note 67065 added to ref.sem

I was confused by two things that caused strange behaviour in my use of semaphores with php scripts running under apache. Often enough page requests will end up being filled by the same process as other simultaneous requests. So semaphores will block when you may not have expected. Also note that sem_remove() will remove it for all processes, not just the calling one. So you have to be sure that the last process running removes the semaphore and none before. I thought there was some failures occurring when my child processes were dropping out with errors. So you can't just use get, acquire, release, remove in one script that will be hit by a web user. (1) They may end up in the same process and will wait on the other, and (2) the first one to finish will destroy the semaphore for others. I left out the remove call, and it works ok, but I still wonder if the semaphore is removed by php when the last script that did a get finishes? Also creating a child process to do the work using proc_open works to ensure seperate processes but to be careful you would want to limit the number somehow as well. ---- Server IP: 66.163.161.117 Probable Submitter: 58.136.71.134 (proxied: 58.136.71.134) ---- X-Spam-Status: No, hits=3.4 required=5.0 tests=DATE_MISSING,FROM_NO_LOWER, REMOVE_REMOVAL_NEAR autolearn=no version=2.64 ---- Manual Page -- http://www.php.net/manual/en/ref.sem.php Edit -- http://master.php.net/note/edit/67065 Del: integrated -- http://master.php.net/note/delete/67065/integrated Del: useless -- http://master.php.net/note/delete/67065/useless Del: bad code -- http://master.php.net/note/delete/67065/bad+code Del: spam -- http://master.php.net/note/delete/67065/spam Del: non-english -- http://master.php.net/note/delete/67065/non-english Del: in docs -- http://master.php.net/note/delete/67065/in+docs Del: other reasons-- http://master.php.net/note/delete/67065 Reject -- http://master.php.net/note/reject/67065 Search -- http://master.php.net/manage/user-notes.php