Hi,

For publishers & subscribers once can set QOS setting for liveliness and then can set a call back function in case of the such an event.

rclcpp::SubscriptionOptions->event_callbacks.liveliness_callback =  
    [](rclcpp::QOSLivelinessChangedInfo & event)
    {
        // do some thing
    };

I am looking some things similar in case of service & client . Is there a way where I can set QOS liveliness policy and has a call back function when it fails ?

Thanks you