---
title: "readAttributeOctetString(completion:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclusterunittesting/readattributeoctetstring(completion:)"
---

# readAttributeOctetString(completion:)

## Declaration

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

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