--- fcntl_lock_thread.c.orig	2013-07-17 20:04:39.181918422 -0700
+++ fcntl_lock_thread.c	2013-07-17 20:07:17.767919133 -0700
@@ -97,7 +97,10 @@
 	lock.l_pid = getpid();
 
 	/* set a 4 byte write lock */
-	fcntl(fd,F_SETLK,&lock);
+	ret = fcntl(fd,F_SETLK,&lock);
+	if (ret == -1) {
+		fprintf(stderr,"ERROR: lock test failed (ret=%d errno=%d)\n", ret, (int)errno);
+	}
 
 	sleep(4);  /* allow thread to try getting lock */