---
title: os_activity_id_t
framework: os
role: symbol
role_heading: Type Alias
platforms: [iOS 8.0+, iPadOS 8.0+, Mac Catalyst 13.1+, macOS 10.10+, tvOS 9.0+, visionOS 1.0+, watchOS 2.0+]
path: os/os_activity_id_t
---

# os_activity_id_t

A number that uniquely identifies an activity.

## Declaration

```occ
typedef uint64_t os_activity_id_t;
```

## See Also

### Retrieving an Activity Identifier

- [os_activity_get_identifier](os/os_activity_get_identifier.md)