---
title: kern_event_msg
framework: Kernel
role: symbol
platforms: [macOS 10.9+]
path: kernel/kern_event_msg
---

# kern_event_msg

## Declaration

```occ
struct kern_event_msg {
    ...
};
```

## Discussion

Discussion This structure is prepended to all kernel events. This structure is used to determine the format of the remainder of the kernel event. This structure will appear on all messages received on a kernel event socket. To post a kernel event, a slightly different structure is used.

## Topics

### Fields

- [total_size](kernel/kern_event_msg/1446925-total_size.md)
- [vendor_code](kernel/kern_event_msg/1446929-vendor_code.md)
- [kev_class](kernel/kern_event_msg/1446955-kev_class.md)
- [kev_subclass](kernel/kern_event_msg/1446935-kev_subclass.md)
- [id](kernel/kern_event_msg/1446959-id.md)
- [event_code](kernel/kern_event_msg/1446927-event_code.md)
- [event_data](kernel/kern_event_msg/1446985-event_data.md)