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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">Configuration</h2>
       </td>
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   </table>
   <hr>

   <dl class="page-index">
     <dt><a href="#GeneralConfiguration">General configuration</a></dt>

     <dd><a href="#Introduction">Introduction</a></dd>

     <dd><a href="#DebugModeCompilationOptions">Debug mode compilation
     options</a></dd>

     <dd><a href="#ReleaseModeCompilationOptions">Release mode compilation
     options</a></dd>

     <dd><a href="#ApplicationDefinedMacros">Application Defined
     Macros</a></dd>
   </dl>

   <h1><a id="GeneralConfiguration" name="GeneralConfiguration">General
   configuration</a></h1>

   <h2><a id="Introduction" name="Introduction">Introduction</a></h2>

   <p>The library uses several configuration macros in <a href=
   "../../../libs/config/config.htm">&lt;boost/config.hpp&gt;</a>, as well as
   two configuration macros meant to be supplied by the application. Moreover,
   two commonly available compiler options also have an impact on the
   available features.</p>

   <h2><a id="DebugModeCompilationOptions" name=
   "DebugModeCompilationOptions">Debug mode compilation options</a></h2>

   <ul>
     <li>C++ RTTI must be turned on (used by various asserts)</li>

     <li>C++ exception handling can be turned on or off. When turned off,
     obviously the library's <a href="tutorial.html#ExceptionHandling">error
     handling support</a> is no longer available</li>
   </ul>

   <h2><a id="ReleaseModeCompilationOptions" name=
   "ReleaseModeCompilationOptions">Release mode compilation options</a></h2>

   <ul>
     <li>C++ RTTI can be turned on or off. When turned off, the use of
     <code><a href="reference.html#state_cast">state_cast&lt;&gt;()</a></code>
     leads to a compile time error (<code><a href=
     "reference.html#state_downcast">state_downcast&lt;&gt;()</a></code> is
     still available). Moreover, <code>BOOST_STATECHART_USE_NATIVE_RTTI</code>
     must not be defined simultaneously</li>

     <li>C++ exception handling can be turned on or off. When turned off,
     obviously the library's <a href="tutorial.html#ExceptionHandling">error
     handling support</a> is no longer available</li>
   </ul>

   <h2><a id="ApplicationDefinedMacros" name=
   "ApplicationDefinedMacros">Application Defined Macros</a></h2>

   <p>The following macros may be defined by an application using the
   library:</p>

   <table summary="application defined macros" width="100%" cellpadding="2"
   border="3">
     <tr>
       <td width="226"><b>Macro</b></td>

       <td width="893"><b>Meaning</b></td>
     </tr>

     <tr>
       <td width="226"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></td>

       <td width="893">
         When defined, the library no longer uses its own speed-optimized RTTI
         implementation. Instead, native C++ RTTI is employed (see <a href=
         "performance.html#RttiCustomization">RTTI customization</a> in the
         performance document for more information). This has the following
         effects:

         <ul>
           <li><code>state_machine::state_base_type</code> becomes a
           polymorphic type. That is, when <code>typeid</code> is applied to a
           <code>state_machine::state_base_type</code> reference, the result
           refers to a <code>type_info</code> object representing the the type
           of the most derived state type</li>

           <li><a href="tutorial.html#CustomStateTypeInformation">Custom state
           type information</a> is no longer available</li>

           <li>All states need to store one pointer less, leading to a
           best-case state machine memory footprint reduction of about
           15%</li>

           <li>Under most circumstances, dispatch speed degrades. This is
           because native C++ RTTI values are retrieved through an additional
           indirection on almost all platforms. See <a href=
           "performance.html#SpeedVersusScalabilityTradeoffs">Speed versus
           scalability tradeoffs</a> in the performance document for
           timings</li>
         </ul>
       </td>
     </tr>

     <tr>
       <td width="226">
       <code>BOOST_STATECHART_RELAX_TRANSITION_CONTEXT</code></td>

       <td width="893">When defined, the sequence of actions that are called
       during a transition is relaxed. That is, its is no longer necessary
       that all states up to the innermost common context are exited before
       the transition action is called (as mandated by the UML standard).
       Instead, the transition action can be a member of either the transition
       source or any direct or indirect outer context and is called as soon as
       all possibly active inner states have been exited. Then all remaining
       active states up to the innermost common context are exited before
       entering all states down to the transition destination</td>
     </tr>
   </table>

   <p>Both macros need to be consistently defined or undefined for all
   translation units that are later linked into the same executable. Not doing
   so will inevitably lead to ODR violations. Depending on compiler and linker
   technology such violations may or may not manifest themselves in link-time
   errors.</p>

   <p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
   "../../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
   height="31" width="88"></a></p>

   <p>Revised 05 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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	<link rel="stylesheet" type="text/css" href="../../../boost.css">

	<title>The Boost Statechart Library - Configuration</title>
	</head>

	<body link="#0000FF" vlink="#800080">
	<table border="0" cellpadding="7" cellspacing="0" width="100%" summary=
	"header">
	<tr>
	<td valign="top" width="300">
	<h3><a href="../../../index.htm"><img alt="C++ Boost" src=
	"../../../boost.png" border="0" width="277" height="86"></a></h3>
	</td>

	<td valign="top">
	<h1 align="center">The Boost Statechart Library</h1>

	<h2 align="center">Configuration</h2>
	</td>
	</tr>
	</table>
	<hr>

	<dl class="page-index">
	<dt><a href="#GeneralConfiguration">General configuration</a></dt>

	<dd><a href="#Introduction">Introduction</a></dd>

	<dd><a href="#DebugModeCompilationOptions">Debug mode compilation
	options</a></dd>

	<dd><a href="#ReleaseModeCompilationOptions">Release mode compilation
	options</a></dd>

	<dd><a href="#ApplicationDefinedMacros">Application Defined
	Macros</a></dd>
	</dl>

	<h1><a id="GeneralConfiguration" name="GeneralConfiguration">General
	configuration</a></h1>

	<h2><a id="Introduction" name="Introduction">Introduction</a></h2>

	<p>The library uses several configuration macros in <a href=
	"../../../libs/config/config.htm"><boost/config.hpp></a>, as well as
	two configuration macros meant to be supplied by the application. Moreover,
	two commonly available compiler options also have an impact on the
	available features.</p>

	<h2><a id="DebugModeCompilationOptions" name=
	"DebugModeCompilationOptions">Debug mode compilation options</a></h2>

	<ul>
	<li>C++ RTTI must be turned on (used by various asserts)</li>

	<li>C++ exception handling can be turned on or off. When turned off,
	obviously the library's <a href="tutorial.html#ExceptionHandling">error
	handling support</a> is no longer available</li>
	</ul>

	<h2><a id="ReleaseModeCompilationOptions" name=
	"ReleaseModeCompilationOptions">Release mode compilation options</a></h2>

	<ul>
	<li>C++ RTTI can be turned on or off. When turned off, the use of
	<code><a href="reference.html#state_cast">state_cast<>()</a></code>
	leads to a compile time error (<code><a href=
	"reference.html#state_downcast">state_downcast<>()</a></code> is
	still available). Moreover, <code>BOOST_STATECHART_USE_NATIVE_RTTI</code>
	must not be defined simultaneously</li>

	<li>C++ exception handling can be turned on or off. When turned off,
	obviously the library's <a href="tutorial.html#ExceptionHandling">error
	handling support</a> is no longer available</li>
	</ul>

	<h2><a id="ApplicationDefinedMacros" name=
	"ApplicationDefinedMacros">Application Defined Macros</a></h2>

	<p>The following macros may be defined by an application using the
	library:</p>

	<table summary="application defined macros" width="100%" cellpadding="2"
	border="3">
	<tr>
	<td width="226"><b>Macro</b></td>

	<td width="893"><b>Meaning</b></td>
	</tr>

	<tr>
	<td width="226"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></td>

	<td width="893">
	When defined, the library no longer uses its own speed-optimized RTTI
	implementation. Instead, native C++ RTTI is employed (see <a href=
	"performance.html#RttiCustomization">RTTI customization</a> in the
	performance document for more information). This has the following
	effects:

	<ul>
	<li><code>state_machine::state_base_type</code> becomes a
	polymorphic type. That is, when <code>typeid</code> is applied to a
	<code>state_machine::state_base_type</code> reference, the result
	refers to a <code>type_info</code> object representing the the type
	of the most derived state type</li>

	<li><a href="tutorial.html#CustomStateTypeInformation">Custom state
	type information</a> is no longer available</li>

	<li>All states need to store one pointer less, leading to a
	best-case state machine memory footprint reduction of about
	15%</li>

	<li>Under most circumstances, dispatch speed degrades. This is
	because native C++ RTTI values are retrieved through an additional
	indirection on almost all platforms. See <a href=
	"performance.html#SpeedVersusScalabilityTradeoffs">Speed versus
	scalability tradeoffs</a> in the performance document for
	timings</li>
	</ul>
	</td>
	</tr>

	<tr>
	<td width="226">
	<code>BOOST_STATECHART_RELAX_TRANSITION_CONTEXT</code></td>

	<td width="893">When defined, the sequence of actions that are called
	during a transition is relaxed. That is, its is no longer necessary
	that all states up to the innermost common context are exited before
	the transition action is called (as mandated by the UML standard).
	Instead, the transition action can be a member of either the transition
	source or any direct or indirect outer context and is called as soon as
	all possibly active inner states have been exited. Then all remaining
	active states up to the innermost common context are exited before
	entering all states down to the transition destination</td>
	</tr>
	</table>

	<p>Both macros need to be consistently defined or undefined for all
	translation units that are later linked into the same executable. Not doing
	so will inevitably lead to ODR violations. Depending on compiler and linker
	technology such violations may or may not manifest themselves in link-time
	errors.</p>

	<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
	"../../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
	height="31" width="88"></a></p>

	<p>Revised 05 January, 2008</p>

	<p><i>Copyright © 2003-2008 <a href="contact.html">Andreas Huber
	Dönni</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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