Fix MoveIt Servo compilation on macOS

moveit_ros/moveit_servo/include/moveit_servo/servo_parameters.h

@@ -50,11 +50,6 @@ constexpr size_t ROS_QUEUE_SIZE = 2;
 
 using SetParameterCallbackType = std::function<rcl_interfaces::msg::SetParametersResult(const rclcpp::Parameter&)>;
 
-// Helper template for declaring and getting ros param
-template <typename T>
-void declareOrGetParam(T& output_value, const std::string& param_name, const rclcpp::Node::SharedPtr& node,
-                       const rclcpp::Logger& logger, const T default_value = T{});
-
 // ROS params to be read. See the yaml file in /config for a description of each.
 struct ServoParameters
 {
@@ -155,4 +150,32 @@ struct ServoParameters
   rcl_interfaces::msg::SetParametersResult setParametersCallback(std::vector<rclcpp::Parameter> parameters);
 };
 
+// Helper template for declaring and getting ros param
+// Must be declared here to ensure template class is built for required templates when included.
+// (The CPP file can't just be included because not everything there is templated, so you'd get duplicate symbols)
+template <typename T>
+void declareOrGetParam(T& output_value, const std::string& param_name, const rclcpp::Node::SharedPtr& node,
+                       const rclcpp::Logger& logger, const T default_value = T{})
+{
+  try
+  {
+    if (node->has_parameter(param_name))
+    {
+      node->get_parameter<T>(param_name, output_value);
+    }
+    else
+    {
+      output_value = node->declare_parameter<T>(param_name, default_value);
+    }
+  }
+  catch (const rclcpp::exceptions::InvalidParameterTypeException& e)
+  {
+    RCLCPP_WARN_STREAM(logger, "InvalidParameterTypeException(" << param_name << "): " << e.what());
+    RCLCPP_ERROR_STREAM(logger, "Error getting parameter \'" << param_name << "\', check parameter type in YAML file");
+    throw e;
+  }
+
+  RCLCPP_INFO_STREAM(logger, "Found parameter - " << param_name << ": " << output_value);
+}
+
 }  // namespace moveit_servo

moveit_ros/moveit_servo/src/servo_parameters.cpp

@@ -47,31 +47,6 @@ using namespace std::placeholders;  // for _1, _2 etc.
 
 namespace moveit_servo
 {
-template <typename T>
-void declareOrGetParam(T& output_value, const std::string& param_name, const rclcpp::Node::SharedPtr& node,
-                       const rclcpp::Logger& logger, const T default_value)
-{
-  try
-  {
-    if (node->has_parameter(param_name))
-    {
-      node->get_parameter<T>(param_name, output_value);
-    }
-    else
-    {
-      output_value = node->declare_parameter<T>(param_name, default_value);
-    }
-  }
-  catch (const rclcpp::exceptions::InvalidParameterTypeException& e)
-  {
-    RCLCPP_WARN_STREAM(logger, "InvalidParameterTypeException(" << param_name << "): " << e.what());
-    RCLCPP_ERROR_STREAM(logger, "Error getting parameter \'" << param_name << "\', check parameter type in YAML file");
-    throw e;
-  }
-
-  RCLCPP_INFO_STREAM(logger, "Found parameter - " << param_name << ": " << output_value);
-}
-
 rcl_interfaces::msg::SetParametersResult
 ServoParameters::setParametersCallback(std::vector<rclcpp::Parameter> parameters)
 {