---
title: "withUnsafeBlockBuffer(_:)"
framework: coremedia
role: symbol
role_heading: Instance Method
path: "coremedia/cmmutabledatablockbuffer/withunsafeblockbuffer(_:)"
---

# withUnsafeBlockBuffer(_:)

Access the underlying CMBlockBuffer instance.

## Declaration

```swift
func withUnsafeBlockBuffer<R>(_ body: (CMBlockBuffer) throws -> sending R) rethrows -> sending R where R : ~Copyable
```