Linker Error with static vector

Tiddlypeeps

In C++ Im trying to create an object that contains a static list. In the constructor im trying to add the this pointer to the list. Im not really used to using static variables so im probably just making a syntax mistake, but can anyone take a look at this code and take a guess as to why it won't compile.

#ifndef TPRIGIDBODY
#define TPRIGIDBODY

#include <iostream>
#include <vector>

using namespace std;

class tpRigidBody{
private:

public:

    static vector<tpRigidBody * const> *rigidBodyList;

    tpRigidBody();
    ~tpRigidBody();

};

#endif // TPRIGIDBODY

#include "tpRigidBody.h"

tpRigidBody::tpRigidBody(){
    rigidBodyList->push_back(this);
}

tpRigidBody::~tpRigidBody(){

}

the linker error i get when i try to compile is;
error LNK2001: unresolved external symbol "public: static class std::vector<class tpRigidBody * const,class std::allocator<class tpRigidBody * const> > * tpRigidBody::rigidBodyList" (?rigidBodyList@tpRigidBody@@2PAV?$vector@QAVtpRigidBody@@std@@A) tpRigidBody.obj

ronivek

A static variable is one which must be initialised before the program begins; and this initialisation must be carried out in what's called file scope.

Effectively this means changing your implementation file to the following;

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#include "tpRigidBody.h"

vector<tpRigidBody * const> *tpRigidBody::rigidBodyList = new vector<tpRigidBody * const>();

tpRigidBody::tpRigidBody(){
rigidBodyList->push_back(this);
}

tpRigidBody::~tpRigidBody(){

}
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