My apologies in advance if this is the incorrect forum...
Given that the new form of auto_ptr does not set its pointer to null when
it loses ownership, how can a user of determine if the pointer is valid?

example:
auto_ptr<MyClass> pmyClass(new myClass);
if(true)
{
 // transfer ownership to pTemp, which then deletes the pointer
 // when it loses scope
 auto_ptr<MyClass> pTemp = pmyClass;
}
MyClass *pNoGood = pMyClass.get(); // pNoGood != 0, but points to deleted
object!

Is there a way to test ownership? Is some sort of "IsPointerValid" function
required? I'm using the implementation that comes with MS Visual C v5.0.
Thanks in advance,
Keith
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Keith Lancaster wrote:
>
> Given that the new form of auto_ptr does not set its pointer to null when
> it loses ownership, how can a user of determine if the pointer is valid?
>
> example:
> auto_ptr<MyClass> pmyClass(new myClass);
> if(true)
> {
>         // transfer ownership to pTemp, which then deletes the pointer
>         // when it loses scope
>         auto_ptr<MyClass> pTemp = pmyClass;
> }
> MyClass *pNoGood = pMyClass.get(); // pNoGood != 0, but points to deleted
> object!
>
> Is there a way to test ownership? Is some sort of "IsPointerValid" function
> required? I'm using the implementation that comes with MS Visual C v5.0.

Nope. You have to make sure you don't do that sort of thing with
auto_ptr. It's not idiot-proof.

In fact, I prefer an even more idiot-sensitive version that doesn't even
do ownership bookkeeping, which I just call ptr<T>. I find it is usually
what I want, and doesn't have the unnecessary overhead of auto_ptr.

--

Ciao,
Paul

(Please remove the extra dots from the return address,
which has been altered to foil junk mail senders.)
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