PCNTL fork process

PHP PCNTL fork process

    <?php
    $pid = pcntl_fork();
    if ($pid == -1) {
         die("could not fork"); 
    } else if ($pid) {
         exit(); // we are the parent 
    } else {
         // we are the child
    }
    if (posix_setsid() == -1) {
        die("could not detach from terminal");
    }
    pcntl_signal(SIGTERM, "sig_handler");
    pcntl_signal(SIGHUP, "sig_handler");
    while (1)
    {
    }
    function sig_handler($signo) 
    {
         switch ($signo) {
             case SIGTERM:
                 // handle shutdown tasks
                 exit;
                 break;
             case SIGHUP:
                 // handle restart tasks
                 break;
             default:
                 // handle all other signals
        echo time();
         }
    }
    var_dump($pid);