for more information</td>
</tr>
<tr>
<td><code>pS-&gt;exit();</code></td>
<td>&nbsp;</td>
<td>Exits the state <code>S</code> (first stage). The
definition of an <code>exit</code> member function within models of the
SimpleState concept is optional since <code>simple_state&lt;&gt;</code>
already defines the following public member: <code>void exit()
{}</code>. <code>exit()</code> is not called when a state is exited
while an exception is pending, see <code><a href=
"#simple_state::terminate">simple_state&lt;&gt;::terminate()</a></code>
for more information</td>
</tr>
<tr>
<td><code>delete pS;</code></td>
<td>&nbsp;</td>
<td>Exits the state <code>S</code> (second stage)</td>
</tr>
<tr>
<td><code>S::reactions</code></td>
<td>An <code>mpl::list&lt;&gt;</code> that is either empty
or contains instantiations of the <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction</a></code>,
<code><a href=
"#ClassTemplatein_state_reaction">in_state_reaction</a></code>,
<code><a href="#ClassTemplatedeferral">deferral</a></code>,
<code><a href="#ClassTemplatetermination">termination</a></code> or
<code><a href="#ClassTemplatetransition">transition</a></code> class
templates. If there is only a single reaction then it can also be
<code>typedef</code>ed directly, without wrapping it into an
<code>mpl::list&lt;&gt;</code></td>
<td>The declaration of a <code>reactions</code> member
<code>typedef</code> within models of the SimpleState concept is
optional since <code>simple_state&lt;&gt;</code> already defines the
following public member: <code>typedef mpl::list&lt;&gt;
reactions;</code></td>
</tr>
</table>
<h2><a name="State" id="State">State</a> concept</h2>
<p>A State is a <b>refinement</b> of <a href="#SimpleState">SimpleState</a>
(that is, except for the default constructor a State type must also satisfy
SimpleState requirements). For a State type <code>S</code>, a pointer
<code>pS</code> of type <code>S *</code> pointing to an object of type
<code>S</code> allocated with <code>new</code>, and an object
<code>mc</code> of type <code>state&lt; S, C, I, h
&gt;</code><code>::my_context</code> the following expressions/statements
must be well-formed:</p>
<table border="3" cellpadding="2" width="100%" summary="State concept">
<tr>
<td><b>Expression/Statement</b></td>
<td><b>Type</b></td>
<td><b>Effects/Result/Notes</b></td>
</tr>
<tr>
<td><code><a href="#ClassTemplatestate">state</a>&lt;&nbsp;S,&nbsp;C,&nbsp;I,&nbsp;h&nbsp;&gt;&nbsp;*<br>
&nbsp;&nbsp;pB = pS;</code></td>
<td>&nbsp;</td>
<td><code>state&lt; S, C, I, h &gt;</code> must be an
unambiguous public base of <code>S</code>. See <code><a href=
"#ClassTemplatestate">state&lt;&gt;</a></code> documentation for the
requirements and semantics of <code>C</code>, <code>I</code> and
<code>h</code></td>
</tr>
<tr>
<td><code>new S( mc )</code></td>
<td><code>S *</code></td>
<td>Enters the state <code>S</code>. No restrictions exist
regarding the functions that can be called from <code>S::S()</code> (in
contrast to the constructors of models of the SimpleState concept).
<code>mc</code> must be forwarded to <code>state&lt; S, C, I, h
&gt;::state()</code></td>
</tr>
</table>
<h2><a name="Event" id="Event">Event</a> concept</h2>
<p>A Event type defines an event for which state machines can define
reactions.</p>
<p>For a Event type <code>E</code> and a pointer <code>pCE</code> of type
<code>const E *</code> pointing to an object of type <code>E</code>
allocated with <code>new</code> the following expressions/statements must
be well-formed and have the indicated effects/results:</p>
<table border="3" cellpadding="2" width="100%" summary="Event concept">
<tr>
<td><b>Expression/Statement</b></td>
<td><b>Type</b></td>
<td><b>Effects/Result/Notes</b></td>
</tr>
<tr>
<td><code>const <a href="#ClassTemplateevent">event</a>&lt;
E &gt; * pCB = pCE;</code></td>
<td>&nbsp;</td>
<td><code>event&lt; E &gt;</code> must be an unambiguous
public base of <code>E</code></td>
</tr>
<tr>
<td><code>new E( *pCE )</code></td>
<td><code>E *</code></td>
<td>Makes a copy of <code>pE</code></td>
</tr>
</table>
<h1>Header &lt;boost/statechart/<a name="state_machine.hpp" id=
"state_machine.hpp">state_machine.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatestate_machine" id=
"ClassTemplatestate_machine">Class template
<code>state_machine</code></a></h2>
<p>This is the base class template of all synchronous state machines.</p>
<h3>Class template <code>state_machine</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"state_machine parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>MostDerived</code></td>
<td>The most-derived subtype of this class template</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>InitialState</code></td>
<td>A model of the <a href="#SimpleState">SimpleState</a>
or <a href="#State">State</a> concepts. The <code>Context</code>
argument passed to the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base
of&nbsp; <code>InitialState</code> must be <code>MostDerived</code>.
That is, <code>InitialState</code> must be an <a href=
"definitions.html#OutermostState">outermost state</a> of this state
machine</td>
<td>The state that is entered when
<code>state_machine&lt;&gt;<br>
::initiate()</code> is called</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>Allocator</code></td>
<td>A model of the standard Allocator concept</td>
<td><code>Allocator::rebind&lt;&gt;::other</code> is used
to allocate and deallocate all <code>simple_state</code> subtype
objects and internal objects of dynamic storage duration</td>
<td><code>std::allocator&lt; void &gt;</code></td>
</tr>
<tr>
<td><code>ExceptionTranslator</code></td>
<td>A model of the ExceptionTranslator concept</td>
<td>see <a href=
"#ExceptionTranslator">ExceptionTranslator</a> concept</td>
<td><code>null_exception_translator</code></td>
</tr>
</table>
<h3>Class template <code>state_machine</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt;
class MostDerived,
class InitialState,
class Allocator = std::allocator&lt; void &gt;,
class ExceptionTranslator = null_exception_translator &gt;
class state_machine : noncopyable
{
public:
typedef MostDerived outermost_context_type;
void <a href="#initiate">initiate</a>();
void <a href="#terminate">terminate</a>();
bool <a href="#terminated">terminated</a>() const;
void <a href="#process_event">process_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; );
template&lt; class Target &gt;
Target <a href="#state_cast">state_cast</a>() const;
template&lt; class Target &gt;
Target <a href="#state_downcast">state_downcast</a>() const;
// a model of the <a href="#StateBase">StateBase</a> concept
typedef <i>implementation-defined</i> state_base_type;
// a model of the standard Forward Iterator concept
typedef <i>implementation-defined</i> state_iterator;
state_iterator <a href="#state_begin">state_begin</a>() const;
state_iterator <a href="#state_end">state_end</a>() const;
void <a href="#unconsumed_event">unconsumed_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; ) {}
protected:
<a href="#state_machine">state_machine</a>();
<a href="#state_machinedtor">~state_machine</a>();
void <a href="#post_event2">post_event</a>(
const intrusive_ptr&lt; const <a href=
"#Classevent_base">event_base</a> &gt; &amp; );
void <a href="#post_event3">post_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; );
const event_base * <a href="#triggering_event1">triggering_event</a>() const;
};
}
}
</pre>
<h3>Class template <code>state_machine</code> constructor and
destructor</h3>
<pre>
<a name="state_machine" id="state_machine">state_machine</a>();
</pre>
<p><b>Effects</b>: Constructs a non-running state machine</p>
<pre>
<a name="state_machinedtor" id="state_machinedtor">~state_machine</a>();
</pre>
<p><b>Effects</b>: Destructs the currently active outermost state and all
its direct and indirect inner states. Innermost states are destructed
first. Other states are destructed as soon as all their direct and indirect
inner states have been destructed. The inner states of each state are
destructed according to the number of their orthogonal region. The state in
the orthogonal region with the highest number is always destructed first,
then the state in the region with the second-highest number and so on<br>
<b>Note</b>: Does not attempt to call any <code>exit</code> member
functions</p>
<h3>Class template <code>state_machine</code> modifier functions</h3>
<pre>
void <a name="initiate" id="initiate">initiate</a>();
</pre>
<p><b>Effects</b>:</p>
<ol>
<li>Calls <code>terminate()</code></li>
<li>Constructs a function object <code>action</code> with a
parameter-less <code>operator()()</code> returning <code><a href=
"#Classresult">result</a></code> that
<ol type="a">
<li>enters (constructs) the state specified with the
<code>InitialState</code> template parameter</li>
<li>enters the tree formed by the direct and indirect inner initial
states of <code>InitialState</code> depth first. The inner states of
each state are entered according to the number of their orthogonal
region. The state in orthogonal region 0 is always entered first,
then the state in region 1 and so on</li>
</ol>
</li>
<li>Constructs a function object <code>exceptionEventHandler</code> with
an <code>operator()()</code> returning <code>result</code> and accepting
an exception event parameter that processes the passed exception event,
with the following differences to the processing of normal events:
<ul type="disc">
<li>From the moment when the exception has been thrown until right
after the execution of the exception event reaction, states that need
to be exited are only destructed but no <code>exit</code> member
functions are called</li>
<li><a href="definitions.html#Reaction">Reaction</a> search always
starts with the outermost <a href=
"definitions.html#UnstableState">unstable state</a></li>
<li>As for normal events, reaction search moves outward when the
current state cannot handle the event. However, if there is no outer
state (an <a href="definitions.html#OutermostState">outermost
state</a> has been reached) the reaction search is considered
unsuccessful. That is, exception events will never be dispatched to
orthogonal regions other than the one that caused the exception
event</li>
<li>Should an exception be thrown during exception event reaction
search or reaction execution then the exception is propagated out of
the <code>exceptionEventHandler</code> function object (that is,
<code>ExceptionTranslator</code> is <b>not</b> used to translate
exceptions thrown while processing an exception event)</li>
<li>If no reaction could be found for the exception event or if the
state machine is not stable after processing the exception event, the
original exception is rethrown. Otherwise, a <code><a href=
"#Classresult">result</a></code> object is returned equal to the one
returned by <code>simple_state&lt;&gt;::discard_event()</code></li>
</ul>
</li>
<li>Passes <code>action</code> and <code>exceptionEventHandler</code> to
<code>ExceptionTranslator::operator()()</code>. If
<code>ExceptionTranslator::operator()()</code> throws an exception, the
exception is propagated to the caller. If the caller catches the
exception, the currently active outermost state and all its direct and
indirect inner states are destructed. Innermost states are destructed
first. Other states are destructed as soon as all their direct and
indirect inner states have been destructed. The inner states of each
state are destructed according to the number of their orthogonal region.
The state in the orthogonal region with the highest number is always
destructed first, then the state in the region with the second-highest
number and so on. Continues with step 5 otherwise (the return value is
discarded)</li>
<li>Processes all posted events (see <code>process_event()</code>).
Returns to the caller if there are no more posted events</li>
</ol>
<p><b>Throws</b>: Any exceptions propagated from
<code>ExceptionTranslator::operator()()</code>. Exceptions never originate
in the library itself but only in code supplied through template
parameters:</p>
<ul>
<li><code>Allocator::rebind&lt;&gt;::other::allocate()</code></li>
<li>state constructors</li>
<li><code>react</code> member functions</li>
<li><code>exit</code> member functions</li>
<li>transition-actions</li>
</ul>
<pre>
void <a name="terminate" id="terminate">terminate</a>();
</pre>
<p><b>Effects</b>:</p>
<ol>
<li>Constructs a function object <code>action</code> with a
parameter-less <code>operator()()</code> returning <code><a href=
"#Classresult">result</a></code> that <a href=
"#simple_state::terminate">terminates</a> the currently active outermost
state, discards all remaining events and clears all history
information</li>
<li>Constructs a function object <code>exceptionEventHandler</code> with
an <code>operator()()</code> returning <code><a href=
"#Classresult">result</a></code> and accepting an exception event
parameter that processes the passed exception event, with the following
differences to the processing of normal events:
<ul type="disc">
<li>From the moment when the exception has been thrown until right
after the execution of the exception event reaction, states that need
to be exited are only destructed but no <code>exit</code> member
functions are called</li>
<li><a href="definitions.html#Reaction">Reaction</a> search always
starts with the outermost <a href=
"definitions.html#UnstableState">unstable state</a></li>
<li>As for normal events, reaction search moves outward when the
current state cannot handle the event. However, if there is no outer
state (an <a href="definitions.html#OutermostState">outermost
state</a> has been reached) the reaction search is considered
unsuccessful. That is, exception events will never be dispatched to
orthogonal regions other than the one that caused the exception
event</li>
<li>Should an exception be thrown during exception event reaction
search or reaction execution then the exception is propagated out of
the <code>exceptionEventHandler</code> function object (that is,
<code>ExceptionTranslator</code> is <b>not</b> used to translate
exceptions thrown while processing an exception event)</li>
<li>If no reaction could be found for the exception event or if the
state machine is not stable after processing the exception event, the
original exception is rethrown. Otherwise, a <code><a href=
"#Classresult">result</a></code> object is returned equal to the one
returned by <code>simple_state&lt;&gt;::discard_event()</code></li>
</ul>
</li>
<li>Passes <code>action</code> and <code>exceptionEventHandler</code> to
<code>ExceptionTranslator::operator()()</code>. If
<code>ExceptionTranslator::operator()()</code> throws an exception, the
exception is propagated to the caller. If the caller catches the
exception, the currently active outermost state and all its direct and
indirect inner states are destructed. Innermost states are destructed
first. Other states are destructed as soon as all their direct and
indirect inner states have been destructed. The inner states of each
state are destructed according to the number of their orthogonal region.
The state in the orthogonal region with the highest number is always
destructed first, then the state in the region with the second-highest
number and so on. Otherwise, returns to the caller</li>
</ol>
<p><b>Throws</b>: Any exceptions propagated from
<code>ExceptionTranslator::operator()</code>. Exceptions never originate in
the library itself but only in code supplied through template
parameters:</p>
<ul>
<li><code>Allocator::rebind&lt;&gt;::other::allocate()</code></li>
<li>state constructors</li>
<li><code>react</code> member functions</li>
<li><code>exit</code> member functions</li>
<li>transition-actions</li>
</ul>
<pre>
void <a name="process_event" id=
"process_event">process_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; );
</pre>
<p><b>Effects</b>:</p>
<ol>
<li>Selects the passed event as the current event (henceforth referred to
as <code>currentEvent</code>)</li>
<li>Starts a new <a href="definitions.html#Reaction">reaction</a>
search</li>
<li>Selects an arbitrary but in this reaction search not yet visited
state from all the currently active <a href=
"definitions.html#InnermostState">innermost states</a>. If no such state
exists then continues with step 10</li>
<li>Constructs a function object <code>action</code> with a
parameter-less <code>operator()()</code> returning <code><a href=
"#Classresult">result</a></code> that does the following:
<ol type="a">
<li>Searches a reaction suitable for <code>currentEvent</code>,
starting with the current innermost state and moving outward until a
state defining a reaction for the event is found. Returns
<code>simple_state&lt;&gt;::forward_event()</code> if no reaction has
been found</li>
<li>Executes the found reaction. If the reaction result is equal to
the return value of
<code>simple_state&lt;&gt;::forward_event()</code> then resumes the
reaction search (step a). Returns the reaction result otherwise</li>
</ol>
</li>
<li>Constructs a function object <code>exceptionEventHandler</code>
returning <code><a href="#Classresult">result</a></code> and accepting an
exception event parameter that processes the passed exception event, with
the following differences to the processing of normal events:
<ul type="disc">
<li>From the moment when the exception has been thrown until right
after the execution of the exception event reaction, states that need
to be exited are only destructed but no <code>exit</code> member
functions are called</li>
<li>If the state machine is stable when the exception event is
processed then exception event reaction search starts with the
innermost state that was last visited during the last normal event
reaction search (the exception event was generated as a result of
this normal reaction search)</li>
<li>If the state machine is <a href=
"definitions.html#UnstableStateMachine">unstable</a> when the
exception event is processed then exception event reaction search
starts with the outermost <a href=
"definitions.html#UnstableState">unstable state</a></li>
<li>As for normal events, reaction search moves outward when the
current state cannot handle the event. However, if there is no outer
state (an <a href="definitions.html#OutermostState">outermost
state</a> has been reached) the reaction search is considered
unsuccessful. That is, exception events will never be dispatched to
orthogonal regions other than the one that caused the exception
event</li>
<li>Should an exception be thrown during exception event reaction
search or reaction execution then the exception is propagated out of
the <code>exceptionEventHandler</code> function object (that is,
<code>ExceptionTranslator</code> is <b>not</b> used to translate
exceptions thrown while processing an exception event)</li>
<li>If no reaction could be found for the exception event or if the
state machine is not stable after processing the exception event, the
original exception is rethrown. Otherwise, a <code><a href=
"#Classresult">result</a></code> object is returned equal to the one
returned by <code>simple_state&lt;&gt;::discard_event()</code></li>
</ul>
</li>
<li>Passes <code>action</code> and <code>exceptionEventHandler</code> to
<code>ExceptionTranslator::operator()()</code>. If
<code>ExceptionTranslator::operator()()</code> throws an exception, the
exception is propagated to the caller. If the caller catches the
exception, the currently active outermost state and all its direct and
indirect inner states are destructed. Innermost states are destructed
first. Other states are destructed as soon as all their direct and
indirect inner states have been destructed. The inner states of each
state are destructed according to the number of their orthogonal region.
The state in the orthogonal region with the highest number is always
destructed first, then the state in the region with the second-highest
number and so on. Otherwise continues with step 7</li>
<li>If the return value of <code>ExceptionTranslator::operator()()</code>
is equal to the one of <code>simple_state&lt;&gt;::forward_event()</code>
then continues with step 3</li>
<li>If the return value of <code>ExceptionTranslator::operator()()</code>
is equal to the one of <code>simple_state&lt;&gt;::defer_event()</code>
then the return value of <code>currentEvent.<a href=
"#intrusive_from_this">intrusive_from_this</a>()</code> is stored in a
state-specific queue. Continues with step 11</li>
<li>If the return value of <code>ExceptionTranslator::operator()()</code>
is equal to the one of <code>simple_state&lt;&gt;::discard_event()</code>
then continues with step 11</li>
<li>Calls <code>static_cast&lt; MostDerived * &gt;( this
)-&gt;unconsumed_event( currentEvent )</code>. If
<code>unconsumed_event()</code> throws an exception, the exception is
propagated to the caller. Such an exception never leads to the
destruction of any states (in contrast to exceptions propagated from
<code>ExceptionTranslator::operator()()</code>)</li>
<li>If the posted events queue is non-empty then dequeues the first
event, selects it as <code>currentEvent</code> and continues with step 2.
Returns to the caller otherwise</li>
</ol>
<p><b>Throws</b>: Any exceptions propagated from
<code>MostDerived::unconsumed_event()</code> or
<code>ExceptionTranslator::operator()</code>. Exceptions never originate in
the library itself but only in code supplied through template
parameters:</p>
<ul>
<li><code>Allocator::rebind&lt;&gt;::other::allocate()</code></li>
<li>state constructors</li>
<li><code>react</code> member functions</li>
<li><code>exit</code> member functions</li>
<li>transition-actions</li>
<li><code>MostDerived::unconsumed_event()</code></li>
</ul>
<pre>
void <a name="post_event2" id="post_event2">post_event</a>(
const intrusive_ptr&lt; const <a href=
"#Classevent_base">event_base</a> &gt; &amp; );
</pre>
<p><b>Effects</b>: Pushes the passed event into the posted events queue<br>
<b>Throws</b>: Any exceptions propagated from
<code>Allocator::allocate()</code></p>
<pre>
void <a name="post_event3" id="post_event3">post_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; evt );
</pre>
<p><b>Effects</b>: <code>post_event( evt.intrusive_from_this()
);</code><br>
<b>Throws</b>: Any exceptions propagated from
<code>Allocator::allocate()</code></p>
<pre>
void <a name="unconsumed_event" id=
"unconsumed_event">unconsumed_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; evt );
</pre>
<p><b>Effects</b>: None<br>
<b>Note</b>: This function (or, if present, the equally named derived class
member function) is called by <a href="#process_event">process_event</a>()
whenever a dispatched event did not trigger a reaction, see <a href=
"#process_event">process_event</a>() effects, point 10 for more
information.</p>
<h3>Class template <code>state_machine</code> observer functions</h3>
<pre>
bool <a name="terminated" id="terminated">terminated</a>() const;
</pre>
<p><b>Returns</b>: <code>true</code>, if the machine is terminated. Returns
<code>false</code> otherwise<br>
<b>Note</b>: Is equivalent to <code>state_begin() == state_end()</code></p>
<pre>
template&lt; class Target &gt;
Target <a name="state_cast" id="state_cast">state_cast</a>() const;
</pre>
<p><b>Returns</b>: Depending on the form of <code>Target</code> either a
reference or a pointer to <code>const</code> if at least one of the
currently active states can successfully be <code>dynamic_cast</code> to
<code>Target</code>. Returns <code>0</code> for pointer targets and throws
<code>std::bad_cast</code> for reference targets otherwise.
<code>Target</code> can take either of the following forms: <code>const
Class *</code> or <code>const Class &amp;</code><br>
<b>Throws</b>: <code>std::bad_cast</code> if <code>Target</code> is a
reference type and none of the active states can be
<code>dynamic_cast</code> to Target<br>
<b>Note</b>: The search sequence is the same as for <code><a href=
"#process_event">process_event</a>()</code></p>
<pre>
template&lt; class Target &gt;
Target <a name="state_downcast" id=
"state_downcast">state_downcast</a>() const;
</pre>
<p><b>Requires</b>: For reference targets the compiler must support partial
specialization of class templates, otherwise a compile-time error will
result. The type denoted by <code>Target</code> must be a model of the
<a href="#SimpleState">SimpleState</a> or <a href="#State">State</a>
concepts<br>
<b>Returns</b>: Depending on the form of <code>Target</code> either a
reference or a pointer to <code>const</code> if <code>Target</code> is
equal to the most-derived type of a currently active state. Returns
<code>0</code> for pointer targets and throws <code>std::bad_cast</code>
for reference targets otherwise. <code>Target</code> can take either of the
following forms: <code>const Class *</code> or <code>const Class
&amp;</code><br>
<b>Throws</b>: <code>std::bad_cast</code> if <code>Target</code> is a
reference type and none of the active states has a most derived type equal
to <code>Target</code><br>
<b>Note</b>: The search sequence is the same as for <code><a href=
"#process_event">process_event</a>()</code></p>
<pre>
state_iterator <a name="state_begin" id=
"state_begin">state_begin</a>() const;
</pre>
<pre>
state_iterator <a name="state_end" id="state_end">state_end</a>() const;
</pre>
<p><b>Return</b>: Iterator objects, the range [<code>state_begin()</code>,
<code>state_end()</code>) refers to all currently active <a href=
"definitions.html#InnermostState">innermost states</a>. For an object
<code>i</code> of type <code>state_iterator</code>, <code>*i</code> returns
a <code>const state_base_type &amp;</code> and
<code>i.operator-&gt;()</code> returns a <code>const state_base_type
*</code><br>
<b>Note</b>: The position of a given innermost state in the range is
arbitrary. It may change with each call to a modifier function. Moreover,
all iterators are invalidated whenever a modifier function is called</p>
<pre>
const event_base * <a name="triggering_event1" id="triggering_event1">triggering_event</a>();
</pre>
<p><b>Returns</b>: A pointer to the event that triggered the reaction that is currently
being executed. Returns <code>0</code> if no reaction is being executed or if the current
reaction was triggered by either <code><a href="#initiate">initiate</a>()</code> or
<code><a href="#terminate">terminate</a>()</code>
</p>
<h1>Header &lt;boost/statechart/<br>
<a name="asynchronous_state_machine.hpp" id=
"asynchronous_state_machine.hpp">asynchronous_state_machine.hpp</a>&gt;</h1>
<h2><a name="ClassTemplateasynchronous_state_machine" id=
"ClassTemplateasynchronous_state_machine">Class template
<code>asynchronous_state_machine</code></a></h2>
<p>This is the base class template of all asynchronous state machines.</p>
<h3>Class template <code>asynchronous_state_machine</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"asynchronous_state_machine parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>MostDerived</code></td>
<td>The most-derived subtype of this class template</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>InitialState</code></td>
<td>A model of the <a href="#SimpleState">SimpleState</a>
or <a href="#State">State</a> concepts. The <code>Context</code>
argument passed to the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base of
<code>InitialState</code> must be <code>MostDerived</code>. That is,
<code>InitialState</code> must be an <a href=
"definitions.html#OutermostState">outermost state</a> of this state
machine</td>
<td>The state that is entered when the state machine is
initiated through the <code>Scheduler</code> object</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>Scheduler</code></td>
<td>A model of the Scheduler concept</td>
<td>see <a href="#Scheduler">Scheduler</a> concept</td>
<td><code>fifo_scheduler&lt;&gt;</code></td>
</tr>
<tr>
<td><code>Allocator</code></td>
<td>A model of the standard Allocator concept</td>
<td>&nbsp;</td>
<td><code>std::allocator&lt; void &gt;</code></td>
</tr>
<tr>
<td><code>ExceptionTranslator</code></td>
<td>A model of the ExceptionTranslator concept</td>
<td>see <a href=
"#ExceptionTranslator">ExceptionTranslator</a> concept</td>
<td><code>null_exception_translator</code></td>
</tr>
</table>
<h3>Class template <code>asynchronous_state_machine</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt;
class MostDerived,
class InitialState,
class Scheduler = fifo_scheduler&lt;&gt;,
class Allocator = std::allocator&lt; void &gt;,
class ExceptionTranslator = null_exception_translator &gt;
class asynchronous_state_machine :
public state_machine&lt;
MostDerived, InitialState, Allocator, ExceptionTranslator &gt;,
public event_processor&lt; Scheduler &gt;
{
protected:
typedef asynchronous_state_machine my_base;
asynchronous_state_machine(
typename event_processor&lt; Scheduler &gt;::my_context ctx );
~asynchronous_state_machine();
};
}
}
</pre>
<h3>Class template <code>asynchronous_state_machine</code> constructor and
destructor</h3>
<pre>
asynchronous_state_machine(
typename event_processor&lt; Scheduler &gt;::my_context ctx );
</pre>
<p><b>Effects</b>: Constructs a non-running asynchronous state machine<br>
<b>Note</b>: Users cannot create
<code>asynchronous_state_machine&lt;&gt;</code> subtype objects directly.
This can only be done through an object of the <code>Scheduler</code>
class</p>
<pre>
~asynchronous_state_machine();
</pre>
<p><b>Effects</b>: Destructs the state machine<br>
<b>Note</b>: Users cannot destruct
<code>asynchronous_state_machine&lt;&gt;</code> subtype objects directly.
This can only be done through an object of the <code>Scheduler</code>
class</p>
<h1>Header &lt;boost/statechart/<a name="event_processor.hpp" id=
"event_processor.hpp">event_processor.hpp</a>&gt;</h1>
<h2><a name="ClassTemplateevent_processor" id=
"ClassTemplateevent_processor">Class template
<code>event_processor</code></a></h2>
<p>This is the base class template of all types that process events.
<code>asynchronous_state_machine&lt;&gt;</code> is just one possible event
processor implementation.</p>
<h3>Class template <code>event_processor</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"event_processor parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
</tr>
<tr>
<td><code>Scheduler</code></td>
<td>A model of the Scheduler concept</td>
<td>see <a href="#Scheduler">Scheduler</a> concept</td>
</tr>
</table>
<h3>Class template <code>event_processor</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt; class Scheduler &gt;
class event_processor
{
public:
virtual <a href="#event_processordtor">~event_processor</a>();
Scheduler &amp; <a href="#my_scheduler">my_scheduler</a>() const;
typedef typename Scheduler::processor_handle
processor_handle;
processor_handle <a href="#my_handle">my_handle</a>() const;
void <a href="#event_processor::initiate">initiate</a>();
void <a href=
"#event_processor::process_event">process_event</a>( const event_base &amp; evt );
void <a href="#event_processor::terminate">terminate</a>();
protected:
typedef const typename Scheduler::processor_context &amp;
my_context;
<a href="#event_processor">event_processor</a>( my_context ctx );
private:
virtual void initiate_impl() = 0;
virtual void process_event_impl(
const event_base &amp; evt ) = 0;
virtual void terminate_impl() = 0;
};
}
}
</pre>
<h3>Class template <code>event_processor</code> constructor and
destructor</h3>
<pre>
<a name="event_processor" id=
"event_processor">event_processor</a>( my_context ctx );
</pre>
<p><b>Effects</b>: Constructs an event processor object and stores copies
of the reference returned by <code>myContext.my_scheduler()</code> and the
object returned by <code>myContext.my_handle()</code><br>
<b>Note</b>: Users cannot create <code>event_processor&lt;&gt;</code>
subtype objects directly. This can only be done through an object of the
<code>Scheduler</code> class</p>
<pre>
virtual <a name="event_processordtor" id=
"event_processordtor">~event_processor</a>();
</pre>
<p><b>Effects</b>: Destructs an event processor object<br>
<b>Note</b>: Users cannot destruct <code>event_processor&lt;&gt;</code>
subtype objects directly. This can only be done through an object of the
<code>Scheduler</code> class</p>
<h3>Class template <code>event_processor</code> modifier functions</h3>
<pre>
void <a name="event_processor::initiate" id=
"event_processor::initiate">initiate</a>();
</pre>
<p><b>Effects</b>: <code>initiate_impl();<br></code><b>Throws</b>: Any
exceptions propagated from the implementation of
<code>initiate_impl()</code></p>
<pre>
void <a name="event_processor::process_event" id=
"event_processor::process_event">process_event</a>( const event_base &amp; evt );
</pre>
<p><b>Effects</b>: <code>process_event_impl( evt
);<br></code><b>Throws</b>: Any exceptions propagated from the
implementation of <code>process_event_impl()</code></p>
<pre>
void <a name="event_processor::terminate" id=
"event_processor::terminate">terminate</a>();
</pre>
<p><b>Effects</b>: <code>terminate_impl();<br></code><b>Throws</b>: Any
exceptions propagated from the implementation of
<code>terminate_impl()</code></p>
<h3>Class template <code>event_processor</code> observer functions</h3>
<pre>
Scheduler &amp; <a name="my_scheduler" id=
"my_scheduler">my_scheduler</a>() const;
</pre>
<p><b>Returns</b>: The <code>Scheduler</code> reference obtained in the
constructor</p>
<pre>
processor_handle <a name="my_handle" id="my_handle">my_handle</a>() const;
</pre>
<p><b>Returns</b>: The <code>processor_handle</code> object obtained in the
constructor</p>
<h1>Header &lt;boost/statechart/<a name="fifo_scheduler.hpp" id=
"fifo_scheduler.hpp">fifo_scheduler.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatefifo_scheduler" id=
"ClassTemplatefifo_scheduler">Class template
<code>fifo_scheduler</code></a></h2>
<p>This class template is a model of the <a href="#Scheduler">Scheduler</a>
concept.</p>
<h3>Class template <code>fifo_scheduler</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"fifo_scheduler parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>FifoWorker</code></td>
<td>A model of the FifoWorker concept</td>
<td>see <a href="#FifoWorker">FifoWorker</a> concept</td>
<td><code>fifo_worker&lt;&gt;</code></td>
</tr>
<tr>
<td><code>Allocator</code></td>
<td>A model of the standard Allocator concept</td>
<td>&nbsp;</td>
<td><code>std::allocator&lt;&nbsp;void&nbsp;&gt;</code></td>
</tr>
</table>
<h3>Class template <code>fifo_scheduler</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt;
class FifoWorker = fifo_worker&lt;&gt;,
class Allocator = std::allocator&lt; void &gt; &gt;
class fifo_scheduler : noncopyable
{
public:
<a href=
"#fifo_scheduler::fifo_scheduler">fifo_scheduler</a>( bool waitOnEmptyQueue = false );
typedef <i>implementation-defined</i> processor_handle;
class processor_context : noncopyable
{
processor_context(
fifo_scheduler &amp; scheduler,
const processor_handle &amp; theHandle );
fifo_scheduler &amp; my_scheduler() const;
const processor_handle &amp; my_handle() const;
friend class fifo_scheduler;
friend class event_processor&lt; fifo_scheduler &gt;;
};
template&lt; class Processor &gt;
processor_handle <a href="#create_processor">create_processor</a>();
template&lt; class Processor, typename Param1 &gt;
processor_handle <a href=
"#create_processor1">create_processor</a>( Param1 param1 );
// More create_processor overloads
void <a href=
"#destroy_processor">destroy_processor</a>( processor_handle processor );
void <a href=
"#initiate_processor">initiate_processor</a>( processor_handle processor );
void <a href=
"#terminate_processor">terminate_processor</a>( processor_handle processor );
typedef intrusive_ptr&lt; const event_base &gt; event_ptr_type;
void <a href="#queue_event">queue_event</a>(
const processor_handle &amp; processor,
const event_ptr_type &amp; pEvent );
typedef typename FifoWorker::work_item work_item;
void <a href=
"#queue_work_item">queue_work_item</a>( const work_item &amp; item );
void <a href="#fifo_scheduler::terminate">terminate</a>();
bool <a href="#fifo_scheduler::terminated">terminated</a>() const;
unsigned long <a href="#operatorfuncall">operator()</a>(
unsigned long maxEventCount = 0 );
};
}
}
</pre>
<h3>Class template <code>fifo_scheduler</code> constructor</h3>
<pre>
<a name="fifo_scheduler::fifo_scheduler" id=
"fifo_scheduler::fifo_scheduler">fifo_scheduler</a>( bool waitOnEmptyQueue = false );
</pre>
<p><b>Effects</b>: Constructs a <code>fifo_scheduler&lt;&gt;</code> object.
In multi-threaded builds, <code>waitOnEmptyQueue</code> is forwarded to the
constructor of a data member of type <code>FifoWorker</code>. In
single-threaded builds, the <code>FifoWorker</code> data member is
default-constructed<br>
<b>Note</b>: In single-threaded builds the
<code>fifo_scheduler&lt;&gt;</code> constructor does not accept any
parameters and <code>operator()()</code> thus always returns to the caller
when the event queue is empty</p>
<h3>Class template <code>fifo_scheduler</code> modifier functions</h3>
<pre>
template&lt; class Processor &gt;
processor_handle <a name="create_processor" id=
"create_processor">create_processor</a>();
</pre>
<p><b>Requires</b>: The <code>Processor</code> type must be a direct or
indirect subtype of the <a href=
"#ClassTemplateevent_processor"><code>event_processor</code></a> class
template<br>
<b>Effects</b>: Creates and passes to
<code>FifoWorker::queue_work_item()</code> an object of type
<code>FifoWorker::work_item</code> that, when later executed in
<code>FifoWorker::operator()()</code>, leads to a call to the constructor
of <code>Processor</code>, passing an appropriate
<code>processor_context</code> object as the only argument<br>
<b>Returns</b>: A <code>processor_handle</code> object that henceforth
identifies the created event processor object<br>
<b>Throws</b>: Any exceptions propagated from
<code>FifoWorker::work_item()</code> and
<code>FifoWorker::queue_work_item()</code><br>
<b>Caution</b>: The current implementation of this function makes an
(indirect) call to global <code>operator new()</code>. Unless global
<code>operator new()</code> is replaced, care must be taken when to call
this function in applications with hard real-time requirements</p>
<pre>
template&lt; class Processor, typename Param1 &gt;
processor_handle <a name="create_processor1" id=
"create_processor1">create_processor( Param1 param1 )</a>;
</pre>
<p><b>Requires</b>: The <code>Processor</code> type must be a direct or
indirect subtype of the <a href=
"#ClassTemplateevent_processor"><code>event_processor</code></a> class
template<br>
<b>Effects</b>: Creates and passes to
<code>FifoWorker::queue_work_item()</code> an object of type
<code>FifoWorker::work_item</code> that, when later executed in
<code>FifoWorker::operator()()</code>, leads to a call to the constructor
of <code>Processor</code>, passing an appropriate
<code>processor_context</code> object and <code>param1</code> as
arguments<br>
<b>Returns</b>: A <code>processor_handle</code> object that henceforth
identifies the created event processor object<br>
<b>Throws</b>: Any exceptions propagated from
<code>FifoWorker::work_item()</code> and
<code>FifoWorker::queue_work_item()</code><b><br>
Note</b>: <code>boost::ref()</code> and <code>boost::cref()</code> can be
used to pass arguments by reference rather than by copy.
<code>fifo_scheduler&lt;&gt;</code> has 5 additional
<code>create_processor&lt;&gt;</code> overloads, allowing to pass up to 6
custom arguments to the constructors of event processors<br>
<b>Caution</b>: The current implementation of this and all other overloads
make (indirect) calls to global <code>operator new()</code>. Unless global
<code>operator new()</code> is replaced, care must be taken when to call
these overloads in applications with hard real-time requirements</p>
<pre>
void <a name="destroy_processor" id=
"destroy_processor">destroy_processor</a>( processor_handle processor );
</pre>
<p><b>Requires</b>: <code>processor</code> was obtained from a call to one
of the <code>create_processor&lt;&gt;()</code> overloads on the same
<code>fifo_scheduler&lt;&gt;</code> object<br>
<b>Effects</b>: Creates and passes to
<code>FifoWorker::queue_work_item()</code> an object of type
<code>FifoWorker::work_item</code> that, when later executed in
<code>FifoWorker::operator()()</code>, leads to a call to the destructor of
the event processor object associated with <code>processor</code>. The
object is silently discarded if the event processor object has been
destructed before<br>
<b>Throws</b>: Any exceptions propagated from
<code>FifoWorker::work_item()</code> and
<code>FifoWorker::queue_work_item()</code><br>
<b>Caution</b>: The current implementation of this function leads to an
(indirect) call to global <code>operator delete()</code> (the call is made
when the last <code>processor_handle</code> object associated with the
event processor object is destructed). Unless global <code>operator
delete()</code> is replaced, care must be taken when to call this function
in applications with hard real-time requirements</p>
<pre>
void <a name="initiate_processor" id=
"initiate_processor">initiate_processor</a>( processor_handle processor );
</pre>
<p><b>Requires</b>: <code>processor</code> was obtained from a call to one
of the <code>create_processor()</code> overloads on the same
<code>fifo_scheduler&lt;&gt;</code> object<br>
<b>Effects</b>: Creates and passes to
<code>FifoWorker::queue_work_item()</code> an object of type
<code>FifoWorker::work_item</code> that, when later executed in
<code>FifoWorker::operator()()</code>, leads to a call to <code><a href=
"#event_processor::initiate">initiate</a>()</code> on the event processor
object associated with <code>processor</code>. The object is silently
discarded if the event processor object has been destructed before<br>
<b>Throws</b>: Any exceptions propagated from
<code>FifoWorker::work_item()</code> and
<code>FifoWorker::queue_work_item()</code></p>
<pre>
void <a name="terminate_processor" id=
"terminate_processor">terminate_processor</a>( processor_handle processor );
</pre>
<p><b>Requires</b>: <code>processor</code> was obtained from a call to one
of the <code>create_processor&lt;&gt;()</code> overloads on the same
<code>fifo_scheduler&lt;&gt;</code> object<br>
<b>Effects</b>: Creates and passes to
<code>FifoWorker::queue_work_item()</code> an object of type
<code>FifoWorker::work_item</code> that, when later executed in
<code>FifoWorker::operator()()</code>, leads to a call to <code><a href=
"#event_processor::terminate">terminate</a>()</code> on the event processor
object associated with <code>processor</code>. The object is silently
discarded if the event processor object has been destructed before<br>
<b>Throws</b>: Any exceptions propagated from
<code>FifoWorker::work_item()</code> and
<code>FifoWorker::queue_work_item()</code></p>
<pre>
void <a name="queue_event" id="queue_event">queue_event</a>(
const processor_handle &amp; processor,
const event_ptr_type &amp; pEvent );
</pre>
<p><b>Requires</b>: <code>pEvent.get() != 0</code> and
<code>processor</code> was obtained from a call to one of the
<code>create_processor&lt;&gt;()</code> overloads on the same
<code>fifo_scheduler&lt;&gt;</code> object<br>
<b>Effects</b>: Creates and passes to
<code>FifoWorker::queue_work_item()</code> an object of type
<code>FifoWorker::work_item</code> that, when later executed in
<code>FifoWorker::operator()()</code>, leads to a call to <code><a href=
"#event_processor::process_event">process_event</a>( *pEvent )</code> on
the event processor object associated with <code>processor</code>. The
object is silently discarded if the event processor object has been
destructed before<br>
<b>Throws</b>: Any exceptions propagated from
<code>FifoWorker::work_item()</code> and
<code>FifoWorker::queue_work_item()</code></p>
<pre>
void <a name="queue_work_item" id=
"queue_work_item">queue_work_item</a>( const work_item &amp; item );
</pre>
<p><b>Effects</b>: <code>FifoWorker::queue_work_item( item );</code><br>
<b>Throws</b>: Any exceptions propagated from the above call</p>
<pre>
void <a name="fifo_scheduler::terminate" id=
"fifo_scheduler::terminate">terminate</a>();
</pre>
<p><b>Effects</b>: <code>FifoWorker::terminate()</code><br>
<b>Throws</b>: Any exceptions propagated from the above call</p>
<pre>
unsigned long <a name="operatorfuncall" id=
"operatorfuncall">operator()</a>( unsigned long maxEventCount = 0 );
</pre>
<p><b>Requires</b>: Must only be called from exactly one thread<b><br>
Effects</b>: <code>FifoWorker::operator()( maxEventCount )</code><br>
<b>Returns</b>: The return value of the above call<br>
<b>Throws</b>: Any exceptions propagated from the above call</p>
<h3>Class template <code>fifo_scheduler</code> observer functions</h3>
<pre>
bool <a name="fifo_scheduler::terminated" id=
"fifo_scheduler::terminated">terminated</a>() const;
</pre>
<p><b>Requires</b>: Must only be called from the thread that also calls
<code>operator()()</code><br>
<b>Returns</b>: <code>FifoWorker::terminated();</code></p>
<h1>Header &lt;boost/statechart/<a name="exception_translator.hpp" id=
"exception_translator.hpp">exception_translator.hpp</a>&gt;</h1>
<h2><a name="ClassTemplateexception_translator" id=
"ClassTemplateexception_translator">Class template
<code>exception_translator</code></a></h2>
<p>This class template is a model of the <a href=
"#ExceptionTranslator">ExceptionTranslator</a> concept.</p>
<h3>Class template <code>exception_translator</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"exception_translator parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>ExceptionEvent</code></td>
<td>A model of the <a href="#Event">Event</a> concept</td>
<td>The type of event that is dispatched when an exception
is propagated into the framework</td>
<td><code>exception_thrown</code></td>
</tr>
</table>
<h3>Class template <code>exception_translator</code> synopsis &amp;
semantics</h3>
<pre>
namespace boost
{
namespace statechart
{
class exception_thrown : public event&lt; exception_thrown &gt; {};
template&lt; class ExceptionEvent = exception_thrown &gt;
class exception_translator
{
public:
template&lt; class Action, class ExceptionEventHandler &gt;
result operator()(
Action action,
ExceptionEventHandler eventHandler )
{
try
{
return action();
}
catch( ... )
{
return eventHandler( ExceptionEvent() );
}
}
};
}
}
</pre>
<h1>Header &lt;boost/statechart/<br>
<a name="null_exception_translator.hpp" id=
"null_exception_translator.hpp">null_exception_translator.hpp</a>&gt;</h1>
<h2><a name="Classnull_exception_translator" id=
"Classnull_exception_translator">Class
<code>null_exception_translator</code></a></h2>
<p>This class is a model of the <a href=
"#ExceptionTranslator">ExceptionTranslator</a> concept.</p>
<h3>Class <code>null_exception_translator</code> synopsis &amp;
semantics</h3>
<pre>
namespace boost
{
namespace statechart
{
class null_exception_translator
{
public:
template&lt; class Action, class ExceptionEventHandler &gt;
result operator()(
Action action, ExceptionEventHandler )
{
return action();
}
};
}
}
</pre>
<h1>Header &lt;boost/statechart/<a name="simple_state.hpp" id=
"simple_state.hpp">simple_state.hpp</a>&gt;</h1>
<h2><a name="Enumhistory_mode" id="Enumhistory_mode">Enum
<code>history_mode</code></a></h2>
<p>Defines the history type of a state.</p>
<pre>
namespace boost
{
namespace statechart
{
enum history_mode
{
has_no_history,
has_shallow_history,
has_deep_history,
has_full_history // shallow &amp; deep
};
}
}
</pre>
<h2><a name="ClassTemplatesimple_state" id=
"ClassTemplatesimple_state">Class template
<code>simple_state</code></a></h2>
<p>This is the base class template for all models of the <a href=
"#SimpleState">SimpleState</a> concept. Such models must not call any of
the following <code>simple_state&lt;&gt;</code> member functions from their
constructors:</p>
<pre>
void <b>post_event</b>(
const intrusive_ptr&lt; const event_base &gt; &amp; );
void <b>post_event</b>( const event_base &amp; );
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <b>clear_shallow_history</b>();
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <b>clear_deep_history</b>();
outermost_context_type &amp; <b>outermost_context</b>();
const outermost_context_type &amp; <b>outermost_context</b>() const;
template&lt; class OtherContext &gt;
OtherContext &amp; <b>context</b>();
template&lt; class OtherContext &gt;
const OtherContext &amp; <b>context</b>() const;
template&lt; class Target &gt;
Target <b>state_cast</b>() const;
template&lt; class Target &gt;
Target <b>state_downcast</b>() const;
state_iterator <b>state_begin</b>() const;
state_iterator <b>state_end</b>() const;
const event_base * <b>triggering_event</b>() const;
</pre>
<p>States that need to call any of these member functions from their
constructors must derive from the <code><a href=
"#ClassTemplatestate">state</a></code> class template.</p>
<h3>Class template <code>simple_state</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"simple_state parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>MostDerived</code></td>
<td>The most-derived subtype of this class template</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>Context</code></td>
<td>A most-derived direct or indirect subtype of the
<code><a href="#ClassTemplatestate_machine">state_machine</a></code> or
<code><a href=
"#ClassTemplateasynchronous_state_machine">asynchronous_state_machine</a></code>
class templates or a model of the <a href=
"#SimpleState">SimpleState</a> or <a href="#State">State</a> concepts
or an instantiation of the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;::orthogonal</a></code>
class template. Must be a complete type</td>
<td>Defines the states' position in the state
hierarchy</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>InnerInitial</code></td>
<td>An <code>mpl::list&lt;&gt;</code> containing models of
the <a href="#SimpleState">SimpleState</a> or <a href=
"#State">State</a> concepts or instantiations of the <code><a href=
"#ClassTemplateshallow_history">shallow_history</a></code> or
<code><a href="#ClassTemplatedeep_history">deep_history</a></code>
class templates. If there is only a single inner initial state that is
not a template instantiation then it can also be passed directly,
without wrapping it into an <code>mpl::list&lt;&gt;</code>. The
<code>Context</code> argument passed to the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base
of&nbsp;each state in the list must correspond to the orthogonal region
it belongs to. That is, the first state in the list must pass
<code>MostDerived::orthogonal&lt; 0 &gt;</code>, the second
<code>MostDerived::orthogonal&lt; 1 &gt;</code> and so forth.
<code>MostDerived::orthogonal&lt; 0 &gt;</code> and
<code>MostDerived</code> are synonymous</td>
<td>Defines the inner initial state for each orthogonal
region. By default, a state does not have inner states</td>
<td><i><code>unspecified</code></i></td>
</tr>
<tr>
<td><code>historyMode</code></td>
<td>One of the values defined in the <code><a href=
"#Enumhistory_mode">history_mode</a></code> enumeration</td>
<td>Defines whether the state saves shallow, deep or both
histories upon exit</td>
<td><code>has_no_history</code></td>
</tr>
</table>
<h3>Class template <code>simple_state</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt;
class MostDerived,
class Context,
class InnerInitial = <i>unspecified</i>,
history_mode historyMode = has_no_history &gt;
class simple_state : <i>implementation-defined</i>
{
public:
// by default, a state has no reactions
typedef mpl::list&lt;&gt; reactions;
// see template parameters
template&lt; <i>implementation-defined-unsigned-integer-type
</i> innerOrthogonalPosition &gt;
struct orthogonal
{
// <i>implementation-defined</i>
};
typedef typename Context::outermost_context_type
outermost_context_type;
outermost_context_type &amp; <a href=
"#outermost_context">outermost_context</a>();
const outermost_context_type &amp; <a href=
"#outermost_contextconst">outermost_context</a>() const;
template&lt; class OtherContext &gt;
OtherContext &amp; <a href="#context">context</a>();
template&lt; class OtherContext &gt;
const OtherContext &amp; <a href="#contextconst">context</a>() const;
template&lt; class Target &gt;
Target <a href="#simple_state::state_cast">state_cast</a>() const;
template&lt; class Target &gt;
Target <a href=
"#simple_state::state_downcast">state_downcast</a>() const;
// a model of the StateBase concept
typedef <i>implementation-defined</i> state_base_type;
// a model of the standard Forward Iterator concept
typedef <i>implementation-defined</i> state_iterator;
state_iterator <a href=
"#simple_state::state_begin">state_begin</a>() const;
state_iterator <a href=
"#simple_state::state_end">state_end</a>() const;
const event_base * <a href="#triggering_event0">triggering_event</a>() const;
void <a href="#post_event0">post_event</a>(
const intrusive_ptr&lt; const <a href=
"#Classevent_base">event_base</a> &gt; &amp; );
void <a href="#post_event1">post_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; );
<a href="#Classresult">result</a> <a href=
"#discard_event">discard_event</a>();
<a href="#Classresult">result</a> <a href=
"#forward_event">forward_event</a>();
<a href="#Classresult">result</a> <a href=
"#defer_event">defer_event</a>();
template&lt; class DestinationState &gt;
<a href="#Classresult">result</a> <a href="#transit1">transit</a>();
template&lt;
class DestinationState,
class TransitionContext,
class Event &gt;
<a href="#Classresult">result</a> <a href="#transit2">transit</a>(
void ( TransitionContext::* )( const Event &amp; ),
const Event &amp; );
<a href="#Classresult">result</a> <a href=
"#simple_state::terminate">terminate</a>();
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <a href="#clear_shallow_history">clear_shallow_history</a>();
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <a href="#clear_deep_history">clear_deep_history</a>();
static id_type <a href="#static_type">static_type</a>();
template&lt; class CustomId &gt;
static const CustomId * <a href=
"#custom_static_type_ptr">custom_static_type_ptr</a>();
template&lt; class CustomId &gt;
static void <a href=
"#custom_static_type_ptr1">custom_static_type_ptr</a>( const CustomId * );
// see <a href="#transit1">transit</a>() or <a href=
"#simple_state::terminate">terminate</a>() effects
void exit() {}
protected:
<a href="#simple_state">simple_state</a>();
<a href="#simple_statedtor">~simple_state</a>();
};
}
}
</pre>
<h3>Class template <code>simple_state</code> constructor and
destructor</h3>
<pre>
<a name="simple_state" id="simple_state">simple_state</a>();
</pre>
<p><b>Effects</b>: Constructs a state object</p>
<pre>
<a name="simple_statedtor" id="simple_statedtor">~simple_state</a>();
</pre>
<p><b>Effects</b>: Pushes all events deferred by the state into the posted
events queue</p>
<h3>Class template <code>simple_state</code> modifier functions</h3>
<pre>
void <a name="post_event0" id="post_event0">post_event</a>(
const intrusive_ptr&lt; const <a href=
"#Classevent_base">event_base</a> &gt; &amp; pEvt );
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template<b>.</b> All direct and indirect
callers must be exception-neutral<b><br>
Effects</b>: <a href=
"#outermost_context"><code>outermost_context</code></a><code>().<a href=
"#post_event2">post_event</a>( pEvt );</code><br>
<b>Throws</b>: Whatever the above call throws</p>
<pre>
void <a name="post_event1" id="post_event1">post_event</a>( const <a href=
"#Classevent_base">event_base</a> &amp; evt );
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template<b>.</b> All direct and indirect
callers must be exception-neutral<b><br>
Effects</b>: <a href=
"#outermost_context"><code>outermost_context</code></a><code>().<a href=
"#post_event3">post_event</a>( evt );</code><br>
<b>Throws</b>: Whatever the above call throws</p>
<pre>
<a href="#Classresult">result</a> <a name="discard_event" id=
"discard_event">discard_event</a>();
</pre>
<p><b>Requires</b>: Must only be called from within <code>react</code>
member functions, which are called by <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction&lt;&gt;</a></code>
instantiations. All direct and indirect callers must be
exception-neutral<br>
<b>Effects</b>: Instructs the state machine to discard the current event
and to continue with the processing of the remaining events (see
<code><a href=
"#process_event">state_machine&lt;&gt;::process_event</a>()</code> for
details)<br>
<b>Returns</b>: A <code><a href="#Classresult">result</a></code> object.
The user-supplied <code>react</code> member function must return this
object to its caller</p>
<pre>
<a href="#Classresult">result</a> <a name="forward_event" id=
"forward_event">forward_event</a>();
</pre>
<p><b>Requires</b>: Must only be called from within <code>react</code>
member functions, which are called by <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction&lt;&gt;</a></code>
instantiations. All direct and indirect callers must be
exception-neutral<br>
<b>Effects</b>: Instructs the state machine to forward the current event to
the next state (see <code><a href=
"#process_event">state_machine&lt;&gt;::process_event</a>()</code> for
details)<br>
<b>Returns</b>: A <code><a href="#Classresult">result</a></code> object.
The user-supplied <code>react</code> member function must return this
object to its caller</p>
<pre>
<a href="#Classresult">result</a> <a name="defer_event" id=
"defer_event">defer_event</a>();
</pre>
<p><b>Requires</b>: Must only be called from within <code>react</code>
member functions, which are called by <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction&lt;&gt;</a></code>
instantiations. All direct and indirect callers must be
exception-neutral<br>
<b>Effects</b>: Instructs the state machine to defer the current event and
to continue with the processing of the remaining events (see <code><a href=
"#process_event">state_machine&lt;&gt;::process_event</a>()</code> for
details)<br>
<b>Returns</b>: A <code><a href="#Classresult">result</a></code> object.
The user-supplied <code>react</code> member function must return this
object to its caller<br>
<b>Throws</b>: Any exceptions propagated from
<code>Allocator::rebind&lt;&gt;::other::allocate()</code> (the template
parameter passed to the base class of
<code>outermost_context_type</code>)</p>
<pre>
template&lt; class DestinationState &gt;
<a href="#Classresult">result</a> <a name="transit1" id=
"transit1">transit</a>();
</pre>
<p><b>Requires</b>: Must only be called from within <code>react</code>
member functions, which are called by <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction&lt;&gt;</a></code>
instantiations. All direct and indirect callers must be
exception-neutral<br>
<b>Effects</b>:</p>
<ol>
<li>Exits all currently active direct and indirect inner states of the
innermost common context of this state and <code>DestinationState</code>.
Innermost states are exited first. Other states are exited as soon as all
their direct and indirect inner states have been exited. The inner states
of each state are exited according to the number of their orthogonal
region. The state in the orthogonal region with the highest number is
always exited first, then the state in the region with the second-highest
number and so on.<br>
The process of exiting a state consists of the following steps:
<ol>
<li>If there is an exception pending that has not yet been handled
successfully then only step 5 is executed</li>
<li>Calls the <code>exit</code> member function (see <a href=
"#ClassTemplatesimple_state">synopsis</a>) of the most-derived state
object. If <code>exit()</code> throws then steps 3 and 4 are not
executed</li>
<li>If the state has shallow history then shallow history information
is saved</li>
<li>If the state is an innermost state then deep history information
is saved for all direct and indirect outer states that have deep
history</li>
<li>The state object is destructed</li>
</ol>
</li>
<li>Enters (constructs) the state that is both a direct inner state of
the innermost common context and either the <code>DestinationState</code>
itself or a direct or indirect outer state of
<code>DestinationState</code></li>
<li>Enters (constructs) the tree formed by the direct and indirect inner
states of the previously entered state down to the
<code>DestinationState</code> and beyond depth first. The inner states of
each state are entered according to the number of their orthogonal
region. The state in orthogonal region 0 is always entered first, then
the state in region 1 and so on</li>
<li>Instructs the state machine to discard the current event and to
continue with the processing of the remaining events (see <code><a href=
"#process_event">state_machine&lt;&gt;::process_event</a>()</code> for
details)</li>
</ol>
<p><b>Returns</b>: A <code><a href="#Classresult">result</a></code> object.
The user-supplied <code>react</code> member function must return this
object to its caller<br>
<b>Throws</b>: Any exceptions propagated from:</p>
<ul>
<li><code>Allocator::rebind&lt;&gt;::other::allocate()</code> (the
template parameter passed to the base class of
<code>outermost_context_type</code>)</li>
<li>state constructors</li>
<li><code>exit</code> member functions</li>
</ul>
<p><b>Caution</b>: Inevitably destructs this state before returning to the
calling <code>react</code> member function, which must therefore not
attempt to access anything except stack objects before returning to its
caller</p>
<pre>
template&lt;
class DestinationState,
class TransitionContext,
class Event &gt;
<a href="#Classresult">result</a> <a name="transit2" id=
"transit2">transit</a>(
void ( TransitionContext::* )( const Event &amp; ),
const Event &amp; );
</pre>
<p><b>Requires</b>: Must only be called from within <code>react</code>
member functions, which are called by <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction&lt;&gt;</a></code>
instantiations. All direct and indirect callers must be
exception-neutral<br>
<b>Effects</b>:</p>
<ol>
<li>Exits all currently active direct and indirect inner states of the
innermost common context of this state and <code>DestinationState</code>.
Innermost states are exited first. Other states are exited as soon as all
their direct and indirect inner states have been exited. The inner states
of each state are exited according to the number of their orthogonal
region. The state in the orthogonal region with the highest number is
always exited first, then the state in the region with the second-highest
number and so on.<br>
The process of exiting a state consists of the following steps:
<ol>
<li>If there is an exception pending that has not yet been handled
successfully then only step 5 is executed</li>
<li>Calls the <code>exit</code> member function (see <a href=
"#ClassTemplatesimple_state">synopsis</a>) of the most-derived state
object. If <code>exit()</code> throws then steps 3 and 4 are not
executed</li>
<li>If the state has shallow history then shallow history information
is saved</li>
<li>If the state is an innermost state then deep history information
is saved for all direct and indirect outer states that have deep
history</li>
<li>The state object is destructed</li>
</ol>
</li>
<li>Executes the passed transition action, forwarding the passed
event</li>
<li>Enters (constructs) the state that is both a direct inner state of
the innermost common context and either the <code>DestinationState</code>
itself or a direct or indirect outer state of
<code>DestinationState</code></li>
<li>Enters (constructs) the tree formed by the direct and indirect inner
states of the previously entered state down to the
<code>DestinationState</code> and beyond depth first. The inner states of
each state are entered according to the number of their orthogonal
region. The state in orthogonal region 0 is always entered first, then
the state in region 1 and so on</li>
<li>Instructs the state machine to discard the current event and to
continue with the processing of the remaining events (see <code><a href=
"#process_event">state_machine&lt;&gt;::process_event</a>()</code> for
details)</li>
</ol>
<p><b>Returns</b>: A <code><a href="#Classresult">result</a></code> object.
The user-supplied <code>react</code> member function must return this
object to its caller<br>
<b>Throws</b>: Any exceptions propagated from:</p>
<ul>
<li><code>Allocator::rebind&lt;&gt;::other::allocate()</code> (the
template parameter passed to the base class of
<code>outermost_context_type</code>)</li>
<li>state constructors</li>
<li><code>exit</code> member functions</li>
<li>the transition action</li>
</ul>
<p><b>Caution</b>: Inevitably destructs this state before returning to the
calling <code>react</code> member function, which must therefore not
attempt to access anything except stack objects before returning to its
caller</p>
<pre>
<a href="#Classresult">result</a> <a name="simple_state::terminate" id=
"simple_state::terminate">terminate</a>();
</pre>
<p><b>Requires</b>: Must only be called from within <code>react</code>
member functions, which are called by <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction&lt;&gt;</a></code>
instantiations. All direct and indirect callers must be
exception-neutral<br>
<b>Effects</b>: Exits this state and all its direct and indirect inner
states. Innermost states are exited first. Other states are exited as soon
as all their direct and indirect inner states have been exited. The inner
states of each state are exited according to the number of their orthogonal
region. The state in the orthogonal region with the highest number is
always exited first, then the state in the region with the second-highest
number and so on.<br>
The process of exiting a state consists of the following steps:</p>
<ol>
<li>If there is an exception pending that has not yet been handled
successfully then only step 5 is executed</li>
<li>Calls the <code>exit</code> member function (see <a href=
"#ClassTemplatesimple_state">synopsis</a>) of the most-derived state
object. If <code>exit()</code> throws then steps 3 and 4 are not
executed</li>
<li>If the state has shallow history then shallow history information is
saved</li>
<li>If the state is an innermost state then deep history information is
saved for all direct and indirect outer states that have deep
history</li>
<li>The state object is destructed</li>
</ol>
<p>Also instructs the state machine to discard the current event and to
continue with the processing of the remaining events (see <code><a href=
"#process_event">state_machine&lt;&gt;::process_event</a>()</code> for
details)<br>
<b>Returns</b>: A <code><a href="#Classresult">result</a></code> object.
The user-supplied <code>react</code> member function must return this
object to its caller<br>
<b>Throws</b>: Any exceptions propagated from:</p>
<ul>
<li><code>Allocator::rebind&lt;&gt;::other::allocate()</code> (the
template parameter passed to the base class of
<code>outermost_context_type</code>, used to allocate space to save
history)</li>
<li><code>exit</code> member functions</li>
</ul>
<p><b>Note</b>: If this state is the only currently active inner state of
its direct outer state then the direct outer state is terminated also. The
same applies recursively for all indirect outer states<br>
<b>Caution</b>: Inevitably destructs this state before returning to the
calling <code>react</code> member function, which must therefore not
attempt to access anything except stack objects before returning to its
caller</p>
<pre>
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <a name="clear_shallow_history" id=
"clear_shallow_history">clear_shallow_history</a>();
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template. The <code>historyMode</code>
argument passed to the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base
of&nbsp;<code>HistoryContext</code> must be equal to
<code>has_shallow_history</code> or <code>has_full_history</code><br>
<b>Effects</b>: Clears the shallow history of the orthogonal region
specified by <code>orthogonalPosition</code> of the state specified by
<code>HistoryContext</code><br>
<b>Throws</b>: Any exceptions propagated from
<code>Allocator::rebind&lt;&gt;::other::allocate()</code> (the template
parameter passed to the base class of
<code>outermost_context_type</code>)</p>
<pre>
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <a name="clear_deep_history" id=
"clear_deep_history">clear_deep_history</a>();
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template. The <code>historyMode</code>
argument passed to the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base
of&nbsp;<code>HistoryContext</code> must be equal to
<code>has_deep_history</code> or <code>has_full_history</code><br>
<b>Effects</b>: Clears the deep history of the orthogonal region specified
by <code>orthogonalPosition</code> of the state specified by
<code>HistoryContext</code><br>
<b>Throws</b>: Any exceptions propagated from
<code>Allocator::rebind&lt;&gt;::other::allocate()</code> (the template
parameter passed to the base class of
<code>outermost_context_type</code>)</p>
<h3>Class template <code>simple_state</code> observer functions</h3>
<pre>
outermost_context_type &amp; <a name="outermost_context" id=
"outermost_context">outermost_context</a>();
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template. If called from a destructor of a
direct or indirect subtype then the <code>state_machine&lt;&gt;</code> subclass
portion must still exist<br>
<b>Returns</b>: A reference to the outermost context, which is always the
state machine this state belongs to<br></p>
<pre>
const outermost_context_type &amp; <a name="outermost_contextconst" id=
"outermost_contextconst">outermost_context() const</a>;
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template. If called from a destructor of a
direct or indirect subtype then the <code>state_machine&lt;&gt;</code> subclass
portion must still exist<br>
<b>Returns</b>: A reference to the const outermost context, which is always
the state machine this state belongs to</p>
<pre>
template&lt; class OtherContext &gt;
OtherContext &amp; <a name="context" id="context">context</a>();
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template. If called from a destructor of a
direct or indirect subtype with a <code>state_machine&lt;&gt;</code> subtype as
argument then the <code>state_machine&lt;&gt;</code> subclass portion must still
exist<br>
<b>Returns</b>: A reference to a direct or indirect context or any public base
type of the contexts</p>
<pre>
template&lt; class OtherContext &gt;
const OtherContext &amp; <a name="contextconst" id=
"contextconst">context() const</a>;
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template. If called from a destructor of a
direct or indirect subtype with a <code>state_machine&lt;&gt;</code> subtype as
argument then the <code>state_machine&lt;&gt;</code> subclass portion must still
exist<br>
<b>Returns</b>: A reference to a const direct or indirect context or any public
base type of the contexts</p>
<pre>
template&lt; class Target &gt;
Target <a name="simple_state::state_cast" id=
"simple_state::state_cast">state_cast</a>() const;
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template<b><br>
Returns</b>: Has exactly the same semantics as <code><a href=
"#state_cast">state_machine&lt;&gt;::state_cast</a>&lt;&gt;()</code><br>
<b>Throws</b>: Has exactly the same semantics as <code><a href=
"#state_cast">state_machine&lt;&gt;::state_cast</a>&lt;&gt;()</code><b><br>
Note</b>: The result is <b>unspecified</b> if this function is called when
the machine is <a href=
"definitions.html#UnstableStateMachine">unstable</a></p>
<pre>
template&lt; class Target &gt;
Target <a name="simple_state::state_downcast" id=
"simple_state::state_downcast">state_downcast</a>() const;
</pre>
<p><b>Requires</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template. Moreover, <code><a href=
"#state_downcast">state_machine&lt;&gt;::state_downcast</a>&lt;&gt;()</code>
requirements also apply<br>
<b>Returns</b>: Has exactly the same semantics as <code><a href=
"#state_downcast">state_machine&lt;&gt;::state_downcast</a>&lt;&gt;()</code><br>
<b>Throws</b>: Has exactly the same semantics as <code><a href=
"#state_downcast">state_machine&lt;&gt;::state_downcast</a>&lt;&gt;()</code><b><br>
Note</b>: The result is <b>unspecified</b> if this function is called when
the machine is <a href=
"definitions.html#UnstableStateMachine">unstable</a></p>
<pre>
state_iterator <a name="simple_state::state_begin" id=
"simple_state::state_begin">state_begin</a>() const;
</pre>
<pre>
state_iterator <a name="simple_state::state_end" id=
"simple_state::state_end">state_end</a>() const;
</pre>
<p><b>Require</b>: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the <code>state</code> class template<b><br>
Return</b>: Have exactly the same semantics as <code><a href=
"#state_begin">state_machine&lt;&gt;::state_begin</a>()</code> and
<code><a href=
"#state_end">state_machine&lt;&gt;::state_end</a>()</code><br>
<b>Note</b>: The result is <b>unspecified</b> if these functions are called
when the machine is <a href=
"definitions.html#UnstableStateMachine">unstable</a></p>
<pre>
const event_base * <a name="triggering_event0" id="triggering_event0">triggering_event</a>();
</pre>
<p><b>Returns</b>: Has exactly the same semantics as
<code><a href="#triggering_event1">state_machine&lt;&gt;::triggering_event</a>()</code></p>
<h3>Class template <code>simple_state</code> static functions</h3>
<pre>
static id_type <a name="static_type" id="static_type">static_type</a>();
</pre>
<p><b>Returns</b>: A value unambiguously identifying the type of
<code>MostDerived</code><br>
<b>Note</b>: <code>id_type</code> values are comparable with
<code>operator==()</code> and <code>operator!=()</code>. An unspecified
collating order can be established with <code>std::less&lt; id_type
&gt;</code></p>
<pre>
template&lt; class CustomId &gt;
static const CustomId * <a name="custom_static_type_ptr" id=
"custom_static_type_ptr">custom_static_type_ptr</a>();
</pre>
<p><b>Requires</b>: If a custom type identifier has been set then
<code>CustomId</code> must match the type of the previously set
pointer<b><br>
Returns</b>: The pointer to the custom type identifier for
<code>MostDerived</code> or <code>0</code><br>
<b>Note</b>: This function is not available if <a href=
"configuration.html#ApplicationDefinedMacros"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></a>
is defined</p>
<pre>
template&lt; class CustomId &gt;
static void <a name="custom_static_type_ptr1" id=
"custom_static_type_ptr1">custom_static_type_ptr( const CustomId * )</a>;
</pre>
<p><b>Effects</b>: Sets the pointer to the custom type identifier for
<code>MostDerived</code><br>
<b>Note</b>: This function is not available if <a href=
"configuration.html#ApplicationDefinedMacros"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></a>
is defined</p>
<h1>Header &lt;boost/statechart/<a name="state.hpp" id=
"state.hpp">state.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatestate" id="ClassTemplatestate">Class template
<code>state</code></a></h2>
<p>This is the base class template for all models of the <a href=
"#State">State</a> concept. Such models typically need to call at least one
of the following <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> member
functions from their constructors:</p>
<pre>
void <b>post_event</b>(
const intrusive_ptr&lt; const event_base &gt; &amp; );
void <b>post_event</b>( const event_base &amp; );
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <b>clear_shallow_history</b>();
template&lt;
class HistoryContext,
<i>implementation-defined-unsigned-integer-type
</i> orthogonalPosition &gt;
void <b>clear_deep_history</b>();
outermost_context_type &amp; <b>outermost_context</b>();
const outermost_context_type &amp; <b>outermost_context</b>() const;
template&lt; class OtherContext &gt;
OtherContext &amp; <b>context</b>();
template&lt; class OtherContext &gt;
const OtherContext &amp; <b>context</b>() const;
template&lt; class Target &gt;
Target <b>state_cast</b>() const;
template&lt; class Target &gt;
Target <b>state_downcast</b>() const;
state_iterator <b>state_begin</b>() const;
state_iterator <b>state_end</b>() const;
const event_base * <b>triggering_event</b>() const;
</pre>
<p>States that do not need to call any of these member functions from their
constructors should rather derive from the <code><a href=
"#ClassTemplatesimple_state">simple_state</a></code> class template, what
saves the implementation of the forwarding constructor.</p>
<h3>Class template <code>state</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt;
class MostDerived,
class Context,
class InnerInitial = <i>unspecified</i>,
history_mode historyMode = has_no_history &gt;
class state : public simple_state&lt;
MostDerived, Context, InnerInitial, historyMode &gt;
{
protected:
struct my_context
{
// <i>implementation-defined</i>
};
typedef state my_base;
state( my_context ctx );
~state();
};
}
}
</pre>
<p>Direct and indirect subtypes of <code>state&lt;&gt;</code> must provide
a constructor with the same signature as the <code>state&lt;&gt;</code>
constructor, forwarding the context parameter.</p>
<h1>Header &lt;boost/statechart/<a name="shallow_history.hpp" id=
"shallow_history.hpp">shallow_history.hpp</a>&gt;</h1>
<h2><a name="ClassTemplateshallow_history" id=
"ClassTemplateshallow_history">Class template
<code>shallow_history</code></a></h2>
<p>This class template is used to specify a shallow history transition
target or a shallow history inner initial state.</p>
<h3>Class template <code>shallow_history</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"shallow_history parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
</tr>
<tr>
<td><code>DefaultState</code></td>
<td>A model of the <a href="#SimpleState">SimpleState</a>
or <a href="#State">State</a> concepts. The type passed as
<code>Context</code> argument to the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base
of&nbsp;<code>DefaultState</code> must itself pass
<code>has_shallow_history</code> or <code>has_full_history</code> as
<code>historyMode</code> argument to its <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base</td>
<td>The state that is entered if shallow history is not available</td>
</tr>
</table>
<h3>Class template <code>shallow_history</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt; class DefaultState &gt;
class shallow_history
{
// <i>implementation-defined</i>
};
}
}
</pre>
<h1>Header &lt;boost/statechart/<a name="deep_history.hpp" id=
"deep_history.hpp">deep_history.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatedeep_history" id=
"ClassTemplatedeep_history">Class template
<code>deep_history</code></a></h2>
<p>This class template is used to specify a deep history transition target
or a deep history inner initial state. The current deep history
implementation has some <a href=
"rationale.html#Limitations">limitations</a>.</p>
<h3>Class template <code>deep_history</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"deep_history parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
</tr>
<tr>
<td><code>DefaultState</code></td>
<td>A model of the <a href="#SimpleState">SimpleState</a>
or <a href="#State">State</a> concepts. The type passed as
<code>Context</code> argument to the <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base
of&nbsp;<code>DefaultState</code> must itself pass
<code>has_deep_history</code> or <code>has_full_history</code> as
<code>historyMode</code> argument to its <code><a href=
"#ClassTemplatesimple_state">simple_state&lt;&gt;</a></code> or
<code><a href="#ClassTemplatestate">state&lt;&gt;</a></code> base</td>
<td>The state that is entered if deep history is not available</td>
</tr>
</table>
<h3>Class template <code>deep_history</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt; class DefaultState &gt;
class deep_history
{
// <i>implementation-defined</i>
};
}
}
</pre>
<h1>Header &lt;boost/statechart/<a name="event_base.hpp" id=
"event_base.hpp">event_base.hpp</a>&gt;</h1>
<h2><a name="Classevent_base" id="Classevent_base">Class
<code>event_base</code></a></h2>
<p>This is the common base of all events.</p>
<h3>Class <code>event_base</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
class event_base
{
public:
intrusive_ptr&lt; const event_base &gt;
<a href="#intrusive_from_this">intrusive_from_this</a>() const;
typedef <i>implementation-defined</i> id_type;
id_type <a href="#event_base::dynamic_type">dynamic_type</a>() const;
template&lt; typename CustomId &gt;
const CustomId * <a href=
"#event_base::custom_dynamic_type_ptr">custom_dynamic_type_ptr</a>() const;
protected:
<a href="#event_base">event_base</a>( <i>unspecified-parameter </i>);
virtual <a href="#event_basedtor">~event_base</a>();
};
}
}
</pre>
<h3>Class <code>event_base</code> constructor and destructor</h3>
<pre>
<a name="event_base" id=
"event_base">event_base</a>( <i>unspecified-parameter </i>);
</pre>
<p><b>Effects</b>: Constructs the common base portion of an event</p>
<pre>
virtual <a name="event_basedtor" id="event_basedtor">~event_base</a>();
</pre>
<p><b>Effects</b>: Destructs the common base portion of an event</p>
<h3>Class <code>event_base</code> observer functions</h3>
<pre>
intrusive_ptr&lt; const event_base &gt; <a name="intrusive_from_this" id=
"intrusive_from_this">intrusive_from_this</a>() const;
</pre>
<p><b>Returns</b>: Another <code>intrusive_ptr&lt; const event_base
&gt;</code> referencing <code>this</code> <b>if</b> <code>this</code> is
already referenced by an <code>intrusive_ptr&lt;&gt;</code>. Otherwise,
returns an <code>intrusive_ptr&lt; const event_base &gt;</code> referencing
a newly created copy of the most-derived object</p>
<pre>
id_type <a name="event_base::dynamic_type" id=
"event_base::dynamic_type">dynamic_type</a>() const;
</pre>
<p><b>Returns</b>: A value unambiguously identifying the most-derived
type<br>
<b>Note</b>: <code>id_type</code> values are comparable with
<code>operator==()</code> and <code>operator!=()</code>. An unspecified
collating order can be established with <code>std::less&lt; id_type
&gt;</code>. In contrast to <code>typeid( cs )</code>, this function is
available even on platforms that do not support C++ RTTI (or have been
configured to not support it)</p>
<pre>
template&lt; typename CustomId &gt;
const CustomId * <a name="event_base::custom_dynamic_type_ptr" id=
"event_base::custom_dynamic_type_ptr">custom_dynamic_type_ptr</a>() const;
</pre>
<p><b>Requires</b>: If a custom type identifier has been set then
<code>CustomId</code> must match the type of the previously set
pointer<b><br>
Returns</b>: A pointer to the custom type identifier or <code>0</code><br>
<b>Note</b>: This function is not available if <a href=
"configuration.html#ApplicationDefinedMacros"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></a>
is defined</p>
<h1>Header &lt;boost/statechart/<a name="event.hpp" id=
"event.hpp">event.hpp</a>&gt;</h1>
<h2><a name="ClassTemplateevent" id="ClassTemplateevent">Class template
<code>event</code></a></h2>
<p>This is the base class template of all events.</p>
<h3>Class template <code>event</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary="event parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>MostDerived</code></td>
<td>The most-derived subtype of this class template</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>Allocator</code></td>
<td>A model of the standard Allocator concept</td>
<td><code>Allocator::rebind&lt; MostDerived
&gt;::other</code> is used to allocate and deallocate all event subtype
objects of dynamic storage duration, see <code><a href=
"#event::operatornew">operator new</a></code></td>
<td><code>std::allocator&lt; void &gt;</code></td>
</tr>
</table>
<h3>Class template <code>event</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt; class MostDerived, class Allocator = std::allocator&lt; void &gt; &gt;
class event : <i>implementation-defined</i>
{
public:
static void * <a href=
"#event::operatornew">operator new</a>( std::size_t size );
static void * <a href=
"#event::operatornew2">operator new</a>( std::size_t size, void * p );
static void <a href=
"#event::operatordelete">operator delete</a>( void * pEvent );
static id_type <a href="#event::static_type">static_type</a>();
template&lt; class CustomId &gt;
static const CustomId * <a href=
"#event::custom_static_type_ptr">custom_static_type_ptr</a>();
template&lt; class CustomId &gt;
static void <a href=
"#event::custom_static_type_ptr1">custom_static_type_ptr</a>( const CustomId * );
protected:
<a href="#event::event">event</a>();
virtual <a href="#eventdtor">~event</a>();
};
}
}
</pre>
<h3>Class template <code>event</code> constructor and destructor</h3>
<pre>
<a name="event::event" id="event::event">event</a>();
</pre>
<p><b>Effects</b>: Constructs an event</p>
<pre>
virtual <a name="eventdtor" id="eventdtor">~event</a>();
</pre>
<p><b>Effects</b>: Destructs an event</p>
<h3>Class template <code>event</code> static functions</h3>
<pre>
static void * <a name="event::operatornew" id=
"event::operatornew">operator new</a>( std::size_t size );
</pre>
<p><b>Effects</b>: <code>Allocator::rebind&lt; MostDerived
&gt;::other().allocate( 1, static_cast&lt; MostDerived * &gt;( 0 )
);</code><br>
<b>Returns</b>: The return value of the above call<br>
<b>Throws</b>: Whatever the above call throws</p>
<pre>
static void * <a name="event::operatornew2" id=
"event::operatornew2">operator new</a>( std::size_t size, void * p );
</pre>
<p><b>Effects</b>: None<br>
<b>Returns</b>: <code>p</code></p>
<pre>
static void <a name="event::operatordelete" id=
"event::operatordelete">operator delete</a>( void * pEvent );
</pre>
<p><b>Effects</b>: <code>Allocator::rebind&lt; MostDerived
&gt;::other().deallocate( static_cast&lt; MostDerived * &gt;( pEvent ), 1
);</code></p>
<pre>
static id_type <a name="event::static_type" id=
"event::static_type">static_type</a>();
</pre>
<p><b>Returns</b>: A value unambiguously identifying the type of
<code>MostDerived</code><br>
<b>Note</b>: <code>id_type</code> values are comparable with
<code>operator==()</code> and <code>operator!=()</code>. An unspecified
collating order can be established with <code>std::less&lt; id_type
&gt;</code></p>
<pre>
template&lt; class CustomId &gt;
static const CustomId * <a name="event::custom_static_type_ptr" id=
"event::custom_static_type_ptr">custom_static_type_ptr</a>();
</pre>
<p><b>Requires</b>: If a custom type identifier has been set then
<code>CustomId</code> must match the type of the previously set
pointer<b><br>
Returns</b>: The pointer to the custom type identifier for
<code>MostDerived</code> or <code>0</code><br>
<b>Note</b>: This function is not available if <a href=
"configuration.html#ApplicationDefinedMacros"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></a>
is defined</p>
<pre>
template&lt; class CustomId &gt;
static void <a name="event::custom_static_type_ptr1" id=
"event::custom_static_type_ptr1">custom_static_type_ptr( const CustomId * )</a>;
</pre>
<p><b>Effects</b>: Sets the pointer to the custom type identifier for
<code>MostDerived</code><br>
<b>Note</b>: This function is not available if <a href=
"configuration.html#ApplicationDefinedMacros"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></a>
is defined</p>
<h1>Header &lt;boost/statechart/<a name="transition.hpp" id=
"transition.hpp">transition.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatetransition" id="ClassTemplatetransition">Class
template <code>transition</code></a></h2>
<p>This class template is used to specify a transition reaction.
Instantiations of this template can appear in the <code>reactions</code>
member <code>typedef</code> in models of the <a href=
"#SimpleState">SimpleState</a> and <a href="#State">State</a> concepts.</p>
<h3>Class template <code>transition</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"transition parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>Event</code></td>
<td>A model of the <a href="#Event">Event</a> concept or
the class <code><a href="#Classevent_base">event_base</a></code></td>
<td>The event triggering the transition. If <code><a href=
"#Classevent_base">event_base</a></code> is specified, the transition
is triggered by all models of the <a href="#Event">Event</a>
concept</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>Destination</code></td>
<td>A model of the <a href="#SimpleState">SimpleState</a>
or <a href="#State">State</a> concepts, any of their public base types or an instantiation of the
<code><a href=
"#ClassTemplateshallow_history">shallow_history</a></code> or
<code><a href="#ClassTemplatedeep_history">deep_history</a></code>
class templates. The source state (the state for which this transition
is defined) and <code>Destination</code> must have a common direct or
indirect context</td>
<td>The destination state to make a transition to</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>TransitionContext</code></td>
<td>A common context of the source and
<code>Destination</code> state</td>
<td>The state of which the transition action is a
member</td>
<td><i><code>unspecified</code></i></td>
</tr>
<tr>
<td><code>pTransitionAction</code></td>
<td>A pointer to a member function of
<code>TransitionContext</code>. The member function must accept a
<code>const Event &amp;</code> parameter and return
<code>void</code></td>
<td>The transition action that is executed during the
transition. By default no transition action is executed</td>
<td><i><code>unspecified</code></i></td>
</tr>
</table>
<h3>Class template <code>transition</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt;
class Event,
class Destination,
class TransitionContext = <i>unspecified</i>,
void ( TransitionContext::*pTransitionAction )(
const Event &amp; ) = <i>unspecified</i> &gt;
class transition
{
// <i>implementation-defined</i>
};
}
}
</pre>
<h3>Class template <code>transition</code> semantics</h3>
<p>When executed, one of the following calls to a member function of the
state for which the reaction was defined is made:</p>
<ul>
<li><code><a href="#transit1">transit&lt; Destination &gt;()</a></code>,
if no transition action was specified</li>
<li><code><a href="#transit2">transit&lt; Destination &gt;(
pTransitionAction, <i>currentEvent</i> )</a></code>, if a transition
action was specified</li>
</ul>
<h1>Header &lt;boost/statechart/<a name="in_state_reaction.hpp" id=
"in_state_reaction.hpp">in_state_reaction.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatein_state_reaction" id=
"ClassTemplatein_state_reaction">Class template
<code>in_state_reaction</code></a></h2>
<p>This class template is used to specify an in-state reaction.
Instantiations of this template can appear in the <code>reactions</code>
member <code>typedef</code> in models of the <a href=
"#SimpleState">SimpleState</a> and <a href="#State">State</a> concepts.</p>
<h3>Class template <code>in_state_reaction</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"in_state_reaction parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
<td><b>Default</b></td>
</tr>
<tr>
<td><code>Event</code></td>
<td>A model of the <a href="#Event">Event</a> concept or
the class <code><a href="#Classevent_base">event_base</a></code></td>
<td>The event triggering the in-state reaction. If
<code><a href="#Classevent_base">event_base</a></code> is specified,
the in-state reaction is triggered by all models of the <a href=
"#Event">Event</a> concept</td>
<td>&nbsp;</td>
</tr>
<tr>
<td><code>ReactionContext</code></td>
<td>Either the state defining the in-state reaction itself, one of its direct or indirect contexts
or any of their public base types</td>
<td>The state of which the action is a member</td>
<td><i><code>unspecified</code></i></td>
</tr>
<tr>
<td><code>pAction</code></td>
<td>A pointer to a member function of
<code>ReactionContext</code>. The member function must accept a
<code>const Event &amp;</code> parameter and return
<code>void</code></td>
<td>The action that is executed during the in-state
reaction</td>
<td><i><code>unspecified</code></i></td>
</tr>
</table>
<h3>Class template <code>in_state_reaction</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt;
class Event,
class ReactionContext = <i>unspecified</i>,
void ( ReactionContext::*pAction )(
const Event &amp; ) = <i>unspecified</i> &gt;
class in_state_reaction
{
// <i>implementation-defined</i>
};
}
}
</pre>
<h3>Class template <code>in_state_reaction</code> semantics</h3>
<p>When executed then the following happens:</p>
<ol>
<li>If an action was specified, <code>pAction</code> is called, passing
the triggering event as the only argument</li>
<li>A call is made to the <code><a href="#discard_event">discard_event</a>
</code> member function of the state for which the reaction was defined
</li>
</ol>
<h1>Header &lt;boost/statechart/<a name="termination.hpp" id=
"termination.hpp">termination.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatetermination" id="ClassTemplatetermination">Class
template <code>termination</code></a></h2>
<p>This class template is used to specify a termination reaction.
Instantiations of this template can appear in the <code>reactions</code>
member <code>typedef</code> in models of the <a href=
"#SimpleState">SimpleState</a> and <a href="#State">State</a> concepts.</p>
<h3>Class template <code>termination</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"termination parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
</tr>
<tr>
<td><code>Event</code></td>
<td>A model of the <a href="#Event">Event</a> concept or
the class <code><a href="#Classevent_base">event_base</a></code></td>
<td>The event triggering the termination. If <code><a href=
"#Classevent_base">event_base</a></code> is specified, the termination
is triggered by all models of the <a href="#Event">Event</a>
concept</td>
</tr>
</table>
<h3>Class template <code>termination</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt; class Event &gt;
class termination
{
// <i>implementation-defined</i>
};
}
}
</pre>
<h3>Class template <code>termination</code> semantics</h3>
<p>When executed, a call is made to the <code><a href=
"#simple_state::terminate">terminate</a></code> member function of the
state for which the reaction was defined.</p>
<h1>Header &lt;boost/statechart/<a name="deferral.hpp" id=
"deferral.hpp">deferral.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatedeferral" id="ClassTemplatedeferral">Class
template <code>deferral</code></a></h2>
<p>This class template is used to specify a deferral reaction.
Instantiations of this template can appear in the <code>reactions</code>
member <code>typedef</code> in models of the <a href=
"#SimpleState">SimpleState</a> and <a href="#State">State</a> concepts.</p>
<h3>Class template <code>deferral</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"deferral parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
</tr>
<tr>
<td><code>Event</code></td>
<td>A model of the <a href="#Event">Event</a> concept or
the class <code><a href="#Classevent_base">event_base</a></code></td>
<td>The event triggering the deferral. If <code><a href=
"#Classevent_base">event_base</a></code> is specified, the deferral is
triggered by all models of the <a href="#Event">Event</a> concept</td>
</tr>
</table>
<h3>Class template <code>deferral</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt; class Event &gt;
class deferral
{
// <i>implementation-defined</i>
};
}
}
</pre>
<h3>Class template <code>deferral</code> semantics</h3>
<p>When executed, a call is made to the <a href=
"#defer_event"><code>defer_event</code></a> member function of the state
for which the reaction was defined.</p>
<h1>Header &lt;boost/statechart/<a name="custom_reaction.hpp" id=
"custom_reaction.hpp">custom_reaction.hpp</a>&gt;</h1>
<h2><a name="ClassTemplatecustom_reaction" id=
"ClassTemplatecustom_reaction">Class template
<code>custom_reaction</code></a></h2>
<p>This class template is used to specify a custom reaction. Instantiations
of this template can appear in the <code>reactions</code> member
<code>typedef</code> in models of the <a href=
"#SimpleState">SimpleState</a> and <a href="#State">State</a> concepts.</p>
<h3>Class template <code>custom_reaction</code> parameters</h3>
<table border="3" cellpadding="2" width="100%" summary=
"custom_reaction parameters">
<tr>
<td><b>Template parameter</b></td>
<td><b>Requirements</b></td>
<td><b>Semantics</b></td>
</tr>
<tr>
<td><code>Event</code></td>
<td>A model of the <a href="#Event">Event</a> concept or
the class <code><a href="#Classevent_base">event_base</a></code></td>
<td>The event triggering the custom reaction. If
<code><a href="#Classevent_base">event_base</a></code> is specified,
the custom reaction is triggered by all models of the <a href=
"#Event">Event</a> concept</td>
</tr>
</table>
<h3>Class template <code>custom_reaction</code> synopsis</h3>
<pre>
namespace boost
{
namespace statechart
{
template&lt; class Event &gt;
class custom_reaction
{
// <i>implementation-defined</i>
};
}
}
</pre>
<h3>Class template <code>custom_reaction</code> semantics</h3>
<p>When executed, a call is made to the user-supplied <code>react</code>
member function of the state for which the reaction was defined. The
<code>react</code> member function must have the following signature:</p>
<pre>
<a href="#Classresult">result</a> react( const Event &amp; );
</pre>
<p>and must call exactly one of the following reaction functions and return
the obtained <code><a href="#Classresult">result</a></code> object:</p>
<pre>
<a href="#Classresult">result</a> <a href=
"#discard_event">discard_event</a>();
<a href="#Classresult">result</a> <a href=
"#forward_event">forward_event</a>();
<a href="#Classresult">result</a> <a href="#defer_event">defer_event</a>();
template&lt; class DestinationState &gt;
<a href="#Classresult">result</a> <a href="#transit1">transit</a>();
template&lt;
class DestinationState,
class TransitionContext,
class Event &gt;
<a href="#Classresult">result</a> <a href="#transit2">transit</a>(
void ( TransitionContext::* )( const Event &amp; ),
const Event &amp; );
<a href="#Classresult">result</a> <a href=
"#simple_state::terminate">terminate</a>();
</pre>
<h1>Header &lt;boost/statechart/<a name="result.hpp" id=
"result.hpp">result.hpp</a>&gt;</h1>
<h2><a name="Classresult" id="Classresult">Class
<code>result</code></a></h2>
<p>Defines the nature of the reaction taken in a user-supplied
<code>react</code> member function (called when a <code><a href=
"#ClassTemplatecustom_reaction">custom_reaction</a></code> is executed).
Objects of this type are always obtained by calling one of the reaction
functions and must be returned from the <code>react</code> member function
immediately.</p>
<pre>
namespace boost
{
namespace statechart
{
class result
{
public:
<a href="#result0">result</a>( const result &amp; other );
<a href="#resultdtor">~result</a>();
private:
// Result objects are not assignable
result &amp; operator=( const result &amp; other );
};
}
}
</pre>
<h3>Class <code>result</code> constructor and destructor</h3>
<pre>
<a name="result0" id="result0">result</a>( const result &amp; other );
</pre>
<p><b>Requires</b>: <code>other</code> is <b>not</b> consumed<br>
<b>Effects</b>: Copy-constructs a new <code>result</code> object and marks
<code>other</code> as consumed. That is, <code>result</code> has
destructive copy semantics</p>
<pre>
<a name="resultdtor" id="resultdtor">~result</a>();
</pre>
<p><b>Requires</b>: <code>this</code> is marked as consumed<br>
<b>Effects</b>: Destructs the result object</p>
<hr>
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<p>Revised 06 January, 2008</p>
<p><i>Copyright &copy; 2003-2008 <a href="contact.html">Andreas Huber
D&ouml;nni</a></i></p>
<p><i>Distributed under the Boost Software License, Version 1.0. (See
accompanying file <a href="../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
copy at <a href=
"http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p>
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