c++ - How to create a std::function alike wrapper? -

attempted this:

template <class r, class... ts> class myfunction { public:     using func_type = r(*)(ts...);      myfunction(func_type f)       : m_func(f)      {     }      r operator()(ts ... args)      {         return m_func(args...);     }  private:     func_type m_func; };  int testfn(int a) {     std::cout << "value " << a;     return 42; }  void testing() {     myfunction<int(int)> func(testfn);     std::cout << "ret " << func(1) << std::endl; } 

but fails with:

 error c2064: term not evaluate function taking 1  c2091: function returns function     c2091: function returns  c2664: 'myfunction<int (int),>::myfunction(const myfunction<int  (int),> &)' : cannot convert argument 1 'int (__cdecl *)(int)'  'int (__cdecl *(__cdecl  *)(void))' 

compiler msvc2013.

it should this:

template <typename t> class myfunction;  template<typename r, class... ts> class myfunction<r(ts...)> { public:     using func_type = r(*)(ts...);      myfunction(func_type f)       : m_func(f)      {     }      r operator()(ts ... args)      {         return m_func(args...);     }  private:     func_type m_func; }; 

myfunction should specialized function signature type. note: std::function more complicated.