全局变量/对象上的pcntl_signal（php）

I'm trying to catch a signal (ie SIGUSR1) and call a function from an object.

class obj {
...
  public function debug() {
    var_dump($this->varfoo);
  }
}

$o = new obj();
declare(ticks = 1);
function sig_handler($signo) {
    switch ($signo) {
        case SIGUSR1:
            echo "Caught SIGUSR1...
";
            $o->debug();
            break;
        default:
            // handle all other signals
    }
}
pcntl_signal(SIGUSR1, "sig_handler");

As soon as I send the signal, I get a php fatal error: Call to a member function debug();

So, I tried something else:

Instead of that:

function sig_handler($signo) {
...
}

pcntl_signal(SIGUSR1, "sig_handler");

I used that:

pcntl_signal(SIGUSR1, function ($signal, $o) {
    echo gettype($o); //this prints null, I was hoping for object
    echo "Caught SIGUSR1...
";
    $o->debug();
});

I know it doesn't look right, but I can't figure out how to pass the $o inside the signal handler.

Thank you

It worked by adding the handler inside the class like this:

class obj {
...
public function __construct() {
    ...
    pcntl_signal(SIGUSR1, function ($signal) { 
        echo "Caught SIGUSR1...
";
        $this->debug();
    });
}

Not sure if it's the best way, but seems to be working.