1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>How to use Boost.Intrusive</title> 6<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../intrusive.html" title="Chapter 19. Boost.Intrusive"> 10<link rel="prev" href="intrusive_vs_nontrusive.html" title="Intrusive and non-intrusive containers"> 11<link rel="next" href="usage_when.html" title="When to use?"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> 16<td align="center"><a href="../../../index.html">Home</a></td> 17<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="intrusive_vs_nontrusive.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../intrusive.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="usage_when.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="section"> 27<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 28<a name="intrusive.usage"></a><a class="link" href="usage.html" title="How to use Boost.Intrusive">How to use Boost.Intrusive</a> 29</h2></div></div></div> 30<div class="toc"><dl class="toc"> 31<dt><span class="section"><a href="usage.html#intrusive.usage.usage_base_hook">Using base hooks</a></span></dt> 32<dt><span class="section"><a href="usage.html#intrusive.usage.usage_member_hook">Using member hooks</a></span></dt> 33<dt><span class="section"><a href="usage.html#intrusive.usage.usage_both_hooks">Using both hooks</a></span></dt> 34<dt><span class="section"><a href="usage.html#intrusive.usage.usage_lifetime">Object lifetime</a></span></dt> 35</dl></div> 36<p> 37 If you plan to insert a class in an intrusive container, you have to make some 38 decisions influencing the class definition itself. Each class that will be 39 used in an intrusive container needs some appropriate data members storing 40 the information needed by the container. We will take a simple intrusive container, 41 the intrusive list (<code class="computeroutput"><a class="link" href="../boost/intrusive/list.html" title="Class template list">boost::intrusive::list</a></code>), 42 for the following examples, but all <span class="bold"><strong>Boost.Intrusive</strong></span> 43 containers are very similar. To compile the example using <code class="computeroutput"><a class="link" href="../boost/intrusive/list.html" title="Class template list">boost::intrusive::list</a></code>, 44 just include: 45 </p> 46<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">intrusive</span><span class="special">/</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 47</pre> 48<p> 49 Every class to be inserted in an intrusive container, needs to contain a hook 50 that will offer the necessary data and resources to be insertable in the container. 51 With <span class="bold"><strong>Boost.Intrusive</strong></span> you just choose the hook 52 to be a public base class or a public member of the class to be inserted. 53 <span class="bold"><strong>Boost.Intrusive</strong></span> also offers more flexible 54 hooks for advanced users, as explained in the chapter <a class="link" href="function_hooks.html" title="Using function hooks">Using 55 function hooks</a>, but usually base or member hooks are good enough for 56 most users. 57 </p> 58<div class="section"> 59<div class="titlepage"><div><div><h3 class="title"> 60<a name="intrusive.usage.usage_base_hook"></a><a class="link" href="usage.html#intrusive.usage.usage_base_hook" title="Using base hooks">Using base hooks</a> 61</h3></div></div></div> 62<p> 63 For <code class="computeroutput"><a class="link" href="../boost/intrusive/list.html" title="Class template list">list</a></code>, you can publicly 64 derive from <code class="computeroutput"><a class="link" href="../boost/intrusive/list_base_hook.html" title="Class template list_base_hook">list_base_hook</a></code>. 65 </p> 66<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="special">...</span><span class="identifier">Options</span><span class="special">></span> 67<span class="keyword">class</span> <span class="identifier">list_base_hook</span><span class="special">;</span> 68</pre> 69<p> 70 The class can take several options. <span class="bold"><strong>Boost.Intrusive</strong></span> 71 classes receive arguments in the form <code class="computeroutput"><span class="identifier">option_name</span><span class="special"><</span><span class="identifier">option_value</span><span class="special">></span></code>. You can specify the following options: 72 </p> 73<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 74<li class="listitem"> 75 <span class="bold"><strong><code class="computeroutput"><span class="identifier">tag</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">Tag</span><span class="special">></span></code></strong></span>: 76 this argument serves as a tag, so you can derive from more than one 77 <code class="computeroutput"><a class="link" href="../boost/intrusive/list_base_hook.html" title="Class template list_base_hook">list_base_hook</a></code> 78 and hence put an object in multiple intrusive lists at the same time. 79 An incomplete type can serve as a tag. If you specify two base hooks, 80 you <span class="bold"><strong>must</strong></span> specify a different tag for 81 each one. Example: <code class="computeroutput"><span class="identifier">list_base_hook</span><span class="special"><</span> <span class="identifier">tag</span><span class="special"><</span><span class="identifier">tag1</span><span class="special">></span> <span class="special">></span></code>. 82 If no tag is specified a default one will be used (more on default tags 83 later). 84 </li> 85<li class="listitem"> 86 <span class="bold"><strong><code class="computeroutput"><span class="identifier">link_mode</span><span class="special"><</span><span class="identifier">link_mode_type</span> 87 <span class="identifier">LinkMode</span><span class="special">></span></code></strong></span>: 88 The second template argument controls the linking policy. <span class="bold"><strong>Boost.Intrusive</strong></span> 89 currently supports 3 modes: <code class="computeroutput"><span class="identifier">normal_link</span></code>, 90 <code class="computeroutput"><span class="identifier">safe_link</span></code> and <code class="computeroutput"><span class="identifier">auto_unlink</span></code>. By default, <code class="computeroutput"><span class="identifier">safe_link</span></code> mode is used. More about 91 these in sections <a class="link" href="safe_hook.html" title="Safe hooks">Safe hooks</a> 92 and <a class="link" href="auto_unlink_hooks.html" title="Auto-unlink hooks">Auto-unlink hooks</a>. 93 Example: <code class="computeroutput"><span class="identifier">list_base_hook</span><span class="special"><</span> <span class="identifier">link_mode</span><span class="special"><</span><span class="identifier">auto_unlink</span><span class="special">></span> <span class="special">></span></code> 94 </li> 95<li class="listitem"> 96 <span class="bold"><strong><code class="computeroutput"><span class="identifier">void_pointer</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">VoidPointer</span><span class="special">></span></code></strong></span>: 97 this option is the pointer type to be used internally in the hook. The 98 default value is <code class="computeroutput"><span class="keyword">void</span> <span class="special">*</span></code>, 99 which means that raw pointers will be used in the hook. More about this 100 in the section titled <a class="link" href="using_smart_pointers.html" title="Using smart pointers with Boost.Intrusive containers">Using 101 smart pointers with Boost.Intrusive containers</a>. Example: <code class="computeroutput"><span class="identifier">list_base_hook</span><span class="special"><</span> 102 <span class="identifier">void_pointer</span><span class="special"><</span> 103 <span class="identifier">my_smart_ptr</span><span class="special"><</span><span class="keyword">void</span><span class="special">></span> <span class="special">></span></code> 104 </li> 105</ul></div> 106<p> 107 For the following examples, let's forget the options and use the default 108 values: 109 </p> 110<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">intrusive</span><span class="special">/</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 111 112<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">intrusive</span><span class="special">;</span> 113 114<span class="keyword">class</span> <span class="identifier">Foo</span> 115 <span class="comment">//Base hook with default tag, raw pointers and safe_link mode</span> 116 <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">list_base_hook</span><span class="special"><></span> 117<span class="special">{</span> <span class="comment">/**/</span> <span class="special">};</span> 118</pre> 119<p> 120 After that, we can define the intrusive list: 121 </p> 122<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">class</span> <span class="special">...</span><span class="identifier">Options</span><span class="special">></span> 123<span class="keyword">class</span> <span class="identifier">list</span><span class="special">;</span> 124</pre> 125<p> 126 <code class="computeroutput"><span class="identifier">list</span></code> receives the type to 127 be inserted in the container (<code class="computeroutput"><span class="identifier">T</span></code>) 128 as the first parameter and optionally, the user can specify options. We have 129 3 option types: 130 </p> 131<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 132<li class="listitem"> 133 <span class="bold"><strong><code class="computeroutput"><span class="identifier">base_hook</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">Hook</span><span class="special">></span></code></strong></span> 134 / <span class="bold"><strong><code class="computeroutput"><span class="identifier">member_hook</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Hook</span><span class="special">,</span> <span class="identifier">Hook</span> <span class="identifier">T</span><span class="special">::*</span> <span class="identifier">PtrToMember</span><span class="special">></span></code></strong></span> 135 / <span class="bold"><strong><code class="computeroutput"><span class="identifier">value_traits</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">ValueTraits</span><span class="special">></span></code></strong></span>: 136 All these options specify the relationship between the type <code class="computeroutput"><span class="identifier">T</span></code> to be inserted in the list and the 137 hook (since we can have several hooks in the same <code class="computeroutput"><span class="identifier">T</span></code> 138 type). <code class="computeroutput"><span class="identifier">member_hook</span></code> will 139 be explained a bit later and <code class="computeroutput"><span class="identifier">value_traits</span></code> 140 will be explained in the <a class="link" href="value_traits.html" title="Containers with custom ValueTraits">Containers 141 with custom ValueTraits</a> section. <span class="bold"><strong>If no option 142 is specified, the container will be configured to use the base hook with 143 the default tag</strong></span>. Some options configured for the hook (the 144 type of the pointers, link mode, etc.) will be propagated to the container. 145 </li> 146<li class="listitem"> 147 <span class="bold"><strong><code class="computeroutput"><span class="identifier">constant_time_size</span><span class="special"><</span><span class="keyword">bool</span> <span class="identifier">Enabled</span><span class="special">></span></code></strong></span>: 148 Specifies if a constant time <code class="computeroutput"><span class="identifier">size</span><span class="special">()</span></code> function is demanded for the container. 149 This will instruct the intrusive container to store an additional member 150 to keep track of the current size of the container. By default, constant-time 151 size is activated. 152 </li> 153<li class="listitem"> 154 <span class="bold"><strong><code class="computeroutput"><span class="identifier">size_type</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">SizeType</span><span class="special">></span></code></strong></span>: 155 Specifies an unsigned type that can hold the size of the container. This 156 type will be the type returned by <code class="computeroutput"><span class="identifier">list</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span></code> and the type stored in the intrusive 157 container if <code class="computeroutput"><span class="identifier">constant_time_size</span><span class="special"><</span><span class="keyword">true</span><span class="special">></span></code> is requested. The user normally will 158 not need to change this type, but some containers can have a <code class="computeroutput"><span class="identifier">size_type</span></code> that might be different from 159 <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code> (for example, STL-like containers 160 use the <code class="computeroutput"><span class="identifier">size_type</span></code> defined 161 by their allocator). <span class="bold"><strong>Boost.Intrusive</strong></span> 162 can be used to implement such containers specifying the type of the size. 163 By default the type is <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>. 164 </li> 165</ul></div> 166<p> 167 Example of a constant-time size intrusive list that will store Foo objects, 168 using the base hook with the default tag: 169 </p> 170<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">list</span><span class="special"><</span><span class="identifier">Foo</span><span class="special">></span> <span class="identifier">FooList</span><span class="special">;</span> 171</pre> 172<p> 173 Example of an intrusive list with non constant-time size that will store 174 Foo objects: 175 </p> 176<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">list</span><span class="special"><</span><span class="identifier">Foo</span><span class="special">,</span> <span class="identifier">constant_time_size</span><span class="special"><</span><span class="keyword">false</span><span class="special">></span> <span class="special">></span> <span class="identifier">FooList</span><span class="special">;</span> 177</pre> 178<p> 179 Remember that the user must specify the base hook in the container declaration 180 if the base hook has no default tag, because that usually means that the 181 type has more than one base hook, and a container shall know which hook will 182 be using: 183 </p> 184<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">intrusive</span><span class="special">/</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 185 186<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">intrusive</span><span class="special">;</span> 187 188<span class="keyword">struct</span> <span class="identifier">my_tag1</span><span class="special">;</span> 189<span class="keyword">struct</span> <span class="identifier">my_tag2</span><span class="special">;</span> 190 191<span class="keyword">typedef</span> <span class="identifier">list_base_hook</span><span class="special"><</span> <span class="identifier">tag</span><span class="special"><</span><span class="identifier">my_tag</span><span class="special">></span> <span class="special">></span> <span class="identifier">BaseHook</span><span class="special">;</span> 192<span class="keyword">typedef</span> <span class="identifier">list_base_hook</span><span class="special"><</span> <span class="identifier">tag</span><span class="special"><</span><span class="identifier">my_tag2</span><span class="special">></span> <span class="special">></span> <span class="identifier">BaseHook2</span><span class="special">;</span> 193<span class="keyword">class</span> <span class="identifier">Foo</span> <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">BaseHook</span><span class="special">,</span> <span class="keyword">public</span> <span class="identifier">BaseHook2</span> 194<span class="special">{</span> <span class="comment">/**/</span> <span class="special">};</span> 195 196<span class="keyword">typedef</span> <span class="identifier">list</span><span class="special"><</span> <span class="identifier">Foo</span><span class="special">,</span> <span class="identifier">base_hook</span><span class="special"><</span><span class="identifier">BaseHook</span><span class="special">></span> <span class="special">></span> <span class="identifier">FooList</span><span class="special">;</span> 197<span class="keyword">typedef</span> <span class="identifier">list</span><span class="special"><</span> <span class="identifier">Foo</span><span class="special">,</span> <span class="identifier">base_hook</span><span class="special"><</span><span class="identifier">BaseHook2</span><span class="special">></span> <span class="special">></span> <span class="identifier">FooList2</span><span class="special">;</span> 198</pre> 199<p> 200 Once the list is defined, we can use it: 201 </p> 202<pre class="programlisting"><span class="comment">//An object to be inserted in the list</span> 203<span class="identifier">Foo</span> <span class="identifier">foo_object</span><span class="special">;</span> 204<span class="identifier">FooList</span> <span class="identifier">list</span><span class="special">;</span> 205 206<span class="identifier">list</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">object</span><span class="special">);</span> 207 208<span class="identifier">assert</span><span class="special">(&</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">front</span><span class="special">()</span> <span class="special">==</span> <span class="special">&</span><span class="identifier">foo_object</span><span class="special">);</span> 209</pre> 210</div> 211<div class="section"> 212<div class="titlepage"><div><div><h3 class="title"> 213<a name="intrusive.usage.usage_member_hook"></a><a class="link" href="usage.html#intrusive.usage.usage_member_hook" title="Using member hooks">Using member hooks</a> 214</h3></div></div></div> 215<p> 216 Sometimes an 'is-a' relationship between list hooks and the list value types 217 is not desirable. In this case, using a member hook as a data member instead 218 of 'disturbing' the hierarchy might be the right way: you can add a public 219 data member <code class="computeroutput"><span class="identifier">list_member_hook</span><span class="special"><...></span></code> to your class. This class can 220 be configured with the same options as <code class="computeroutput"><span class="identifier">list_base_hook</span></code> 221 except the option <code class="computeroutput"><span class="identifier">tag</span></code>: 222 </p> 223<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="special">...</span><span class="identifier">Options</span><span class="special">></span> 224<span class="keyword">class</span> <span class="identifier">list_member_hook</span><span class="special">;</span> 225</pre> 226<p> 227 Example: 228 </p> 229<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">intrusive</span><span class="special">/</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 230 231<span class="keyword">class</span> <span class="identifier">Foo</span> 232<span class="special">{</span> 233 <span class="keyword">public</span><span class="special">:</span> 234 <span class="identifier">list_member_hook</span><span class="special"><></span> <span class="identifier">hook_</span><span class="special">;</span> 235 <span class="comment">//...</span> 236<span class="special">};</span> 237</pre> 238<p> 239 When member hooks are used, the <code class="computeroutput"><span class="identifier">member_hook</span></code> 240 option is used to configure the list: 241 </p> 242<pre class="programlisting"><span class="comment">//This option will configure "list" to use the member hook</span> 243<span class="keyword">typedef</span> <span class="identifier">member_hook</span><span class="special"><</span><span class="identifier">Foo</span><span class="special">,</span> <span class="identifier">list_member_hook</span><span class="special"><>,</span> <span class="special">&</span><span class="identifier">Foo</span><span class="special">::</span><span class="identifier">hook_</span><span class="special">></span> <span class="identifier">MemberHookOption</span><span class="special">;</span> 244 245<span class="comment">//This list will use the member hook</span> 246<span class="keyword">typedef</span> <span class="identifier">list</span><span class="special"><</span><span class="identifier">Foo</span><span class="special">,</span> <span class="identifier">MemberHookOption</span><span class="special">></span> <span class="identifier">FooList</span><span class="special">;</span> 247</pre> 248<p> 249 Now we can use the container: 250 </p> 251<pre class="programlisting"><span class="comment">//An object to be inserted in the list</span> 252<span class="identifier">Foo</span> <span class="identifier">foo_object</span><span class="special">;</span> 253<span class="identifier">FooList</span> <span class="identifier">list</span><span class="special">;</span> 254 255<span class="identifier">list</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">object</span><span class="special">);</span> 256 257<span class="identifier">assert</span><span class="special">(&</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">front</span><span class="special">()</span> <span class="special">==</span> <span class="special">&</span><span class="identifier">foo_object</span><span class="special">);</span> 258</pre> 259</div> 260<p> 261 However, member hooks have some implementation limitations: If there is a virtual 262 inheritance relationship between the parent and the member hook, then the distance 263 between the parent and the hook is not a compile-time fixed value so obtaining 264 the address of the parent from the member hook is not possible without reverse 265 engineering compiler produced RTTI. Apart from this, the non-standard pointer 266 to member implementation for classes with complex inheritance relationships 267 in MSVC ABI compatible-compilers is not supported by member hooks since it 268 also depends on compiler-produced RTTI information. 269 </p> 270<div class="section"> 271<div class="titlepage"><div><div><h3 class="title"> 272<a name="intrusive.usage.usage_both_hooks"></a><a class="link" href="usage.html#intrusive.usage.usage_both_hooks" title="Using both hooks">Using both hooks</a> 273</h3></div></div></div> 274<p> 275 You can insert the same object in several intrusive containers at the same 276 time, using one hook per container. This is a full example using base and 277 member hooks: 278 </p> 279<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">intrusive</span><span class="special">/</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 280<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> 281 282<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">intrusive</span><span class="special">;</span> 283 284<span class="keyword">class</span> <span class="identifier">MyClass</span> <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">list_base_hook</span><span class="special"><></span> 285<span class="special">{</span> 286 <span class="keyword">int</span> <span class="identifier">int_</span><span class="special">;</span> 287 288 <span class="keyword">public</span><span class="special">:</span> 289 <span class="identifier">list_member_hook</span><span class="special"><></span> <span class="identifier">member_hook_</span><span class="special">;</span> 290 291 <span class="identifier">MyClass</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span><span class="special">)</span> <span class="special">:</span> <span class="identifier">int_</span><span class="special">(</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{}</span> 292<span class="special">};</span> 293 294<span class="comment">//Define a list that will store MyClass using the base hook</span> 295<span class="keyword">typedef</span> <span class="identifier">list</span><span class="special"><</span><span class="identifier">MyClass</span><span class="special">></span> <span class="identifier">BaseList</span><span class="special">;</span> 296 297<span class="comment">//Define a list that will store MyClass using the member hook</span> 298<span class="keyword">typedef</span> <span class="identifier">member_hook</span> 299 <span class="special"><</span> <span class="identifier">MyClass</span><span class="special">,</span> <span class="identifier">list_member_hook</span><span class="special"><>,</span> <span class="special">&</span><span class="identifier">MyClass</span><span class="special">::</span><span class="identifier">member_hook_</span><span class="special">></span> <span class="identifier">MemberOption</span><span class="special">;</span> 300<span class="keyword">typedef</span> <span class="identifier">list</span><span class="special"><</span><span class="identifier">MyClass</span><span class="special">,</span> <span class="identifier">MemberOption</span><span class="special">></span> <span class="identifier">MemberList</span><span class="special">;</span> 301 302<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 303<span class="special">{</span> 304 <span class="keyword">typedef</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">MyClass</span><span class="special">>::</span><span class="identifier">iterator</span> <span class="identifier">VectIt</span><span class="special">;</span> 305 306 <span class="comment">//Create several MyClass objects, each one with a different value</span> 307 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">MyClass</span><span class="special">></span> <span class="identifier">values</span><span class="special">;</span> 308 <span class="keyword">for</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="number">100</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="identifier">values</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">MyClass</span><span class="special">(</span><span class="identifier">i</span><span class="special">));</span> 309 310 <span class="identifier">BaseList</span> <span class="identifier">baselist</span><span class="special">;</span> 311 <span class="identifier">MemberList</span> <span class="identifier">memberlist</span><span class="special">;</span> 312 313 <span class="comment">//Now insert them in the reverse order in the base hook list</span> 314 <span class="keyword">for</span><span class="special">(</span><span class="identifier">VectIt</span> <span class="identifier">it</span><span class="special">(</span><span class="identifier">values</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()),</span> <span class="identifier">itend</span><span class="special">(</span><span class="identifier">values</span><span class="special">.</span><span class="identifier">end</span><span class="special">())</span> 315 <span class="special">;</span> <span class="identifier">it</span> <span class="special">!=</span> <span class="identifier">itend</span> <span class="special">;</span> <span class="special">++</span><span class="identifier">it</span><span class="special">){</span> 316 <span class="identifier">baselist</span><span class="special">.</span><span class="identifier">push_front</span><span class="special">(*</span><span class="identifier">it</span><span class="special">);</span> 317 <span class="special">}</span> 318 319 <span class="comment">//Now insert them in the same order as in vector in the member hook list</span> 320 <span class="keyword">for</span><span class="special">(</span><span class="identifier">VectIt</span> <span class="identifier">it</span><span class="special">(</span><span class="identifier">values</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()),</span> <span class="identifier">itend</span><span class="special">(</span><span class="identifier">values</span><span class="special">.</span><span class="identifier">end</span><span class="special">());</span> <span class="identifier">it</span> <span class="special">!=</span> <span class="identifier">itend</span><span class="special">;</span> <span class="special">++</span><span class="identifier">it</span><span class="special">)</span> 321 <span class="identifier">memberlist</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(*</span><span class="identifier">it</span><span class="special">);</span> 322 323 <span class="comment">//Now test lists</span> 324 <span class="special">{</span> 325 <span class="identifier">BaseList</span><span class="special">::</span><span class="identifier">reverse_iterator</span> <span class="identifier">rbit</span><span class="special">(</span><span class="identifier">baselist</span><span class="special">.</span><span class="identifier">rbegin</span><span class="special">());</span> 326 <span class="identifier">MemberList</span><span class="special">::</span><span class="identifier">iterator</span> <span class="identifier">mit</span><span class="special">(</span><span class="identifier">memberlist</span><span class="special">.</span><span class="identifier">begin</span><span class="special">());</span> 327 <span class="identifier">VectIt</span> <span class="identifier">it</span><span class="special">(</span><span class="identifier">values</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()),</span> <span class="identifier">itend</span><span class="special">(</span><span class="identifier">values</span><span class="special">.</span><span class="identifier">end</span><span class="special">());</span> 328 329 <span class="comment">//Test the objects inserted in the base hook list</span> 330 <span class="keyword">for</span><span class="special">(;</span> <span class="identifier">it</span> <span class="special">!=</span> <span class="identifier">itend</span><span class="special">;</span> <span class="special">++</span><span class="identifier">it</span><span class="special">,</span> <span class="special">++</span><span class="identifier">rbit</span><span class="special">)</span> 331 <span class="keyword">if</span><span class="special">(&*</span><span class="identifier">rbit</span> <span class="special">!=</span> <span class="special">&*</span><span class="identifier">it</span><span class="special">)</span> <span class="keyword">return</span> <span class="number">1</span><span class="special">;</span> 332 333 <span class="comment">//Test the objects inserted in the member hook list</span> 334 <span class="keyword">for</span><span class="special">(</span><span class="identifier">it</span> <span class="special">=</span> <span class="identifier">values</span><span class="special">.</span><span class="identifier">begin</span><span class="special">();</span> <span class="identifier">it</span> <span class="special">!=</span> <span class="identifier">itend</span><span class="special">;</span> <span class="special">++</span><span class="identifier">it</span><span class="special">,</span> <span class="special">++</span><span class="identifier">mit</span><span class="special">)</span> 335 <span class="keyword">if</span><span class="special">(&*</span><span class="identifier">mit</span> <span class="special">!=</span> <span class="special">&*</span><span class="identifier">it</span><span class="special">)</span> <span class="keyword">return</span> <span class="number">1</span><span class="special">;</span> 336 <span class="special">}</span> 337 338 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 339<span class="special">}</span> 340</pre> 341</div> 342<div class="section"> 343<div class="titlepage"><div><div><h3 class="title"> 344<a name="intrusive.usage.usage_lifetime"></a><a class="link" href="usage.html#intrusive.usage.usage_lifetime" title="Object lifetime">Object lifetime</a> 345</h3></div></div></div> 346<p> 347 Even if the interface of <code class="computeroutput"><a class="link" href="../boost/intrusive/list.html" title="Class template list">list</a></code> 348 is similar to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">list</span></code>, its usage is a bit different: You 349 always have to keep in mind that you directly store objects in intrusive 350 containers, not copies. The lifetime of a stored object is not bound to or 351 managed by the container: 352 </p> 353<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 354<li class="listitem"> 355 When the container gets destroyed before the object, the object is not 356 destroyed, so you have to be careful to avoid resource leaks. 357 </li> 358<li class="listitem"> 359 When the object is destroyed before the container, your program is likely 360 to crash, because the container contains a pointer to an non-existing 361 object. 362 </li> 363</ul></div> 364</div> 365</div> 366<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 367<td align="left"></td> 368<td align="right"><div class="copyright-footer">Copyright © 2005 Olaf Krzikalla<br>Copyright © 2006-2015 Ion Gaztanaga<p> 369 Distributed under the Boost Software License, Version 1.0. (See accompanying 370 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 371 </p> 372</div></td> 373</tr></table> 374<hr> 375<div class="spirit-nav"> 376<a accesskey="p" href="intrusive_vs_nontrusive.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../intrusive.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="usage_when.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 377</div> 378</body> 379</html> 380
