---
title: restartPolling()
framework: corenfc
role: symbol
role_heading: Instance Method
path: corenfc/nfcndefreadersession/restartpolling()
---

# restartPolling()

Restarts the polling sequence so the reader session can discover new tags.

## Declaration

```swift
func restartPolling()
```

## Discussion

Discussion After restarting the polling sequence, the reader session sends newly detected tags to the session’s delegate method readerSession(_:didDetect:). note: Tags detected before polling restarts are invalid. Your app should discard any references it has to the invalid tags to free system resources. Calling restartPolling() has no effect when: The session is invalid. If you need to restart the reader session, create a new NFCNDEFReaderSession. The session’s delegate doesn’t implement the readerSession(_:didDetect:) method. When this method is missing, the session calls readerSession(_:didDetectNDEFs:) to inform the delegate of new NDEF messages, then restarts the polling sequence.