diff --git a/src/gui_gtk_f.c b/src/gui_gtk_f.c
index 23a9417..d88499e 100644
--- a/src/gui_gtk_f.c
+++ b/src/gui_gtk_f.c
@@ -229,6 +229,7 @@
     {
 	GtkTypeInfo form_info;
 
+	vim_memset(&form_info, 0, sizeof(form_info));
 	form_info.type_name = "GtkForm";
 	form_info.object_size = sizeof(GtkForm);
 	form_info.class_size = sizeof(GtkFormClass);