| UriManager.IllFormedUri uri -> sprintf "invalid uri: %s" uri
| CicEnvironment.Object_not_found uri ->
sprintf "object not found: %s" (UriManager.string_of_uri uri)
+ | Unix.Unix_error (code, api, param) ->
+ let err = Unix.error_message code in
+ "Unix Error (" ^ api ^ "): " ^ err
| exn -> "Uncaught exception: " ^ Printexc.to_string exn