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Telephony Cell Broadcast API

Cell Broadcast Service (CBS) provides cell broadcast capabilities over cellular networks, commonly used for receiving government emergency alerts (earthquakes, tsunamis) and carrier announcements.

Header: #include <tapi_cbs.h>

openvela Implementation Notes

• Power control: Enable/disable cell broadcast reception via set_cell_broadcast_power_on
• Topic subscription: Configure broadcast topic ranges (by channel ID) via set_cell_broadcast_topics
• Event callback: Register event callbacks via tapi_cbs_register to receive broadcast messages
• SIM identification: All interfaces include a slot_id parameter for multi-SIM devices
• Related protocol: Corresponds to the Cell Broadcast procedure defined in 3GPP TS 23.041

Power Control

tapi_sms_set_cell_broadcast_power_on

int tapi_sms_set_cell_broadcast_power_on(tapi_context context, int slot_id, bool enabled);

Enable or disable cell broadcast reception.

Parameters:

• context Telephony context handle.
• slot_id SIM card slot ID.
• enabled true to enable, false to disable.

Returns:

Returns 0 on success, or a negative error code on failure.

tapi_sms_get_cell_broadcast_power_on

int tapi_sms_get_cell_broadcast_power_on(tapi_context context, int slot_id, bool* enabled);

Query the cell broadcast reception power state.

Parameters:

• context Telephony context handle.
• slot_id SIM card slot ID.
• enabled Output parameter, returns the current power state.

Returns:

Returns 0 on success, or a negative error code on failure.

Topic Subscription

tapi_sms_set_cell_broadcast_topics

int tapi_sms_set_cell_broadcast_topics(tapi_context context, int slot_id, char* topics);

Configure the cell broadcast topic range (channel ID list).

Parameters:

• context Telephony context handle.
• slot_id SIM card slot ID.
• topics Topic string, typically comma-separated channel IDs or ranges (e.g., "4352-4356,919").

Returns:

Returns 0 on success, or a negative error code on failure.

tapi_sms_get_cell_broadcast_topics

int tapi_sms_get_cell_broadcast_topics(tapi_context context, int slot_id, char** topics);

Query the currently configured cell broadcast topics.

Parameters:

• context Telephony context handle.
• slot_id SIM card slot ID.
• topics Output parameter, returns the topic string (caller is responsible for freeing).

Returns:

Returns 0 on success, or a negative error code on failure.

Event Subscription

tapi_cbs_register

int tapi_cbs_register(tapi_context context, int slot_id, tapi_indication_msg msg,
                      void* user_obj, tapi_async_function p_handle);

Register a cell broadcast event callback.

Parameters:

• context Telephony context handle.
• slot_id SIM card slot ID.
• msg Event type to listen for.
• user_obj User data, passed back to the callback function.
• p_handle Asynchronous callback function.

Returns:

Returns the event subscription watch ID on success, or a negative error code on failure.