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    <p>This doesn't really answer your question, because a callback has to be a template, unless you want to pass a parameter through <code>void*</code> (which is totally crazy idea in my opinion).</p> <p>I asked a similar question : <a href="https://stackoverflow.com/questions/5656691/what-is-wrong-with-this-variadic-templates-example">What is wrong with this variadic templates example?</a> </p> <p>One of answers gave a complete solution : </p> <pre><code>#include &lt;memory&gt; template&lt; typename R, typename ... Args &gt; class CallbackBase { public: typedef std::shared_ptr&lt; CallbackBase&lt; R, Args... &gt; &gt; CallbackPtr; virtual ~CallbackBase() { } virtual R Call( Args ... args) = 0; }; template&lt; typename R, typename ... Args &gt; class FunctionCallback : public CallbackBase&lt; R, Args... &gt; { public: typedef R (*funccb)(Args...); FunctionCallback( funccb cb_ ) : CallbackBase&lt; R, Args... &gt;(), cb( cb_ ) { } virtual ~FunctionCallback() { } virtual R Call(Args... args) { return cb( args... ); } private: funccb cb; }; template &lt; typename R, typename ...Args &gt; typename CallbackBase&lt; R, Args... &gt;::CallbackPtr MakeCallback( R (*cb)(Args...) ) { typename CallbackBase&lt; R, Args... &gt;::CallbackPtr p( new FunctionCallback&lt; R, Args... &gt;( cb ) ); return p; } bool Foo_1args( const int &amp; t) { return true; } int main() { auto cbObj = MakeCallback( &amp; Foo_1args ); } </code></pre> <p>Hope it helps. If you hate templates, you can always use a typedef.</p>
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    1. POC++ Callback -- How to decouple the call back type
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    1. USBЈовић
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    1. COThanks. I found another sample code, which is similar, but I believe is better. The public API is template free. What I am still missing is how to handle variable length argument list of the callback function. I'll post that sample code as another answer to this question. Please check
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    2. COI can not answer my own question within 8 hours. I've pasted the code to the end of my question. Please check.
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