From cppreference.com
enumclasspointer_safety{relaxed,preferred,strict};(since C++11)
(removed in C++23)The scoped enumeration type pointer_safety lists the pointer safety modes supported by C++.
Enumeration constants
Enumerator Meaning pointer_safety::strictOnly safely-derived pointers (pointers to objects allocated with new or subobjects thereof) may be dereferenced or deallocated. Garbage collector may be active. pointer_safety::preferredAll pointers are considered valid and may be dereferenced or deallocated. A reachability-based leak detector may be active. pointer_safety::relaxedAll pointers are considered valid and may be dereferenced or deallocated. See also