---
title: mMessageHeader
framework: kernel
role: symbol
role_heading: Instance Property
path: kernel/iovideodevicenotificationmessage/1411394-mmessageheader
---

# mMessageHeader

The mach message header.

## Declaration

```occ
mach_msg_header_t mMessageHeader;
```

## See Also

### Fields

- [mClientData](kernel/iovideodevicenotificationmessage/1411358-mclientdata.md)
- [mNumberNotifications](kernel/iovideodevicenotificationmessage/1411444-mnumbernotifications.md)
- [mNotifications](kernel/iovideodevicenotificationmessage/1411390-mnotifications.md)