This function gives you the total number of bytes in a directory. The result is always a float (in order to hold a larger value than an integer). If the directory doesn’t exist, false is returned.

If you give a file instead of a directory, the function’s behaviour is unspecified.

$bytes = disk_free_space('/php/dev/');   // 38416797696
$bytes = disk_total_space('/php/dev/');  // 87097450496
$bytes = disk_total_space('/php/devq/'); // false