diff --git a/src/libs/util/ask.c b/src/libs/util/ask.c
index d93d5e7..7b4731e 100644
--- a/src/libs/util/ask.c
+++ b/src/libs/util/ask.c
@@ -144,7 +144,7 @@ int ask_selection(int nsel, int default_sel, const char **choices,
     for (i = 10; i < nsel; i++) f[i] = (char) (55 + i);
   }
 
-  if (*head) ncq = snprintf(q+ncq, 4095, "%s\n", head);
+  if (*head) ncq = snprintf(q+ncq, 4095-ncq, "%s\n", head);
   ncq += snprintf(q+ncq, 4095-ncq, "Select %c for %s,\n", f[0], choices[0]);
   for (i = 1; i < nsel-1; i++) {
    ncq += snprintf(q+ncq, 4095-ncq, "       %c for %s,\n", f[i], choices[i]);