[ROS 2] How is the name of the typesupport library generated?

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Hi,

I have a package where I create custom messages.

In my application I create a subscription that uses this custom type. If I look into the RMW implementation code (FastRTPS for example) I think I found where the typesupport library is loaded

  const rosidl_message_type_support_t * type_support = get_message_typesupport_handle(
    type_supports, rosidl_typesupport_introspection_c__identifier);
  if (!type_support) {
    type_support = get_message_typesupport_handle(
      type_supports, rosidl_typesupport_introspection_cpp::typesupport_identifier);
    if (!type_support) {
      RMW_SET_ERROR_MSG("type support not from this implementation");
      return nullptr;
    }
  }

https://github.com/ros2/rmw_fastrtps/...

As you can see, this uses a type_supports handle and an identifier. These are used to genereate the name of a shared library (for example my_custom_msg_rosidl_typesupport_fastrtps_cpp)

I would like to know where is the code that generates that name

thank you