how to check if a pointer is unbound?

[Jess]

Hello,

I tried a program as follows:

include<iostrea m>

using namespace std;

class A{
public:
int x;
A():x(10){}
};

int main(){
A a;
A* p = &a;
A* q = p;
delete p;
cout << q << endl;
return 0;
}

Since "q" should be unbound, I thought the output would be "0".
However, the result was segmentation fault. How can I check if a
pointer is unbound?

Thanks,
Jess

[JohnQ]

"Marcus Kwok" <ri******@gehen nom.invalidwrot e in message
news:f3******** **@news-int2.gatech.edu ...

JohnQ <jo************ ***********@yah oo.comwrote:

>Why doesn't/can't C++ set deleted pointers (and freed memory pointers
therefor) to null?

See The Creator's FAQ:
http://www.research.att.com/~bs/bs_f...ml#delete-zero

In which he states: "C++ explicitly allows an implementation of delete to
zero out an lvalue operand, and I had hoped that implementations would do
that, but that idea doesn't seem to have become popular with implementers. "

That's probably why void*& as the argument to the delete operator works. Now
I'm wondering if I have to overload the void* version also to be sure my
operators will be called. (I won't be back into compile mode for a few more
days, else I'd test it).

John