I am new to ROS. I wrote a program that subscribe to [/camera/depth/color/points]. It has been proved the traffic can be caught. average: 14.75MB/s mean: 1.16MB min: 0.56MB max: 2.32MB window: 3

But it seems not responding. Where did I go wrong.

include "ros/ros.h"

include "std_msgs/String.h"

include <sensor_msgs pointcloud2.h="">

bool new_cloud_available_flag;

void callback(const sensor_msgs::PointCloud2ConstPtr&){

std::cout << "Entering callback";
new_cloud_available_flag = true;

}

int main (int argc, char** argv) {

ros::init(argc, argv, "pointcloudlistener");
ros::NodeHandle nh;
std::string topic = nh.resolveName("/camera/depth/color/points");
uint32_t queue_size = 1;
new_cloud_available_flag = false;

ros::Subscriber sub = nh.subscribe<sensor_msgs::PointCloud2> (topic, queue_size, callback);

while(!new_cloud_available_flag) 
{
    ros::Time t0 = ros::Time::now();
    while(ros::Time::now()-t0 < ros::Duration(0.001));
}

}