I am trying to write poses to text file, the code is :

#include <ros/ros.h>
#include <nav_msgs/Odometry.h>
#include <iostream>
#include <string>
#include <fstream>

#include <sstream>
#include <stdio.h>

std::ofstream ofs ("home/basma/catkin_ws/poses.txt",std::ofstream::app);
void callhandler(const nav_msgs::Odometry::ConstPtr& msg)

{ if (ofs.is_open())
           //store array contents to text file

           ofs <<msg.pose.pose.x<<"\n";
    else printf("Unable to open file \n");

}

int main(int argc, char **argv)
{
    ros::init(argc, argv, "main");
    ros::NodeHandle nh;
    ros::Subscriber Listener = nh.subscribe<nav_msgs::Odometry>("/odom", 100, callhandler);
    ros::spin();

    return 0;
}

But when use catkin_make the following error occure:

/home/basma/catkin_ws/src/poses_to_fileC/src/poses_to_fileC.cpp: In function ‘void callhandler(const ConstPtr&)’:
/home/basma/catkin_ws/src/poses_to_fileC/src/poses_to_fileC.cpp:15:22: error: ‘const ConstPtr’ {aka ‘const class boost::shared_ptr<const nav_msgs::Odometry_<std::allocator<void> > >’} has no member named ‘pose’

Could anyone help me? 15 | ofs <<msg.pose.pose.x<<"\n";