Merrill Cornish wrote:
With an ordinary C++ pointer, if I have a BaseClass and a DerivedClass derived from BaseClass, then I can do
BaseClass* objectPtr; objectPtr = new DerivedClass();
Later, if BaseClass has a virtual destructor, I can call delete(objectPtr) and the DerivedClass destructor will be called.
Now, does this work with shared_ptr?
shared_ptr<BaseClass> objectPtr; objectPtr = shared_ptr<DerivedClass>(new DerivedClass());
and later, delete(objectPtr).
No, you shouldn't call delete directly. It's done for you automatically when the last shared_ptr that points to your object is destroyed.
Does any of the magic going on behind the scenes prevent shared_ptrs from being used like this?
shared_ptr would be close to useless if it didn't. In fact, shared
pointer does *more* to remember the dynamic type than ordinary pointers.
Forex, you can do this:
{
shared_ptr<void> voidPtr;
voidPtr = shared_ptr