@event = $observer_session->receiveEvent( [ $timeout ] );
Listen for subscribed events from the Domain Manager.
The received events are returned as an array or, in scalar context, a reference to an array containing three or more elements. “Event subscription” on page 22 describes the different events to which you can subscribe.
The first element of all events is the timestamp, on the Domain Manager's system clock, and not the client's clock. The second element is a string defining the event type. The other elements are event-specific.
The $timeout is optional, and specifies a timeout period, in seconds, that the script is prepared to wait for an incoming event. If no event arrives in this time period, an event of type TIMEOUT is returned. The $timeout can be specified in fractions of a second, or “float”; for example, 0.25 = a quarter second.