Open library resource file read-only
diff --git a/Mac/Python/macshlglue.c b/Mac/Python/macshlglue.c
index a6885d4..c079812 100644
--- a/Mac/Python/macshlglue.c
+++ b/Mac/Python/macshlglue.c
@@ -60,6 +60,6 @@
 	
 	if ( !library_fss_valid ) 
 		return;
-	fd = FSpOpenResFile(&library_fss, fsRdWrShPerm);
+	fd = FSpOpenResFile(&library_fss, fsRdPerm);
 }