note 68875 added to function.flock

Indeed, flock() will not work reliably when the underlying filesystem is NFS. The proper way to perform file locking, in this case, would be to use PHP's link() function. From the Linux man page of open(): O_EXCL When used with O_CREAT, if the file already exists it is an error and the open will fail. In this context, a symbolic link exists, regardless of where its points to. O_EXCL is broken on NFS file systems, programs which rely on it for performing lock- ing tasks will contain a race condition. The solution for per- forming atomic file locking using a lockfile is to create a unique file on the same fs (e.g., incorporating hostname and pid), use link(2) to make a link to the lockfile. If link() returns 0, the lock is successful. Otherwise, use stat(2) on the unique file to check if its link count has increased to 2, in which case the lock is also successful. ---- Server IP: 195.221.21.36 Probable Submitter: 88.191.21.42 ---- 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 -- https://master.php.net/note/edit/68875 Del: integrated -- https://master.php.net/note/delete/68875/integrated Del: useless -- https://master.php.net/note/delete/68875/useless Del: bad code -- https://master.php.net/note/delete/68875/bad+code Del: spam -- https://master.php.net/note/delete/68875/spam Del: non-english -- https://master.php.net/note/delete/68875/non-english Del: in docs -- https://master.php.net/note/delete/68875/in+docs Del: other reasons-- https://master.php.net/note/delete/68875 Reject -- https://master.php.net/note/reject/68875 Search -- https://master.php.net/manage/user-notes.php