diff --git a/ocaml/Block.ml b/ocaml/Block.ml
index 1d969aa..21cbf62 100644
--- a/ocaml/Block.ml
+++ b/ocaml/Block.ml
@@ -122,10 +122,15 @@ let update_raw_data ?(locked=true) () =
 
   let result =
     let rec aux ic accu =
-      try
-        aux ic ( (input_line ic)::accu )
-      with
-      | End_of_file -> List.rev accu
+      let l =
+        try
+          Some (input_line ic)
+        with
+        | End_of_file -> None
+      in
+      match l with
+      | None -> List.rev accu
+      | Some l -> (aux [@tailcall]) ic (l::accu)
     in
     List.concat_map (fun filename ->
       let ic = open_in filename in