---
title: kIOMaximumBlockCountReadKey
framework: IOKit
role: symbol
role_heading: Global Variable
platforms: [iOS 16.0+, iPadOS 16.0+, Mac Catalyst 13.0+, macOS 10.1+, visionOS 1.0+]
path: iokit/kiomaximumblockcountreadkey
---

# kIOMaximumBlockCountReadKey

## Declaration

```swift
var kIOMaximumBlockCountReadKey: String { get }
```