php file renaming while running - is a lock possible?

Solution:

Yes, please see the manual entry for flock function

Example from the manual:

<?php

$fp = fopen("/tmp/lock.txt", "r+");

if (flock($fp, LOCK_EX)) {  // acquire an exclusive lock
    ftruncate($fp, 0);      // truncate file
    fwrite($fp, "Write something here\n");
    fflush($fp);            // flush output before releasing the lock
    flock($fp, LOCK_UN);    // release the lock
} else {
    echo "Couldn't get the lock!";
}

fclose($fp);

?>
Copy code

Apparently there are some caveats, for instance if you're using an antiquated filesystem (FAT)flock() will always return false. If you're using PHP as an ISAPI extension, thenflock will not lock the file from being modified/read by other PHP Scripts running in parallel threads.

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