diff --git a/file.c b/file.c
index 2038316..3564746 100644
--- a/file.c
+++ b/file.c
@@ -3732,7 +3732,7 @@ Str
 process_button(struct parsed_tag *tag)
 {
     Str tmp = NULL;
-    char *p, *q, *r, *qq = NULL;
+    char *p, *q, *r, *qq = "";
     int qlen, v;
 
     if (cur_form_id < 0) {