sk_TYPE_value() returns element B<idx> in B<sk>, where B<idx> starts at
zero. If B<idx> is out of range then B<NULL> is returned.
-sk_TYPE_new() allocates a new empty stack using comparison function B<compar>.
-If B<compar> is B<NULL> then no comparison function is used.
+sk_TYPE_new() allocates a new empty stack using comparison function B<compare>.
+If B<compare> is B<NULL> then no comparison function is used.
sk_TYPE_new_null() allocates a new empty stack with no comparison function.
-sk_TYPE_set_cmp_func() sets the comparison function of B<sk> to B<compar>.
+sk_TYPE_set_cmp_func() sets the comparison function of B<sk> to B<compare>.
The previous comparison function is returned or B<NULL> if there was
no previous comparison function.