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POBinding to a weak_ptr
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  1. POBinding to a weak_ptr
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    copied!<p>Is there a way to <strong>std::bind to a std::weak_ptr</strong>? I'd like to store a "weak function" callback that automatically "disconnects" when the callee is destroyed.</p> <p>I know how to create a std::function using a shared_ptr:</p> <pre><code>std::function&lt;void()&gt; MyClass::GetCallback() { return std::function&lt;void()&gt;(std::bind(&amp;MyClass::CallbackFunc, shared_from_this())); } </code></pre> <p>However the returned std::function keeps my object alive forever. So I'd like to bind it to a <strong>weak_ptr</strong>:</p> <pre><code>std::function&lt;void()&gt; MyClass::GetCallback() { std::weak_ptr&lt;MyClass&gt; thisWeakPtr(shared_from_this()); return std::function&lt;void()&gt;(std::bind(&amp;MyClass::CallbackFunc, thisWeakPtr)); } </code></pre> <p>But that doesn't compile. (std::bind will accept no weak_ptr!) Is there any way to bind to a weak_ptr?</p> <p>I've found discussions about this (see below), but there seems to be no standard implementation. What is the best solution for storing a "weak function", in particular if Boost is not available?</p> <hr> <p>Discussions / research (all of these use Boost and are not standardized):</p> <ul> <li><a href="http://lists.boost.org/Archives/boost/2012/01/189510.php">weak_function</a></li> <li><a href="https://svn.boost.org/trac/boost/ticket/810">weak_ptr binding</a></li> <li><a href="http://lists.boost.org/boost-users/2011/09/70647.php">"weak" binding</a> (and a <a href="http://lists.boost.org/Archives/boost/2012/01/189529.php">fix</a> for it)</li> <li><a href="http://permalink.gmane.org/gmane.comp.lib.boost.devel/227213">weak_fn</a></li> <li>Another <a href="http://lists.boost.org/Archives/boost/2009/03/149980.php">weak_fn</a></li> </ul>
 

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