.. _program_listing_file__tmp_ws_src_twist_mux_include_twist_mux_params_helpers.hpp:

Program Listing for File params_helpers.hpp
===========================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_twist_mux_include_twist_mux_params_helpers.hpp>` (``/tmp/ws/src/twist_mux/include/twist_mux/params_helpers.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // Copyright 2020 PAL Robotics S.L.
   //
   // Redistribution and use in source and binary forms, with or without
   // modification, are permitted provided that the following conditions are met:
   //
   //    * Redistributions of source code must retain the above copyright
   //      notice, this list of conditions and the following disclaimer.
   //
   //    * Redistributions in binary form must reproduce the above copyright
   //      notice, this list of conditions and the following disclaimer in the
   //      documentation and/or other materials provided with the distribution.
   //
   //    * Neither the name of the PAL Robotics S.L. nor the names of its
   //      contributors may be used to endorse or promote products derived from
   //      this software without specific prior written permission.
   //
   // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
   // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   // POSSIBILITY OF SUCH DAMAGE.
   
   /*
    * @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_