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copied!<p>Indeed, there is a race condition between the destructor of the local <code>promise</code> object (at the end of the constructor and the call to <code>set_value()</code> from the thread. That is, <code>set_value()</code> wakes the main tread, that just next destroys the promise object, but the <code>set_value()</code> function has not yet finished, and dead-locks.</p> <p>Reading the C++11 standard, I'm not sure if your use is allowed:</p> <blockquote> <p><code>void promise<void>::set_value();</code></p> <p>Effects: atomically stores the value r in the shared state and makes that state ready.</p> </blockquote> <p>But somewhere else:</p> <blockquote> <p>The set_value, set_exception, set_value_at_thread_exit, and set_exception_at_thread_exit member functions behave as though they acquire a <strong>single mutex</strong> associated with the promise object while updating the promise object.</p> </blockquote> <p>Are <code>set_value()</code> calls supposed to be atomic with regards to other functions, such as the destructor? </p> <p>IMHO, I'd say no. The effects would be comparable to destroying a mutex while other thread is still locking it. The result is undefined.</p> <p>The solution would be to make <code>p</code> outlive the thread. Two solutions that I can think of:</p> <ol> <li><p>Make <code>p</code> a member of the class, just as Michael Burr suggested in the other answer.</p></li> <li><p>Move the promise into the thread.</p></li> </ol> <p>In the constructor:</p> <pre><code>std::promise<void> p; std::future <void> f = p.get_future(); _thread = std::thread(&foo::run, this, std::move(p)); </code></pre> <p>BTW, you don't need the call to <code>bind</code>, (the thread constructor is already overloaded), or call to <code>std::move</code> to move the thread (the right value is already an r-value). The call to <code>std::move</code> into the promise is mandatory, though.</p> <p>And the thread function does not receive a reference, but the moved promise:</p> <pre><code>void run(std::promise<void> p) { p.set_value(); } </code></pre> <p>I think that this is precisely why C++11 defines two different classes: <code>promise</code> and <code>future</code>: you move the promise into the thread, but you keep the future to recover the result.</p>

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