PHP文件写入线程问题

<?php
$start = time();
echo \'Started at \'.$start.\'<br />\';
$filename = \'D:\\Kindle\\books\\Brenson_Teryaya_nevinnost__Avtobiografiya_66542.mobi\';
$fp = fopen($filename, \'w+\') or die(\'have no access to \'.$filename);

if (flock($fp, LOCK_EX)) {
    echo \'File was locked at \'.time().\'. Granted exclusive access to write<br />\';
}
else {
    echo \'File is locked by other user<br />\';
}
sleep(3);
flock($fp, LOCK_UN);
echo \'File lock was released at \'.time().\'<br />\';
fclose($fp);
$end = time();
echo \'Finished at \'.$end.\'<br />\';
echo \'Proccessing time \'.($end - $start).\'<br />\';