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# NSUndefinedKeyException userInfo Keys

These constants are keys into an `NSUndefinedKeyException` `userInfo` dictionary

## Discussion

For additional information see [Key Value Coding Exception Names](/documentation/ObjectiveC/key-value-coding-exception-names).

## Topics

### Constants

[NSTargetObjectUserInfoKey](/documentation/ObjectiveC/nstargetobjectuserinfokey)

The object on which the key value coding operation failed.

[NSUnknownUserInfoKey](/documentation/ObjectiveC/nsunknownuserinfokey)

The key for which the key value coding operation failed.


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