diff --git a/examples/decodedline_elf.ml b/examples/decodedline_elf.ml
index c7ef6ac..4417957 100644
--- a/examples/decodedline_elf.ml
+++ b/examples/decodedline_elf.ml
@@ -28,7 +28,7 @@ let () =
   | None -> ()
   | Some section ->
     let pointers_to_other_sections =
-      Some (Owee_elf.debug_line_pointers buffer sections)
+      Owee_elf.debug_line_pointers buffer sections
     and body =
       Owee_buf.cursor (Owee_elf.section_body buffer section)
     in
diff --git a/examples/decodedline_macho.ml b/examples/decodedline_macho.ml
index 49d33e7..2513207 100644
--- a/examples/decodedline_macho.ml
+++ b/examples/decodedline_macho.ml
@@ -26,7 +26,7 @@ let debug_section segment = function
     as section ->
     let body = Owee_buf.cursor (Owee_macho.section_body buffer segment section) in
     let rec aux () =
-      match Owee_debug_line.read_chunk body ~pointers_to_other_sections:None with
+      match Owee_debug_line.read_chunk body ?pointers_to_other_sections:None with
       | None -> ()
       | Some (header, chunk) ->
         let check header state () =
diff --git a/src/owee_debug_line.ml b/src/owee_debug_line.ml
index e5cc764..d9f87e0 100644
--- a/src/owee_debug_line.ml
+++ b/src/owee_debug_line.ml
@@ -233,7 +233,7 @@ let read_header t ~pointers_to_other_sections =
   in
   (header, chunk)
 
-let read_chunk t ~pointers_to_other_sections =
+let read_chunk ?pointers_to_other_sections t =
   if at_end t
   then None
   else Some (read_header t ~pointers_to_other_sections)
diff --git a/src/owee_debug_line.mli b/src/owee_debug_line.mli
index 0fdea8c..f8a920a 100644
--- a/src/owee_debug_line.mli
+++ b/src/owee_debug_line.mli
@@ -18,8 +18,8 @@ type pointers_to_other_sections = {
     pointers to strings in entirely separate sections of DWARF. You can use
     {! Owee_elf.debug_line_pointers} to construct such a value. *)
 val read_chunk
-  :  cursor
-  -> pointers_to_other_sections:pointers_to_other_sections option
+  : ?pointers_to_other_sections:pointers_to_other_sections
+  -> cursor
   -> (header * cursor) option
 
 (** State of the linenumber automaton.
diff --git a/src/owee_location.ml b/src/owee_location.ml
index b7cca9c..11fb9f9 100644
--- a/src/owee_location.ml
+++ b/src/owee_location.ml
@@ -76,7 +76,7 @@ let extract_debug_info buffer =
     (*Printf.eprintf "Looking for 0x%X\n" t;*)
     let body = Owee_elf.section_body buffer section in
     let pointers_to_other_sections =
-      Some (Owee_elf.debug_line_pointers buffer sections) in
+      Owee_elf.debug_line_pointers buffer sections in
     let count = count_rows body ~pointers_to_other_sections in
     let debug_entries = Array.make count
         {addr_lo = max_int; addr_hi = max_int; payload = None} in