diff --git a/epan/tap.c b/epan/tap.c
index 6c8529414c..ada6275a2d 100644
--- a/epan/tap.c
+++ b/epan/tap.c
@@ -268,7 +268,7 @@ tap_push_tapped_queue(epan_dissect_t *edt)
  * use "filters" and should specify the "filter" as NULL when registering
  * the tap listener.
  */
-void * 
+const void * 
 fetch_tapped_data(int tap_id, int idx)
 {
 	tap_packet_t *tp;
diff --git a/epan/tap.h b/epan/tap.h
index 8a7e79b25b..d24c3d72f1 100644
--- a/epan/tap.h
+++ b/epan/tap.h
@@ -50,6 +50,6 @@ extern GString *register_tap_listener(const char *tapname, void *tapdata,
     tap_draw_cb tap_draw);
 extern void remove_tap_listener(void *tapdata);
 extern gboolean have_tap_listeners(void);
-extern void *fetch_tapped_data(int tap_id, int idx);
+extern const void *fetch_tapped_data(int tap_id, int idx);
 
 #endif