diff --git a/src/baselib/ocsigen_loader.ml b/src/baselib/ocsigen_loader.ml
index 2714ccc89..a0df48fc0 100644
--- a/src/baselib/ocsigen_loader.ml
+++ b/src/baselib/ocsigen_loader.ml
@@ -96,31 +96,39 @@ let loadfiles pre post force modules =
   aux modules
 
 let set_module_init_function name f =
-  init_functions := M.add name f !init_functions;
-  (* print_endline ("Added init_function for " ^ name); *)
-  (* print_endline ("get_init_on_load: " ^ string_of_bool (get_init_on_load ())); *)
+  init_functions := M.add name [f] !init_functions;
+  if get_init_on_load () then f ()
+
+let add_module_init_function name f =
+  let update = function
+    | None (* no binding so far *) -> Some [f]
+    | Some old -> Some (f :: old)
+  in
+  init_functions := M.update name update !init_functions;
   if get_init_on_load () then f ()
 
 let init_module pre post force name =
   let f =
-    try M.find name !init_functions
-    with Not_found as e -> raise (Dynlink_error ("named module " ^ name, e))
+    try
+      let l = List.rev @@ M.find name !init_functions in
+      fun () -> List.iter (fun f -> f ()) l
+    with Not_found ->
+      Lwt_log.ign_info_f ~section "No init function for named module %s." name;
+      fun () -> ()
   in
-  try
-    if force
-    then (
-      pre ();
-      Lwt_log.ign_info_f ~section
-        "Initializing %s (will be initialized every time)" name;
-      try f (); post () with e -> post (); raise e)
-    else if not (isloaded name)
-    then (
-      pre ();
-      Lwt_log.ign_info_f ~section "Initializing module %s " name;
-      (try f (); post () with e -> post (); raise e);
-      addloaded name)
-    else Lwt_log.ign_info_f ~section "Module %s already initialized." name
-  with e -> raise (Dynlink_error (name, e))
+  if force
+  then (
+    pre ();
+    Lwt_log.ign_info_f ~section
+      "Initializing %s (will be initialized every time)" name;
+    try f (); post () with e -> post (); raise e)
+  else if not (isloaded name)
+  then (
+    pre ();
+    Lwt_log.ign_info_f ~section "Initializing module %s " name;
+    (try f (); post () with e -> post (); raise e);
+    addloaded name)
+  else Lwt_log.ign_info_f ~section "Module %s already initialized." name
 
 (************************************************************************)
 (* Manipulating Findlib's search path *)
diff --git a/src/baselib/ocsigen_loader.mli b/src/baselib/ocsigen_loader.mli
index 976c6c843..1d4a7bf0a 100644
--- a/src/baselib/ocsigen_loader.mli
+++ b/src/baselib/ocsigen_loader.mli
@@ -58,9 +58,15 @@ val loadfiles : (unit -> unit) -> (unit -> unit) -> bool -> string list -> unit
     but the last one, and [loadfile pre post force] for the last one
     (if any). *)
 
+val add_module_init_function : string -> (unit -> unit) -> unit
+(** [add_module_init_function name f] adds function [f]
+    to the initialisation functions to be run
+    when [init_module name] is called.  *)
+
 val set_module_init_function : string -> (unit -> unit) -> unit
 (** [set_module_init_function name f] registers the function [f], which will
-    be used to initialize the module when [init_module name] is called.  *)
+    be used to initialize the module when [init_module name] is called.
+    Will replace the prvious value.  *)
 
 val init_module : (unit -> unit) -> (unit -> unit) -> bool -> string -> unit
 (** [init_module pre post force name] runs the init function for the module
diff --git a/src/server/ocsigen_server.mli b/src/server/ocsigen_server.mli
index 89ae13806..c57e04a9d 100644
--- a/src/server/ocsigen_server.mli
+++ b/src/server/ocsigen_server.mli
@@ -58,6 +58,6 @@ module Site : sig
       configuration file options defined by extensions (<staticmod/> ...)*)
 
   val register : ?site:t -> instruction -> unit
-  (** [register t s e] registers instruction [e] to be run inside site [s]. 
+  (** [register ~site:s e] registers instruction [e] to be run inside site [s]. 
       Use this if you want to create an extension yourself. *)
 end