diff --git a/packages/PLStream/pl-file.c b/packages/PLStream/pl-file.c
index e78679d8c..d20d84970 100755
--- a/packages/PLStream/pl-file.c
+++ b/packages/PLStream/pl-file.c
@@ -4732,6 +4732,7 @@ init_yap(void)
   PL_register_extensions(foreigns);
   fileerrors = TRUE;
   SinitStreams();
+  initOs();
 }
 #endif