diff --git a/bgpd/bgp_filter.h b/bgpd/bgp_filter.h
index 8c27a93..c1da904 100644
--- a/bgpd/bgp_filter.h
+++ b/bgpd/bgp_filter.h
@@ -33,7 +33,7 @@
 extern enum as_filter_type as_list_apply (struct as_list *, void *);
 
 extern struct as_list *as_list_lookup (const char *);
-extern void as_list_add_hook (void (*func) ());
-extern void as_list_delete_hook (void (*func) ());
+extern void as_list_add_hook (void (*func) (void));
+extern void as_list_delete_hook (void (*func) (void));
 
 #endif /* _QUAGGA_BGP_FILTER_H */