---
title: "failWithError(_:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/nscoder/failwitherror(_:)"
---

# failWithError(_:)

Signals to this coder that the decode operation has failed.

## Declaration

```swift
func failWithError(_ error: any Error)
```

## Parameters

- `error`: An error that indicates why decoding failed.

## Discussion

Discussion Typically, you call this method in your init(coder:) implementation. You should set the error when you detect problems such as lack of secure coding, data corruption, or a domain validation failure. This method is only meaningful to call for decodes. The effect of calling this method depends on the value of decodingFailurePolicy, as follows: If the policy is NSCoder.DecodingFailurePolicy.raiseException, calling this method throws an exception immediately. Swift code cannot catch this kind of exception. If the policy is NSCoder.DecodingFailurePolicy.setErrorAndReturn, calling this method sets the error property once per call to one of the decode methods. Calling it repeatedly has no effect until the call stack unwinds to one of these methods’ entry points.

## See Also

### Managing Decode Errors

- [error](foundation/nscoder/error.md)