64-bit LispWorks only: Returns if the object is allocated in its own segment.
allocated-in-its-own-segment-p object => result
allocated-in-its-own-segment-p returns true if object is allocated in its own own segment and false otherwise.
An object is allocated in its own segment if it is "very large". Currently that means larger than 64 MB for the ordinary 64-bit GC, or larger than 1 MB for the Mobile GC.
allocated-in-its-own-segment-p is intended to help to decide whether to call the functions that are useful only for such objects (make-object-permanent and release-object-and-nullify).
LispWorks User Guide and Reference Manual - 20 Sep 2017