think\Process::getTermSignal PHP Method

    public function getTermSignal()
    {
        $this->requireProcessIsTerminated(__FUNCTION__);
        if ($this->isSigchildEnabled()) {
            throw new \RuntimeException('This PHP has been compiled with --enable-sigchild. Term signal can not be retrieved.');
        }
        $this->updateStatus(false);
        return $this->processInformation['termsig'];
    }