b02910e3   
   From: daniel.kruegler@googlemail.com   
      
   On 2011-10-31 06:43, Ralph Zhang wrote:   
   > Suppose I have a functor s, which is noncopyable but movable, how can   
   > I store it in a std::function? i.e, how to make the following code   
   > compile? (using gcc 4.6)   
      
   First of all, you don't need std::bind in your example, the assignment   
   of a callable functor to std::function can be done directly as   
      
    func = std::move(s);   
      
   This doesn't solve your problem though. There exists a fundamental   
   requirement, that the wrapped functor is CopyConstructible. This is   
   related to the fact, that std::function performs type-erasure on the   
   wrapped function object. So, if you need to wrap your move-only functor   
   anyway, you either need to wrap a reference of it (e.g. using   
   std::reference_wrapper) or you need to perform dynamic memory allocation   
   and user a wrapping function object of your move-only functor e.g.   
      
   struct WS   
   {   
     std::shared_ptr ps;   
     void operator()() { (*ps)(); }   
   };   
      
   It depends on the life-cycle of the std::function wrapper, whether you   
   can use the reference_wrapper approach (Obviously you cannot return an   
   automatic variable of S out of the function scope), or whether you need   
   to use dynamic memory allocation.   
      
   HTH & Greetings from Bremen,   
      
   Daniel Krügler   
      
      
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