No output from subscriber - c++

Question

This is a part of the subscriber code. I would like to print out ytmp in the callback, but nothing was being printed, not even once. No idea what is wrong with my code here. It does print out ytmp inside the while(ros::ok()). Why did it skip the callback ??
#include <ros/ros.h>
#include <visualization_msgs/Marker.h>
#include "std_msgs/String.h"
#include <geometry_msgs/Vector3.h>
double ytmp,ztmp;
void SubCallback(const geometry_msgs::Vector3::ConstPtr& msg)
{
//ROS_INFO("I heard: [%f]", msg->y);
//ROS_INFO("I heard: [%f]", msg->z);
ytmp = msg->y;
ztmp = msg->z;
std::cout<<"ytmp CALLBACK = "<<ytmp<<std::endl;
}
int main( int argc, char** argv )
{
ros::init(argc, argv, "basic_shapes");
ros::NodeHandle n;
ros::Rate r(1);
ros::Subscriber sub = n.subscribe("intersect_values", 1000, SubCallback);
ros::Publisher marker_pub = n.advertise<visualization_msgs::Marker>("visualization_marker", 10);
// Set our initial shape type to be a cube
uint32_t shape = visualization_msgs::Marker::SPHERE;
while (ros::ok())
{
std::cout<<"abc = "<<ytmp<<std::endl;
visualization_msgs::Marker marker;
// Set the frame ID and timestamp. See the TF tutorials for information on these.
marker.header.frame_id = "world";
marker.header.stamp = ros::Time::now();
// Set the namespace and id for this marker. This serves to create a unique ID
// Any marker sent with the same namespace and id will overwrite the old one
marker.ns = "basic_shapes";
marker.id = 0;
// Set the marker type. Initially this is CUBE, and cycles between that and SPHERE, ARROW, and CYLINDER
// Set the marker action. Options are ADD, DELETE, and new in ROS Indigo: 3 (DELETEALL)
marker.action = visualization_msgs::Marker::ADD;
// Set the pose of the marker. This is a full 6DOF pose relative to the frame/time specified in the header
marker.pose.position.x = 0;// rwr_x;// joint1_x; // 2.52782791;
marker.pose.position.y = ytmp;//cord_y;// rwr_y;//joint1_y; //0.0182385;
std::cout<<"ytmp = "<<ytmp<<std::endl;
marker.pose.position.z = ztmp;//cord_z;// rwr_z;//joint1_z; //0;
marker.pose.orientation.x = 0.0;
marker.pose.orientation.y = 0.0;
marker.pose.orientation.z = 0.0;
marker.pose.orientation.w = 1.0;
// Set the scale of the marker -- 1x1x1 here means 1m on a side
marker.scale.x = 0.2;
marker.scale.y = 0.2;
marker.scale.z = 0.2;
// Set the color -- be sure to set alpha to something non-zero!
marker.color.r = 1.0f;
marker.color.g = 1.0f;
marker.color.b = 0.0f;
marker.color.a = 2.0;
marker.lifetime = ros::Duration();
// Publish the marker
/* while (marker_pub.getNumSubscribers() < 1)
{
//std::cout << "marker_pub.getNumSubscribers() = " << marker_pub.getNumSubscribers() << std::endl;
if (!ros::ok())
{
return 0;
}
ROS_WARN_ONCE("Please create a subscriber to the marker");
//sleep(1);
}*/
marker_pub.publish(marker);
r.sleep();
}
}