Hi all!

I've made this question: http://stackoverflow.com/questions/2921469/php-mutual-exclusion-mutex

As said there, I want several sources to send their stats once in a while, and these stats will be showed at the website's main page.
My problem is that I want this to be done in an atomic manner, so no update of the stats will overlap another one running in the background.

Now, I came up with this solution and I want you PHP experts to judge it.

stats.php

<?php
define("my_counter", 12);
?>

index.php

<?php
include "stats.php";

echo constant("my_counter");
?>

update.php

<?php
$old_error_reporting = error_reporting(0);

include "stats.php";

define("my_stats_template",'
<?php
define("my_counter", %d);
?>
');

$fd = fopen("stats.php", "w+");
if($fd)
{
    if (flock($fd, LOCK_EX))
    {
        $my_counter = 0;

        try
        {
            $my_counter = constant("my_counter");
        }
        catch(Exception $e) { }

        $my_counter++;

        $new_stats = sprintf(constant("my_stats_template"), $my_counter);

        echo "Counter should stand at $my_counter";
        fwrite($fd, $new_stats);
    }
    flock($fd, LOCK_UN);
    fclose($fd);
}

error_reporting($old_error_reporting);
?>

Several clients will call the "update.php" file once every 60sec each. The "index.php" is going to use the "stats.php" file all the time as you can see.

What's your opinion?