Implemented for Internal, External and System classes.
integer ← objref.⎕OID integer ← classref.⎕OID integer ← ⎕OID (Within user-defined method, same as ⎕THIS.⎕OID)
⎕OID returns an integer which uniquely identifies a given object instance or class definition within the workspace. It starts at 1 for the first-ever object created in the workspace, and increments by one each time a new object is created (for example by a call to ⎕NEW or ⎕CLONE).
On 32-bit versions of APLX, ⎕OID may return a floating-point data type if you have created more object instances than will fit in a 32-bit signed integer.