# onThrow(error:) Invoked when the distributed target execution of a target has thrown an error. ``` func onThrow(error: Err) async throws where Err : Error ``` ## Discussion It is not guaranteed that the error conform to the [`SerializationRequirement`](/documentation/Distributed/DistributedTargetInvocationResultHandler/SerializationRequirement); This guarantee is only given to return values (and offered by `onReturn`). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)