diff --git a/pl/yio.yap b/pl/yio.yap
index 9a406d509..89d1510b1 100644
--- a/pl/yio.yap
+++ b/pl/yio.yap
@@ -1209,3 +1209,21 @@ with_output_to(Output, Command) :-
 	atom_codes(Char, [Code]),
 	'$codes_to_chars'(String0, String, Chars).
 
+prolog_to_os_filename(Prolog, OS) :-
+	'$undefined'(swi_prolog_to_os_filename(Prolog, OS), system),
+	'$current_module'(Old, system),
+	load_foreign_files([libplstream], [], initIO),
+	'$current_module'(system, Old),
+	fail.
+prolog_to_os_filename(Prolog, OS) :-
+	system:swi_prolog_to_os_filename(Prolog, OS).
+
+
+
+
+
+
+
+
+
+