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

# readAttributeOctetString(completionHandler:)

## Declaration

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

```swift
func readAttributeOctetString() async throws -> Data
```