---
title: "mmioRead(atOffset:)"
framework: Paravirtualized Graphics
role: symbol
role_heading: Instance Method
platforms: [Mac Catalyst 14.0+, macOS 11.0+]
path: "paravirtualizedgraphics/pgdevice/mmioread(atoffset:)"
---

# mmioRead(atOffset:)

Reads data from the virtual graphics device’s memory-mapped I/O region.

## Declaration

```swift
func mmioRead(atOffset offset: Int) -> UInt32
```

## Parameters

- `offset`: The offset into the MMIO bar to write to.

## Return Value

Return Value The 32-bit unsigned integer from the MMIO region.

## Discussion

Discussion Call this method whenever the guest virtual machine reads from the graphics device’s memory-mapped I/O region.

## See Also

### Handling Memory-Mapped I/O

- [mmioWrite(atOffset:value:)](paravirtualizedgraphics/pgdevice/mmiowrite(atoffset:value:).md)