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| <a name="intrusive.thread_safety"></a><a class="link" href="thread_safety.html" title="Thread safety guarantees">Thread safety guarantees</a> |
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| <p> |
| Intrusive containers have thread safety guarantees similar to STL containers. |
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| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
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| Several threads having read or write access to different instances is safe |
| as long as inserted objects are different. |
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| <li class="listitem"> |
| Concurrent read-only access to the same container is safe. |
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| Some Intrusive hooks (auto-unlink hooks, for example) modify containers without |
| having a reference to them: this is considered a write access to the container. |
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| <p> |
| Other functions, like checking if an object is already inserted in a container |
| using the <code class="computeroutput"><span class="identifier">is_linked</span><span class="special">()</span></code> |
| member of safe hooks, constitute read access on the container without having |
| a reference to it, so no other thread should have write access (direct or indirect) |
| to that container. |
| </p> |
| <p> |
| Since the same object can be inserted in several containers at the same time |
| using different hooks, the thread safety of <span class="bold"><strong>Boost.Intrusive</strong></span> |
| is related to the containers and also to the object whose lifetime is manually |
| managed by the user. |
| </p> |
| <p> |
| As we can see, the analysis of the thread-safety of a program using <span class="bold"><strong>Boost.Intrusive</strong></span> is harder than with non-intrusive containers. |
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| To analyze the thread safety, consider the following points: |
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| The auto-unlink hook's destructor and <code class="computeroutput"><span class="identifier">unlink</span><span class="special">()</span></code> functions modify the container indirectly. |
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| The safe mode and auto-unlink hooks' <code class="computeroutput"><span class="identifier">is_linked</span><span class="special">()</span></code> functions are a read access to the container. |
| </li> |
| <li class="listitem"> |
| Inserting an object in containers that will be modified by different threads |
| has no thread safety guarantee, although in most platforms it will be thread-safe |
| without locking. |
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| <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>) |
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