Program Listing for File params_helpers.hpp

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// Copyright 2020 PAL Robotics S.L.
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/*
 * @author Paul Mathieu
 * @author Jeremie Deray
 */

#ifndef TWIST_MUX__PARAMS_HELPERS_HPP_
#define TWIST_MUX__PARAMS_HELPERS_HPP_

#include <rclcpp/rclcpp.hpp>

#include <memory>
#include <sstream>
#include <string>

namespace twist_mux
{
class ParamsHelperException : public std::runtime_error
{
public:
  explicit ParamsHelperException(const std::string & what)
  : std::runtime_error(what)
  {
  }
};

template<class T>
void fetch_param(std::shared_ptr<rclcpp::Node> nh, const std::string & param_name, T & output)
{
  rclcpp::Parameter param;
  if (!nh->get_parameter(param_name, param)) {
    std::ostringstream err_msg;
    err_msg << "could not load parameter '" << param_name << "'. (namespace: " <<
      nh->get_namespace() << ")";
    throw ParamsHelperException(err_msg.str());
  }

  output = param.get_value<T>();
}

}  // namespace twist_mux

#endif  // TWIST_MUX__PARAMS_HELPERS_HPP_