diff --git a/src/tstsout.c b/src/tstsout.c
index ce0b250..f1f0780 100644
--- a/src/tstsout.c
+++ b/src/tstsout.c
@@ -48,7 +48,7 @@ void check_sysout(char *sysout_file_name, int verbose) {
    */
 
   /* open SysoutFile */
-  sysout = open(sysout_file_name, O_RDONLY, NULL);
+  sysout = open(sysout_file_name, O_RDONLY);
   if (sysout == -1) {
     sprintf(errmsg, "sysout_loader: can't open sysout file: %s", sysout_file_name);
     perror(errmsg);