checks whether a predicate is globally accessible
void(Goal) (i) call to predicate to be checked out
Tests whether a predicate is currently defined in the global symbol table of the node. Succeeds if the predicate with an argument count fitting the Goal is defined, fails otherwise.
read(X), ( exists(X),call(X),! ; write(X," does not exists!")nl ).
No runtime errors.
prolog-process, client-server, object
call , exec , xcall