diff --git a/src/engine/scan.c b/src/engine/scan.c
index 77ecee94e..0c27b4bed 100644
--- a/src/engine/scan.c
+++ b/src/engine/scan.c
@@ -218,6 +218,7 @@ int yypeek()
             ungetc( ch, incp->file );
         return ch;
     }
+    return EOF;
 }
 
 /*