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# MTLIOScratchBuffer

A protocol your app implements that wraps a Metal buffer instance to serve as scratch memory for an input/output command queue.

```
protocol MTLIOScratchBuffer : NSObjectProtocol
```

## Overview

Your app can reintegrate an [`MTLIOScratchBuffer`](/documentation/Metal/MTLIOScratchBuffer) instance’s underlying memory back into a memory pool by overriding your type’s <doc://com.apple.documentation/documentation/ObjectiveC/NSObject-swift.class/dealloc> method. The system calls the method when an input/output command queue no longer needs a scratch buffer.

## Topics

### Wrapping a buffer

[`buffer`](/documentation/Metal/MTLIOScratchBuffer/buffer)

A Metal buffer that serves as scratch memory for an input/output command queue.


---

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