Exception in get_state: std::future_error: No associated state

[AaronLPS]

https://github.com/ros2/demos/blob/69aa0e4d8662b7bd06138462cc328415b3198263/lifecycle/src/lifecycle_service_client.cpp#L124C25-L124C38

The std::future::get() function can only be called once as it will invalidate the std::future after it's called. In this code, future_result.get() is called multiple times.

[fujitatomoya]

that is why we are using std::shared_future here?

https://github.com/ros2/demos/blob/69aa0e4d8662b7bd06138462cc328415b3198263/lifecycle/src/lifecycle_service_client.cpp#L108

or are you receiving the std::future_error exception with this demo in your environment?

[AaronLPS]

std::shared_future solves the issue. I was looking at the outdated demo version in Foxy branch, which uses auto future_result = client_get_state->async_send_request(request);