diff --git a/lib/calib_lex.l b/lib/calib_lex.l
index 4d7e02f..ba018e4 100644
--- a/lib/calib_lex.l
+++ b/lib/calib_lex.l
@@ -1,4 +1,5 @@
 %option noyywrap
+%option nounput
 
 %{