---
title: Keys for Notification UserInfo Dictionary
framework: foundation
role: collectionGroup
role_heading: API Collection
path: foundation/keys-for-notification-userinfo-dictionary
---

# Keys for Notification UserInfo Dictionary

Strings that the system uses as keys in a userinfo dictionary during a file handle notification.

## Topics

### Constants

- [NSFileHandleNotificationFileHandleItem](foundation/nsfilehandlenotificationfilehandleitem.md)
- [NSFileHandleNotificationDataItem](foundation/nsfilehandlenotificationdataitem.md)
- [NSFileHandleNotificationMonitorModes](foundation/nsfilehandlenotificationmonitormodes.md)

## See Also

### Working with constants

- [Exception Names](foundation/exception-names.md)