---
title: "copy(from:sourceOffset:to:destinationOffset:size:)"
framework: metal
role: symbol
role_heading: Instance Method
path: "metal/mtlblitcommandencoder/copy(from:sourceoffset:to:destinationoffset:size:)"
---

# copy(from:sourceOffset:to:destinationOffset:size:)

Encodes a command that copies data from one buffer into another.

## Declaration

```swift
func copy(from sourceBuffer: any MTLBuffer, sourceOffset: Int, to destinationBuffer: any MTLBuffer, destinationOffset: Int, size: Int)
```

## Parameters

- `sourceBuffer`: A buffer the command copies data from.
- `sourceOffset`: A byte offset within sourceBuffer the command copies from. In macOS, sourceOffset needs to be a multiple of 4, but can be any value in iOS and tvOS.
- `destinationBuffer`: The destination buffer for the copy operation.
- `destinationOffset`: A byte offset within destinationBuffer the command copies to. In macOS, destinationOffset needs to be a multiple of 4, but can be any value in iOS and tvOS.
- `size`: The number of bytes the command copies from sourceBuffer to destinationBuffer. In macOS, size needs to be a multiple of 4, but can be any value in iOS and tvOS.

## Mentioned in

Copying data to a private resource

## Discussion

Discussion You can pass the same buffer to the sourceBuffer and destinationBuffer parameters if size is less than the distance between sourceOffset and destinationOffset. important: Copying data to overlapping regions within the same buffer may result in unexpected behavior.