Index: uspace/lib/c/include/loc.h
===================================================================
--- uspace/lib/c/include/loc.h	(revision b7fd2a02e4161f4edd38548e7f8456b8021549be)
+++ uspace/lib/c/include/loc.h	(revision d4475a449597f547fae3e36ba0148dad1a28a423)
@@ -40,5 +40,5 @@
 #include <stdbool.h>
 
-typedef void (*loc_cat_change_cb_t)(void);
+typedef void (*loc_cat_change_cb_t)(void *);
 
 extern async_exch_t *loc_exchange_begin_blocking(iface_t);
@@ -75,6 +75,5 @@
 extern size_t loc_get_services(service_id_t, loc_sdesc_t **);
 extern errno_t loc_get_categories(category_id_t **, size_t *);
-extern errno_t loc_register_cat_change_cb(loc_cat_change_cb_t);
-
+extern errno_t loc_register_cat_change_cb(loc_cat_change_cb_t, void *);
 
 #endif