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| <div class="section"> |
| <div class="titlepage"><div><div><h2 class="title" style="clear: both"> |
| <a name="intrusive.using_smart_pointers"></a><a class="link" href="using_smart_pointers.html" title="Using smart pointers with Boost.Intrusive containers">Using smart pointers with |
| Boost.Intrusive containers</a> |
| </h2></div></div></div> |
| <div class="toc"><dl><dt><span class="section"><a href="using_smart_pointers.html#intrusive.using_smart_pointers.smart_pointers_requirements">Requirements |
| for smart pointers compatible with Boost.Intrusive</a></span></dt></dl></div> |
| <p> |
| <span class="bold"><strong>Boost.Intrusive</strong></span> hooks can be configured to |
| use other pointers than raw pointers. When a <span class="bold"><strong>Boost.Intrusive</strong></span> |
| hook is configured with a smart pointer as an argument, this pointer configuration |
| is passed to the containers. For example, if the following hook is configured |
| with a smart pointer (for example, an offset pointer from <span class="bold"><strong>Boost.Interprocess</strong></span>): |
| </p> |
| <p> |
| |
| </p> |
| <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> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">interprocess</span><span class="special">/</span><span class="identifier">offset_ptr</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <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> |
| <span class="keyword">namespace</span> <span class="identifier">ip</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">interprocess</span><span class="special">;</span> |
| |
| <span class="keyword">class</span> <span class="identifier">shared_memory_data</span> |
| <span class="comment">//Declare the hook with an offset_ptr from Boost.Interprocess |
| </span> <span class="comment">//to make this class compatible with shared memory |
| </span> <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">list_base_hook</span><span class="special"><</span> <span class="identifier">void_pointer</span><span class="special"><</span> <span class="identifier">ip</span><span class="special">::</span><span class="identifier">offset_ptr</span><span class="special"><</span><span class="keyword">void</span><span class="special">></span> <span class="special">></span> <span class="special">></span> |
| <span class="special">{</span> |
| <span class="keyword">int</span> <span class="identifier">data_id_</span><span class="special">;</span> |
| <span class="keyword">public</span><span class="special">:</span> |
| |
| <span class="keyword">int</span> <span class="identifier">get</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">data_id_</span><span class="special">;</span> <span class="special">}</span> |
| <span class="keyword">void</span> <span class="identifier">set</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">id</span><span class="special">)</span> <span class="special">{</span> <span class="identifier">data_id_</span> <span class="special">=</span> <span class="identifier">id</span><span class="special">;</span> <span class="special">}</span> |
| <span class="special">};</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Any intrusive list constructed using this hook will be ready for shared memory, |
| because the intrusive list will also use offset pointers internally. For example, |
| we can create an intrusive list in shared memory combining <span class="bold"><strong>Boost.Interprocess</strong></span> |
| and <span class="bold"><strong>Boost.Intrusive</strong></span>: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">interprocess</span><span class="special">/</span><span class="identifier">managed_shared_memory</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">interprocess</span><span class="special">/</span><span class="identifier">containers</span><span class="special">/</span><span class="identifier">vector</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">interprocess</span><span class="special">/</span><span class="identifier">containers</span><span class="special">/</span><span class="identifier">list</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">interprocess</span><span class="special">/</span><span class="identifier">allocators</span><span class="special">/</span><span class="identifier">allocator</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <span class="comment">//Definition of the shared memory friendly intrusive list |
| </span><span class="keyword">typedef</span> <span class="identifier">ip</span><span class="special">::</span><span class="identifier">list</span><span class="special"><</span><span class="identifier">shared_memory_data</span><span class="special">></span> <span class="identifier">shm_list_t</span><span class="special">;</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="comment">//Now create an intrusive list in shared memory: |
| </span> <span class="comment">//nodes and the container itself must be created in shared memory |
| </span> <span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">MaxElem</span> <span class="special">=</span> <span class="number">100</span><span class="special">;</span> |
| <span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">ShmSize</span> <span class="special">=</span> <span class="number">50000</span><span class="special">;</span> |
| <span class="keyword">const</span> <span class="keyword">char</span> <span class="special">*</span><span class="identifier">ShmName</span> <span class="special">=</span> <span class="identifier">get_shared_memory_name</span><span class="special">();</span> |
| <span class="special">{</span> |
| <span class="comment">//Erase all old shared memory |
| </span> <span class="identifier">ip</span><span class="special">::</span><span class="identifier">shared_memory_object</span><span class="special">::</span><span class="identifier">remove</span><span class="special">(</span><span class="identifier">ShmName</span><span class="special">);</span> |
| <span class="identifier">ip</span><span class="special">::</span><span class="identifier">managed_shared_memory</span> <span class="identifier">shm</span><span class="special">(</span><span class="identifier">ip</span><span class="special">::</span><span class="identifier">create_only</span><span class="special">,</span> <span class="identifier">ShmName</span><span class="special">,</span> <span class="identifier">ShmSize</span><span class="special">);</span> |
| |
| <span class="comment">//Create all nodes in shared memory using a shared memory vector |
| </span> <span class="comment">//See Boost.Interprocess documentation for more information on this |
| </span> <span class="keyword">typedef</span> <span class="identifier">ip</span><span class="special">::</span><span class="identifier">allocator</span> |
| <span class="special"><</span> <span class="identifier">shared_memory_data</span><span class="special">,</span> <span class="identifier">ip</span><span class="special">::</span><span class="identifier">managed_shared_memory</span><span class="special">::</span><span class="identifier">segment_manager</span><span class="special">></span> |
| <span class="identifier">shm_allocator_t</span><span class="special">;</span> |
| <span class="keyword">typedef</span> <span class="identifier">ip</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">shared_memory_data</span><span class="special">,</span> <span class="identifier">shm_allocator_t</span><span class="special">></span> <span class="identifier">shm_vector_t</span><span class="special">;</span> |
| <span class="identifier">shm_allocator_t</span> <span class="identifier">shm_alloc</span><span class="special">(</span><span class="identifier">shm</span><span class="special">.</span><span class="identifier">get_segment_manager</span><span class="special">());</span> |
| <span class="identifier">shm_vector_t</span> <span class="special">*</span><span class="identifier">pshm_vect</span> <span class="special">=</span> |
| <span class="identifier">shm</span><span class="special">.</span><span class="identifier">construct</span><span class="special"><</span><span class="identifier">shm_vector_t</span><span class="special">>(</span><span class="identifier">ip</span><span class="special">::</span><span class="identifier">anonymous_instance</span><span class="special">)(</span><span class="identifier">shm_alloc</span><span class="special">);</span> |
| <span class="identifier">pshm_vect</span><span class="special">-></span><span class="identifier">resize</span><span class="special">(</span><span class="identifier">MaxElem</span><span class="special">);</span> |
| |
| <span class="comment">//Initialize all the nodes |
| </span> <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="identifier">MaxElem</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">(*</span><span class="identifier">pshm_vect</span><span class="special">)[</span><span class="identifier">i</span><span class="special">].</span><span class="identifier">set</span><span class="special">(</span><span class="identifier">i</span><span class="special">);</span> |
| |
| <span class="comment">//Now create the shared memory intrusive list |
| </span> <span class="identifier">shm_list_t</span> <span class="special">*</span><span class="identifier">plist</span> <span class="special">=</span> <span class="identifier">shm</span><span class="special">.</span><span class="identifier">construct</span><span class="special"><</span><span class="identifier">shm_list_t</span><span class="special">>(</span><span class="identifier">ip</span><span class="special">::</span><span class="identifier">anonymous_instance</span><span class="special">)();</span> |
| <span class="identifier">plist</span><span class="special">-></span><span class="identifier">insert</span><span class="special">(</span><span class="identifier">plist</span><span class="special">-></span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">pshm_vect</span><span class="special">-></span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">pshm_vect</span><span class="special">-></span><span class="identifier">end</span><span class="special">());</span> |
| |
| <span class="comment">//Check all the inserted nodes |
| </span> <span class="keyword">int</span> <span class="identifier">checker</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> |
| <span class="keyword">for</span><span class="special">(</span> <span class="identifier">shm_list_t</span><span class="special">::</span><span class="identifier">const_iterator</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">plist</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">plist</span><span class="special">-></span><span class="identifier">end</span><span class="special">())</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">checker</span><span class="special">){</span> |
| <span class="keyword">if</span><span class="special">(</span><span class="identifier">it</span><span class="special">-></span><span class="identifier">get</span><span class="special">()</span> <span class="special">!=</span> <span class="identifier">checker</span><span class="special">)</span> <span class="keyword">return</span> <span class="keyword">false</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="comment">//Now delete the list and after that, the nodes |
| </span> <span class="identifier">shm</span><span class="special">.</span><span class="identifier">destroy_ptr</span><span class="special">(</span><span class="identifier">plist</span><span class="special">);</span> |
| <span class="identifier">shm</span><span class="special">.</span><span class="identifier">destroy_ptr</span><span class="special">(</span><span class="identifier">pshm_vect</span><span class="special">);</span> |
| <span class="special">}</span> |
| <span class="identifier">ip</span><span class="special">::</span><span class="identifier">shared_memory_object</span><span class="special">::</span><span class="identifier">remove</span><span class="special">(</span><span class="identifier">ShmName</span><span class="special">);</span> |
| <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| </p> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="intrusive.using_smart_pointers.smart_pointers_requirements"></a><a class="link" href="using_smart_pointers.html#intrusive.using_smart_pointers.smart_pointers_requirements" title="Requirements for smart pointers compatible with Boost.Intrusive">Requirements |
| for smart pointers compatible with Boost.Intrusive</a> |
| </h3></div></div></div> |
| <p> |
| Not every smart pointer is compatible with <span class="bold"><strong>Boost.Intrusive</strong></span>; |
| the smart pointer must have the following features: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| It must support the same operations as a raw pointer, except casting. |
| </li> |
| <li class="listitem"> |
| It must be convertible to a raw pointer and constructible from a raw |
| pointer. |
| </li> |
| <li class="listitem"> |
| It must have the same ownership semantics as a raw pointer. This means |
| that resource management smart pointers (like <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_ptr</span></code>) |
| can't be used. |
| </li> |
| </ul></div> |
| <p> |
| The conversion from the smart pointer to a raw pointer must be implemented |
| following Boost smart pointer <code class="computeroutput"><span class="identifier">detail</span><span class="special">::</span><span class="identifier">get_pointer</span><span class="special">()</span></code> function. This function will be found using |
| ADL. For example, for <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">interprocess</span><span class="special">::</span><span class="identifier">offset_ptr</span></code>, |
| <code class="computeroutput"><span class="identifier">detail</span><span class="special">::</span><span class="identifier">get_pointer</span></code> is defined as follows: |
| </p> |
| <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="identifier">T</span> <span class="special">*</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">get_pointer</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">interprocess</span><span class="special">::</span><span class="identifier">offset_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">p</span><span class="special">)</span> |
| <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">get</span><span class="special">();</span> <span class="special">}</span> |
| </pre> |
| </div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2005 Olaf Krzikalla, 2006-2010 Ion Gaztanaga<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 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>) |
| </p> |
| </div></td> |
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