Availability:C-language interface function
int PL_get_nil_ex(term_t
l)As PL_get_nil(),
but raises a type or instantiation error if
t is not the empty list. Because PL_get_nil_ex()
is commonly used after a while loop over PL_get_list_ex(),
it fails immediately if there is an exception pending (from PL_get_list_ex()).