---
title: ar_session_set_data_provider_state_change_handler_f
framework: arkit
role: symbol
role_heading: Function
path: arkit/ar_session_set_data_provider_state_change_handler_f
---

# ar_session_set_data_provider_state_change_handler_f

Sets the handler function for responding to a state change of one or more data providers.

## Declaration

```occ
extern void ar_session_set_data_provider_state_change_handler_f(ar_session_t session, dispatch_queue_t queue, void *context, ar_session_data_provider_state_change_handler_function_t data_provider_state_change_handler_function);
```

## Parameters

- `session`: The ar_session_t instance.
- `queue`: The queue on which the function will be called. Passing NULL will default to the main queue.
- `context`: The application-defined context parameter to pass to the function.
- `data_provider_state_change_handler_function`: The data provider state change handler function.

## Discussion

Discussion note: Setting this will override the handler set using ar_session_set_data_provider_state_change_handler.

## See Also

### Sessions

- [ar_session_t](arkit/ar_session_t.md)
- [ar_session_create](arkit/ar_session_create.md)
- [ar_session_create_with_device](arkit/ar_session_create_with_device.md)
- [ar_session_query_authorization_results](arkit/ar_session_query_authorization_results.md)
- [ar_session_query_authorization_results_f](arkit/ar_session_query_authorization_results_f.md)
- [ar_session_request_authorization](arkit/ar_session_request_authorization.md)
- [ar_session_request_authorization_f](arkit/ar_session_request_authorization_f.md)
- [ar_session_run](arkit/ar_session_run.md)
- [ar_session_set_authorization_update_handler](arkit/ar_session_set_authorization_update_handler.md)
- [ar_session_set_authorization_update_handler_f](arkit/ar_session_set_authorization_update_handler_f.md)
- [ar_session_copy_data_providers](arkit/ar_session_copy_data_providers.md)
- [ar_session_set_data_provider_state_change_handler](arkit/ar_session_set_data_provider_state_change_handler.md)
- [ar_session_data_provider_state_change_handler_t](arkit/ar_session_data_provider_state_change_handler_t.md)
- [ar_session_stop](arkit/ar_session_stop.md)
- [ar_device_t](arkit/ar_device_t.md)