Function metadata 

pub const fn metadata<T>(ptr: *const T) -> <T as Pointee>::Metadata
where
    T: ?Sized,

🔬This is a nightly-only experimental API. (ptr_metadata #81513)

This item is validated for IEC 61508 (SIL 2) and ISO 26262 (ASIL B).

Extracts the metadata component of a pointer.

Values of type *mut T, &T, or &mut T can be passed directly to this function as they implicitly coerce to *const T.

Example

#![feature(ptr_metadata)]

assert_eq!(std::ptr::metadata("foo"), 3_usize);