add get_domain_id method to rclcpp:Context.

Signed-off-by: Tomoya.Fujita <[email protected]>

Author: fujitatomoya

rclcpp/include/rclcpp/context.hpp

@@ -139,6 +139,11 @@ class Context : public std::enable_shared_from_this<Context>
   rclcpp::InitOptions
   get_init_options();
 
+  /// Return actual domain id.
+  RCLCPP_PUBLIC
+  size_t
+  get_domain_id() const;
+
   /// Return the shutdown reason, or empty string if not shutdown.
   /**
    * This function is thread-safe.

rclcpp/src/rclcpp/context.cpp

@@ -275,6 +275,17 @@ Context::get_init_options()
   return init_options_;
 }
 
+size_t
+Context::get_domain_id() const
+{
+  size_t domain_id;
+  rcl_ret_t ret = rcl_context_get_domain_id(rcl_context_.get(), &domain_id);
+  if (RCL_RET_OK != ret) {
+    rclcpp::exceptions::throw_from_rcl_error(ret, "failed to get domain id from context");
+  }
+  return domain_id;
+}
+
 std::string
 Context::shutdown_reason()
 {