How to pass arguments to add_action() [duplicate]

I declared an action for a single event in WordPress which accepts an array as an argument:

$asins = array(); //I had to declare this since I'm getting a notice of undefined variable if I don't

add_action('z_purge_products_cache', array($this, 'purge_products_cache', $asins));

I also tried this one, but it doesn’t perform the action either:

add_action('z_purge_products_cache', array($this, 'purge_products_cache'));

Then I schedule it:

wp_schedule_single_event(time() + 20, 'z_purge_products_cache', $asins_r);

Then here’s the function that will be called once wp cron executes the action:

public function purge_products_cache($asins){
  //send email here
}

Any ideas?

The parameter needs to be passed to the callback function in the wp_schedule_single_event function, not the add_action function.

Try this:

add_action('z_purge_products_cache', array($this, 'purge_products_cache'));

Then schedule the event, putting the parameter in an array:

wp_schedule_single_event(time() + 20, 'z_purge_products_cache', array($asins_r));

Your purge_products_cache function will be called with parameter $asins_r.