improve subsciber api

src/examples/subscriber/subscriber.cpp

@@ -75,6 +75,7 @@ int main(int argc, char **argv)
 	 * away the oldest ones.
 	 */
 	px4::Subscriber* sub = n.subscribe("rc_channels", rc_channels_callback);
+	PX4_INFO("subscribed");
 
 	/**
 	 * px4::spin() will enter a loop, pumping callbacks.  With this version, all

src/platforms/px4_nodehandle.h

@@ -50,8 +50,9 @@ class NodeHandle : private ros::NodeHandle
 public:
 	template<class M>
 	Subscriber* subscribe(const char *topic, void(*fp)(M)) {
-		ros::NodeHandle::subscribe("rc_channels", 1000, fp);
-		return new Subscriber();
+		ros::Subscriber ros_sub = ros::NodeHandle::subscribe(topic, 1000, fp);
+		//XXX create list here, for ros and nuttx
+		return new Subscriber(ros_sub);
 	}
 };
 #else

src/platforms/px4_subscriber.h

@@ -47,8 +47,11 @@ namespace px4
 #if defined(__linux) || (defined(__APPLE__) && defined(__MACH__))
 class Subscriber
 {
+private:
+	ros::Subscriber _ros_sub;
 public:
-	Subscriber() {};
+	Subscriber(ros::Subscriber ros_sub) : _ros_sub(ros_sub)
+	{}
 	~Subscriber() {};
 };
 #else