Function rcl_get_subscriptions_info_by_topic

Defined in File graph.h

Function Documentation

rcl_ret_t rcl_get_subscriptions_info_by_topic(const rcl_node_t *node, rcutils_allocator_t *allocator, const char *topic_name, bool no_mangle, rcl_topic_endpoint_info_array_t *subscriptions_info)

Return a list of all subscriptions to a topic.

The node parameter must point to a valid node.

The topic_name parameter must not be NULL.

When the no_mangle parameter is true, the provided topic_name should be a valid topic name for the middleware (useful when combining ROS with native middleware (e.g. DDS) apps). When the no_mangle parameter is false, the provided topic_name should follow ROS topic name conventions. In either case, the topic name should always be fully qualified.

Each element in the subscriptions_info array will contain the node name, node namespace, topic type, gid and the qos profile of the subscription. It is the responsibility of the caller to ensure that subscriptions_info parameter points to a valid struct of type rcl_topic_endpoint_info_array_t. The count field inside the struct must be set to 0 and the info_array

field inside the struct must be set to null.

The

allocator will be used to allocate memory to the info_array member inside of subscriptions_info. Moreover, every const char * member inside of rmw_topic_endpoint_info_t will be assigned a copied value on allocated memory.

Attribute	Adherence
Allocates Memory	Yes
Thread-Safe	No
Uses Atomics	No
Lock-Free	Maybe [1]

[1] implementation may need to protect the data structure with a lock