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# init(subsystem:category:)

Creates a signposter that uses the specified subsystem and system-defined log category.

```
init(subsystem: String, category: OSLog.Category)
```

## Parameters

`subsystem`

The string that identifies the subsystem that emits signposts. Typically, you use the same value as your app’s *bundle ID*. For more information, see <doc://com.apple.documentation/documentation/BundleResources/Information-Property-List/CFBundleIdentifier>.

`category`

The system-defined category, which the system uses to categorize emitted signposts. For possible values, see [`OSLog.Category`](/documentation/os/OSLog/Category).

---

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