Index: src_plugins/lib_gtk_common/util_watch.c
===================================================================
--- src_plugins/lib_gtk_common/util_watch.c	(revision 13560)
+++ src_plugins/lib_gtk_common/util_watch.c	(revision 13561)
@@ -62,7 +62,7 @@
 }
 
 pcb_hidval_t pcb_gtk_watch_file(pcb_gtk_common_t *com, int fd, unsigned int condition,
-								void (*func) (pcb_hidval_t watch, int fd, unsigned int condition, pcb_hidval_t user_data),
+								pcb_bool (*func)(pcb_hidval_t watch, int fd, unsigned int condition, pcb_hidval_t user_data),
 								pcb_hidval_t user_data)
 {
 	GuiWatch *watch = g_new0(GuiWatch, 1);
Index: src_plugins/lib_gtk_common/util_watch.h
===================================================================
--- src_plugins/lib_gtk_common/util_watch.h	(revision 13560)
+++ src_plugins/lib_gtk_common/util_watch.h	(revision 13561)
@@ -2,7 +2,7 @@
 #include "glue.h"
 
 pcb_hidval_t pcb_gtk_watch_file(pcb_gtk_common_t *com, int fd, unsigned int condition,
-								void (*func) (pcb_hidval_t watch, int fd, unsigned int condition, pcb_hidval_t user_data),
+								pcb_bool (*func)(pcb_hidval_t watch, int fd, unsigned int condition, pcb_hidval_t user_data),
 								pcb_hidval_t user_data);
 
 void pcb_gtk_unwatch_file(pcb_hidval_t data);