note 79915 deleted from function.flock by danbrown

Note Submitter: jpriebe at cbcnewmedia dot com ---- mallory.dessaintes' message leads to another challenge with flock() -- if the file handle goes out of scope, the locking mechanism doesn't work. Imagine you have a long-running command-line PHP script. You schedule it to run via cron every minute, but you only want one copy at a time to run. You might implement a function like this: <?php function get_lock () { $fp = @fopen ('/tmp/myscript.lock', 'w+'); if (!$fp) { return false; } if (flock ($fp, LOCK_EX + LOCK_NB)) { return true; } return false; } ?> But when the function returns, the $fp variable goes out of scope, and the lock is broken. You need to make your file handle variable global like this: <?php function get_lock () { global $g_lock_fp; $g_lock_fp = @fopen ('/tmp/myscript.lock', 'w+'); if (!$g_lock_fp) { return false; } if (flock ($g_lock_fp, LOCK_EX + LOCK_NB)) { return true; } return false; } ?>