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    <p>These are just reformulations of <a href="https://stackoverflow.com/a/2251472/315052">Steve Jessop's C solution</a> into C++. These toy examples (note the lack of error checking) use templates to make it obvious how to change the code to use some type other than <code>double</code>. For example, the <code>double</code> could be replaced with a <code>class</code> type if more than one value needed to be returned after the work is done. In practice, the base class and template would likely be removed and the <code>work()</code> method of <code>MyWorker</code> would be called directly by the invoker rather than via a virtual method.</p> <p>First, using <code>pthread</code>:</p> <pre><code>#include &lt;iostream&gt; #include &lt;pthread.h&gt; class WorkerBase { protected: virtual ~WorkerBase () {} public: virtual void * work () = 0; }; template &lt;typename T&gt; struct Worker : public WorkerBase { T result; }; extern "C" void *invoke_worker (void *arg) { return static_cast&lt;WorkerBase *&gt;(arg)-&gt;work(); } struct MyWorker : public Worker&lt;double&gt; { void * work () { result = 4.2; return 0; } }; int main () { pthread_t t; MyWorker w; pthread_create(&amp;t, 0, invoke_worker, &amp;w); pthread_join(t, 0); std::cout &lt;&lt; "result: " &lt;&lt; w.result &lt;&lt; std::endl; return 0; } </code></pre> <p>Second, using C++11 <code>std::thread</code>:</p> <pre><code>#include &lt;iostream&gt; #include &lt;thread&gt; class WorkerBase { protected: virtual ~WorkerBase () {} public: virtual void work () = 0; static void invoke (WorkerBase *w) { w-&gt;work(); } }; template &lt;typename T&gt; struct Worker : public WorkerBase { T result; }; class MyWorker : public Worker&lt;double&gt; { void work () { result = 4.2; } }; int main () { MyWorker w; std::thread t(MyWorker::invoke, &amp;w); t.join(); std::cout &lt;&lt; "result: " &lt;&lt; w.result &lt;&lt; std::endl; return 0; } </code></pre> <p>You had another question in your post that I had missed:</p> <blockquote> <p>And if I have a static array of 10 positions and 10 pthreads modifiying different positions each time, will I have trouble?</p> </blockquote> <p>Whether or not this gives you trouble will likely depend on the array element type and your hardware architecture. In practice, I have not observed this being a problem on x86 architectures for array elements that are aligned on machine word boundaries.</p>
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    1. POHow to return a double value from pthread in c++?
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    1. POHow to return a double value from pthread in c++?
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    1. COThanks for your long answer, but passing around structures and objects is, if I am not mistaken, quite heavier than simply writing the double into a static array (a one time access to write) once the pthread has done it's job :S
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    2. CO@Flame_Phoenix: I modified the C++11 so that it no longer passes an object. If you object to pointers being passed, then the only solution would be a global variable.
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    3. CO@Flame_Phoenix: You don't even have working code and you're worried about whether or not something is "heavy"? Threads themselves are way heavier than any struct you'll pass a pointer to.
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