Subscriber in a class; NO matching function error

[Harsh Sharma]

Ubuntu 18.04 ; ROS2 Eloquent
I am trying to run this code by definubg callback in the class.

#include "rclcpp/rclcpp.hpp"
#include "sensor_msgs/msg/image.hpp"

using namespace std::placeholders;

class MinimalDepthSubscriber : public rclcpp::Node {
  public:
    MinimalDepthSubscriber()
        : Node("zed_depth_tutorial") {

        // https://github.com/ros2/ros2/wiki/About-Quality-of-Service-Settings
        rmw_qos_profile_t camera_qos_profile = rmw_qos_profile_sensor_data;

        /* Note: it is very important to use a QOS profile for the subscriber that is compatible
         * with the QOS profile of the publisher.
         * The ZED node uses a "rmw_qos_profile_sensor_data" profile for depth data,
         * so reliability is "BEST_EFFORT" and durability is "VOLATILE".
         * To be able to receive the subscribed topic the subscriber must use the
         * same parameters, so setting the QOS to "rmw_qos_profile_sensor_data" as the publisher
         * is the better solution.
         */

        mSub = create_subscription<sensor_msgs::msg::Image>(
                   "/zed/zed_node/depth/depth_registered",
                   std::bind(&MinimalDepthSubscriber::depthCallback, this, _1),
                   camera_qos_profile);
    }

 protected:
    void depthCallback(const sensor_msgs::msg::Image::SharedPtr msg) {
        // Get a pointer to the depth values casting the data
        // pointer to floating point
        float* depths = (float*)(&msg->data[0]);

        // Image coordinates of the center pixel
        int u = msg->width / 2;
        int v = msg->height / 2;

        // Linear index of the center pixel
        int centerIdx = u + msg->width * v;

        // Output the measure
        RCLCPP_INFO(get_logger(), "Center distance : %g m", depths[centerIdx]);
    }

 private:
    rclcpp::Subscription<sensor_msgs::msg::Image>::SharedPtr mSub;
};


// The main function
int main(int argc, char* argv[]) {
    rclcpp::init(argc, argv);

    auto depth_node = std::make_shared<MinimalDepthSubscriber>();

    rclcpp::spin(depth_node);
    rclcpp::shutdown();
    return 0;
}

The error I get is this -

colcon build --packages-select stereo_ground_surface
Starting >>> stereo_ground_surface
--- stderr: stereo_ground_surface                             
/home/hsharma/Documents/internship/ws/ros2_ws/src/stereo_ground_surface/simulation_ws/src/stereo_detection/src/multisense_subscriber.cpp: In constructor ‘MinimalDepthSubscriber::MinimalDepthSubscriber()’:
/home/hsharma/Documents/internship/ws/ros2_ws/src/stereo_ground_surface/simulation_ws/src/stereo_detection/src/multisense_subscriber.cpp:87:38: error: no matching function for call to ‘MinimalDepthSubscriber::create_subscription<sensor_msgs::msg::Image>(const char [37], std::_Bind_helper<false, void (MinimalDepthSubscriber::*)(std::shared_ptr<sensor_msgs::msg::Image_<std::allocator<void> > >), MinimalDepthSubscriber*, const std::_Placeholder<1>&>::type, rmw_qos_profile_t&)’
                    camera_qos_profile);

What is happening here? Is my function definition wrong? Are there changes to the rclcpp::Node::create_subscription function

[Chris Lalancette]

I don't know if you've seen our support guidelines, but please ask questions like this on https://answers.ros.org. That way we have all of the questions in one easily searchable place. I'll close this out for now.