Should one really set pointers to `NULL` after freeing them?

Question

There seem to be two arguments why one should set a pointer to NULL after freeing them.

Avoid crashing when double-freeing pointers.

Short

Answer 1

There's no guarantee that the program crashes when accessing the NULL pointer.

Maybe not by the standard, but you'd be hard-pressed to find an implementation which does not define it as an illegal operation that causes a crash or exception (as appropriate to the runtime environment).