private function generateRequestId()
{
static $pid = -1;
static $addr = -1;
if ($pid == -1) {
$pid = getmypid();
}
if ($addr == -1) {
if (array_key_exists('SERVER_ADDR', $_SERVER)) {
$addr = ip2long($_SERVER['SERVER_ADDR']);
} else {
$addr = php_uname('n');
}
}
return $addr . $pid . $_SERVER['REQUEST_TIME'] . mt_rand(0, 0xffff);
}