$re = '/.*pos_start=(\d+).*end_position=(\d+).*log_type=(\d+).*length=(\d+).*block_id=(\d+).*block_position=(\d+).*/';
$str = '<log pos_start="40652288" end_position="40689664" log_type="1" length="37376" block_id="4024" block_position="18"/>';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php