• Anonymous
  An opaque handle, written <pce>(Address,Class), as produced by new/2 and get/3 for an object that has no name. It can be passed to send/2 and get/3, compared with ==/2 and used as a key, but it is not a term to take apart. Use object_reference/2 for the XPCE-level reference and is_object_reference/1 to test a term.
• Named
  The term @Atom, where Atom is the name of a global object such as @display. See pce_global/2.

In all other cases this predicate fails silently. It also fails for a reference whose object has been freed, and it cannot be misled: as long as Prolog holds the handle the object's administration is kept, so the handle cannot come to denote whatever was created in its place.

@Integer is not a reference. XPCE identifies an anonymous object internally by its address, which object<-object_reference still reports, but that number is not accepted as a reference: after the object is freed and its memory reused it would denote a different object. There is no way to turn one back into an object, and therefore no way to hold a reference that lies.

object/2 converts an object into a descriptive term. See the User Guide for complete information.

See also @pce<-object_from_reference and object->name_reference.