subscribe to sensor_msg::PointCloud2

edit

Hi, my ros subscriber is having trouble entering the callback. I'm using ROS_INFO to tell me if the callback is in. In the rqt_graph, it shows that the subscriber node is subscribed to the topic that the publisher is publishing. Using rostopic echo "topic", it is displaying a lots of numbers that i'm presuming that it is the pointcloud.

below is my code.

Publisher

typedef pcl::PointCloud<pcl::PointXYZ> PointCloud;

int main(int argc, char** argv) {
 ros::init (argc, argv, "pub_pcl");
 ros::Publisher pub;
 pub = nh.advertise<sensor_msgs::PointCloud2> ("input_cloud", 1);
 pcl::PCLPointCloud2::Ptr cloud_blob (new pcl::PCLPointCloud2);
 pcl::PCDReader reader;
 reader.read (argv[1], *cloud_blob);
 sensor_msgs::PointCloud2 output;
 pcl_conversions::fromPCL(*cloud_blob, output);
 ros::Rate loop_rate(10);
 while (nh.ok())
 {
   pub.publish (output);
   ros::spinOnce ();
   loop_rate.sleep ();
 }
}

Subscriber

void cloud_callback (const sensor_msgs::PointCloud2ConstPtr& cloud_msg){
 ROS_INFO("inside callback");
}

int main (int argc, char** argv) {
 ros::init (argc, argv, "cloud_sub");
 ros::NodeHandle nh;
 ros::Rate loop_rate(10);
 ros::Subscriber sub;
 while (nh.ok()) {
   sub = nh.subscribe ("input_cloud", 1, cloud_callback);
   ros::spinOnce ();
   loop_rate.sleep ();
 }
}