diff --git a/reference/filesystem/functions/flock.xml b/reference/filesystem/functions/flock.xml
index 5fd582f31a..adeadb0f8e 100644
--- a/reference/filesystem/functions/flock.xml
+++ b/reference/filesystem/functions/flock.xml
@@ -132,10 +132,10 @@
 <![CDATA[
 <?php
 
-$fp = fopen("/tmp/lock.txt", "w");
+$fp = fopen("/tmp/lock.txt", "r+");
 
 if (flock($fp, LOCK_EX)) { // do an exclusive lock
-    ftruncate($fp, 0);  // truncate file
+    ftruncate($fp, 0); // truncate file
     fwrite($fp, "Write something here\n");
     flock($fp, LOCK_UN); // release the lock
 } else {