best way to obtain a lock in php

Question

I\'m trying to update a variable in APC, and will be many processes trying to do that.

APC doesn\'t provide locking functionality, so I\'m considering using other me

Answer 1

If you don't mind basing your lock on the filesystem, then you could use fopen() with mode 'x'. Here is an example:

$f = fopen("lockFile.txt", 'x');
if($f) {
    $me = getmypid();
    $now = date('Y-m-d H:i:s');
    fwrite($f, "Locked by $me at $now\n");
    fclose($f);
    doStuffInLock();
    unlink("lockFile.txt"); // unlock        
}
else {
    echo "File is locked: " . file_get_contents("lockFile.txt");
    exit;
}

See www.php.net/fopen