---
title: "MTLIOCompressionContextAppendData(_:_:_:)"
framework: metal
role: symbol
role_heading: Function
path: "metal/mtliocompressioncontextappenddata(_:_:_:)"
---

# MTLIOCompressionContextAppendData(_:_:_:)

Adds data to a compression context.

## Declaration

```swift
func MTLIOCompressionContextAppendData(_ context: MTLIOCompressionContext, _ data: UnsafeRawPointer, _ size: Int)
```

## Parameters

- `context`: An doc://com.apple.metal/documentation/Metal/MTLIOCompressionContext instance that you create with the doc://com.apple.metal/documentation/Metal/MTLIOCreateCompressionContext(_:_:_:) function.
- `data`: A pointer to memory that contains the data the function adds to the compression context.
- `size`: The number of bytes the function adds to the compression context from the data pointer.

## See Also

### Asset compression

- [MTLIOCreateCompressionContext(_:_:_:)](metal/mtliocreatecompressioncontext(_:_:_:).md)
- [MTLIOCompressionMethod](metal/mtliocompressionmethod.md)
- [MTLIOCompressionContextDefaultChunkSize()](metal/mtliocompressioncontextdefaultchunksize().md)
- [MTLIOCompressionContext](metal/mtliocompressioncontext.md)
- [MTLIOFlushAndDestroyCompressionContext(_:)](metal/mtlioflushanddestroycompressioncontext(_:).md)
- [MTLIOCompressionStatus](metal/mtliocompressionstatus.md)