note 62568 deleted from function.flock by danbrown

Note Submitter: Niels Jaeckel ---- hi dranger at export dash japan dot com, you are right with your thoughts about process-switching. But I think the following kind of code would work in race-conditions, because it is very improbably that the CPU switches after just ONE statement: <?php // here my own lock-function WITHOUT flock() // you can call it a mutex... // lock ... compare to P(mutex) function lock($filename) { $filename .= '.lock'; while (true) { if (! file_exists($filename)) { if (! file_exists($filename)) { if (! file_exists($filename)) { return touch($filename); } } } } } // unlock ... compare to V(mutex) function unlock($filename) { unlink($filename . '.lock'); } ?> If you want to solve the reader/writer problem (many readers, just one exclusive writer) you can add some flock() - code instead of touch(...) hth