---
title: "startPeriodicEvents(afterDelay:withPeriod:)"
framework: appkit
role: symbol
role_heading: Type Method
path: "appkit/nsevent/startperiodicevents(afterdelay:withperiod:)"
---

# startPeriodicEvents(afterDelay:withPeriod:)

Begins generating periodic events for the current thread.

## Declaration

```swift
class func startPeriodicEvents(afterDelay delay: TimeInterval, withPeriod period: TimeInterval)
```

## Parameters

- `delay`: The number of seconds that NSEvent should wait before beginning to generate periodic events.
- `period`: The period in seconds between the generated events.

## Discussion

Discussion Raises an NSInternalInconsistencyException if periodic events are already being generated for the current thread. This method is typically used in a modal loop while tracking mouse-dragged events.

## See Also

### Requesting and stopping periodic events

- [stopPeriodicEvents()](appkit/nsevent/stopperiodicevents().md)