being_smart_about_ownership_5.cpp

//Return a weak pointer, this resource is shared but whoever gets it shouldn't own it
weak_ptr get_widget();

void use_widget() {
auto widget_weak_ptr = get_widget();

    
//Check if the underylingwidget has already been destroyed.
if(auto widget_ptr = widget_weak_ptr.lock()) {
    //If it's available to use create a shared pointer
    //When we are done, it's destroyed and we loss shared ownership
    widget_ptr->lock_widget_mutex();
    if(widget_ptr->get_status() == 42)
        widget_ptr->trigger_event();
    widget_ptr->unlock_widget_mutex();
    //Once the smart pointer is gone we still have the weak pointer left,
    //in case we to try and access the widget again in the future
} else {
    panic("Widget unavailable");
    //Move forward by handling the error or throw
}