Re: [Boost-users] What would happen if boost::shared_ptr is reset to an address in the stack

Peng Yu wrote:

Hi,

The following program runs well in my system. However, if I change 1 to 0, it will terminate at the line with "delete". Does this mean that boost::shared_ptr can tell if the pointer is from the stack or the heap and does different things based on where the pointer is from?

Thanks, Peng

Hi Peng, No, shared_ptr still calls delete on 'a', which is undefined behavior. Undefined behavior means just that: it is totally undefined what will happen. It could crash, or continue merrily along, or anything else. The following may show you what is going on better. If you put a breakpoint (for VS 7.1) in boost/checked_delete.hpp in the checked_delete(T * x) function, you'll see that it does call delete. (It will also call delete in your original function, it just does it when p goes out of scope, which is at the end of main.) #include <iostream> #include int main() { int a[100]; boost::shared_ptr<int> p(a); p.reset(); // calls delete here std::cout << std::endl; } David