use subs qw(frob); frob 3..10;
Unlike pragmas that affect the $^H hints variable, the "use vars" and "use subs" declarations are not BLOCK-scoped. They are thus effective for the entire file in which they appear. You may not rescind such declarations with "no vars" or "no subs".
See ``Pragmatic Modules'' in perlmodlib and ``strict subs'' in strict.