diff --git a/uLispZero.ino b/uLispZero.ino
index 1809d71..f3b9de9 100644
--- a/uLispZero.ino
+++ b/uLispZero.ino
@@ -88,6 +88,8 @@ volatile char Escape = 0;
 
 // Forward references
 object *tee;
+void pfstring (PGM_P s);
+void error (PGM_P string);
 
 // Set up workspace