note 64096 added to function.flock

dranger at export dash japan dot com is right, i once had the problem of a race condition in a database action because the script was very cpu-intensive so i looked around for some kind of mutex. I finally came up to this which uses no files (and no flock) and survived all of my tests (on linux): <?php function generate_shmkey ($string) { // Private: output unique integer based on $string return abs(crc32($string)); } function vmutex_lock ($lockId, $maxAcquire = 1) { // Public: take cover of semaphores and lock when possible global $shm_handle; $shm_key = generate_shmkey($lockId); if ($shm_handle = sem_get($shm_key, $maxAcquire)) { if (sem_acquire($shm_handle)) { return true; } } return false; } function vmutex_unlock ($lockId) { // Public: remove lock global $shm_handle; return sem_release($shm_handle); } ?> ---- Server IP: 217.13.201.10 Probable Submitter: 87.123.214.9 ---- X-Spam-Status: No, hits=3.1 required=5.0 tests=DATE_MISSING,FROM_NO_LOWER autolearn=no version=2.64 ---- Manual Page -- http://www.php.net/manual/en/function.flock.php Edit -- http://master.php.net/note/edit/64096 Del: integrated -- http://master.php.net/note/delete/64096/integrated Del: useless -- http://master.php.net/note/delete/64096/useless Del: bad code -- http://master.php.net/note/delete/64096/bad+code Del: spam -- http://master.php.net/note/delete/64096/spam Del: non-english -- http://master.php.net/note/delete/64096/non-english Del: in docs -- http://master.php.net/note/delete/64096/in+docs Del: other reasons-- http://master.php.net/note/delete/64096 Reject -- http://master.php.net/note/reject/64096 Search -- http://master.php.net/manage/user-notes.php