---
title: readOnly
framework: IOSurface
role: symbol
role_heading: Type Property
platforms: [iOS 11.0+, iPadOS 11.0+, Mac Catalyst 13.0+, macOS 10.6+, tvOS 11.0+, visionOS 1.0+]
path: iosurface/iosurfacelockoptions/readonly
---

# readOnly

## Declaration

```swift
static var readOnly: IOSurfaceLockOptions { get }
```

## Discussion

Discussion If you are not going to modify the data while you hold the lock, you should set this flag to avoid invalidating any existing caches of the buffer contents. This flag should be passed both to the lock and unlock functions. Non-symmentrical usage of this flag will result in undefined behavior.

## See Also

### Options

- [avoidSync](iosurface/iosurfacelockoptions/avoidsync.md)