When is an integer<->pointer cast actually correct?

Question

The common folklore says that:

• The type system exists for a reason. Integers and pointers are distinct types, casting between them is a malpractice in the m

Answer 1

Pointer values can also be a useful source of entropy for seeding a random number generator:

int* p = new int();
seed(intptr_t(p) ^ *p);
delete p;

The boost UUID library uses this trick, and some others.