---
title: CBCentralManagerOptionRestoreIdentifierKey
framework: corebluetooth
role: symbol
role_heading: Global Variable
path: corebluetooth/cbcentralmanageroptionrestoreidentifierkey
---

# CBCentralManagerOptionRestoreIdentifierKey

A string containing a unique identifier (UID) for the central manager to instantiate.

## Declaration

```swift
let CBCentralManagerOptionRestoreIdentifierKey: String
```

## Discussion

Discussion The value for this key is an NSString. The system uses this UID to identify a specific CBCentralManager, so the UID must be identical across executions of the app. In scene-based apps that adopt UISceneDelegate, launchOptions is always nil on launch, so UIApplicationLaunchOptionsBluetoothCentralsKey is not available to deliver identifiers. Persist the UID yourself (for example, in UserDefaults) and pass it to init(delegate:queue:options:) on every launch. Providing this key causes Core Bluetooth to call centralManager(_:willRestoreState:) with the preserved state when restoration is available. For a description of the state dictionary keys your delegate receives, see Central Manager State Restoration Options.

## See Also

### Constants

- [CBCentralManagerOptionShowPowerAlertKey](corebluetooth/cbcentralmanageroptionshowpoweralertkey.md)