---
title: hv_ion_message_t
framework: Hypervisor
role: symbol
role_heading: Structure
path: hypervisor/hv_ion_message_t
---

# hv_ion_message_t

The structure that describes the Mach message that the Hypervisor sends when an I/O notifier delivers the notifications you request.

## Declaration

```swift
struct hv_ion_message_t
```

## Topics

### Initializers

- [init()](hypervisor/hv_ion_message_t/init().md)
- [init(header:addr:size:value:trailer:)](hypervisor/hv_ion_message_t/init(header:addr:size:value:trailer:).md)

### Instance properties

- [addr](hypervisor/hv_ion_message_t/addr.md)
- [header](hypervisor/hv_ion_message_t/header.md)
- [size](hypervisor/hv_ion_message_t/size.md)
- [trailer](hypervisor/hv_ion_message_t/trailer.md)
- [value](hypervisor/hv_ion_message_t/value.md)

## Relationships

### Conforms To

- [BitwiseCopyable](swift/bitwisecopyable.md)
- [Sendable](swift/sendable.md)

## See Also

### I/O notifier functions

- [hv_vm_add_pio_notifier(_:_:_:_:_:)](hypervisor/hv_vm_add_pio_notifier(_:_:_:_:_:).md)
- [hv_vm_remove_pio_notifier(_:_:_:_:_:)](hypervisor/hv_vm_remove_pio_notifier(_:_:_:_:_:).md)
- [hv_ion_flags_t](hypervisor/hv_ion_flags_t.md)
- [I/O Notifier Flags](hypervisor/3727903-i-o-notifier-flags.md)