---
title: "writeAttributeOctetString(withValue:params:completionHandler:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclustertestcluster/writeattributeoctetstring(withvalue:params:completionhandler:)"
---

# writeAttributeOctetString(withValue:params:completionHandler:)

## Declaration

```swift
func writeAttributeOctetString(withValue value: Data, params: MTRWriteParams?, completionHandler: @escaping @Sendable ((any Error)?) -> Void)
```

```swift
func writeAttributeOctetString(withValue value: Data, params: MTRWriteParams?) async throws
```