---
title: kOSAsyncRef64Size
framework: Kernel
role: symbol
role_heading: Enumeration Case
platforms: [macOS 10.12+]
path: kernel/1645642-anonymous/kosasyncref64size
---

# kOSAsyncRef64Size

## Declaration

```occ
kOSAsyncRef64Size = kOSAsyncRef64Count * ((int) sizeof(io_user_reference_t))
```