diff --git a/src/errors.h b/src/errors.h
index e5b8cd2..e39e404 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -852,3 +852,5 @@
 	INIT(= N_("E1254: Cannot use script variable in for loop"));
 EXTERN char e_cmd_mapping_must_end_with_cr[]
 	INIT(= N_("E1255: <Cmd> mapping must end with <CR>"));
+EXTERN char e_string_or_function_required_for_argument_nr[]
+	INIT(= N_("E1256: String or function required for argument %d"));