Class GenericSubscription

• Defined in File generic_subscription.hpp

Inheritance Relationships

Base Type

• public rclcpp::SubscriptionBase (Class SubscriptionBase)

Class Documentation

class GenericSubscription : public rclcpp::SubscriptionBase

Subscription for serialized messages whose type is not known at compile time.

Since the type is not known at compile time, this is not a template, and the dynamic library containing type support information has to be identified and loaded based on the type name.

It does not support intra-process handling.

Public Functions

template<typename AllocatorT = std::allocator<void>>
inline GenericSubscription(rclcpp::node_interfaces::NodeBaseInterface *node_base, const std::shared_ptr<rcpputils::SharedLibrary> ts_lib, const std::string &topic_name, const std::string &topic_type, const rclcpp::QoS &qos, AnySubscriptionCallback<rclcpp::SerializedMessage, AllocatorT> callback, const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> &options)

Constructor.

In order to properly subscribe to a topic, this subscription needs to be added to the node_topic_interface of the node passed into this constructor.

See also

rclcpp::Node::create_generic_subscription() or rclcpp::create_generic_subscription() for creating an instance of this class and adding it to the node_topic_interface.

Parameters:

• node_base – Pointer to parent node’s NodeBaseInterface

• ts_lib – Type support library, needs to correspond to topic_type

• topic_name – Topic name

• topic_type – Topic type

• qos – QoS settings

• callback – Callback for new messages of serialized form

• options – Subscription options. Not all subscription options are currently respected, the only relevant options for this subscription are event_callbacks, use_default_callbacks, ignore_local_publications, and callback_group.

virtual ~GenericSubscription() = default

virtual std::shared_ptr<void> create_message() override

Borrow a new message.

Returns:

Shared pointer to the fresh message.

virtual std::shared_ptr<rclcpp::SerializedMessage> create_serialized_message() override

Borrow a new serialized message.

Returns:

Shared pointer to a rcl_message_serialized_t.

virtual void disable_callbacks() override

Disable callbacks from being called.

This method will block, until any subscription’s callbacks provided during construction currently being executed are finished.

Note

This method also temporary removes the on new message callback and all on new event callbacks from the rmw layer to prevent them from being called. However, this method will not block and wait until the currently executing on_new_[message]event callbacks are finished.

virtual void enable_callbacks() override

Enable the callbacks to be called.

This method is thread safe, and provides a safe way to atomically enable the callbacks in a multithreaded environment.

virtual void handle_message(std::shared_ptr<void> &message, const rclcpp::MessageInfo &message_info) override

Cast the message to a rclcpp::SerializedMessage and call the callback.

virtual void handle_serialized_message(const std::shared_ptr<rclcpp::SerializedMessage> &serialized_message, const rclcpp::MessageInfo &message_info) override

Handle dispatching rclcpp::SerializedMessage to user callback.

virtual void handle_loaned_message(void *loaned_message, const rclcpp::MessageInfo &message_info) override

This function is currently not implemented.

virtual void return_message(std::shared_ptr<void> &message) override

Return the message borrowed in create_message.

Parameters:

message – [in] Shared pointer to the returned message.

virtual void return_serialized_message(std::shared_ptr<rclcpp::SerializedMessage> &message) override

Return the message borrowed in create_serialized_message.

Parameters:

message – [in] Shared pointer to the returned message.

virtual rclcpp::dynamic_typesupport::DynamicMessageType::SharedPtr get_shared_dynamic_message_type() override

virtual rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr get_shared_dynamic_message() override

virtual rclcpp::dynamic_typesupport::DynamicSerializationSupport::SharedPtr get_shared_dynamic_serialization_support() override

virtual rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr create_dynamic_message() override

Borrow a new serialized message (this clones!)

Returns:

Shared pointer to a rclcpp::dynamic_typesupport::DynamicMessage.

virtual void return_dynamic_message(rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr &message) override

virtual void handle_dynamic_message(const rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr &message, const rclcpp::MessageInfo &message_info) override