How to typedef a class constructor inside the class definition

Question

The title might be unclear but the code is simple and should explain itself. I would like to typedef a constructor to my class inside the class and then set the address of said constructor elsewhere.

class Dog {
public:
    typedef Dog* (__thiscall* Constructor_T)(Dog* thisptr);
    static Constructor_T Constructor;

    Dog() {
        Constructor(this);
    }
};

void SetDogConstructor() {
    Dog::Constructor = (Dog::Constructor_T)0x1234;
}

The error I receive is:

Error   2   error LNK2001: unresolved external symbol "public: static class Dog * (__thiscall* Dog::Constructor)(class Dog *)" (?Constructor@Dog@@2P6EPAV1@PAV1@@ZA)

possible duplicate of [Static constructor in c++](http://stackoverflow.com/questions/5803953/static-constructor-in-c) — Luis Yanes, May 30 '15 at 03:02
You cannot "typedef a constructor". A constructor is a function. A type is a type. — Lightness Races in Orbit, May 30 '15 at 04:16

score 1 · Accepted Answer · answered May 30 '15 at 03:04

1

A static member needs a definition outside the class. In your case, you would put

Dog::Constructor_T Dog::Constructor = nullptr;

in Dog.cpp.

answered May 30 '15 at 03:04

aschepler

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How to typedef a class constructor inside the class definition

1 Answers1