---
title: "add(_:queue:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrdevicecontroller/add(_:queue:)"
---

# add(_:queue:)

Adds a Delegate to the device controller as well as the Queue on which the Delegate callbacks will be triggered

## Declaration

```swift
func add(_ delegate: any MTRDeviceControllerDelegate, queue: dispatch_queue_t)
```

## Discussion

Discussion Multiple delegates can be added to monitor MTRDeviceController state changes. Note that there should only be one delegate that responds to pairing related callbacks. If a delegate is added a second time, the call would be ignored. All delegates are held by weak references, and so if a delegate object goes away, it will be automatically removed.