---
title: NotificationCenter.BaseMessageIdentifier
framework: foundation
role: symbol
role_heading: Structure
path: foundation/notificationcenter/basemessageidentifier
---

# NotificationCenter.BaseMessageIdentifier

A type for use when defining optional Message identifiers.

## Declaration

```swift
struct BaseMessageIdentifier<MessageType>
```

## Overview

Overview See NotificationCenter.MessageIdentifier for an example of how to use this type when defining your own message identifiers.

## Topics

### Creating an identifier for a main actor message

- [init()](foundation/notificationcenter/basemessageidentifier/init()-66tt2.md)

### Creating an identifier for an asynchronous message

- [init()](foundation/notificationcenter/basemessageidentifier/init()-2yi72.md)

## Relationships

### Conforms To

- [NotificationCenter.MessageIdentifier](foundation/notificationcenter/messageidentifier.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Using message identifiers

- [NotificationCenter.MessageIdentifier](foundation/notificationcenter/messageidentifier.md)