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# 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.

```
struct hv_ion_message_t
```

## Topics

### Initializers

[`init()`](/documentation/Hypervisor/hv_ion_message_t/init())

Creates a new I/O notifier message.

[`init(header:addr:size:value:trailer:)`](/documentation/Hypervisor/hv_ion_message_t/init(header:addr:size:value:trailer:))

Creates a new I/O notifier message with the parameters you provide.

### Instance properties

[`addr`](/documentation/Hypervisor/hv_ion_message_t/addr)

The address of the I/O write.

[`header`](/documentation/Hypervisor/hv_ion_message_t/header)

The Mach message header.

[`size`](/documentation/Hypervisor/hv_ion_message_t/size)

The size of the value written by the notifier.

[`trailer`](/documentation/Hypervisor/hv_ion_message_t/trailer)

The Mach message trailer.

[`value`](/documentation/Hypervisor/hv_ion_message_t/value)

An unsigned 64-bit integer that represents the contents of an I/O notifier message.


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