---
title: kIOUCVariableStructureSize
framework: Kernel
role: symbol
role_heading: Enumeration Case
platforms: [macOS 10.12+]
path: kernel/1646103-anonymous/kioucvariablestructuresize
---

# kIOUCVariableStructureSize

## Declaration

```occ
kIOUCVariableStructureSize = 0xffffffff
```

## Discussion

Discussion Use in the structures IOExternalMethod, IOExternalAsyncMethod, IOExternalMethodDispatch to specify the size of the structure is variable.