ndproxy.c | 4 ++--

diff --git a/ndproxy.c b/ndproxy.c
index d2bac05df48a0dcda3aa10d105ffb37168905e27..1b45586209f67b69927dd116efdd89457cece137 100644
--- a/ndproxy.c
+++ b/ndproxy.c
@@ -54,7 +54,7 @@ #ifdef PFIL_VERSION
 
 static pfil_hook_t pfh_hook;
 
-static void register_hook() {
+static void register_hook(void) {
   struct pfil_hook_args pha;
   struct pfil_link_args pla;
 
@@ -78,7 +78,7 @@
   hook_added = true;
 }
 
-static void unregister_hook() {
+static void unregister_hook(void) {
   if (!hook_added) return;
   pfil_remove_hook(pfh_hook);
 }