Function rmw_subscription_get_actual_qos

Function Documentation

rmw_ret_t rmw_subscription_get_actual_qos(const rmw_subscription_t *subscription, rmw_qos_profile_t *qos)

Retrieve the actual qos settings of the subscription.

Query the underlying middleware to determine the qos settings of the subscription. The actual configuration applied when using RMW_*_SYSTEM_DEFAULT can only be resolved after the creation of the subscription, and it depends on the underlying rmw implementation. If the underlying setting in use can’t be represented in ROS terms, it will be set to RMW_*_UNKNOWN.

Attribute

Adherence

Allocates Memory

Maybe [1]

Thread-Safe

No

Uses Atomics

Maybe [1]

Lock-Free

Maybe [1]

[1] rmw implementation defined, check the implementation documentation

Note

The value of avoid_ros_namespace_conventions field is not resolved with this function. The rcl function rcl_subscription_get_actual_qos() resolves it.

Parameters:

  • subscription – [in] the subscription object to inspect

  • qos – [out] the actual qos settings

Returns:

RMW_RET_OK if successful, or

Returns:

RMW_RET_INVALID_ARGUMENT if either argument is null, or

Returns:

RMW_RET_INCORRECT_RMW_IMPLEMENTATION if subscription implementation identifier does not match, or

Returns:

RMW_RET_ERROR if an unexpected error occurs.