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# Keys for Notification UserInfo Dictionary

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

## Topics

### Constants

[`let NSFileHandleNotificationFileHandleItem: String`](/documentation/Foundation/NSFileHandleNotificationFileHandleItem)

A key in the userinfo dictionary in a [`NSFileHandleConnectionAccepted`](/documentation/Foundation/NSNotification/Name-swift.struct/NSFileHandleConnectionAccepted) notification.

[`let NSFileHandleNotificationDataItem: String`](/documentation/Foundation/NSFileHandleNotificationDataItem)

A key in the userinfo dictionary in a [`readCompletionNotification`](/documentation/Foundation/FileHandle/readCompletionNotification) and [`NSFileHandleReadToEndOfFileCompletion`](/documentation/Foundation/NSNotification/Name-swift.struct/NSFileHandleReadToEndOfFileCompletion).

[`let NSFileHandleNotificationMonitorModes: String`](/documentation/Foundation/NSFileHandleNotificationMonitorModes)

Currently unused.


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