---
title: "readAttributeNullableInt64u(completionHandler:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclustertestcluster/readattributenullableint64u(completionhandler:)"
---

# readAttributeNullableInt64u(completionHandler:)

## Declaration

```swift
func readAttributeNullableInt64u(completionHandler: @escaping @Sendable (NSNumber?, (any Error)?) -> Void)
```

```swift
func readAttributeNullableInt64u() async throws -> NSNumber
```