c++ - How to pass a function pointer that points to constructor?

Question

I'm working on implementing a reflection mechanism in C++. All objects within my code are a subclass of Object(my own generic type) that contain a static member datum of type Class.

class Class{
public:
   Class(const std::string &n, Object *(*c)());
protected:
   std::string name;     // Name for subclass
   Object *(*create)();  // Pointer to creation function for subclass
};

For any subclass of Object with a static Class member datum, I want to be able to initialize 'create' with a pointer to the constructor of that subclass.

question from:https://stackoverflow.com/questions/954548/how-to-pass-a-function-pointer-that-points-to-constructor

Answer 1

You cannot take the address of a constructor (C++98 Standard 12.1/12 Constructors - "12.1-12 Constructors - "The address of a constructor shall not be taken.")

Your best bet is to have a factory function/method that creates the Object and pass the address of the factory:

class Object;

class Class{
public:
   Class(const std::string &n, Object *(*c)()) : name(n), create(c) {};
protected:
   std::string name;     // Name for subclass
   Object *(*create)();  // Pointer to creation function for subclass
};

class Object {};

Object* ObjectFactory()
{
    return new Object;
}



int main(int argc, char**argv)
{
    Class foo( "myFoo", ObjectFactory);

    return 0;
}