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# CBPeripheralDelegate

A protocol that provides updates on the use of a peripheral’s services.

```
protocol CBPeripheralDelegate : NSObjectProtocol
```

## Overview

The delegate of a [`CBPeripheral`](/documentation/CoreBluetooth/CBPeripheral) object must adopt the [`CBPeripheralDelegate`](/documentation/CoreBluetooth/CBPeripheralDelegate) protocol. The delegate uses this protocol’s methods to monitor the discovery, exploration, and interaction of a remote peripheral’s services and properties. This protocol doesn’t have any required methods.

## Topics

### Discovering Services

[`peripheral(_:didDiscoverServices:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didDiscoverServices:))

Tells the delegate that peripheral service discovery succeeded.

[`peripheral(_:didDiscoverIncludedServicesFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didDiscoverIncludedServicesFor:error:))

Tells the delegate that discovering included services within the indicated service completed.

### Discovering Characteristics and their Descriptors

[`peripheral(_:didDiscoverCharacteristicsFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didDiscoverCharacteristicsFor:error:))

Tells the delegate that the peripheral found characteristics for a service.

[`peripheral(_:didDiscoverDescriptorsFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didDiscoverDescriptorsFor:error:))

Tells the delegate that the peripheral found descriptors for a characteristic.

### Retrieving Characteristic and Descriptor Values

[`peripheral(_:didUpdateValueFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didUpdateValueFor:error:)-1xyna)

Tells the delegate that retrieving the specified characteristic’s value succeeded, or that the characteristic’s value changed.

[`peripheral(_:didUpdateValueFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didUpdateValueFor:error:)-1t3wm)

Tells the delegate that retrieving a specified characteristic descriptor’s value succeeded.

### Writing Characteristic and Descriptor Values

[`peripheral(_:didWriteValueFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didWriteValueFor:error:)-4f5ea)

Tells the delegate that the peripheral successfully set a value for the characteristic.

[`peripheral(_:didWriteValueFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didWriteValueFor:error:)-1ybl3)

Tells the delegate that the peripheral successfully set a value for the descriptor.

[`peripheralIsReady(toSendWriteWithoutResponse:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheralIsReady(toSendWriteWithoutResponse:))

Tells the delegate that a peripheral is again ready to send characteristic updates.

### Managing Notifications for a Characteristic’s Value

[`peripheral(_:didUpdateNotificationStateFor:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didUpdateNotificationStateFor:error:))

Tells the delegate that the peripheral received a request to start or stop providing notifications for a specified characteristic’s value.

### Retrieving a Peripheral’s RSSI Data

[`peripheral(_:didReadRSSI:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didReadRSSI:error:))

Tells the delegate that retrieving the value of the peripheral’s current Received Signal Strength Indicator (RSSI) succeeded.

[`peripheralDidUpdateRSSI(_:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheralDidUpdateRSSI(_:error:))

Tells the delegate that retrieving the value of the peripheral’s current Received Signal Strength Indicator (RSSI) succeeded.

### Monitoring Changes to a Peripheral’s Name or Services

[`peripheralDidUpdateName(_:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheralDidUpdateName(_:))

Tells the delegate that a peripheral’s name changed.

[`peripheral(_:didModifyServices:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didModifyServices:))

Tells the delegate that a peripheral’s services changed.

### Monitoring L2CAP Channels

[`peripheral(_:didOpen:error:)`](/documentation/CoreBluetooth/CBPeripheralDelegate/peripheral(_:didOpen:error:))

Delivers the result of an attempt to open an L2CAP channel.


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