a3d66e46   
   From: daniel.kruegler@googlemail.com   
      
   Am 09.05.2012 21:27, schrieb Peter:   
   > Hi Folks,   
   >   
   > given this typedef   
   >   
   > typedef bool (*on_hit_test_type)(widget_interactive *, point const*,   
   > bool *);   
   >   
   > and this member definition   
   >   
   > std::function   
   > on_hit_test;   
   >   
   > Is there a way to convert one to the other? (The typedef to the   
   > std::function template argument or the other way round)   
      
   Do you mean something like this:   
      
   std::function::type> on_hit_test;   
      
   in one direction? The other direction requires a little more efforts:   
   You could invent a small trait like the following   
      
   template   
   struct function_signature;   
      
   template   
   struct function_signature>   
   {   
     typedef R type(Args...);   
   };   
      
   Now you are able to go backwards via:   
      
   typedef std::add_pointer::type>::type fu_ptr;   
      
   The following assertion should hold:   
      
   static_assert(std::is_same::value, "");   
      
   > The reason I'm asking is that I have a ton of them, and it's easy to   
   > make errors in these somwhat duplicate constructs.   
   >   
   > Ideally, I'd like to write one and derive the other somehow from it.   
      
   I don't understand how you mean this - how is derivation related to that?   
      
   HTH & Greetings from Bremen,   
      
   Daniel Krügler   
      
      
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