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# UIAlertControllerSeverity

Constants for specifying the severity of an alert in apps built with Mac Catalyst.

```
enum UIAlertControllerSeverity
```

## Overview

This enumeration defines the severity options used by the [`severity`](/documentation/UIKit/UIAlertController/severity) property of [`UIAlertController`](/documentation/UIKit/UIAlertController). In apps built with Mac Catalyst, the severity determines the style of the presented alert. A [`UIAlertControllerSeverity.critical`](/documentation/UIKit/UIAlertControllerSeverity/critical) alert appears with a caution icon, and an alert with a [`UIAlertControllerSeverity.default`](/documentation/UIKit/UIAlertControllerSeverity/default) severity doesn’t. UIKit ignores the alert severity on iOS.

You should only use the [`UIAlertControllerSeverity.critical`](/documentation/UIKit/UIAlertControllerSeverity/critical) severity if an alert truly requires special attention from the user. For more information, see the [Human Interface Guidelines](https://developer.apple.com/design/human-interface-guidelines/macos/windows-and-views/alerts/) on alerts.

## Topics

### Constants

[`UIAlertControllerSeverity.critical`](/documentation/UIKit/UIAlertControllerSeverity/critical)

Indicates that the system should present the alert using the critical, or caution, style.

[`UIAlertControllerSeverity.default`](/documentation/UIKit/UIAlertControllerSeverity/default)

Indicates that the system should present the alert using the standard alert style.


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