db_reference/1db_reference(+Term) since release 4.1
Term is currently instantiated to
a compound term with principal functor '$ref'/2
denoting a unique reference to a dynamic clause.
| ?- db_reference(9).
no
| ?- db_reference(_X).
no
| ?- assertz(foo(a), R), db_reference(R).
R = '$ref'(1816730,128)
None.