diff --git a/libpatricia/patricia.c b/libpatricia/patricia.c
index f0fc987..a493f23 100644
--- a/libpatricia/patricia.c
+++ b/libpatricia/patricia.c
@@ -235,7 +235,7 @@ New_Prefix (int family, void *dest, int bitlen)
 /* ascii2prefix
  */
 prefix_t *
-ascii2prefix (int family, char *string)
+ascii2prefix (int family, const char *string)
 {
     u_long bitlen, maxbitlen = 0;
     char *cp;
diff --git a/libpatricia/patricia.h b/libpatricia/patricia.h
index e853cf1..b2ac050 100644
--- a/libpatricia/patricia.h
+++ b/libpatricia/patricia.h
@@ -92,10 +92,12 @@ void patricia_process (patricia_tree_t *patricia, void_fn_t func);
 
 char *prefix_toa (prefix_t * prefix);
 
+void Deref_Prefix (prefix_t * prefix);
+
 /* { from demo.c */
 
 prefix_t *
-ascii2prefix (int family, char *string);
+ascii2prefix (int family, const char *string);
 
 patricia_node_t *
 make_and_lookup (patricia_tree_t *tree, char *string);