Question

The problem I am having is that when my class CLimb runs its destructor, if member *parent is NULL I get an “Access violation writing location 0xcccccccc” error, after the destructor is called, but before the body is executed.

limb.h

class CLimb
{
public:
    CLimb(void);
    CLimb(CLimb *_parent);
    ~CLimb(void);

    float cut;
    float bone;
    float resistance;

    CLimb *parent;
};

limb.cpp

#include "limb.h"


CLimb::CLimb(void) :
    cut(0),
    bone(0),
    resistance(0)
{
    parent = NULL;
}

CLimb::CLimb(CLimb *_parent) :
    cut(0),
    bone(0),
    resistance(0)
{
    parent = _parent;
}

CLimb::~CLimb(void)
{
}

I was also wondering if I had 2 instances, limb01 and limb02, where limb02 is the parent of limb01, if limb02 is deleted limb01->parent now points to an incorrect address. How would I resolve this? Would I have to add a *child pointer as well?

Answer 1

Smart pointers are a solution. In particular, you can use a weak pointer here. A weak pointer is automatically reset when the reference count of the pointed-to object drops to zero (i.e. when it’s deleted).