1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2 3<html> 4<head> 5 <meta http-equiv="Content-Language" content="en-us"> 6 <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> 7 <meta name="GENERATOR" content="Microsoft FrontPage 6.0"> 8 <meta name="ProgId" content="FrontPage.Editor.Document"> 9 <link rel="stylesheet" type="text/css" href="../../../boost.css"> 10 11 <title>The Boost Statechart Library - Configuration</title> 12</head> 13 14<body link="#0000FF" vlink="#800080"> 15 <table border="0" cellpadding="7" cellspacing="0" width="100%" summary= 16 "header"> 17 <tr> 18 <td valign="top" width="300"> 19 <h3><a href="../../../index.htm"><img alt="C++ Boost" src= 20 "../../../boost.png" border="0" width="277" height="86"></a></h3> 21 </td> 22 23 <td valign="top"> 24 <h1 align="center">The Boost Statechart Library</h1> 25 26 <h2 align="center">Configuration</h2> 27 </td> 28 </tr> 29 </table> 30 <hr> 31 32 <dl class="page-index"> 33 <dt><a href="#GeneralConfiguration">General configuration</a></dt> 34 35 <dd><a href="#Introduction">Introduction</a></dd> 36 37 <dd><a href="#DebugModeCompilationOptions">Debug mode compilation 38 options</a></dd> 39 40 <dd><a href="#ReleaseModeCompilationOptions">Release mode compilation 41 options</a></dd> 42 43 <dd><a href="#ApplicationDefinedMacros">Application Defined 44 Macros</a></dd> 45 </dl> 46 47 <h1><a id="GeneralConfiguration" name="GeneralConfiguration">General 48 configuration</a></h1> 49 50 <h2><a id="Introduction" name="Introduction">Introduction</a></h2> 51 52 <p>The library uses several configuration macros in <a href= 53 "../../../libs/config/config.htm"><boost/config.hpp></a>, as well as 54 two configuration macros meant to be supplied by the application. Moreover, 55 two commonly available compiler options also have an impact on the 56 available features.</p> 57 58 <h2><a id="DebugModeCompilationOptions" name= 59 "DebugModeCompilationOptions">Debug mode compilation options</a></h2> 60 61 <ul> 62 <li>C++ RTTI must be turned on (used by various asserts)</li> 63 64 <li>C++ exception handling can be turned on or off. When turned off, 65 obviously the library's <a href="tutorial.html#ExceptionHandling">error 66 handling support</a> is no longer available</li> 67 </ul> 68 69 <h2><a id="ReleaseModeCompilationOptions" name= 70 "ReleaseModeCompilationOptions">Release mode compilation options</a></h2> 71 72 <ul> 73 <li>C++ RTTI can be turned on or off. When turned off, the use of 74 <code><a href="reference.html#state_cast">state_cast<>()</a></code> 75 leads to a compile time error (<code><a href= 76 "reference.html#state_downcast">state_downcast<>()</a></code> is 77 still available). Moreover, <code>BOOST_STATECHART_USE_NATIVE_RTTI</code> 78 must not be defined simultaneously</li> 79 80 <li>C++ exception handling can be turned on or off. When turned off, 81 obviously the library's <a href="tutorial.html#ExceptionHandling">error 82 handling support</a> is no longer available</li> 83 </ul> 84 85 <h2><a id="ApplicationDefinedMacros" name= 86 "ApplicationDefinedMacros">Application Defined Macros</a></h2> 87 88 <p>The following macros may be defined by an application using the 89 library:</p> 90 91 <table summary="application defined macros" width="100%" cellpadding="2" 92 border="3"> 93 <tr> 94 <td width="226"><b>Macro</b></td> 95 96 <td width="893"><b>Meaning</b></td> 97 </tr> 98 99 <tr> 100 <td width="226"><code>BOOST_STATECHART_USE_NATIVE_RTTI</code></td> 101 102 <td width="893"> 103 When defined, the library no longer uses its own speed-optimized RTTI 104 implementation. Instead, native C++ RTTI is employed (see <a href= 105 "performance.html#RttiCustomization">RTTI customization</a> in the 106 performance document for more information). This has the following 107 effects: 108 109 <ul> 110 <li><code>state_machine::state_base_type</code> becomes a 111 polymorphic type. That is, when <code>typeid</code> is applied to a 112 <code>state_machine::state_base_type</code> reference, the result 113 refers to a <code>type_info</code> object representing the the type 114 of the most derived state type</li> 115 116 <li><a href="tutorial.html#CustomStateTypeInformation">Custom state 117 type information</a> is no longer available</li> 118 119 <li>All states need to store one pointer less, leading to a 120 best-case state machine memory footprint reduction of about 121 15%</li> 122 123 <li>Under most circumstances, dispatch speed degrades. This is 124 because native C++ RTTI values are retrieved through an additional 125 indirection on almost all platforms. See <a href= 126 "performance.html#SpeedVersusScalabilityTradeoffs">Speed versus 127 scalability tradeoffs</a> in the performance document for 128 timings</li> 129 </ul> 130 </td> 131 </tr> 132 133 <tr> 134 <td width="226"> 135 <code>BOOST_STATECHART_RELAX_TRANSITION_CONTEXT</code></td> 136 137 <td width="893">When defined, the sequence of actions that are called 138 during a transition is relaxed. That is, its is no longer necessary 139 that all states up to the innermost common context are exited before 140 the transition action is called (as mandated by the UML standard). 141 Instead, the transition action can be a member of either the transition 142 source or any direct or indirect outer context and is called as soon as 143 all possibly active inner states have been exited. Then all remaining 144 active states up to the innermost common context are exited before 145 entering all states down to the transition destination</td> 146 </tr> 147 </table> 148 149 <p>Both macros need to be consistently defined or undefined for all 150 translation units that are later linked into the same executable. Not doing 151 so will inevitably lead to ODR violations. Depending on compiler and linker 152 technology such violations may or may not manifest themselves in link-time 153 errors.</p> 154 155 <p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src= 156 "../../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional" 157 height="31" width="88"></a></p> 158 159 <p>Revised 05 January, 2008</p> 160 161 <p><i>Copyright © 2003-2008 <a href="contact.html">Andreas Huber 162 Dönni</a></i></p> 163 164 <p><i>Distributed under the Boost Software License, Version 1.0. (See 165 accompanying file <a href="../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or 166 copy at <a href= 167 "http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p> 168</body> 169</html> 170
