Function dangling_mut 

pub const fn dangling_mut<T>() -> *mut T

Creates a new pointer that is dangling, but non-null and well-aligned.

This is useful for initializing types which lazily allocate, like Vec::new does.

Note that the address of the returned pointer may potentially be that of a valid pointer, which means this must not be used as a “not yet initialized” sentinel value. Types that lazily allocate must track initialization by some other means.