diff --git a/src/filo.ads b/src/filo.ads
index 21f1545..e4d559c 100644
--- a/src/filo.ads
+++ b/src/filo.ads
@@ -61,4 +61,8 @@
    is
       (Ch = ' ' or (Tab <= Ch and Ch <= Carriage_Return));
 
+   function Equal (Str : String; Buf : Buffer_Type) return Boolean
+   with
+      Pre => Str'Length = Buf'Length;
+
 end FILO;