think\Process::validateTimeout PHP 메소드

    private function validateTimeout($timeout)
    {
        $timeout = (double) $timeout;
        if (0.0 === $timeout) {
            $timeout = null;
        } elseif ($timeout < 0) {
            throw new \InvalidArgumentException('The timeout value must be a valid positive integer or float number.');
        }
        return $timeout;
    }