Trying to make a plugin for gazebo connected with ROS2. I am using the rclcpp API but creating subscriptions is cauting errors. The load function is shown below:

void Load(physics::WorldPtr _world, sdf::ElementPtr _sdf)
{

    int argc = 0;
    char **argv = NULL;
    rclcpp::init(argc, argv);
    // rclcpp::spin(std::make_shared<MinimalSubscriber>());
    // rclcpp::shutdown();
    auto node = rclcpp::Node::make_shared("ObiWan");
    node->create_subscription<std_msgs::msg::String>(
        "topic",
        10,
        [node](std_msgs::msg::String::UniquePtr msg) {
            RCLCPP_INFO(node->get_logger(), "I heard: '%s'", msg->data.c_str());
        });


    //Logs to node log, pretty cool really! :D
    RCLCPP_INFO(node->get_logger(),
                "PLease help me kenobi '%s'", node->get_name());
}

The problem seems to arrive when calling the create_subscription(...).

I get the error:

gzserver: symbol lookup error: /home/lars/gaz-tryout3/build/libhello_world.so: undefined symbol: _ZN22rosidl_typesupport_cpp31get_message_type_support_handleIN8std_msgs3msg7String_ISaIvEEEEEPK29rosidl_message_type_support_tv

any ideas for a fix, or some info on why this is happening?

Running gazebo9 ROS2 dashing and ros-dashing-gazebo-ros-pkgs

cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
set (CMAKE_CXX_STANDARD 11)
find_package(gazebo REQUIRED)
find_package(rclcpp REQUIRED)
find_package(std_msgs REQUIRED)

include_directories(${rclcpp_INCLUDE_DIRS})
include_directories(${std_msgs_INCLUDE_DIRS})
include_directories(${GAZEBO_INCLUDE_DIRS})
link_directories(${GAZEBO_LIBRARY_DIRS})
list(APPEND CMAKE_CXX_FLAGS "${GAZEBO_CXX_FLAGS}")

add_library(hello_world SHARED hello_world.cc)
target_link_libraries(hello_world ${GAZEBO_LIBRARIES} ${rclcpp_LIBRARIES})

You were right, forgot to link the std_msgs. I linked them properly and now it works :)

target_link_libraries(hello_world ${GAZEBO_LIBRARIES} ${rclcpp_LIBRARIES} ${std_msgs_LIBRARIES})

If anybody needs the same