Generic Attribute (GATT) Profile

You can use the GATT Profile library to receive service changed indications from a connected peer. It is used in the Bluetooth: Peripheral ANCS client sample.

API documentation

Header file: include/bluetooth/services/gattp.h

Source file: subsys/bluetooth/services/gattp.c

group bt_gattp

API for the Bluetooth LE Generic Attribute (GATT) Profile.

Typedefs

typedef void (*bt_gattp_indicate_cb)(struct bt_gattp *gattp, const struct bt_gattp_handle_range *handle_range, int err)

Service Changed Indication callback function.

Param gattp:

[in] GATT profile instance.

Param handle_range:

[in] Affected handle range.

Param err:

[in] 0 if the indication is valid. Otherwise, contains a (negative) error code.

Functions

int bt_gattp_init(struct bt_gattp *gattp)

Initialize the GATT profile instance.

Parameters:

• gattp – [inout] GATT profile instance.

Return values:

0 – If the instance is initialized successfully. Otherwise, a (negative) error code is returned.

int bt_gattp_handles_assign(struct bt_gatt_dm *dm, struct bt_gattp *gattp)

Assign handles to the GATT profile instance.

Call this function when a link has been established with a peer to associate the link to this instance of the module. This makes it possible to handle several links and associate each link to a particular instance of this module.

Parameters:

• dm – [in] Discovery object.

• gattp – [inout] GATT profile instance.

Return values:

0 – If the operation is successful. Otherwise, a (negative) error code is returned.

int bt_gattp_subscribe_service_changed(struct bt_gattp *gattp, bt_gattp_indicate_cb func)

Subscribe to the Service Changed indication.

Parameters:

• gattp – [in] GATT profile instance.

• func – [in] Indication callback function handler.

Return values:

0 – If the operation is successful. Otherwise, a (negative) error code is returned.

int bt_gattp_unsubscribe_service_changed(struct bt_gattp *gattp)

Unsubscribe from the Service Changed indication.

Parameters:

• gattp – [in] GATT profile instance.

Return values:

0 – If the operation is successful. Otherwise, a (negative) error code is returned.

struct bt_gattp_handle_range

#include <gattp.h>

Structure for Service Changed handle range.

Public Members

uint16_t start_handle

Start handle.

uint16_t end_handle

End handle.

struct bt_gattp

#include <gattp.h>

GATT profile instance.

Public Members

struct bt_conn *conn

Connection object.

uint16_t handle_sc

Handle of the Service Changed Characteristic.

uint16_t handle_sc_ccc

Handle of the CCCD of the Service Changed Characteristic.

struct bt_gatt_subscribe_params indicate_params

GATT subscribe parameters for the Service Changed Characteristic.

bt_gattp_indicate_cb indicate_cb

Callback function for the Service Changed indication.

atomic_t state

Internal state.