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why does my package not enter my main loop when using rosrun?

asked 2018-04-24 09:15:00 -0500

gilprog gravatar image

I have written a few packages which should communicate with each other. However one of them seems to be malfunctioning entirely, this is the code at this moment.

#include "ros/ros.h"
#include "std_msgs/String.h"
#include <pcl/common/centroid.h>
#include <sensor_msgs/PointCloud2.h>
#include <pcl_conversions/pcl_conversions.h>
#include <pcl_ros/transforms.h>

int right_person;
ros::Publisher man;

void AmirCallback(const std_msgs::String::ConstPtr& msg)
std::cout << msg;
  if(msg->data.c_str() == "yes"){
     right_person = 1;
     std::cout << "message received \n";
     right_person = 0;


void personcallback (const sensor_msgs::PointCloud2ConstPtr& input)
std::cout << "responding";
if(right_person ==1){
    pcl::PCLPointCloud2 inputcloud;
    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud (new pcl::PointCloud<pcl::PointXYZ>);

    // Convert to PCL data type

    pcl_conversions::toPCL(*input, inputcloud);
    pcl::fromPCLPointCloud2(inputcloud, *cloud);

    Eigen::Vector4f c;
    pcl::compute3DCentroid<pcl::PointXYZ> (*cloud, c);
    if(c[0] < 2 && c[1]>-1 &&c[1]<1){
        sensor_msgs::PointCloud2 output;
        pcl::PCLPointCloud2* outputcloud = new pcl::PCLPointCloud2;

        pcl::toPCLPointCloud2(*cloud, *outputcloud);
        pcl_conversions::fromPCL(*outputcloud, output);
        std::cout << "model centroid position = "<< c[0] << c[1] << c[2] << "\n";
        std::cout << "model sent \n";



int main(int argc, char **argv)
 ros::init(argc, argv, "personchecker");

 ros::NodeHandle n;

 ros::Subscriber subamir = n.subscribe("/amirs_code", 1, AmirCallback);
 ros::Subscriber sub = n.subscribe("/possible_humans", 1, personcallback);

 man = n.advertise<sensor_msgs::PointCloud2> ("/right_person", 1);
 std::cout << "here";

 ros::spin ();


However when I run this code none of the calls to std::cout are printed. When I publish to either one of the subscribed topics, with rostopic pub or another file nothing happens. I have checked the cmakelists already and it is fine, there are no errors when using catkin_make and only this file has this problem. My other packages are fine. Has anyone run into this problem before and if so what is the solution?

Thanks in advance!

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1 Answer

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answered 2018-04-24 13:19:14 -0500

lucasw gravatar image

updated 2018-04-24 13:39:43 -0500

Put line breaks "\n" (or std::endl ) at the end of your std::cout calls.

You probably also want to dereference msg otherwise you'll only get a point location in hexadecimal:

std::cout << *msg << "\n";

ROS_INFO_STREAM also would work and ends up in a log file among other features, and doesn't need a linebreak.

Additionally, comparing a char* c_str() to a char* isn't what you want, just omit c_str() and do a string to string (automatically created from the char* "yes") comparison:

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Asked: 2018-04-24 09:15:00 -0500

Seen: 124 times

Last updated: Apr 24 '18