read from nodelet

edit

Hello,

I'm working with velodyne 32E and I was subscribing a node from "velodyne_driver" to read data from the topic "velodyne_packets" but the code in the callback wasn't executed everytime the topic was published by the LIDAR. (In callback it just had a counter incrementing, only printing the counter out of callback when the bag file ends or if press Ctrl+C)

I thought if I could change my code to use a nodelet instead of a node to direct access to data but i didn't find how to make it.

To subscribe a node it very easy because then is "sends me" to a callback just like an interruption (I think) and I could do whatever I wanted with the data. But with nodelets it is different and I didn't realized yet how could I get the data in real time.

I want to read directly from nodelet, not to transform a node into a nodelet!

Could you help me?

Thank you, Oportoz

CODE:

#includes.........

int i;

void callback(const velodyne_msgs::VelodyneScan::ConstPtr& msg)
{
 i++; 
}

int main(int argc, char** argv)
{
    ros::init(argc, argv, "subscribe_pack");
    ros::NodeHandle nh;
    ros::Subscriber sub = nh.subscribe<velodyne_msgs::VelodyneScan>("/velodyne_packets", 1, callback);

  while(ros::ok())
    {
        ros::spin(); //
    }
  std::cout << i << std::endl;
return 0;
}