GracefulDeath::waitUntilProcessDiesAndReturnStatus PHP Method

    private function waitUntilProcessDiesAndReturnStatus($pid)
    {
        if (!empty($this->options['catchSignals'])) {
            while (pcntl_waitpid($pid, $status, WNOHANG) <= 0) {
                pcntl_signal_dispatch();
                usleep(100000);
            }
            return $status;
        }
        pcntl_waitpid($pid, $status);
        return $status;
    }