foreign_singleton.m:025: In the C code for predicate `f'/3:
foreign_singleton.m:025:   warning: variable `IO0' does not occur in the C
foreign_singleton.m:025:   code.
foreign_singleton.m:032: In clause for predicate `f'/3:
foreign_singleton.m:032:   warning: variable `X' occurs only once in this
foreign_singleton.m:032:   scope.
foreign_singleton.m:036: In clause for predicate `g'/3:
foreign_singleton.m:036:   warning: variable `X' occurs only once in this
foreign_singleton.m:036:   scope.
foreign_singleton.m:038: In the C code for predicate `g'/3:
foreign_singleton.m:038:   warning: variable `IO0' does not occur in the C
foreign_singleton.m:038:   code.