<?php
$fh = fopen('guestbook.txt','a') or die($php_errormsg);
flock($fh,LOCK_EX) or die($php_errormsg);
fwrite($fh,$_POST['guestbook_entry']) or die($php_errormsg);
fflush($fh) or die($php_errormsg);
flock($fh,LOCK_UN) or die($php_errormsg);
fclose($fh) or die($php_errormsg);
?>